linux/arch/powerpc/mm/hugetlbpage.c

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/*
* PPC Huge TLB Page Support for Kernel.
*
* Copyright (C) 2003 David Gibson, IBM Corporation.
* Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
*
* Based on the IA-32 version:
* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
*/
#include <linux/mm.h>
#include <linux/io.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/hugetlb.h>
#include <linux/export.h>
#include <linux/of_fdt.h>
#include <linux/memblock.h>
#include <linux/bootmem.h>
#include <linux/moduleparam.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/setup.h>
#include <asm/hugetlb.h>
#ifdef CONFIG_HUGETLB_PAGE
#define PAGE_SHIFT_64K 16
#define PAGE_SHIFT_512K 19
#define PAGE_SHIFT_8M 23
#define PAGE_SHIFT_16M 24
#define PAGE_SHIFT_16G 34
unsigned int HPAGE_SHIFT;
/*
* Tracks gpages after the device tree is scanned and before the
* huge_boot_pages list is ready. On non-Freescale implementations, this is
* just used to track 16G pages and so is a single array. FSL-based
* implementations may have more than one gpage size, so we need multiple
* arrays
*/
#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
#define MAX_NUMBER_GPAGES 128
struct psize_gpages {
u64 gpage_list[MAX_NUMBER_GPAGES];
unsigned int nr_gpages;
};
static struct psize_gpages gpage_freearray[MMU_PAGE_COUNT];
#else
#define MAX_NUMBER_GPAGES 1024
static u64 gpage_freearray[MAX_NUMBER_GPAGES];
static unsigned nr_gpages;
#endif
#define hugepd_none(hpd) (hpd_val(hpd) == 0)
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
/* Only called for hugetlbfs pages, hence can ignore THP */
return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL, NULL);
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
}
static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
unsigned long address, unsigned pdshift, unsigned pshift)
{
struct kmem_cache *cachep;
pte_t *new;
int i;
int num_hugepd;
if (pshift >= pdshift) {
cachep = hugepte_cache;
num_hugepd = 1 << (pshift - pdshift);
} else {
cachep = PGT_CACHE(pdshift - pshift);
num_hugepd = 1;
}
new = kmem_cache_zalloc(cachep, GFP_KERNEL);
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
BUG_ON(pshift > HUGEPD_SHIFT_MASK);
BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
if (! new)
return -ENOMEM;
/*
* Make sure other cpus find the hugepd set only after a
* properly initialized page table is visible to them.
* For more details look for comment in __pte_alloc().
*/
smp_wmb();
spin_lock(&mm->page_table_lock);
/*
* We have multiple higher-level entries that point to the same
* actual pte location. Fill in each as we go and backtrack on error.
* We need all of these so the DTLB pgtable walk code can find the
* right higher-level entry without knowing if it's a hugepage or not.
*/
for (i = 0; i < num_hugepd; i++, hpdp++) {
if (unlikely(!hugepd_none(*hpdp)))
break;
else {
#ifdef CONFIG_PPC_BOOK3S_64
*hpdp = __hugepd(__pa(new) |
(shift_to_mmu_psize(pshift) << 2));
#elif defined(CONFIG_PPC_8xx)
*hpdp = __hugepd(__pa(new) |
(pshift == PAGE_SHIFT_8M ? _PMD_PAGE_8M :
_PMD_PAGE_512K) | _PMD_PRESENT);
#else
/* We use the old format for PPC_FSL_BOOK3E */
*hpdp = __hugepd(((unsigned long)new & ~PD_HUGE) | pshift);
#endif
}
}
/* If we bailed from the for loop early, an error occurred, clean up */
if (i < num_hugepd) {
for (i = i - 1 ; i >= 0; i--, hpdp--)
*hpdp = __hugepd(0);
kmem_cache_free(cachep, new);
}
spin_unlock(&mm->page_table_lock);
return 0;
}
/*
* These macros define how to determine which level of the page table holds
* the hpdp.
*/
#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
#define HUGEPD_PGD_SHIFT PGDIR_SHIFT
#define HUGEPD_PUD_SHIFT PUD_SHIFT
#else
#define HUGEPD_PGD_SHIFT PUD_SHIFT
#define HUGEPD_PUD_SHIFT PMD_SHIFT
#endif
/*
* At this point we do the placement change only for BOOK3S 64. This would
* possibly work on other subarchs.
