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linux/arch/powerpc/mm/hugetlbpage.c
Benjamin Herrenschmidt a741e67969 [POWERPC] Make tlb flush batch use lazy MMU mode 
The current tlb flush code on powerpc 64 bits has a subtle race since we
lost the page table lock due to the possible faulting in of new PTEs
after a previous one has been removed but before the corresponding hash
entry has been evicted, which can leads to all sort of fatal problems.

This patch reworks the batch code completely. It doesn't use the mmu_gather
stuff anymore. Instead, we use the lazy mmu hooks that were added by the
paravirt code. They have the nice property that the enter/leave lazy mmu
mode pair is always fully contained by the PTE lock for a given range
of PTEs. Thus we can guarantee that all batches are flushed on a given
CPU before it drops that lock.

We also generalize batching for any PTE update that require a flush.

Batching is now enabled on a CPU by arch_enter_lazy_mmu_mode() and
disabled by arch_leave_lazy_mmu_mode(). The code epects that this is
always contained within a PTE lock section so no preemption can happen
and no PTE insertion in that range from another CPU. When batching
is enabled on a CPU, every PTE updates that need a hash flush will
use the batch for that flush.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-04-13 04:09:38 +10:00

1070 lines
27 KiB
C
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/*
* PPC64 (POWER4) Huge TLB Page Support for Kernel.
*
* Copyright (C) 2003 David Gibson, IBM Corporation.
*
* Based on the IA-32 version:
* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
*/
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/sysctl.h>
#include <asm/mman.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/machdep.h>
#include <asm/cputable.h>
#include <asm/tlb.h>
#include <asm/spu.h>
#include <linux/sysctl.h>
#define NUM_LOW_AREAS (0x100000000UL >> SID_SHIFT)
#define NUM_HIGH_AREAS (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
#ifdef CONFIG_PPC_64K_PAGES
#define HUGEPTE_INDEX_SIZE (PMD_SHIFT-HPAGE_SHIFT)
#else
#define HUGEPTE_INDEX_SIZE (PUD_SHIFT-HPAGE_SHIFT)
#endif
#define PTRS_PER_HUGEPTE (1 << HUGEPTE_INDEX_SIZE)
#define HUGEPTE_TABLE_SIZE (sizeof(pte_t) << HUGEPTE_INDEX_SIZE)
#define HUGEPD_SHIFT (HPAGE_SHIFT + HUGEPTE_INDEX_SIZE)
#define HUGEPD_SIZE (1UL << HUGEPD_SHIFT)
#define HUGEPD_MASK (~(HUGEPD_SIZE-1))
#define huge_pgtable_cache (pgtable_cache[HUGEPTE_CACHE_NUM])
/* Flag to mark huge PD pointers. This means pmd_bad() and pud_bad()
* will choke on pointers to hugepte tables, which is handy for
* catching screwups early. */
#define HUGEPD_OK 0x1
typedef struct { unsigned long pd; } hugepd_t;
#define hugepd_none(hpd) ((hpd).pd == 0)
static inline pte_t *hugepd_page(hugepd_t hpd)
{
BUG_ON(!(hpd.pd & HUGEPD_OK));
return (pte_t *)(hpd.pd & ~HUGEPD_OK);
}
static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr)
{
unsigned long idx = ((addr >> HPAGE_SHIFT) & (PTRS_PER_HUGEPTE-1));
pte_t *dir = hugepd_page(*hpdp);
return dir + idx;
}
static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
unsigned long address)
{
pte_t *new = kmem_cache_alloc(huge_pgtable_cache,
GFP_KERNEL|__GFP_REPEAT);
if (! new)
return -ENOMEM;
spin_lock(&mm->page_table_lock);
if (!hugepd_none(*hpdp))
kmem_cache_free(huge_pgtable_cache, new);
else
hpdp->pd = (unsigned long)new | HUGEPD_OK;
spin_unlock(&mm->page_table_lock);
return 0;
}
/* Modelled after find_linux_pte() */
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pg;
pud_t *pu;
BUG_ON(! in_hugepage_area(mm->context, addr));
addr &= HPAGE_MASK;
