[RFC][PATCH 10/11] um/tlb: Convert to generic mmu_gather

From: Peter Zijlstra
Date: Thu Sep 13 2018 - 05:29:38 EST


Generic mmu_gather provides the simple flush_tlb_range() based range
tracking mmu_gather UM needs.

Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/um/include/asm/tlb.h | 156 ----------------------------------------------
1 file changed, 2 insertions(+), 154 deletions(-)

--- a/arch/um/include/asm/tlb.h
+++ b/arch/um/include/asm/tlb.h
@@ -2,160 +2,8 @@
#ifndef __UM_TLB_H
#define __UM_TLB_H

-#include <linux/pagemap.h>
-#include <linux/swap.h>
-#include <asm/percpu.h>
-#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
-
-#define tlb_start_vma(tlb, vma) do { } while (0)
-#define tlb_end_vma(tlb, vma) do { } while (0)
-#define tlb_flush(tlb) flush_tlb_mm((tlb)->mm)
-
-/* struct mmu_gather is an opaque type used by the mm code for passing around
- * any data needed by arch specific code for tlb_remove_page.
- */
-struct mmu_gather {
- struct mm_struct *mm;
- unsigned int need_flush; /* Really unmapped some ptes? */
- unsigned long start;
- unsigned long end;
- unsigned int fullmm; /* non-zero means full mm flush */
-};
-
-static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
- unsigned long address)
-{
- if (tlb->start > address)
- tlb->start = address;
- if (tlb->end < address + PAGE_SIZE)
- tlb->end = address + PAGE_SIZE;
-}
-
-static inline void init_tlb_gather(struct mmu_gather *tlb)
-{
- tlb->need_flush = 0;
-
- tlb->start = TASK_SIZE;
- tlb->end = 0;
-
- if (tlb->fullmm) {
- tlb->start = 0;
- tlb->end = TASK_SIZE;
- }
-}
-
-static inline void
-arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
- unsigned long start, unsigned long end)
-{
- tlb->mm = mm;
- tlb->start = start;
- tlb->end = end;
- tlb->fullmm = !(start | (end+1));
-
- init_tlb_gather(tlb);
-}
-
-extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
- unsigned long end);
-
-static inline void
-tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
-{
- flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end);
-}
-
-static inline void
-tlb_flush_mmu_free(struct mmu_gather *tlb)
-{
- init_tlb_gather(tlb);
-}
-
-static inline void
-tlb_flush_mmu(struct mmu_gather *tlb)
-{
- if (!tlb->need_flush)
- return;
-
- tlb_flush_mmu_tlbonly(tlb);
- tlb_flush_mmu_free(tlb);
-}
-
-/* arch_tlb_finish_mmu
- * Called at the end of the shootdown operation to free up any resources
- * that were required.
- */
-static inline void
-arch_tlb_finish_mmu(struct mmu_gather *tlb,
- unsigned long start, unsigned long end, bool force)
-{
- if (force) {
- tlb->start = start;
- tlb->end = end;
- tlb->need_flush = 1;
- }
- tlb_flush_mmu(tlb);
-
- /* keep the page table cache within bounds */
- check_pgt_cache();
-}
-
-/* tlb_remove_page
- * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)),
- * while handling the additional races in SMP caused by other CPUs
- * caching valid mappings in their TLBs.
- */
-static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- tlb->need_flush = 1;
- free_page_and_swap_cache(page);
- return false; /* avoid calling tlb_flush_mmu */
-}
-
-static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- __tlb_remove_page(tlb, page);
-}
-
-static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
- struct page *page, int page_size)
-{
- return __tlb_remove_page(tlb, page);
-}
-
-static inline void tlb_remove_page_size(struct mmu_gather *tlb,
- struct page *page, int page_size)
-{
- return tlb_remove_page(tlb, page);
-}
-
-/**
- * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
- *
- * Record the fact that pte's were really umapped in ->need_flush, so we can
- * later optimise away the tlb invalidate. This helps when userspace is
- * unmapping already-unmapped pages, which happens quite a lot.
- */
-#define tlb_remove_tlb_entry(tlb, ptep, address) \
- do { \
- tlb->need_flush = 1; \
- __tlb_remove_tlb_entry(tlb, ptep, address); \
- } while (0)
-
-#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \
- tlb_remove_tlb_entry(tlb, ptep, address)
-
-static inline void tlb_change_page_size(struct mmu_gather *tlb, unsigned int page_size)
-{
-}
-
-#define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)
-
-#define pud_free_tlb(tlb, pudp, addr) __pud_free_tlb(tlb, pudp, addr)
-
-#define pmd_free_tlb(tlb, pmdp, addr) __pmd_free_tlb(tlb, pmdp, addr)
-
-#define tlb_migrate_finish(mm) do {} while (0)
+#include <asm-generic/cacheflush.h>
+#include <asm-generic/tlb.h>

#endif