*/
pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
{
pgd_t *pg;
pud_t *pu;
pmd_t *pm;
hugepd_t *hpdp = NULL;
unsigned pshift = __ffs(sz);
unsigned pdshift = PGDIR_SHIFT;
addr &= ~(sz-1);
pg = pgd_offset(mm, addr);
#ifdef CONFIG_PPC_BOOK3S_64
if (pshift == PGDIR_SHIFT)
/* 16GB huge page */
return (pte_t *) pg;
else if (pshift > PUD_SHIFT)
/*
* We need to use hugepd table
*/
hpdp = (hugepd_t *)pg;
else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (pshift == PUD_SHIFT)
return (pte_t *)pu;
else if (pshift > PMD_SHIFT)
hpdp = (hugepd_t *)pu;
else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
if (pshift == PMD_SHIFT)
/* 16MB hugepage */
return (pte_t *)pm;
else
hpdp = (hugepd_t *)pm;
}
}
#else
if (pshift >= HUGEPD_PGD_SHIFT) {
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
hpdp = (hugepd_t *)pg;
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (pshift >= HUGEPD_PUD_SHIFT) {
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
hpdp = (hugepd_t *)pu;
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
hpdp = (hugepd_t *)pm;
}
}
#endif
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
if (!hpdp)
return NULL;
BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
return NULL;
return hugepte_offset(*hpdp, addr, pdshift);
}
#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
/* Build list of addresses of gigantic pages. This function is used in early
* boot before the buddy allocator is setup.
*/
void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
{
unsigned int idx = shift_to_mmu_psize(__ffs(page_size));
int i;
if (addr == 0)
return;
gpage_freearray[idx].nr_gpages = number_of_pages;
for (i = 0; i < number_of_pages; i++) {
gpage_freearray[idx].gpage_list[i] = addr;
addr += page_size;
}
}
/*
* Moves the gigantic page addresses from the temporary list to the
* huge_boot_pages list.
*/
int alloc_bootmem_huge_page(struct hstate *hstate)
{
struct huge_bootmem_page *m;
int idx = shift_to_mmu_psize(huge_page_shift(hstate));
int nr_gpages = gpage_freearray[idx].nr_gpages;
if (nr_gpages == 0)
return 0;
#ifdef CONFIG_HIGHMEM
/*
* If gpages can be in highmem we can't use the trick of storing the
* data structure in the page; allocate space for this
*/
m = memblock_virt_alloc(sizeof(struct huge_bootmem_page), 0);
m->phys = gpage_freearray[idx].gpage_list[--nr_gpages];
#else
m = phys_to_virt(gpage_freearray[idx].gpage_list[--nr_gpages]);
#endif
list_add(&m->list, &huge_boot_pages);
gpage_freearray[idx].nr_gpages = nr_gpages;
gpage_freearray[idx].gpage_list[nr_gpages] = 0;
m->hstate = hstate;
return 1;
}
/*
* Scan the command line hugepagesz= options for gigantic pages; store those in
* a list that we use to allocate the memory once all options are parsed.
*/
unsigned long gpage_npages[MMU_PAGE_COUNT];
static int __init do_gpage_early_setup(char *param, char *val,
module: add extra argument for parse_params() callback This adds an extra argument onto parse_params() to be used as a way to make the unused callback a bit more useful and generic by allowing the caller to pass on a data structure of its choice. An example use case is to allow us to easily make module parameters for every module which we will do next. @ parse @ identifier name, args, params, num, level_min, level_max; identifier unknown, param, val, doing; type s16; @@ extern char *parse_args(const char *name, char *args, const struct kernel_param *params, unsigned num, s16 level_min, s16 level_max, + void *arg, int (*unknown)(char *param, char *val, const char *doing + , void *arg )); @ parse_mod @ identifier name, args, params, num, level_min, level_max; identifier unknown, param, val, doing; type s16; @@ char *parse_args(const char *name, char *args, const struct kernel_param *params, unsigned num, s16 level_min, s16 level_max, + void *arg, int (*unknown)(char *param, char *val, const char *doing + , void *arg )) { ... } @ parse_args_found @ expression R, E1, E2, E3, E4, E5, E6; identifier func; @@ ( R = parse_args(E1, E2, E3, E4, E5, E6, + NULL, func); | R = parse_args(E1, E2, E3, E4, E5, E6, + NULL, &func); | R = parse_args(E1, E2, E3, E4, E5, E6, + NULL, NULL); | parse_args(E1, E2, E3, E4, E5, E6, + NULL, func); | parse_args(E1, E2, E3, E4, E5, E6, + NULL, &func); | parse_args(E1, E2, E3, E4, E5, E6, + NULL, NULL); ) @ parse_args_unused depends on parse_args_found @ identifier parse_args_found.func; @@ int func(char *param, char *val, const char *unused + , void *arg ) { ... } @ mod_unused depends on parse_args_found @ identifier parse_args_found.func; expression A1, A2, A3; @@ - func(A1, A2, A3); + func(A1, A2, A3, NULL); Generated-by: Coccinelle SmPL Cc: cocci@systeme.lip6.fr Cc: Tejun Heo <tj@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Christoph Hellwig <hch@infradead.org> Cc: Felipe Contreras <felipe.contreras@gmail.com> Cc: Ewan Milne <emilne@redhat.com> Cc: Jean Delvare <jdelvare@suse.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Jani Nikula <jani.nikula@intel.com> Cc: linux-kernel@vger.kernel.org Reviewed-by: Tejun Heo <tj@kernel.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-31 07:20:03 +08:00
const char *unused, void *arg)
{
static phys_addr_t size;
unsigned long npages;
/*
* The hugepagesz and hugepages cmdline options are interleaved. We
* use the size variable to keep track of whether or not this was done
* properly and skip over instances where it is incorrect. Other
* command-line parsing code will issue warnings, so we don't need to.
