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powerpc/64s/exception: program check handler do not branch into a macro

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It is clever, but the small code saving is not worth the spaghetti of
jumping to a label in an expanded macro, particularly when the label
is just a number rather than a descriptive name.

So expand the INT_COMMON macro twice, once for the stack and no stack
cases, and branch to those. The slight code size increase is worth
the improved clarity of branches for this non-performance critical
code.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-35-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2019-08-02 20:56:59 +10:00 committed by Michael Ellerman
parent c7c5cbb42d
commit 1b3599829a
1 changed files with 8 additions and 7 deletions
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15
arch/powerpc/kernel/exceptions-64s.S
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@ -533,11 +533,10 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
andi. r10,r12,MSR_PR /* See if coming from user */
mr r10,r1 /* Save r1 */
subi r1,r1,INT_FRAME_SIZE /* alloc frame on kernel stack */
beq- 1f
beq- 100f
ld r1,PACAKSAVE(r13) /* kernel stack to use */
1: tdgei r1,-INT_FRAME_SIZE /* trap if r1 is in userspace */
EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0
3:
100: tdgei r1,-INT_FRAME_SIZE /* trap if r1 is in userspace */
EMIT_BUG_ENTRY 100b,__FILE__,__LINE__,0
.endif
std r9,_CCR(r1) /* save CR in stackframe */
@ -551,10 +550,10 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
.if \kaup
kuap_save_amr_and_lock r9, r10, cr1, cr0
.endif
beq 4f /* if from kernel mode */
beq 101f /* if from kernel mode */
ACCOUNT_CPU_USER_ENTRY(r13, r9, r10)
SAVE_PPR(\area, r9)
4:
101:
.else
.if \kaup
kuap_save_amr_and_lock r9, r10, cr1
@ -1325,9 +1324,11 @@ EXC_COMMON_BEGIN(program_check_common)
mr r10,r1 /* Save r1 */
ld r1,PACAEMERGSP(r13) /* Use emergency stack */
subi r1,r1,INT_FRAME_SIZE /* alloc stack frame */
b 3f /* Jump into the macro !! */
INT_COMMON 0x700, PACA_EXGEN, 0, 1, 1, 0, 0
b 3f
2:
INT_COMMON 0x700, PACA_EXGEN, 1, 1, 1, 0, 0
3:
bl save_nvgprs
addi r3,r1,STACK_FRAME_OVERHEAD
bl program_check_exception