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-rw-r--r--arch/arm/include/asm/tlb.h102
1 files changed, 89 insertions, 13 deletions
diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h
index f41a6f57cd1..e7690887b95 100644
--- a/arch/arm/include/asm/tlb.h
+++ b/arch/arm/include/asm/tlb.h
@@ -18,7 +18,6 @@
#define __ASMARM_TLB_H
#include <asm/cacheflush.h>
-#include <asm/tlbflush.h>
#ifndef CONFIG_MMU
@@ -27,7 +26,23 @@
#else /* !CONFIG_MMU */
+#include <linux/swap.h>
#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+
+/*
+ * We need to delay page freeing for SMP as other CPUs can access pages
+ * which have been removed but not yet had their TLB entries invalidated.
+ * Also, as ARMv7 speculative prefetch can drag new entries into the TLB,
+ * we need to apply this same delaying tactic to ensure correct operation.
+ */
+#if defined(CONFIG_SMP) || defined(CONFIG_CPU_32v7)
+#define tlb_fast_mode(tlb) 0
+#define FREE_PTE_NR 500
+#else
+#define tlb_fast_mode(tlb) 1
+#define FREE_PTE_NR 0
+#endif
/*
* TLB handling. This allows us to remove pages from the page
@@ -36,12 +51,58 @@
struct mmu_gather {
struct mm_struct *mm;
unsigned int fullmm;
+ struct vm_area_struct *vma;
unsigned long range_start;
unsigned long range_end;
+ unsigned int nr;
+ struct page *pages[FREE_PTE_NR];
};
DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
+/*
+ * This is unnecessarily complex. There's three ways the TLB shootdown
+ * code is used:
+ * 1. Unmapping a range of vmas. See zap_page_range(), unmap_region().
+ * tlb->fullmm = 0, and tlb_start_vma/tlb_end_vma will be called.
+ * tlb->vma will be non-NULL.
+ * 2. Unmapping all vmas. See exit_mmap().
+ * tlb->fullmm = 1, and tlb_start_vma/tlb_end_vma will be called.
+ * tlb->vma will be non-NULL. Additionally, page tables will be freed.
+ * 3. Unmapping argument pages. See shift_arg_pages().
+ * tlb->fullmm = 0, but tlb_start_vma/tlb_end_vma will not be called.
+ * tlb->vma will be NULL.
+ */
+static inline void tlb_flush(struct mmu_gather *tlb)
+{
+ if (tlb->fullmm || !tlb->vma)
+ flush_tlb_mm(tlb->mm);
+ else if (tlb->range_end > 0) {
+ flush_tlb_range(tlb->vma, tlb->range_start, tlb->range_end);
+ tlb->range_start = TASK_SIZE;
+ tlb->range_end = 0;
+ }
+}
+
+static inline void tlb_add_flush(struct mmu_gather *tlb, unsigned long addr)
+{
+ if (!tlb->fullmm) {
+ if (addr < tlb->range_start)
+ tlb->range_start = addr;
+ if (addr + PAGE_SIZE > tlb->range_end)
+ tlb->range_end = addr + PAGE_SIZE;
+ }
+}
+
+static inline void tlb_flush_mmu(struct mmu_gather *tlb)
+{
+ tlb_flush(tlb);
+ if (!tlb_fast_mode(tlb)) {
+ free_pages_and_swap_cache(tlb->pages, tlb->nr);
+ tlb->nr = 0;
+ }
+}
+
static inline struct mmu_gather *
tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
{
@@ -49,6 +110,8 @@ tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
tlb->mm = mm;
tlb->fullmm = full_mm_flush;
+ tlb->vma = NULL;
+ tlb->nr = 0;
return tlb;
}
@@ -56,8 +119,7 @@ tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
static inline void
tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
- if (tlb->fullmm)
- flush_tlb_mm(tlb->mm);
+ tlb_flush_mmu(tlb);
/* keep the page table cache within bounds */
check_pgt_cache();
@@ -71,12 +133,7 @@ tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
static inline void
tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr)
{
- if (!tlb->fullmm) {
- if (addr < tlb->range_start)
- tlb->range_start = addr;
- if (addr + PAGE_SIZE > tlb->range_end)
- tlb->range_end = addr + PAGE_SIZE;
- }
+ tlb_add_flush(tlb, addr);
}
/*
@@ -89,6 +146,7 @@ tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
{
if (!tlb->fullmm) {
flush_cache_range(vma, vma->vm_start, vma->vm_end);
+ tlb->vma = vma;
tlb->range_start = TASK_SIZE;
tlb->range_end = 0;
}
@@ -97,12 +155,30 @@ tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
static inline void
tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
{
- if (!tlb->fullmm && tlb->range_end > 0)
- flush_tlb_range(vma, tlb->range_start, tlb->range_end);
+ if (!tlb->fullmm)
+ tlb_flush(tlb);
+}
+
+static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+ if (tlb_fast_mode(tlb)) {
+ free_page_and_swap_cache(page);
+ } else {
+ tlb->pages[tlb->nr++] = page;
+ if (tlb->nr >= FREE_PTE_NR)
+ tlb_flush_mmu(tlb);
+ }
+}
+
+static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
+ unsigned long addr)
+{
+ pgtable_page_dtor(pte);
+ tlb_add_flush(tlb, addr);
+ tlb_remove_page(tlb, pte);
}
-#define tlb_remove_page(tlb,page) free_page_and_swap_cache(page)
-#define pte_free_tlb(tlb, ptep, addr) pte_free((tlb)->mm, ptep)
+#define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)
#define pmd_free_tlb(tlb, pmdp, addr) pmd_free((tlb)->mm, pmdp)
#define tlb_migrate_finish(mm) do { } while (0)