*
*/
if ((strcmp(param, "default_hugepagesz") == 0) ||
(strcmp(param, "hugepagesz") == 0)) {
size = memparse(val, NULL);
} else if (strcmp(param, "hugepages") == 0) {
if (size != 0) {
if (sscanf(val, "%lu", &npages) <= 0)
npages = 0;
if (npages > MAX_NUMBER_GPAGES) {
pr_warn("MMU: %lu pages requested for page "
#ifdef CONFIG_PHYS_ADDR_T_64BIT
"size %llu KB, limiting to "
#else
"size %u KB, limiting to "
#endif
__stringify(MAX_NUMBER_GPAGES) "\n",
npages, size / 1024);
npages = MAX_NUMBER_GPAGES;
}
gpage_npages[shift_to_mmu_psize(__ffs(size))] = npages;
size = 0;
}
}
return 0;
}
/*
* This function allocates physical space for pages that are larger than the
* buddy allocator can handle. We want to allocate these in highmem because
* the amount of lowmem is limited. This means that this function MUST be
* called before lowmem_end_addr is set up in MMU_init() in order for the lmb
* allocate to grab highmem.
*/
void __init reserve_hugetlb_gpages(void)
{
static __initdata char cmdline[COMMAND_LINE_SIZE];
phys_addr_t size, base;
int i;
strlcpy(cmdline, boot_command_line, COMMAND_LINE_SIZE);
parse_args("hugetlb gpages", cmdline, NULL, 0, 0, 0,
module: add extra argument for parse_params() callback This adds an extra argument onto parse_params() to be used as a way to make the unused callback a bit more useful and generic by allowing the caller to pass on a data structure of its choice. An example use case is to allow us to easily make module parameters for every module which we will do next. @ parse @ identifier name, args, params, num, level_min, level_max; identifier unknown, param, val, doing; type s16; @@ extern char *parse_args(const char *name, char *args, const struct kernel_param *params, unsigned num, s16 level_min, s16 level_max, + void *arg, int (*unknown)(char *param, char *val, const char *doing + , void *arg )); @ parse_mod @ identifier name, args, params, num, level_min, level_max; identifier unknown, param, val, doing; type s16; @@ char *parse_args(const char *name, char *args, const struct kernel_param *params, unsigned num, s16 level_min, s16 level_max, + void *arg, int (*unknown)(char *param, char *val, const char *doing + , void *arg )) { ... } @ parse_args_found @ expression R, E1, E2, E3, E4, E5, E6; identifier func; @@ ( R = parse_args(E1, E2, E3, E4, E5, E6, + NULL, func); | R = parse_args(E1, E2, E3, E4, E5, E6, + NULL, &func); | R = parse_args(E1, E2, E3, E4, E5, E6, + NULL, NULL); | parse_args(E1, E2, E3, E4, E5, E6, + NULL, func); | parse_args(E1, E2, E3, E4, E5, E6, + NULL, &func); | parse_args(E1, E2, E3, E4, E5, E6, + NULL, NULL); ) @ parse_args_unused depends on parse_args_found @ identifier parse_args_found.func; @@ int func(char *param, char *val, const char *unused + , void *arg ) { ... } @ mod_unused depends on parse_args_found @ identifier parse_args_found.func; expression A1, A2, A3; @@ - func(A1, A2, A3); + func(A1, A2, A3, NULL); Generated-by: Coccinelle SmPL Cc: cocci@systeme.lip6.fr Cc: Tejun Heo <tj@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Christoph Hellwig <hch@infradead.org> Cc: Felipe Contreras <felipe.contreras@gmail.com> Cc: Ewan Milne <emilne@redhat.com> Cc: Jean Delvare <jdelvare@suse.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Jani Nikula <jani.nikula@intel.com> Cc: linux-kernel@vger.kernel.org Reviewed-by: Tejun Heo <tj@kernel.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-31 07:20:03 +08:00
NULL, &do_gpage_early_setup);
/*
* Walk gpage list in reverse, allocating larger page sizes first.
