arm64: Convert asm/tlb.h to generic mmu_gather

Over the past couple of years, the generic mmu_gather gained range
tracking - 597e1c3580b7 (mm/mmu_gather: enable tlb flush range in generic
mmu_gather), 2b047252d087 (Fix TLB gather virtual address range
invalidation corner cases) - and tlb_fast_mode() has been removed -
29eb77825cc7 (arch, mm: Remove tlb_fast_mode()).

The new mmu_gather structure is now suitable for arm64 and this patch
converts the arch asm/tlb.h to the generic code. One functional
difference is the shift_arg_pages() case where previously the code was
flushing the full mm (no tlb_start_vma call) but now it flushes the
range given to tlb_gather_mmu() (possibly slightly more efficient
previously).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>

diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
index 717031a..72cadf5 100644 (file)
--- a/arch/arm64/include/asm/tlb.h
+++ b/arch/arm64/include/asm/tlb.h
@@ -19,115 +19,44 @@
 #ifndef __ASM_TLB_H
 #define __ASM_TLB_H
 
-#include <linux/pagemap.h>
-#include <linux/swap.h>
 
-#include <asm/pgalloc.h>
-#include <asm/tlbflush.h>
-
-#define MMU_GATHER_BUNDLE      8
-
-/*
- * TLB handling.  This allows us to remove pages from the page
- * tables, and efficiently handle the TLB issues.
- */
-struct mmu_gather {
-       struct mm_struct        *mm;
-       unsigned int            fullmm;
-       struct vm_area_struct   *vma;
-       unsigned long           start, end;
-       unsigned long           range_start;
-       unsigned long           range_end;
-       unsigned int            nr;
-       unsigned int            max;
-       struct page             **pages;
-       struct page             *local[MMU_GATHER_BUNDLE];
-};
+#include <asm-generic/tlb.h>
 
 /*
- * This is unnecessarily complex.  There's three ways the TLB shootdown
- * code is used:
+ * 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.
+ *     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)
+       if (tlb->fullmm) {
                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;
+       } else if (tlb->end > 0) {
+               struct vm_area_struct vma = { .vm_mm = tlb->mm, };
+               flush_tlb_range(&vma, tlb->start, tlb->end);
+               tlb->start = TASK_SIZE;
+               tlb->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_alloc_page(struct mmu_gather *tlb)
-{
-       unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
-
-       if (addr) {
-               tlb->pages = (void *)addr;
-               tlb->max = PAGE_SIZE / sizeof(struct page *);
+               tlb->start = min(tlb->start, addr);
+               tlb->end = max(tlb->end, addr + PAGE_SIZE);
        }
 }
 
-static inline void tlb_flush_mmu(struct mmu_gather *tlb)
-{
-       tlb_flush(tlb);
-       free_pages_and_swap_cache(tlb->pages, tlb->nr);
-       tlb->nr = 0;
-       if (tlb->pages == tlb->local)
-               __tlb_alloc_page(tlb);
-}
-
-static inline void
-tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
-{
-       tlb->mm = mm;
-       tlb->fullmm = !(start | (end+1));
-       tlb->start = start;
-       tlb->end = end;
-       tlb->vma = NULL;
-       tlb->max = ARRAY_SIZE(tlb->local);
-       tlb->pages = tlb->local;
-       tlb->nr = 0;
-       __tlb_alloc_page(tlb);
-}
-
-static inline void
-tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
-{
-       tlb_flush_mmu(tlb);
-
-       /* keep the page table cache within bounds */
-       check_pgt_cache();
-
-       if (tlb->pages != tlb->local)
-               free_pages((unsigned long)tlb->pages, 0);
-}
-
 /*
  * Memorize the range for the TLB flush.
  */
-static inline void
-tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr)
+static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
+                                         unsigned long addr)
 {
        tlb_add_flush(tlb, addr);
 }
@@ -137,38 +66,24 @@ tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr)
  * case where we're doing a full MM flush.  When we're doing a munmap,
  * the vmas are adjusted to only cover the region to be torn down.
  */
-static inline void
-tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
+static inline void tlb_start_vma(struct mmu_gather *tlb,
+                                struct vm_area_struct *vma)
 {
        if (!tlb->fullmm) {
-               tlb->vma = vma;
-               tlb->range_start = TASK_SIZE;
-               tlb->range_end = 0;
+               tlb->start = TASK_SIZE;
+               tlb->end = 0;
        }
 }
 
-static inline void
-tlb_end_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_flush(tlb);
 }
 
-static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
-       tlb->pages[tlb->nr++] = page;
-       VM_BUG_ON(tlb->nr > tlb->max);
-       return tlb->max - tlb->nr;
-}
-
-static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
-       if (!__tlb_remove_page(tlb, page))
-               tlb_flush_mmu(tlb);
-}
-
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
-       unsigned long addr)
+                                 unsigned long addr)
 {
        pgtable_page_dtor(pte);
        tlb_add_flush(tlb, addr);
@@ -184,16 +99,5 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
 }
 #endif
 
-#define pte_free_tlb(tlb, ptep, addr)  __pte_free_tlb(tlb, ptep, addr)
-#define pmd_free_tlb(tlb, pmdp, addr)  __pmd_free_tlb(tlb, pmdp, addr)
-#define pud_free_tlb(tlb, pudp, addr)  pud_free((tlb)->mm, pudp)
-
-#define tlb_migrate_finish(mm)         do { } while (0)
-
-static inline void
-tlb_remove_pmd_tlb_entry(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr)
-{
-       tlb_add_flush(tlb, addr);
-}
 
 #endif