[PATCH 6/6] powerpc/64/kuap: conditionally restore AMR in kuap_restore_amr asm
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2020-04-29 06:40:21
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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> --- 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