* Skip over unsupported sizes, or sizes that have 0 gpages allocated.
* When we reach the point in the list where pages are no longer
* considered gpages, we're done.
*/
for (i = MMU_PAGE_COUNT-1; i >= 0; i--) {
if (mmu_psize_defs[i].shift == 0 || gpage_npages[i] == 0)
continue;
else if (mmu_psize_to_shift(i) < (MAX_ORDER + PAGE_SHIFT))
break;
size = (phys_addr_t)(1ULL << mmu_psize_to_shift(i));
base = memblock_alloc_base(size * gpage_npages[i], size,
MEMBLOCK_ALLOC_ANYWHERE);
add_gpage(base, size, gpage_npages[i]);
}
}
#else /* !PPC_FSL_BOOK3E */
/* Build list of addresses of gigantic pages. This function is used in early
* boot before the buddy allocator is setup.
*/
void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
{
if (!addr)
return;
while (number_of_pages > 0) {
gpage_freearray[nr_gpages] = addr;
nr_gpages++;
number_of_pages--;
addr += page_size;
}
}
/* Moves the gigantic page addresses from the temporary list to the
* huge_boot_pages list.
*/
int alloc_bootmem_huge_page(struct hstate *hstate)
{
struct huge_bootmem_page *m;
if (nr_gpages == 0)
return 0;
m = phys_to_virt(gpage_freearray[--nr_gpages]);
gpage_freearray[nr_gpages] = 0;
list_add(&m->list, &huge_boot_pages);
m->hstate = hstate;
return 1;
}
#endif
#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
#define HUGEPD_FREELIST_SIZE \
((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
struct hugepd_freelist {
struct rcu_head rcu;
unsigned int index;
void *ptes[0];
};
static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
static void hugepd_free_rcu_callback(struct rcu_head *head)
{
struct hugepd_freelist *batch =
container_of(head, struct hugepd_freelist, rcu);
unsigned int i;
for (i = 0; i < batch->index; i++)
kmem_cache_free(hugepte_cache, batch->ptes[i]);
free_page((unsigned long)batch);
}
static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
{
struct hugepd_freelist **batchp;
batchp = &get_cpu_var(hugepd_freelist_cur);
if (atomic_read(&tlb->mm->mm_users) < 2 ||
cpumask_equal(mm_cpumask(tlb->mm),
cpumask_of(smp_processor_id()))) {
kmem_cache_free(hugepte_cache, hugepte);
put_cpu_var(hugepd_freelist_cur);
return;
}
if (*batchp == NULL) {
*batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
(*batchp)->index = 0;
}
(*batchp)->ptes[(*batchp)->index++] = hugepte;
if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
call_rcu_sched(&(*batchp)->rcu, hugepd_free_rcu_callback);
*batchp = NULL;
}
put_cpu_var(hugepd_freelist_cur);
}
#else
static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}
#endif
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
unsigned long start, unsigned long end,
unsigned long floor, unsigned long ceiling)
{
pte_t *hugepte = hugepd_page(*hpdp);
int i;
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
unsigned long pdmask = ~((1UL << pdshift) - 1);
unsigned int num_hugepd = 1;
unsigned int shift = hugepd_shift(*hpdp);
/* Note: On fsl the hpdp may be the first of several */
if (shift > pdshift)
num_hugepd = 1 << (shift - pdshift);
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
start &= pdmask;
if (start < floor)
return;
if (ceiling) {
ceiling &= pdmask;
if (! ceiling)
return;
}
if (end - 1 > ceiling - 1)
return;
for (i = 0; i < num_hugepd; i++, hpdp++)
*hpdp = __hugepd(0);
if (shift >= pdshift)
hugepd_free(tlb, hugepte);
else
pgtable_free_tlb(tlb, hugepte, pdshift - shift);
}
static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
unsigned long addr, unsigned long end,
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
unsigned long floor, unsigned long ceiling)
{
pmd_t *pmd;
unsigned long next;
unsigned long start;
start = addr;
do {
unsigned long more;
pmd = pmd_offset(pud, addr);
next = pmd_addr_end(addr, end);
if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
/*
* if it is not hugepd pointer, we should already find
* it cleared.
