1 files changed, 89 insertions, 13 deletions

diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h
index f41a6f57cd12..e7690887b958 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)