pg = pgd_offset(mm, addr);
if (!pgd_none(*pg)) {
pu = pud_offset(pg, addr);
if (!pud_none(*pu)) {
#ifdef CONFIG_PPC_64K_PAGES
pmd_t *pm;
pm = pmd_offset(pu, addr);
if (!pmd_none(*pm))
return hugepte_offset((hugepd_t *)pm, addr);
#else
return hugepte_offset((hugepd_t *)pu, addr);
#endif
}
}
return NULL;
}
pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pg;
pud_t *pu;
hugepd_t *hpdp = NULL;
BUG_ON(! in_hugepage_area(mm->context, addr));
addr &= HPAGE_MASK;
pg = pgd_offset(mm, addr);
pu = pud_alloc(mm, pg, addr);
if (pu) {
#ifdef CONFIG_PPC_64K_PAGES
pmd_t *pm;
pm = pmd_alloc(mm, pu, addr);
if (pm)
hpdp = (hugepd_t *)pm;
#else
hpdp = (hugepd_t *)pu;
#endif
}
if (! hpdp)
return NULL;
if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr))
return NULL;
return hugepte_offset(hpdp, addr);
}
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
return 0;
}
static void free_hugepte_range(struct mmu_gather *tlb, hugepd_t *hpdp)
{
pte_t *hugepte = hugepd_page(*hpdp);
hpdp->pd = 0;
tlb->need_flush = 1;
pgtable_free_tlb(tlb, pgtable_free_cache(hugepte, HUGEPTE_CACHE_NUM,
PGF_CACHENUM_MASK));
}
#ifdef CONFIG_PPC_64K_PAGES
static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
unsigned long addr, unsigned long end,
unsigned long floor, unsigned long ceiling)
{
pmd_t *pmd;
unsigned long next;
unsigned long start;
start = addr;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
if (pmd_none(*pmd))
continue;
free_hugepte_range(tlb, (hugepd_t *)pmd);
} while (pmd++, 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);
}
#endif
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;
pud = pud_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
#ifdef CONFIG_PPC_64K_PAGES
if (pud_none_or_clear_bad(pud))
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling);
#else
if (pud_none(*pud))
continue;
free_hugepte_range(tlb, (hugepd_t *)pud);
#endif
} while (pud++, 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);
}
/*
* This function frees user-level page tables of a process.
*
* Must be called with pagetable lock held.
*/
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;
unsigned long start;
/*
* Comments below take from the normal free_pgd_range(). They
* apply here too. The tests against HUGEPD_MASK below are
* essential, because we *don't* test for this at the bottom
* level. Without them we'll attempt to free a hugepte table
* when we unmap just part of it, even if there are other
* active mappings using it.
*
* The next few lines have given us lots of grief...
*
* Why are we testing HUGEPD* at this top level? Because
* often there will be no work to do at all, and we'd prefer
* not to go all the way down to the bottom just to discover
* that.
*
* Why all these "- 1"s? Because 0 represents both the bottom
* of the address space and the top of it (using -1 for the
* top wouldn't help much: the masks would do the wrong thing).
* The rule is that addr 0 and floor 0 refer to the bottom of
* the address space, but end 0 and ceiling 0 refer to the top
* Comparisons need to use "end - 1" and "ceiling - 1" (though
* that end 0 case should be mythical).
*
* Wherever addr is brought up or ceiling brought down, we
* must be careful to reject "the opposite 0" before it
* confuses the subsequent tests. But what about where end is
* brought down by HUGEPD_SIZE below? no, end can't go down to
* 0 there.
*
* Whereas we round start (addr) and ceiling down, by different
* masks at different levels, in order to test whether a table
* now has no other vmas using it, so can be freed, we don't
* bother to round floor or end up - the tests don't need that.
