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powerpc/64s: Avoid saving faulting address into EX_DAR in SLB miss

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The EX_DAR save area is only used in exceptional cases. With r3 no
longer clobbered by slb_allocate_realmode, saving faulting address to
EX_DAR can be deferred to those cases.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2017-05-21 23:15:43 +10:00 committed by Michael Ellerman
parent d59afffdf0
commit 7c28f04828
1 changed files with 8 additions and 5 deletions
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13
arch/powerpc/kernel/exceptions-64s.S
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@ -631,7 +631,6 @@ EXC_COMMON_BEGIN(slb_miss_realmode)
stw r9,PACA_EXSLB+EX_CCR(r13) /* save CR in exc. frame */
std r10,PACA_EXSLB+EX_LR(r13) /* save LR */
std r3,PACA_EXSLB+EX_DAR(r13)
crset 4*cr0+eq
#ifdef CONFIG_PPC_STD_MMU_64
@ -641,11 +640,10 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
#endif
ld r10,PACA_EXSLB+EX_LR(r13)
ld r3,PACA_EXSLB+EX_R3(r13)
lwz r9,PACA_EXSLB+EX_CCR(r13) /* get saved CR */
mtlr r10
beq 8f /* if bad address, make full stack frame */
beq- 8f /* if bad address, make full stack frame */
andi. r10,r12,MSR_RI /* check for unrecoverable exception */
beq- 2f
@ -660,6 +658,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
.machine pop
RESTORE_PPR_PACA(PACA_EXSLB, r9)
ld r3,PACA_EXSLB+EX_R3(r13)
ld r9,PACA_EXSLB+EX_R9(r13)
ld r10,PACA_EXSLB+EX_R10(r13)
ld r11,PACA_EXSLB+EX_R11(r13)
@ -668,7 +667,9 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
rfid
b . /* prevent speculative execution */
2: mfspr r11,SPRN_SRR0
2: std r3,PACA_EXSLB+EX_DAR(r13)
ld r3,PACA_EXSLB+EX_R3(r13)
mfspr r11,SPRN_SRR0
LOAD_HANDLER(r10,unrecov_slb)
mtspr SPRN_SRR0,r10
ld r10,PACAKMSR(r13)
@ -676,7 +677,9 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
rfid
b .
8: mfspr r11,SPRN_SRR0
8: std r3,PACA_EXSLB+EX_DAR(r13)
ld r3,PACA_EXSLB+EX_R3(r13)
mfspr r11,SPRN_SRR0
LOAD_HANDLER(r10,bad_addr_slb)
mtspr SPRN_SRR0,r10
ld r10,PACAKMSR(r13)