diff options
| author | Peter Zijlstra | 2020-02-03 17:36:53 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2020-02-04 03:05:26 +0000 |
| commit | 0758cd8304942292e95a0f750c374533db378b32 (patch) | |
| tree | fdfe709ddee4d1781db6a36fbdea1c31a60ebc01 /include/asm-generic | |
| parent | 0ed1325967ab5f7a4549a2641c6ebe115f76e228 (diff) | |
asm-generic/tlb: avoid potential double flush
Aneesh reported that:
tlb_flush_mmu()
tlb_flush_mmu_tlbonly()
tlb_flush() <-- #1
tlb_flush_mmu_free()
tlb_table_flush()
tlb_table_invalidate()
tlb_flush_mmu_tlbonly()
tlb_flush() <-- #2
does two TLBIs when tlb->fullmm, because __tlb_reset_range() will not
clear tlb->end in that case.
Observe that any caller to __tlb_adjust_range() also sets at least one of
the tlb->freed_tables || tlb->cleared_p* bits, and those are
unconditionally cleared by __tlb_reset_range().
Change the condition for actually issuing TLBI to having one of those bits
set, as opposed to having tlb->end != 0.
Link: http://lkml.kernel.org/r/20200116064531.483522-4-aneesh.kumar@linux.ibm.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/tlb.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 9e22ac369d1d..b36b3bef5661 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -402,7 +402,12 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) { - if (!tlb->end) + /* + * Anything calling __tlb_adjust_range() also sets at least one of + * these bits. + */ + if (!(tlb->freed_tables || tlb->cleared_ptes || tlb->cleared_pmds || + tlb->cleared_puds || tlb->cleared_p4ds)) return; tlb_flush(tlb); |