*/
WARN_ON(!pmd_none_or_clear_bad(pmd));
continue;
}
/*
* Increment next by the size of the huge mapping since
* there may be more than one entry at this level for a
* single hugepage, but all of them point to
* the same kmem cache that holds the hugepte.
*/
more = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
if (more > next)
next = more;
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
addr, next, floor, ceiling);
} while (addr = next, addr != end);
start &= PUD_MASK;
if (start < floor)
return;
if (ceiling) {
ceiling &= PUD_MASK;
if (!ceiling)
return;
}
if (end - 1 > ceiling - 1)
return;
pmd = pmd_offset(pud, start);
pud_clear(pud);
pmd_free_tlb(tlb, pmd, start);
mm_dec_nr_pmds(tlb->mm);
}
static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
unsigned long addr, unsigned long end,
unsigned long floor, unsigned long ceiling)
{
pud_t *pud;
unsigned long next;
unsigned long start;
start = addr;
do {
pud = pud_offset(pgd, addr);
next = pud_addr_end(addr, end);
if (!is_hugepd(__hugepd(pud_val(*pud)))) {
if (pud_none_or_clear_bad(pud))
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
ceiling);
} else {
unsigned long more;
/*
* Increment next by the size of the huge mapping since
* there may be more than one entry at this level for a
* single hugepage, but all of them point to
* the same kmem cache that holds the hugepte.
*/
more = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
if (more > next)
next = more;
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
addr, next, floor, ceiling);
}
} while (addr = next, addr != end);
start &= PGDIR_MASK;
if (start < floor)
return;
if (ceiling) {
ceiling &= PGDIR_MASK;
if (!ceiling)
return;
}
if (end - 1 > ceiling - 1)
return;
pud = pud_offset(pgd, start);
pgd_clear(pgd);
pud_free_tlb(tlb, pud, start);
}
/*
* This function frees user-level page tables of a process.
*/
void hugetlb_free_pgd_range(struct mmu_gather *tlb,
unsigned long addr, unsigned long end,
unsigned long floor, unsigned long ceiling)
{
pgd_t *pgd;
unsigned long next;
/*
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
* Because there are a number of different possible pagetable
* layouts for hugepage ranges, we limit knowledge of how
* things should be laid out to the allocation path
* (huge_pte_alloc(), above). Everything else works out the
* structure as it goes from information in the hugepd
* pointers. That means that we can't here use the
* optimization used in the normal page free_pgd_range(), of
* checking whether we're actually covering a large enough
* range to have to do anything at the top level of the walk
* instead of at the bottom.
*
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
* To make sense of this, you should probably go read the big
* block comment at the top of the normal free_pgd_range(),
* too.
*/
do {
next = pgd_addr_end(addr, end);
pgd = pgd_offset(tlb->mm, addr);
if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
if (pgd_none_or_clear_bad(pgd))
continue;
hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
} else {
unsigned long more;
/*
* Increment next by the size of the huge mapping since
* there may be more than one entry at the pgd level
* for a single hugepage, but all of them point to the
* same kmem cache that holds the hugepte.