*/
addr &= HUGEPD_MASK;
if (addr < floor) {
addr += HUGEPD_SIZE;
if (!addr)
return;
}
if (ceiling) {
ceiling &= HUGEPD_MASK;
if (!ceiling)
return;
}
if (end - 1 > ceiling - 1)
end -= HUGEPD_SIZE;
if (addr > end - 1)
return;
start = addr;
pgd = pgd_offset((*tlb)->mm, addr);
do {
BUG_ON(! in_hugepage_area((*tlb)->mm->context, addr));
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
hugetlb_free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
} while (pgd++, addr = next, addr != end);
}
void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
if (pte_present(*ptep)) {
/* We open-code pte_clear because we need to pass the right
* argument to hpte_need_flush (huge / !huge). Might not be
* necessary anymore if we make hpte_need_flush() get the
* page size from the slices
*/
pte_update(mm, addr & HPAGE_MASK, ptep, ~0UL, 1);
}
*ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
}
pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
unsigned long old = pte_update(mm, addr, ptep, ~0UL, 1);
return __pte(old);
}
struct slb_flush_info {
struct mm_struct *mm;
u16 newareas;
};
static void flush_low_segments(void *parm)
{
struct slb_flush_info *fi = parm;
unsigned long i;
BUILD_BUG_ON((sizeof(fi->newareas)*8) != NUM_LOW_AREAS);
if (current->active_mm != fi->mm)
return;
/* Only need to do anything if this CPU is working in the same
* mm as the one which has changed */
/* update the paca copy of the context struct */
get_paca()->context = current->active_mm->context;
asm volatile("isync" : : : "memory");
for (i = 0; i < NUM_LOW_AREAS; i++) {
if (! (fi->newareas & (1U << i)))
continue;
asm volatile("slbie %0"
: : "r" ((i << SID_SHIFT) | SLBIE_C));
}
asm volatile("isync" : : : "memory");
}
static void flush_high_segments(void *parm)
{
struct slb_flush_info *fi = parm;
unsigned long i, j;
BUILD_BUG_ON((sizeof(fi->newareas)*8) != NUM_HIGH_AREAS);
if (current->active_mm != fi->mm)
return;
/* Only need to do anything if this CPU is working in the same
* mm as the one which has changed */
/* update the paca copy of the context struct */
get_paca()->context = current->active_mm->context;
asm volatile("isync" : : : "memory");
for (i = 0; i < NUM_HIGH_AREAS; i++) {
if (! (fi->newareas & (1U << i)))
continue;
for (j = 0; j < (1UL << (HTLB_AREA_SHIFT-SID_SHIFT)); j++)
asm volatile("slbie %0"
:: "r" (((i << HTLB_AREA_SHIFT)
+ (j << SID_SHIFT)) | SLBIE_C));
}
asm volatile("isync" : : : "memory");
}
static int prepare_low_area_for_htlb(struct mm_struct *mm, unsigned long area)
{
unsigned long start = area << SID_SHIFT;
unsigned long end = (area+1) << SID_SHIFT;
struct vm_area_struct *vma;
BUG_ON(area >= NUM_LOW_AREAS);
/* Check no VMAs are in the region */
vma = find_vma(mm, start);
if (vma && (vma->vm_start < end))
return -EBUSY;
return 0;
}
static int prepare_high_area_for_htlb(struct mm_struct *mm, unsigned long area)
{
unsigned long start = area << HTLB_AREA_SHIFT;
unsigned long end = (area+1) << HTLB_AREA_SHIFT;
struct vm_area_struct *vma;
BUG_ON(area >= NUM_HIGH_AREAS);
/* Hack, so that each addresses is controlled by exactly one
* of the high or low area bitmaps, the first high area starts
* at 4GB, not 0 */
if (start == 0)
start = 0x100000000UL;
/* Check no VMAs are in the region */
vma = find_vma(mm, start);
if (vma && (vma->vm_start < end))
return -EBUSY;
return 0;
}
static int open_low_hpage_areas(struct mm_struct *mm, u16 newareas)
{
unsigned long i;
struct slb_flush_info fi;
BUILD_BUG_ON((sizeof(newareas)*8) != NUM_LOW_AREAS);
BUILD_BUG_ON((sizeof(mm->context.low_htlb_areas)*8) != NUM_LOW_AREAS);
newareas &= ~(mm->context.low_htlb_areas);
if (! newareas)
return 0; /* The segments we want are already open */
for (i = 0; i < NUM_LOW_AREAS; i++)
if ((1 << i) & newareas)
if (prepare_low_area_for_htlb(mm, i) != 0)
return -EBUSY;
mm->context.low_htlb_areas |= newareas;
