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powerpc/64s/kuap: Conditionally restore AMR in kuap_restore_amr asm

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Similar to the C code change, make the AMR restore conditional on
whether the register has changed.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200429065654.1677541-7-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2020-04-29 16:56:54 +10:00 committed by Michael Ellerman
parent 579940bb45
commit d4539074b0
3 changed files with 13 additions and 9 deletions
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10
arch/powerpc/include/asm/book3s/64/kup-radix.h
View File

@ -12,13 +12,17 @@
#ifdef __ASSEMBLY__
.macro kuap_restore_amr gpr
.macro kuap_restore_amr gpr1, gpr2
#ifdef CONFIG_PPC_KUAP
BEGIN_MMU_FTR_SECTION_NESTED(67)
ld \gpr, STACK_REGS_KUAP(r1)
mfspr \gpr1, SPRN_AMR
ld \gpr2, STACK_REGS_KUAP(r1)
cmpd \gpr1, \gpr2
beq 998f
isync
mtspr SPRN_AMR, \gpr
mtspr SPRN_AMR, \gpr2
/* No isync required, see kuap_restore_amr() */
998:
END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67)
#endif
.endm

8
arch/powerpc/kernel/entry_64.S
View File

@ -479,11 +479,11 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
fast_interrupt_return:
_ASM_NOKPROBE_SYMBOL(fast_interrupt_return)
kuap_check_amr r3, r4
ld r4,_MSR(r1)
andi. r0,r4,MSR_PR
ld r5,_MSR(r1)
andi. r0,r5,MSR_PR
bne .Lfast_user_interrupt_return
kuap_restore_amr r3
andi. r0,r4,MSR_RI
kuap_restore_amr r3, r4
andi. r0,r5,MSR_RI
li r3,0 /* 0 return value, no EMULATE_STACK_STORE */
bne+ .Lfast_kernel_interrupt_return
addi r3,r1,STACK_FRAME_OVERHEAD

4
arch/powerpc/kernel/exceptions-64s.S
View File

@ -971,7 +971,7 @@ EXC_COMMON_BEGIN(system_reset_common)
ld r10,SOFTE(r1)
stb r10,PACAIRQSOFTMASK(r13)
kuap_restore_amr r10
kuap_restore_amr r9, r10
EXCEPTION_RESTORE_REGS
RFI_TO_USER_OR_KERNEL
@ -2784,7 +2784,7 @@ EXC_COMMON_BEGIN(soft_nmi_common)
ld r10,SOFTE(r1)
stb r10,PACAIRQSOFTMASK(r13)
kuap_restore_amr r10
kuap_restore_amr r9, r10
EXCEPTION_RESTORE_REGS hsrr=0
RFI_TO_KERNEL