299 lines
9.1 KiB
C
299 lines
9.1 KiB
C
|
/* include/asm-generic/tlb.h
|
||
|
|
*
|
||
|
|
* Generic TLB shootdown code
|
||
|
|
*
|
||
|
|
* Copyright 2001 Red Hat, Inc.
|
||
|
|
* Based on code from mm/memory.c Copyright Linus Torvalds and others.
|
||
|
|
*
|
||
|
|
* Copyright 2011 Red Hat, Inc., Peter Zijlstra
|
||
|
|
*
|
||
|
|
* This program is free software; you can redistribute it and/or
|
||
|
|
* modify it under the terms of the GNU General Public License
|
||
|
|
* as published by the Free Software Foundation; either version
|
||
|
|
* 2 of the License, or (at your option) any later version.
|
||
|
|
*/
|
||
|
|
#ifndef _ASM_GENERIC__TLB_H
|
||
|
|
#define _ASM_GENERIC__TLB_H
|
||
|
|
|
||
|
|
#include <linux/swap.h>
|
||
|
|
#include <asm/pgalloc.h>
|
||
|
|
#include <asm/tlbflush.h>
|
||
|
|
|
||
|
|
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
|
||
|
|
/*
|
||
|
|
* Semi RCU freeing of the page directories.
|
||
|
|
*
|
||
|
|
* This is needed by some architectures to implement software pagetable walkers.
|
||
|
|
*
|
||
|
|
* gup_fast() and other software pagetable walkers do a lockless page-table
|
||
|
|
* walk and therefore needs some synchronization with the freeing of the page
|
||
|
|
* directories. The chosen means to accomplish that is by disabling IRQs over
|
||
|
|
* the walk.
|
||
|
|
*
|
||
|
|
* Architectures that use IPIs to flush TLBs will then automagically DTRT,
|
||
|
|
* since we unlink the page, flush TLBs, free the page. Since the disabling of
|
||
|
|
* IRQs delays the completion of the TLB flush we can never observe an already
|
||
|
|
* freed page.
|
||
|
|
*
|
||
|
|
* Architectures that do not have this (PPC) need to delay the freeing by some
|
||
|
|
* other means, this is that means.
|
||
|
|
*
|
||
|
|
* What we do is batch the freed directory pages (tables) and RCU free them.
|
||
|
|
* We use the sched RCU variant, as that guarantees that IRQ/preempt disabling
|
||
|
|
* holds off grace periods.
|
||
|
|
*
|
||
|
|
* However, in order to batch these pages we need to allocate storage, this
|
||
|
|
* allocation is deep inside the MM code and can thus easily fail on memory
|
||
|
|
* pressure. To guarantee progress we fall back to single table freeing, see
|
||
|
|
* the implementation of tlb_remove_table_one().
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
struct mmu_table_batch {
|
||
|
|
struct rcu_head rcu;
|
||
|
|
unsigned int nr;
|
||
|
|
void *tables[0];
|
||
|
|
};
|
||
|
|
|
||
|
|
#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);
|
||
|
|
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If we can't allocate a page to make a big batch of page pointers
|
||
|
|
* to work on, then just handle a few from the on-stack structure.
|
||
|
|
*/
|
||
|
|
#define MMU_GATHER_BUNDLE 8
|
||
|
|
|
||
|
|
struct mmu_gather_batch {
|
||
|
|
struct mmu_gather_batch *next;
|
||
|
|
unsigned int nr;
|
||
|
|
unsigned int max;
|
||
|
|
struct page *pages[0];
|
||
|
|
};
|
||
|
|
|
||
|
|
#define MAX_GATHER_BATCH \
|
||
|
|
((PAGE_SIZE - sizeof(struct mmu_gather_batch)) / sizeof(void *))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Limit the maximum number of mmu_gather batches to reduce a risk of soft
|
||
|
|
* lockups for non-preemptible kernels on huge machines when a lot of memory
|
||
|
|
* is zapped during unmapping.
|
||
|
|
* 10K pages freed at once should be safe even without a preemption point.
