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linux-next/arch/xtensa/mm/tlb.c
Max Filippov 04c6b3e2b5 xtensa: optimize local_flush_tlb_kernel_range
Don't flush whole TLB if only a small kernel range is requested.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2014-04-06 21:29:17 +04:00

279 lines
6.6 KiB
C

/*
* arch/xtensa/mm/tlb.c
*
* Logic that manipulates the Xtensa MMU. Derived from MIPS.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2003 Tensilica Inc.
*
* Joe Taylor
* Chris Zankel <chris@zankel.net>
* Marc Gauthier
*/
#include <linux/mm.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
static inline void __flush_itlb_all (void)
{
int w, i;
for (w = 0; w < ITLB_ARF_WAYS; w++) {
for (i = 0; i < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); i++) {
int e = w + (i << PAGE_SHIFT);
invalidate_itlb_entry_no_isync(e);
}
}
asm volatile ("isync\n");
}
static inline void __flush_dtlb_all (void)
{
int w, i;
for (w = 0; w < DTLB_ARF_WAYS; w++) {
for (i = 0; i < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); i++) {
int e = w + (i << PAGE_SHIFT);
invalidate_dtlb_entry_no_isync(e);
}
}
asm volatile ("isync\n");
}
void local_flush_tlb_all(void)
{
__flush_itlb_all();
__flush_dtlb_all();
}
/* If mm is current, we simply assign the current task a new ASID, thus,
* invalidating all previous tlb entries. If mm is someone else's user mapping,
* wie invalidate the context, thus, when that user mapping is swapped in,
* a new context will be assigned to it.
*/
void local_flush_tlb_mm(struct mm_struct *mm)
{
int cpu = smp_processor_id();
if (mm == current->active_mm) {
unsigned long flags;
local_irq_save(flags);
mm->context.asid[cpu] = NO_CONTEXT;
activate_context(mm, cpu);
local_irq_restore(flags);
} else {
mm->context.asid[cpu] = NO_CONTEXT;
mm->context.cpu = -1;
}
}
#define _ITLB_ENTRIES (ITLB_ARF_WAYS << XCHAL_ITLB_ARF_ENTRIES_LOG2)
#define _DTLB_ENTRIES (DTLB_ARF_WAYS << XCHAL_DTLB_ARF_ENTRIES_LOG2)
#if _ITLB_ENTRIES > _DTLB_ENTRIES
# define _TLB_ENTRIES _ITLB_ENTRIES
#else
# define _TLB_ENTRIES _DTLB_ENTRIES
#endif
void local_flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
int cpu = smp_processor_id();
struct mm_struct *mm = vma->vm_mm;
unsigned long flags;
if (mm->context.asid[cpu] == NO_CONTEXT)
return;
#if 0
printk("[tlbrange<%02lx,%08lx,%08lx>]\n",
(unsigned long)mm->context.asid[cpu], start, end);
#endif
local_irq_save(flags);
if (end-start + (PAGE_SIZE-1) <= _TLB_ENTRIES << PAGE_SHIFT) {
int oldpid = get_rasid_register();
set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
start &= PAGE_MASK;
if (vma->vm_flags & VM_EXEC)
while(start < end) {
invalidate_itlb_mapping(start);
invalidate_dtlb_mapping(start);
start += PAGE_SIZE;
}
else
while(start < end) {
invalidate_dtlb_mapping(start);
start += PAGE_SIZE;
}
set_rasid_register(oldpid);
} else {
local_flush_tlb_mm(mm);
}
local_irq_restore(flags);
}
void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
int cpu = smp_processor_id();
struct mm_struct* mm = vma->vm_mm;
unsigned long flags;
int oldpid;
if (mm->context.asid[cpu] == NO_CONTEXT)
return;
local_irq_save(flags);
oldpid = get_rasid_register();
set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
if (vma->vm_flags & VM_EXEC)
