From: Peter Zijlstra <[email protected]>
commit 0758cd8304942292e95a0f750c374533db378b32 upstream.
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/[email protected]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Reported-by: "Aneesh Kumar K.V" <[email protected]>
Cc: <[email protected]> # 4.19
Signed-off-by: Santosh Sivaraj <[email protected]>
[santosh: backported to 4.19 stable]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/asm-generic/tlb.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -179,7 +179,12 @@ static inline void __tlb_reset_range(str
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);