*/
more = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
if (more > next)
next = more;
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
addr, next, floor, ceiling);
}
} while (addr = next, addr != end);
}
struct page *follow_huge_pd(struct vm_area_struct *vma,
unsigned long address, hugepd_t hpd,
int flags, int pdshift)
{
pte_t *ptep;
spinlock_t *ptl;
struct page *page = NULL;
unsigned long mask;
int shift = hugepd_shift(hpd);
struct mm_struct *mm = vma->vm_mm;
retry:
ptl = &mm->page_table_lock;
spin_lock(ptl);
ptep = hugepte_offset(hpd, address, pdshift);
if (pte_present(*ptep)) {
mask = (1UL << shift) - 1;
page = pte_page(*ptep);
page += ((address & mask) >> PAGE_SHIFT);
if (flags & FOLL_GET)
get_page(page);
} else {
if (is_hugetlb_entry_migration(*ptep)) {
spin_unlock(ptl);
__migration_entry_wait(mm, ptep, ptl);
goto retry;
}
}
spin_unlock(ptl);
return page;
}
static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
unsigned long sz)
{
unsigned long __boundary = (addr + sz) & ~(sz-1);
return (__boundary - 1 < end - 1) ? __boundary : end;
}
int gup_huge_pd(hugepd_t hugepd, unsigned long addr, unsigned pdshift,
unsigned long end, int write, struct page **pages, int *nr)
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
{
pte_t *ptep;
unsigned long sz = 1UL << hugepd_shift(hugepd);
unsigned long next;
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
ptep = hugepte_offset(hugepd, addr, pdshift);
do {
next = hugepte_addr_end(addr, end, sz);
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr))
return 0;
} while (ptep++, addr = next, addr != end);
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
return 1;
}
#ifdef CONFIG_PPC_MM_SLICES
unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
{
struct hstate *hstate = hstate_file(file);
int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
powerpc: Check for valid hugepage size in hugetlb_get_unmapped_area It looks like most of the hugetlb code is doing the correct thing if hugepages are not supported, but the mmap code is not. If we get into the mmap code when hugepages are not supported, such as in an LPAR which is running Active Memory Sharing, we can oops the kernel. This fixes the oops being seen in this path. oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=1024 NUMA pSeries Modules linked in: nfs(N) lockd(N) nfs_acl(N) sunrpc(N) ipv6(N) fuse(N) loop(N) dm_mod(N) sg(N) ibmveth(N) sd_mod(N) crc_t10dif(N) ibmvscsic(N) scsi_transport_srp(N) scsi_tgt(N) scsi_mod(N) Supported: No NIP: c000000000038d60 LR: c00000000003945c CTR: c0000000000393f0 REGS: c000000077e7b830 TRAP: 0300 Tainted: G (2.6.27.5-bz50170-2-ppc64) MSR: 8000000000009032 <EE,ME,IR,DR> CR: 44000448 XER: 20000001 DAR: c000002000af90a8, DSISR: 0000000040000000 TASK = c00000007c1b8600[4019] 'hugemmap01' THREAD: c000000077e78000 CPU: 6 GPR00: 0000001fffffffe0 c000000077e7bab0 c0000000009a4e78 0000000000000000 GPR04: 0000000000010000 0000000000000001 00000000ffffffff 0000000000000001 GPR08: 0000000000000000 c000000000af90c8 0000000000000001 0000000000000000 GPR12: 000000000000003f c000000000a73880 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000010000 GPR20: 0000000000000000 0000000000000003 0000000000010000 0000000000000001 GPR24: 0000000000000003 0000000000000000 0000000000000001 ffffffffffffffb5 GPR28: c000000077ca2e80 0000000000000000 c00000000092af78 0000000000010000 NIP [c000000000038d60] .slice_get_unmapped_area+0x6c/0x4e0 LR [c00000000003945c] .hugetlb_get_unmapped_area+0x6c/0x80 Call Trace: [c000000077e7bbc0] [c00000000003945c] .hugetlb_get_unmapped_area+0x6c/0x80 [c000000077e7bc30] [c000000000107e30] .get_unmapped_area+0x64/0xd8 [c000000077e7bcb0] [c00000000010b140] .do_mmap_pgoff+0x140/0x420 [c000000077e7bd80] [c00000000000bf5c] .sys_mmap+0xc4/0x140 [c000000077e7be30] [c0000000000086b4] syscall_exit+0x0/0x40 Instruction dump: fac1ffb0 fae1ffb8 fb01ffc0 fb21ffc8 fb41ffd0 fb61ffd8 fb81ffe0 fbc1fff0 fbe1fff8 f821fef1 f8c10158 f8e10160 <7d49002e> f9010168 e92d01b0 eb4902b0 Signed-off-by: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-12-04 12:07:54 +08:00
if (radix_enabled())
return radix__hugetlb_get_unmapped_area(file, addr, len,
pgoff, flags);
return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
}
#endif
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
{
#ifdef CONFIG_PPC_MM_SLICES
unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
/* With radix we don't use slice, so derive it from vma*/
if (!radix_enabled())
return 1UL << mmu_psize_to_shift(psize);
#endif
if (!is_vm_hugetlb_page(vma))
return PAGE_SIZE;
return huge_page_size(hstate_vma(vma));
}
static inline bool is_power_of_4(unsigned long x)
{
if (is_power_of_2(x))
return (__ilog2(x) % 2) ? false : true;
return false;
}
static int __init add_huge_page_size(unsigned long long size)
{
int shift = __ffs(size);
int mmu_psize;
powerpc/mm: Allow more flexible layouts for hugepage pagetables Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27 03:24:31 +08:00
/* Check that it is a page size supported by the hardware and
* that it fits within pagetable and slice limits. */
if (size <= PAGE_SIZE)
return -EINVAL;
#if defined(CONFIG_PPC_FSL_BOOK3E)
if (!is_power_of_4(size))
return -EINVAL;
#elif !defined(CONFIG_PPC_8xx)
if (!is_power_of_2(size) || (shift > SLICE_HIGH_SHIFT))
return -EINVAL;
#endif
if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
return -EINVAL;
#ifdef CONFIG_PPC_BOOK3S_64
/*
* We need to make sure that for different page sizes reported by
* firmware we only add hugetlb support for page sizes that can be
* supported by linux page table layout.