/* the context change must make it to memory before the flush,
* so that further SLB misses do the right thing. */
mb();
fi.mm = mm;
fi.newareas = newareas;
on_each_cpu(flush_low_segments, &fi, 0, 1);
return 0;
}
static int open_high_hpage_areas(struct mm_struct *mm, u16 newareas)
{
struct slb_flush_info fi;
unsigned long i;
BUILD_BUG_ON((sizeof(newareas)*8) != NUM_HIGH_AREAS);
BUILD_BUG_ON((sizeof(mm->context.high_htlb_areas)*8)
!= NUM_HIGH_AREAS);
newareas &= ~(mm->context.high_htlb_areas);
if (! newareas)
return 0; /* The areas we want are already open */
for (i = 0; i < NUM_HIGH_AREAS; i++)
if ((1 << i) & newareas)
if (prepare_high_area_for_htlb(mm, i) != 0)
return -EBUSY;
mm->context.high_htlb_areas |= newareas;
/* the context change must make it to memory before the flush,
* so that further SLB misses do the right thing. */
mb();
fi.mm = mm;
fi.newareas = newareas;
on_each_cpu(flush_high_segments, &fi, 0, 1);
return 0;
}
int prepare_hugepage_range(unsigned long addr, unsigned long len, pgoff_t pgoff)
{
int err = 0;
if (pgoff & (~HPAGE_MASK >> PAGE_SHIFT))
return -EINVAL;
if (len & ~HPAGE_MASK)
return -EINVAL;
if (addr & ~HPAGE_MASK)
return -EINVAL;
if (addr < 0x100000000UL)
err = open_low_hpage_areas(current->mm,
LOW_ESID_MASK(addr, len));
if ((addr + len) > 0x100000000UL)
err = open_high_hpage_areas(current->mm,
HTLB_AREA_MASK(addr, len));
#ifdef CONFIG_SPE_BASE
spu_flush_all_slbs(current->mm);
#endif
if (err) {
printk(KERN_DEBUG "prepare_hugepage_range(%lx, %lx)"
" failed (lowmask: 0x%04hx, highmask: 0x%04hx)\n",
addr, len,
LOW_ESID_MASK(addr, len), HTLB_AREA_MASK(addr, len));
return err;
}
return 0;
}
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
pte_t *ptep;
struct page *page;
if (! in_hugepage_area(mm->context, address))
return ERR_PTR(-EINVAL);
ptep = huge_pte_offset(mm, address);
page = pte_page(*ptep);
if (page)
page += (address % HPAGE_SIZE) / PAGE_SIZE;
return page;
}
int pmd_huge(pmd_t pmd)
{
return 0;
}
struct page *
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
{
BUG();
return NULL;
}
/* Because we have an exclusive hugepage region which lies within the
* normal user address space, we have to take special measures to make
* non-huge mmap()s evade the hugepage reserved regions. */
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long start_addr;
if (len > TASK_SIZE)
return -ENOMEM;
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (((TASK_SIZE - len) >= addr)
&& (!vma || (addr+len) <= vma->vm_start)
&& !is_hugepage_only_range(mm, addr,len))
return addr;
}
if (len > mm->cached_hole_size) {
start_addr = addr = mm->free_area_cache;
} else {
start_addr = addr = TASK_UNMAPPED_BASE;
mm->cached_hole_size = 0;
}
full_search:
vma = find_vma(mm, addr);
while (TASK_SIZE - len >= addr) {
BUG_ON(vma && (addr >= vma->vm_end));
if (touches_hugepage_low_range(mm, addr, len)) {
addr = ALIGN(addr+1, 1<<SID_SHIFT);
vma = find_vma(mm, addr);
continue;
}
if (touches_hugepage_high_range(mm, addr, len)) {
addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT);
vma = find_vma(mm, addr);
continue;
}
if (!vma || addr + len <= vma->vm_start) {
/*
* Remember the place where we stopped the search:
*/
mm->free_area_cache = addr + len;
return addr;
}
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
addr = vma->vm_end;
vma = vma->vm_next;
}
/* Make sure we didn't miss any holes */
if (start_addr != TASK_UNMAPPED_BASE) {
start_addr = addr = TASK_UNMAPPED_BASE;
mm->cached_hole_size = 0;
goto full_search;
}
return -ENOMEM;
}
/*
* This mmap-allocator allocates new areas top-down from below the
* stack's low limit (the base):
*
* Because we have an exclusive hugepage region which lies within the
* normal user address space, we have to take special measures to make
* non-huge mmap()s evade the hugepage reserved regions.
