Messages in this thread Patch in this message |  | | From | Max Filippov <> | Subject | [PATCH] xtensa: don't leave invalid TLB entry in fast_store_prohibited | Date | Sun, 1 May 2022 20:00:29 -0700 |
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When fast_store_prohibited needs to go to the C-level exception handler it leaves TLB entry that caused page fault in the TLB. If the faulting task gets switched to a different CPU and completes page table update there the TLB entry will get out of sync with the page table which may cause a livelock on access to that page. Invalidate faulting TLB entry on a slow path exit from the fast_store_prohibited.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> --- arch/xtensa/kernel/entry.S | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index d703ed31254a..7852481d779c 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1882,7 +1882,11 @@ ENTRY(fast_store_prohibited) j 8b 2: /* If there was a problem, handle fault in C */ - + rsr a1, excvaddr + pdtlb a0, a1 + bbci.l a0, DTLB_HIT_BIT, 1f + idtlb a0 +1: rsr a3, depc # still holds a2 s32i a3, a2, PT_AREG2 mov a1, a2 -- 2.30.2
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