* For now we have
* Radix: 2M
* Hash: 16M and 16G
*/
if (radix_enabled()) {
if (mmu_psize != MMU_PAGE_2M) {
if (cpu_has_feature(CPU_FTR_POWER9_DD1) ||
(mmu_psize != MMU_PAGE_1G))
return -EINVAL;
}
} else {
if (mmu_psize != MMU_PAGE_16M && mmu_psize != MMU_PAGE_16G)
return -EINVAL;
}
#endif
BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
/* Return if huge page size has already been setup */
if (size_to_hstate(size))
return 0;
hugetlb_add_hstate(shift - PAGE_SHIFT);
return 0;
}
static int __init hugepage_setup_sz(char *str)
{
unsigned long long size;
size = memparse(str, &str);
if (add_huge_page_size(size) != 0) {
hugetlb_bad_size();
pr_err("Invalid huge page size specified(%llu)\n", size);
}
return 1;
}
__setup("hugepagesz=", hugepage_setup_sz);
struct kmem_cache *hugepte_cache;
static int __init hugetlbpage_init(void)
{
int psize;
#if !defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_PPC_8xx)
if (!radix_enabled() && !mmu_has_feature(MMU_FTR_16M_PAGE))
return -ENODEV;
#endif
for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
unsigned shift;
unsigned pdshift;
if (!mmu_psize_defs[psize].shift)
continue;
shift = mmu_psize_to_shift(psize);
if (add_huge_page_size(1ULL << shift) < 0)
continue;
if (shift < HUGEPD_PUD_SHIFT)
pdshift = PMD_SHIFT;
else if (shift < HUGEPD_PGD_SHIFT)
pdshift = PUD_SHIFT;
else
pdshift = PGDIR_SHIFT;
/*
* if we have pdshift and shift value same, we don't
* use pgt cache for hugepd.
*/
if (pdshift > shift)
pgtable_cache_add(pdshift - shift, NULL);
#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
else if (!hugepte_cache) {
/*
* Create a kmem cache for hugeptes. The bottom bits in
* the pte have size information encoded in them, so
* align them to allow this
*/
hugepte_cache = kmem_cache_create("hugepte-cache",
sizeof(pte_t),
HUGEPD_SHIFT_MASK + 1,
0, NULL);
if (hugepte_cache == NULL)
panic("%s: Unable to create kmem cache "
"for hugeptes\n", __func__);
}
#endif
}
#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
/* Default hpage size = 4M on FSL_BOOK3E and 512k on 8xx */
if (mmu_psize_defs[MMU_PAGE_4M].shift)
HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_4M].shift;
else if (mmu_psize_defs[MMU_PAGE_512K].shift)
HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_512K].shift;
#else
/* Set default large page size. Currently, we pick 16M or 1M
* depending on what is available
*/
if (mmu_psize_defs[MMU_PAGE_16M].shift)
HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift;
else if (mmu_psize_defs[MMU_PAGE_1M].shift)
HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift;
else if (mmu_psize_defs[MMU_PAGE_2M].shift)
HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_2M].shift;
#endif
return 0;
}
arch_initcall(hugetlbpage_init);
void flush_dcache_icache_hugepage(struct page *page)
{
int i;
void *start;
BUG_ON(!PageCompound(page));
for (i = 0; i < (1UL << compound_order(page)); i++) {
if (!PageHighMem(page)) {
__flush_dcache_icache(page_address(page+i));
} else {
start = kmap_atomic(page+i);
__flush_dcache_icache(start);
kunmap_atomic(start);
}
}
}
#endif /* CONFIG_HUGETLB_PAGE */
/*
* We have 4 cases for pgds and pmds:
* (1) invalid (all zeroes)
* (2) pointer to next table, as normal; bottom 6 bits == 0
* (3) leaf pte for huge page _PAGE_PTE set
* (4) hugepd pointer, _PAGE_PTE = 0 and bits [2..6] indicate size of table
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
*
* So long as we atomically load page table pointers we are safe against teardown,
* we can follow the address down to the the page and take a ref on it.
