Similar to the C code change, make the AMR restore conditional on
whether the register has changed.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/include/asm/book3s/64/kup-radix.h | 10 +++++++---
arch/powerpc/kernel/entry_64.S | 8 ++++----
arch/powerpc/kernel/exceptions-64s.S | 4 ++--
3 files changed, 13 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h
b/arch/powerpc/include/asm/book3s/64/kup-radix.h
index ec8970958a26..e82df54f5681 100644
--- a/arch/powerpc/include/asm/book3s/64/kup-radix.h
+++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h
@@ -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
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index b3c9f15089b6..9d49338e0c85 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -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
diff --git a/arch/powerpc/kernel/exceptions-64s.S
b/arch/powerpc/kernel/exceptions-64s.S
index b0ad930cbae5..ef4a90212664 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -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
@@ -2757,7 +2757,7 @@ 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
--
2.23.0