invalidate_itlb_mapping(page);
invalidate_dtlb_mapping(page);
set_rasid_register(oldpid);
local_irq_restore(flags);
}
void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
if (end > start && start >= TASK_SIZE && end <= PAGE_OFFSET &&
end - start < _TLB_ENTRIES << PAGE_SHIFT) {
start &= PAGE_MASK;
while (start < end) {
invalidate_itlb_mapping(start);
invalidate_dtlb_mapping(start);
start += PAGE_SIZE;
}
} else {
local_flush_tlb_all();
}
}
#ifdef CONFIG_DEBUG_TLB_SANITY
static unsigned get_pte_for_vaddr(unsigned vaddr)
{
struct task_struct *task = get_current();
struct mm_struct *mm = task->mm;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
if (!mm)
mm = task->active_mm;
pgd = pgd_offset(mm, vaddr);
if (pgd_none_or_clear_bad(pgd))
return 0;
pmd = pmd_offset(pgd, vaddr);
if (pmd_none_or_clear_bad(pmd))
return 0;
pte = pte_offset_map(pmd, vaddr);
if (!pte)
return 0;
return pte_val(*pte);
}
enum {
TLB_SUSPICIOUS = 1,
TLB_INSANE = 2,
};
static void tlb_insane(void)
{
BUG_ON(1);
}
static void tlb_suspicious(void)
{
WARN_ON(1);
}
/*
* Check that TLB entries with kernel ASID (1) have kernel VMA (>= TASK_SIZE),
* and TLB entries with user ASID (>=4) have VMA < TASK_SIZE.
*
* Check that valid TLB entries either have the same PA as the PTE, or PTE is
* marked as non-present. Non-present PTE and the page with non-zero refcount
* and zero mapcount is normal for batched TLB flush operation. Zero refcount
* means that the page was freed prematurely. Non-zero mapcount is unusual,
* but does not necessary means an error, thus marked as suspicious.
*/
static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
{
unsigned tlbidx = w | (e << PAGE_SHIFT);
unsigned r0 = dtlb ?
read_dtlb_virtual(tlbidx) : read_itlb_virtual(tlbidx);
unsigned vpn = (r0 & PAGE_MASK) | (e << PAGE_SHIFT);
unsigned pte = get_pte_for_vaddr(vpn);
unsigned mm_asid = (get_rasid_register() >> 8) & ASID_MASK;
unsigned tlb_asid = r0 & ASID_MASK;
bool kernel = tlb_asid == 1;
int rc = 0;
if (tlb_asid > 0 && ((vpn < TASK_SIZE) == kernel)) {
pr_err("%cTLB: way: %u, entry: %u, VPN %08x in %s PTE\n",
dtlb ? 'D' : 'I', w, e, vpn,
kernel ? "kernel" : "user");
rc |= TLB_INSANE;
}
if (tlb_asid == mm_asid) {
unsigned r1 = dtlb ? read_dtlb_translation(tlbidx) :
read_itlb_translation(tlbidx);
if ((pte ^ r1) & PAGE_MASK) {
pr_err("%cTLB: way: %u, entry: %u, mapping: %08x->%08x, PTE: %08x\n",
dtlb ? 'D' : 'I', w, e, r0, r1, pte);
if (pte == 0 || !pte_present(__pte(pte))) {
struct page *p = pfn_to_page(r1 >> PAGE_SHIFT);
pr_err("page refcount: %d, mapcount: %d\n",
page_count(p),
page_mapcount(p));
if (!page_count(p))
rc |= TLB_INSANE;
else if (page_mapped(p))
rc |= TLB_SUSPICIOUS;
} else {
rc |= TLB_INSANE;
}
}
}
return rc;
}
void check_tlb_sanity(void)
{
unsigned long flags;
unsigned w, e;
int bug = 0;
local_irq_save(flags);
for (w = 0; w < DTLB_ARF_WAYS; ++w)
for (e = 0; e < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); ++e)
bug |= check_tlb_entry(w, e, true);
for (w = 0; w < ITLB_ARF_WAYS; ++w)
for (e = 0; e < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); ++e)
bug |= check_tlb_entry(w, e, false);
if (bug & TLB_INSANE)
tlb_insane();
if (bug & TLB_SUSPICIOUS)
tlb_suspicious();
local_irq_restore(flags);
}
#endif /* CONFIG_DEBUG_TLB_SANITY */