|
||
|
|
*/
|
||
|
|
#define MAX_GATHER_BATCH_COUNT (10000UL/MAX_GATHER_BATCH)
|
||
|
|
|
||
|
|
/* 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;
|
||
|
|
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
|
||
|
|
struct mmu_table_batch *batch;
|
||
|
|
#endif
|
||
|
|
unsigned long start;
|
||
|
|
unsigned long end;
|
||
|
|
/* we are in the middle of an operation to clear
|
||
|
|
* a full mm and can make some optimizations */
|
||
|
|
unsigned int fullmm : 1,
|
||
|
|
/* we have performed an operation which
|
||
|
|
* requires a complete flush of the tlb */
|
||
|
|
need_flush_all : 1;
|
||
|
|
|
||
|
|
struct mmu_gather_batch *active;
|
||
|
|
struct mmu_gather_batch local;
|
||
|
|
struct page *__pages[MMU_GATHER_BUNDLE];
|
||
|
|
unsigned int batch_count;
|
||
|
|
int page_size;
|
||
|
|
};
|
||
|
|
|
||
|
|
#define HAVE_GENERIC_MMU_GATHER
|
||
|
|
|
||
|
|
void arch_tlb_gather_mmu(struct mmu_gather *tlb,
|
||
|
|
struct mm_struct *mm, unsigned long start, unsigned long end);
|
||
|
|
void tlb_flush_mmu(struct mmu_gather *tlb);
|
||
|
|
void arch_tlb_finish_mmu(struct mmu_gather *tlb,
|
||
|
|
unsigned long start, unsigned long end, bool force);
|
||
|
|
extern bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page,
|
||
|
|
int page_size);
|
||
|
|
|
||
|
|
static inline void __tlb_adjust_range(struct mmu_gather *tlb,
|
||
|
|
unsigned long address,
|
||
|
|
unsigned int range_size)
|
||
|
|
{
|
||
|
|
tlb->start = min(tlb->start, address);
|
||
|
|
tlb->end = max(tlb->end, address + range_size);
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void __tlb_reset_range(struct mmu_gather *tlb)
|
||
|
|
{
|
||
|
|
if (tlb->fullmm) {
|
||
|
|
tlb->start = tlb->end = ~0;
|
||
|
|
} else {
|
||
|
|
tlb->start = TASK_SIZE;
|
||
|
|
tlb->end = 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void tlb_remove_page_size(struct mmu_gather *tlb,
|
||
|
|
struct page *page, int page_size)
|
||
|
|
{
|
||
|
|
if (__tlb_remove_page_size(tlb, page, page_size))
|
||
|
|
tlb_flush_mmu(tlb);
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
|
||
|
|
{
|
||
|
|
return __tlb_remove_page_size(tlb, page, PAGE_SIZE);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* tlb_remove_page
|
||
|
|
* Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
|
||
|
|
* required.
|
||
|
|
*/
|
||
|
|
static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
|
||
|
|
{
|
||
|
|
return tlb_remove_page_size(tlb, page, PAGE_SIZE);
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifndef tlb_remove_check_page_size_change
|
||
|
|
#define tlb_remove_check_page_size_change tlb_remove_check_page_size_change
|
||
|
|
static inline void tlb_remove_check_page_size_change(struct mmu_gather *tlb,
|
||
|
|
unsigned int page_size)
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* We don't care about page size change, just update
|
||
|
|
* mmu_gather page size here so that debug checks
|
||
|
|
* doesn't throw false warning.
|
||
|
|
*/
|
||
|
|
#ifdef CONFIG_DEBUG_VM
|
||
|
|
tlb->page_size = page_size;
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
#ifndef tlb_start_vma
|
||
|
|
#define tlb_start_vma(tlb, vma) do { } while (0)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#define __tlb_end_vma(tlb, vma) \
|
||
|
|
do { \
|
||
|
|
if (!tlb->fullmm && tlb->end) { \
|
||
|
|
tlb_flush(tlb); \
|
||
|
|
__tlb_reset_range(tlb); \
|
||
|
|
} \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
#ifndef tlb_end_vma
|
||
|
|
#define tlb_end_vma __tlb_end_vma
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#ifndef __tlb_remove_tlb_entry
|
||
|
|
#define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/**
|
||
|
|
* tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
|
||
|
|
*
|
||
|
|
* Record the fact that pte's were really unmapped by updating the range,
|
||
|
|
* 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_adjust_range(tlb, address, PAGE_SIZE); \
|
||
|
|
__tlb_remove_tlb_entry(tlb, ptep, address); \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \
|
||
|
|
do { \
|
||
|
|
__tlb_adjust_range(tlb, address, huge_page_size(h)); \
|
||
|
|
__tlb_remove_tlb_entry(tlb, ptep, address); \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* tlb_remove_pmd_tlb_entry - remember a pmd mapping for later tlb invalidation
|
||
|
|
* This is a nop so far, because only x86 needs it.
