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arm/tlb: Convert to generic mmu_gather 

Generic mmu_gather provides everything that ARM needs:

 - range tracking
 - RCU table free
 - VM_EXEC tracking
 - VIPT cache flushing

The one notable curiosity is the 'funny' range tracking for classical
ARM in __pte_free_tlb().

No change in behavior intended.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2018-09-04 14:09:30 +02:00 committed by Ingo Molnar
parent 96bc9567cb
commit b78180b97d
1 changed files with 13 additions and 241 deletions
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254
arch/arm/include/asm/tlb.h
View File

@ -33,270 +33,42 @@
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#define MMU_GATHER_BUNDLE 8
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
static inline void __tlb_remove_table(void *_table)
{
free_page_and_swap_cache((struct page *)_table);
}
struct mmu_table_batch {
struct rcu_head rcu;
unsigned int nr;
void *tables[0];
};
#include <asm-generic/tlb.h>
#define MAX_TABLE_BATCH \
((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
extern void tlb_table_flush(struct mmu_gather *tlb);
extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
#define tlb_remove_entry(tlb, entry) tlb_remove_table(tlb, entry)
#else
#define tlb_remove_entry(tlb, entry) tlb_remove_page(tlb, entry)
#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
/*
* 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;
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
struct mmu_table_batch *batch;
unsigned int need_flush;
#ifndef CONFIG_HAVE_RCU_TABLE_FREE
#define tlb_remove_table(tlb, entry) tlb_remove_page(tlb, entry)
#endif
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];
};
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_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 *);
}
}
static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
{
tlb_flush(tlb);
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb_table_flush(tlb);
#endif
}
static inline void tlb_flush_mmu_free(struct mmu_gather *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_flush_mmu(struct mmu_gather *tlb)
{
tlb_flush_mmu_tlbonly(tlb);
tlb_flush_mmu_free(tlb);
}
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->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);
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb->batch = NULL;
#endif
}
static inline void
arch_tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end, bool force)
{
if (force) {
tlb->range_start = start;
tlb->range_end = 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)
{
tlb_add_flush(tlb, addr);
}
#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \
tlb_remove_tlb_entry(tlb, ptep, address)
/*
* In the case of tlb vma handling, we can optimise these away in the
* 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)
{
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;
}
}
static inline void
tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
{
if (!tlb->fullmm)
tlb_flush(tlb);
}
static inline bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
tlb->pages[tlb->nr++] = page;
VM_WARN_ON(tlb->nr > tlb->max);
if (tlb->nr == tlb->max)
return true;
return false;
}
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 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);
}
static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
unsigned long addr)
__pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, unsigned long addr)
{
pgtable_page_dtor(pte);
#ifdef CONFIG_ARM_LPAE
tlb_add_flush(tlb, addr);
#else
#ifndef CONFIG_ARM_LPAE
/*
* With the classic ARM MMU, a pte page has two corresponding pmd
* entries, each covering 1MB.
*/
addr &= PMD_MASK;
tlb_add_flush(tlb, addr + SZ_1M - PAGE_SIZE);
tlb_add_flush(tlb, addr + SZ_1M);
addr = (addr & PMD_MASK) + SZ_1M;
__tlb_adjust_range(tlb, addr - PAGE_SIZE, 2 * PAGE_SIZE);
#endif
tlb_remove_entry(tlb, pte);
}
static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
unsigned long addr)
{
#ifdef CONFIG_ARM_LPAE
tlb_add_flush(tlb, addr);
tlb_remove_entry(tlb, virt_to_page(pmdp));
#endif
tlb_remove_table(tlb, pte);
}
static inline void
tlb_remove_pmd_tlb_entry(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr)
__pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr)
{
tlb_add_flush(tlb, addr);
}
#ifdef CONFIG_ARM_LPAE
struct page *page = virt_to_page(pmdp);
#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_change_page_size(struct mmu_gather *tlb,
unsigned int page_size)
{
}
static inline void tlb_flush_remove_tables(struct mm_struct *mm)
{
}
static inline void tlb_flush_remove_tables_local(void *arg)
{
tlb_remove_table(tlb, page);
#endif
}
#endif /* CONFIG_MMU */