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| author | Max Filippov <jcmvbkbc@gmail.com> | 2014-08-02 22:42:38 +0200 |
|---|---|---|
| committer | Max Filippov <jcmvbkbc@gmail.com> | 2014-08-14 09:59:28 +0200 |
| commit | e9500dd852ca6ede346500010545975bf10244dc (patch) | |
| tree | a7689d7b6db4a29d69479c829004bc9a70423c59 /arch/xtensa | |
| parent | xtensa: add double exception fixup handler for fast_unaligned (diff) | |
| download | linux-e9500dd852ca6ede346500010545975bf10244dc.tar.xz linux-e9500dd852ca6ede346500010545975bf10244dc.zip | |
xtensa: make fast_unaligned store restartable
fast_unaligned may encounter DTLB miss or SEGFAULT during the store
emulation. Don't update epc1 and lcount until after the store emulation
is complete, so that the faulting store instruction could be replayed.
Remove duplicate code handling zero overhead loops and calculate new
epc1 and lcount in one place.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa')
| -rw-r--r-- | arch/xtensa/kernel/align.S | 51 |
1 files changed, 19 insertions, 32 deletions
diff --git a/arch/xtensa/kernel/align.S b/arch/xtensa/kernel/align.S index 904f32f05c09..2c7c13d8e91a 100644 --- a/arch/xtensa/kernel/align.S +++ b/arch/xtensa/kernel/align.S @@ -277,18 +277,6 @@ ENTRY(fast_unaligned) /* Set target register. */ 1: - -#if XCHAL_HAVE_LOOPS - rsr a5, lend # check if we reached LEND - bne a7, a5, 1f - rsr a5, lcount # and LCOUNT != 0 - beqz a5, 1f - addi a5, a5, -1 # decrement LCOUNT and set - rsr a7, lbeg # set PC to LBEGIN - wsr a5, lcount -#endif - -1: wsr a7, epc1 # skip load instruction extui a4, a4, INSN_T, 4 # extract target register movi a5, .Lload_table addx8 a4, a4, a5 @@ -358,17 +346,6 @@ ENTRY(fast_unaligned) /* Get memory address */ 1: -#if XCHAL_HAVE_LOOPS - rsr a4, lend # check if we reached LEND - bne a7, a4, 1f - rsr a4, lcount # and LCOUNT != 0 - beqz a4, 1f - addi a4, a4, -1 # decrement LCOUNT and set - rsr a7, lbeg # set PC to LBEGIN - wsr a4, lcount -#endif - -1: wsr a7, epc1 # skip store instruction movi a4, ~3 and a4, a4, a8 # align memory address @@ -380,25 +357,25 @@ ENTRY(fast_unaligned) #endif __ssa8r a8 - __src_b a7, a5, a6 # lo-mask F..F0..0 (BE) 0..0F..F (LE) + __src_b a8, a5, a6 # lo-mask F..F0..0 (BE) 0..0F..F (LE) __src_b a6, a6, a5 # hi-mask 0..0F..F (BE) F..F0..0 (LE) #ifdef UNALIGNED_USER_EXCEPTION l32e a5, a4, -8 #else l32i a5, a4, 0 # load lower address word #endif - and a5, a5, a7 # mask - __sh a7, a3 # shift value - or a5, a5, a7 # or with original value + and a5, a5, a8 # mask + __sh a8, a3 # shift value + or a5, a5, a8 # or with original value #ifdef UNALIGNED_USER_EXCEPTION s32e a5, a4, -8 - l32e a7, a4, -4 + l32e a8, a4, -4 #else s32i a5, a4, 0 # store - l32i a7, a4, 4 # same for upper address word + l32i a8, a4, 4 # same for upper address word #endif __sl a5, a3 - and a6, a7, a6 + and a6, a8, a6 or a6, a6, a5 #ifdef UNALIGNED_USER_EXCEPTION s32e a6, a4, -4 @@ -406,9 +383,19 @@ ENTRY(fast_unaligned) s32i a6, a4, 4 #endif - /* Done. restore stack and return */ - .Lexit: +#if XCHAL_HAVE_LOOPS + rsr a4, lend # check if we reached LEND + bne a7, a4, 1f + rsr a4, lcount # and LCOUNT != 0 + beqz a4, 1f + addi a4, a4, -1 # decrement LCOUNT and set + rsr a7, lbeg # set PC to LBEGIN + wsr a4, lcount +#endif + +1: wsr a7, epc1 # skip emulated instruction + movi a4, 0 rsr a3, excsave1 s32i a4, a3, EXC_TABLE_FIXUP |