*/
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma, *prev_vma;
struct mm_struct *mm = current->mm;
unsigned long base = mm->mmap_base, addr = addr0;
unsigned long largest_hole = mm->cached_hole_size;
int first_time = 1;
/* requested length too big for entire address space */
if (len > TASK_SIZE)
return -ENOMEM;
/* dont allow allocations above current base */
if (mm->free_area_cache > base)
mm->free_area_cache = base;
/* requesting a specific address */
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || addr + len <= vma->vm_start)
&& !is_hugepage_only_range(mm, addr,len))
return addr;
}
if (len <= largest_hole) {
largest_hole = 0;
mm->free_area_cache = base;
}
try_again:
/* make sure it can fit in the remaining address space */
if (mm->free_area_cache < len)
goto fail;
/* either no address requested or cant fit in requested address hole */
addr = (mm->free_area_cache - len) & PAGE_MASK;
do {
hugepage_recheck:
if (touches_hugepage_low_range(mm, addr, len)) {
addr = (addr & ((~0) << SID_SHIFT)) - len;
goto hugepage_recheck;
} else if (touches_hugepage_high_range(mm, addr, len)) {
addr = (addr & ((~0UL) << HTLB_AREA_SHIFT)) - len;
goto hugepage_recheck;
}
/*
* Lookup failure means no vma is above this address,
* i.e. return with success:
*/
if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
return addr;
/*
* new region fits between prev_vma->vm_end and
* vma->vm_start, use it:
*/
if (addr+len <= vma->vm_start &&
(!prev_vma || (addr >= prev_vma->vm_end))) {
/* remember the address as a hint for next time */
mm->cached_hole_size = largest_hole;
return (mm->free_area_cache = addr);
} else {
/* pull free_area_cache down to the first hole */
if (mm->free_area_cache == vma->vm_end) {
mm->free_area_cache = vma->vm_start;
mm->cached_hole_size = largest_hole;
}
}
/* remember the largest hole we saw so far */
if (addr + largest_hole < vma->vm_start)
largest_hole = vma->vm_start - addr;
/* try just below the current vma->vm_start */
addr = vma->vm_start-len;
} while (len <= vma->vm_start);
fail:
/*
* if hint left us with no space for the requested
* mapping then try again:
*/
if (first_time) {
mm->free_area_cache = base;
largest_hole = 0;
first_time = 0;
goto try_again;
}
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
mm->free_area_cache = TASK_UNMAPPED_BASE;
mm->cached_hole_size = ~0UL;
addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
/*
* Restore the topdown base:
*/
mm->free_area_cache = base;
mm->cached_hole_size = ~0UL;
return addr;
}
static int htlb_check_hinted_area(unsigned long addr, unsigned long len)
{
struct vm_area_struct *vma;
vma = find_vma(current->mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || ((addr + len) <= vma->vm_start)))
return 0;
return -ENOMEM;
}
static unsigned long htlb_get_low_area(unsigned long len, u16 segmask)
{
unsigned long addr = 0;
struct vm_area_struct *vma;
vma = find_vma(current->mm, addr);
while (addr + len <= 0x100000000UL) {
BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */
if (! __within_hugepage_low_range(addr, len, segmask)) {
addr = ALIGN(addr+1, 1<<SID_SHIFT);
vma = find_vma(current->mm, addr);
continue;
}
if (!vma || (addr + len) <= vma->vm_start)
return addr;
addr = ALIGN(vma->vm_end, HPAGE_SIZE);
/* Depending on segmask this might not be a confirmed
* hugepage region, so the ALIGN could have skipped
* some VMAs */
vma = find_vma(current->mm, addr);
}
return -ENOMEM;
}
static unsigned long htlb_get_high_area(unsigned long len, u16 areamask)
{
unsigned long addr = 0x100000000UL;
struct vm_area_struct *vma;
vma = find_vma(current->mm, addr);
while (addr + len <= TASK_SIZE_USER64) {
BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */
if (! __within_hugepage_high_range(addr, len, areamask)) {
addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT);
vma = find_vma(current->mm, addr);
continue;
}
if (!vma || (addr + len) <= vma->vm_start)
return addr;
addr = ALIGN(vma->vm_end, HPAGE_SIZE);
/* Depending on segmask this might not be a confirmed
* hugepage region, so the ALIGN could have skipped
* some VMAs */
vma = find_vma(current->mm, addr);
}
return -ENOMEM;
}
unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
{
int lastshift;
u16 areamask, curareas;
if (HPAGE_SHIFT == 0)
return -EINVAL;
if (len & ~HPAGE_MASK)
return -EINVAL;
if (len > TASK_SIZE)
return -ENOMEM;
if (!cpu_has_feature(CPU_FTR_16M_PAGE))
return -EINVAL;
/* Paranoia, caller should have dealt with this */
BUG_ON((addr + len) < addr);
if (test_thread_flag(TIF_32BIT)) {
curareas = current->mm->context.low_htlb_areas;
/* First see if we can use the hint address */
if (addr && (htlb_check_hinted_area(addr, len) == 0)) {
areamask = LOW_ESID_MASK(addr, len);
if (open_low_hpage_areas(current->mm, areamask) == 0)
return addr;
}
/* Next see if we can map in the existing low areas */
addr = htlb_get_low_area(len, curareas);
if (addr != -ENOMEM)
return addr;
/* Finally go looking for areas to open */
lastshift = 0;
for (areamask = LOW_ESID_MASK(0x100000000UL-len, len);
! lastshift; areamask >>=1) {
if (areamask & 1)
lastshift = 1;
addr = htlb_get_low_area(len, curareas | areamask);
if ((addr != -ENOMEM)
&& open_low_hpage_areas(current->mm, areamask) == 0)
return addr;
}
} else {
curareas = current->mm->context.high_htlb_areas;
/* First see if we can use the hint address */
/* We discourage 64-bit processes from doing hugepage
* mappings below 4GB (must use MAP_FIXED) */
if ((addr >= 0x100000000UL)
&& (htlb_check_hinted_area(addr, len) == 0)) {
areamask = HTLB_AREA_MASK(addr, len);
if (open_high_hpage_areas(current->mm, areamask) == 0)
return addr;
}
/* Next see if we can map in the existing high areas */
addr = htlb_get_high_area(len, curareas);
if (addr != -ENOMEM)
return addr;
/* Finally go looking for areas to open */
lastshift = 0;
for (areamask = HTLB_AREA_MASK(TASK_SIZE_USER64-len, len);
! lastshift; areamask >>=1) {
if (areamask & 1)
lastshift = 1;
addr = htlb_get_high_area(len, curareas | areamask);
if ((addr != -ENOMEM)
&& open_high_hpage_areas(current->mm, areamask) == 0)
return addr;
}
}
printk(KERN_DEBUG "hugetlb_get_unmapped_area() unable to open"
" enough areas\n");
return -ENOMEM;
}
/*
* Called by asm hashtable.S for doing lazy icache flush
*/
static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
pte_t pte, int trap)
{
struct page *page;
int i;
if (!pfn_valid(pte_pfn(pte)))
return rflags;
page = pte_page(pte);
/* page is dirty */
if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
if (trap == 0x400) {
for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++)
__flush_dcache_icache(page_address(page+i));
set_bit(PG_arch_1, &page->flags);
} else {
rflags |= HPTE_R_N;
}
}
return rflags;
}
int hash_huge_page(struct mm_struct *mm, unsigned long access,
unsigned long ea, unsigned long vsid, int local,
unsigned long trap)
{
pte_t *ptep;
unsigned long old_pte, new_pte;
unsigned long va, rflags, pa;
long slot;
int err = 1;
ptep = huge_pte_offset(mm, ea);
/* Search the Linux page table for a match with va */
va = (vsid << 28) | (ea & 0x0fffffff);
/*
* If no pte found or not present, send the problem up to
* do_page_fault
*/
if (unlikely(!ptep || pte_none(*ptep)))
goto out;
/*
* Check the user's access rights to the page. If access should be
* prevented then send the problem up to do_page_fault.
