Commit d4539074 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

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



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

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200429065654.1677541-7-npiggin@gmail.com
parent 579940bb

arch/powerpc/include/asm/book3s/64/kup-radix.h

+7 −3
Original line number Diff line number Diff line
@@ -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

arch/powerpc/kernel/entry_64.S

+4 −4
Original line number Diff line number Diff line
@@ -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

arch/powerpc/kernel/exceptions-64s.S

+2 −2
Original line number Diff line number Diff line
@@ -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