|
||
|
|
*/
|
||
|
|
#ifndef __tlb_remove_pmd_tlb_entry
|
||
|
|
#define __tlb_remove_pmd_tlb_entry(tlb, pmdp, address) do {} while (0)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#define tlb_remove_pmd_tlb_entry(tlb, pmdp, address) \
|
||
|
|
do { \
|
||
|
|
__tlb_adjust_range(tlb, address, HPAGE_PMD_SIZE); \
|
||
|
|
__tlb_remove_pmd_tlb_entry(tlb, pmdp, address); \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* tlb_remove_pud_tlb_entry - remember a pud mapping for later tlb
|
||
|
|
* invalidation. This is a nop so far, because only x86 needs it.
|
||
|
|
*/
|
||
|
|
#ifndef __tlb_remove_pud_tlb_entry
|
||
|
|
#define __tlb_remove_pud_tlb_entry(tlb, pudp, address) do {} while (0)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#define tlb_remove_pud_tlb_entry(tlb, pudp, address) \
|
||
|
|
do { \
|
||
|
|
__tlb_adjust_range(tlb, address, HPAGE_PUD_SIZE); \
|
||
|
|
__tlb_remove_pud_tlb_entry(tlb, pudp, address); \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* For things like page tables caches (ie caching addresses "inside" the
|
||
|
|
* page tables, like x86 does), for legacy reasons, flushing an
|
||
|
|
* individual page had better flush the page table caches behind it. This
|
||
|
|
* is definitely how x86 works, for example. And if you have an
|
||
|
|
* architected non-legacy page table cache (which I'm not aware of
|
||
|
|
* anybody actually doing), you're going to have some architecturally
|
||
|
|
* explicit flushing for that, likely *separate* from a regular TLB entry
|
||
|
|
* flush, and thus you'd need more than just some range expansion..
|
||
|
|
*
|
||
|
|
* So if we ever find an architecture
|
||
|
|
* that would want something that odd, I think it is up to that
|
||
|
|
* architecture to do its own odd thing, not cause pain for others
|
||
|
|
* http://lkml.kernel.org/r/CA+55aFzBggoXtNXQeng5d_mRoDnaMBE5Y+URs+PHR67nUpMtaw@mail.gmail.com
|
||
|
|
*
|
||
|
|
* For now w.r.t page table cache, mark the range_size as PAGE_SIZE
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define pte_free_tlb(tlb, ptep, address) \
|
||
|
|
do { \
|
||
|
|
__tlb_adjust_range(tlb, address, PAGE_SIZE); \
|
||
|
|
__pte_free_tlb(tlb, ptep, address); \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
#define pmd_free_tlb(tlb, pmdp, address) \
|
||
|
|
do { \
|
||
|
|
__tlb_adjust_range(tlb, address, PAGE_SIZE); \
|
||
|
|
__pmd_free_tlb(tlb, pmdp, address); \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
#ifndef __ARCH_HAS_4LEVEL_HACK
|
||
|
|
#define pud_free_tlb(tlb, pudp, address) \
|
||
|
|
do { \
|
||
|
|
__tlb_adjust_range(tlb, address, PAGE_SIZE); \
|
||
|
|
__pud_free_tlb(tlb, pudp, address); \
|
||
|
|
} while (0)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#ifndef __ARCH_HAS_5LEVEL_HACK
|
||
|
|
#define p4d_free_tlb(tlb, pudp, address) \
|
||
|
|
do { \
|
||
|
|
__tlb_adjust_range(tlb, address, PAGE_SIZE); \
|
||
|
|
__p4d_free_tlb(tlb, pudp, address); \
|
||
|
|
} while (0)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#define tlb_migrate_finish(mm) do {} while (0)
|
||
|
|
|
||
|
|
#endif /* _ASM_GENERIC__TLB_H */
|