*/
if (unlikely(access & ~pte_val(*ptep)))
goto out;
/*
* At this point, we have a pte (old_pte) which can be used to build
* or update an HPTE. There are 2 cases:
*
* 1. There is a valid (present) pte with no associated HPTE (this is
* the most common case)
* 2. There is a valid (present) pte with an associated HPTE. The
* current values of the pp bits in the HPTE prevent access
* because we are doing software DIRTY bit management and the
* page is currently not DIRTY.
*/
do {
old_pte = pte_val(*ptep);
if (old_pte & _PAGE_BUSY)
goto out;
new_pte = old_pte | _PAGE_BUSY |
_PAGE_ACCESSED | _PAGE_HASHPTE;
} while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
old_pte, new_pte));
rflags = 0x2 | (!(new_pte & _PAGE_RW));
/* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
/* No CPU has hugepages but lacks no execute, so we
* don't need to worry about that case */
rflags = hash_huge_page_do_lazy_icache(rflags, __pte(old_pte),
trap);
/* Check if pte already has an hpte (case 2) */
if (unlikely(old_pte & _PAGE_HASHPTE)) {
/* There MIGHT be an HPTE for this pte */
unsigned long hash, slot;
hash = hpt_hash(va, HPAGE_SHIFT);
if (old_pte & _PAGE_F_SECOND)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += (old_pte & _PAGE_F_GIX) >> 12;
if (ppc_md.hpte_updatepp(slot, rflags, va, mmu_huge_psize,
local) == -1)
old_pte &= ~_PAGE_HPTEFLAGS;
}
if (likely(!(old_pte & _PAGE_HASHPTE))) {
unsigned long hash = hpt_hash(va, HPAGE_SHIFT);
unsigned long hpte_group;
pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
repeat:
hpte_group = ((hash & htab_hash_mask) *
HPTES_PER_GROUP) & ~0x7UL;
/* clear HPTE slot informations in new PTE */
new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
/* Add in WIMG bits */
/* XXX We should store these in the pte */
/* --BenH: I think they are ... */
rflags |= _PAGE_COHERENT;
/* Insert into the hash table, primary slot */
slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
mmu_huge_psize);
/* Primary is full, try the secondary */
if (unlikely(slot == -1)) {
hpte_group = ((~hash & htab_hash_mask) *
HPTES_PER_GROUP) & ~0x7UL;
slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags,
HPTE_V_SECONDARY,
mmu_huge_psize);
if (slot == -1) {
if (mftb() & 0x1)
hpte_group = ((hash & htab_hash_mask) *
HPTES_PER_GROUP)&~0x7UL;
ppc_md.hpte_remove(hpte_group);
goto repeat;
}
}
if (unlikely(slot == -2))
panic("hash_huge_page: pte_insert failed\n");
new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
}
/*
* No need to use ldarx/stdcx here
*/
*ptep = __pte(new_pte & ~_PAGE_BUSY);
err = 0;
out:
return err;
}
static void zero_ctor(void *addr, struct kmem_cache *cache, unsigned long flags)
{
memset(addr, 0, kmem_cache_size(cache));
}
static int __init hugetlbpage_init(void)
{
if (!cpu_has_feature(CPU_FTR_16M_PAGE))
return -ENODEV;
huge_pgtable_cache = kmem_cache_create("hugepte_cache",
HUGEPTE_TABLE_SIZE,
HUGEPTE_TABLE_SIZE,
SLAB_HWCACHE_ALIGN |
SLAB_MUST_HWCACHE_ALIGN,
zero_ctor, NULL);
if (! huge_pgtable_cache)
panic("hugetlbpage_init(): could not create hugepte cache\n");
return 0;
}
module_init(hugetlbpage_init);
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