* This function need to be called with interrupts disabled. We use this variant
* when we have MSR[EE] = 0 but the paca->soft_enabled = 1
*/
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
bool *is_thp, unsigned *shift)
{
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
pgd_t pgd, *pgdp;
pud_t pud, *pudp;
pmd_t pmd, *pmdp;
pte_t *ret_pte;
hugepd_t *hpdp = NULL;
unsigned pdshift = PGDIR_SHIFT;
if (shift)
*shift = 0;
if (is_thp)
*is_thp = false;
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
pgdp = pgdir + pgd_index(ea);
pgd = READ_ONCE(*pgdp);
/*
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
* Always operate on the local stack value. This make sure the
* value don't get updated by a parallel THP split/collapse,
* page fault or a page unmap. The return pte_t * is still not
* stable. So should be checked there for above conditions.
*/
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
if (pgd_none(pgd))
return NULL;
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
else if (pgd_huge(pgd)) {
ret_pte = (pte_t *) pgdp;
goto out;
} else if (is_hugepd(__hugepd(pgd_val(pgd))))
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
hpdp = (hugepd_t *)&pgd;
else {
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
/*
* Even if we end up with an unmap, the pgtable will not
* be freed, because we do an rcu free and here we are
* irq disabled
*/
pdshift = PUD_SHIFT;
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
pudp = pud_offset(&pgd, ea);
pud = READ_ONCE(*pudp);
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
if (pud_none(pud))
return NULL;
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
else if (pud_huge(pud)) {
ret_pte = (pte_t *) pudp;
goto out;
} else if (is_hugepd(__hugepd(pud_val(pud))))
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
hpdp = (hugepd_t *)&pud;
else {
pdshift = PMD_SHIFT;
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
pmdp = pmd_offset(&pud, ea);
pmd = READ_ONCE(*pmdp);
/*
* A hugepage collapse is captured by pmd_none, because
* it mark the pmd none and do a hpte invalidate.
*/
if (pmd_none(pmd))
return NULL;
if (pmd_trans_huge(pmd)) {
if (is_thp)
*is_thp = true;
ret_pte = (pte_t *) pmdp;
goto out;
}
if (pmd_huge(pmd)) {
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
ret_pte = (pte_t *) pmdp;
goto out;
} else if (is_hugepd(__hugepd(pmd_val(pmd))))
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
hpdp = (hugepd_t *)&pmd;
else
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 17:00:22 +08:00
return pte_offset_kernel(&pmd, ea);
}
}
if (!hpdp)
return NULL;
ret_pte = hugepte_offset(*hpdp, ea, pdshift);
pdshift = hugepd_shift(*hpdp);
out:
if (shift)
*shift = pdshift;
return ret_pte;
}
EXPORT_SYMBOL_GPL(__find_linux_pte_or_hugepte);
int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
unsigned long mask;
unsigned long pte_end;
mm: drop tail page refcounting Tail page refcounting is utterly complicated and painful to support. It uses ->_mapcount on tail pages to store how many times this page is pinned. get_page() bumps ->_mapcount on tail page in addition to ->_count on head. This information is required by split_huge_page() to be able to distribute pins from head of compound page to tails during the split. We will need ->_mapcount to account PTE mappings of subpages of the compound page. We eliminate need in current meaning of ->_mapcount in tail pages by forbidding split entirely if the page is pinned. The only user of tail page refcounting is THP which is marked BROKEN for now. Let's drop all this mess. It makes get_page() and put_page() much simpler. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-16 08:52:56 +08:00
struct page *head, *page;
pte_t pte;
int refs;
pte_end = (addr + sz) & ~(sz-1);
if (pte_end < end)
end = pte_end;
pte = READ_ONCE(*ptep);
mask = _PAGE_PRESENT | _PAGE_READ;
/*
* On some CPUs like the 8xx, _PAGE_RW hence _PAGE_WRITE is defined
* as 0 and _PAGE_RO has to be set when a page is not writable
*/
if (write)
mask |= _PAGE_WRITE;
else
mask |= _PAGE_RO;
if ((pte_val(pte) & mask) != mask)
return 0;
/* hugepages are never "special" */
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
refs = 0;
head = pte_page(pte);
page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
do {
VM_BUG_ON(compound_head(page) != head);
pages[*nr] = page;
(*nr)++;
page++;
refs++;
} while (addr += PAGE_SIZE, addr != end);
if (!page_cache_add_speculative(head, refs)) {
*nr -= refs;
return 0;
}
if (unlikely(pte_val(pte) != pte_val(*ptep))) {
/* Could be optimized better */
*nr -= refs;
while (refs--)
put_page(head);
return 0;
}
return 1;
}