[PATCH 05/56] KVM: arm64: Simplify PtrAuth alternative patching
From: Marc Zyngier <maz@kernel.org>
Date: 2020-08-05 17:58:57
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
We currently decide to execute the PtrAuth save/restore code based on a set of branches that evaluate as (ARM64_HAS_ADDRESS_AUTH_ARCH || ARM64_HAS_ADDRESS_AUTH_IMP_DEF). This can be easily replaced by a much simpler test as the ARM64_HAS_ADDRESS_AUTH capability is exactly this expression. Suggested-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/include/asm/kvm_ptrauth.h | 30 ++++++++++------------------ 1 file changed, 11 insertions(+), 19 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_ptrauth.h b/arch/arm64/include/asm/kvm_ptrauth.h
index f1830173fa9e..0ddf98c3ba9f 100644
--- a/arch/arm64/include/asm/kvm_ptrauth.h
+++ b/arch/arm64/include/asm/kvm_ptrauth.h@@ -61,44 +61,36 @@ /* * Both ptrauth_switch_to_guest and ptrauth_switch_to_host macros will - * check for the presence of one of the cpufeature flag - * ARM64_HAS_ADDRESS_AUTH_ARCH or ARM64_HAS_ADDRESS_AUTH_IMP_DEF and + * check for the presence ARM64_HAS_ADDRESS_AUTH, which is defined as + * (ARM64_HAS_ADDRESS_AUTH_ARCH || ARM64_HAS_ADDRESS_AUTH_IMP_DEF) and * then proceed ahead with the save/restore of Pointer Authentication - * key registers. + * key registers if enabled for the guest. */ .macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3 -alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH - b 1000f +alternative_if_not ARM64_HAS_ADDRESS_AUTH + b .L__skip_switch\@ alternative_else_nop_endif -alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF - b 1001f -alternative_else_nop_endif -1000: mrs \reg1, hcr_el2 and \reg1, \reg1, #(HCR_API | HCR_APK) - cbz \reg1, 1001f + cbz \reg1, .L__skip_switch\@ add \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1 ptrauth_restore_state \reg1, \reg2, \reg3 -1001: +.L__skip_switch\@: .endm .macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3 -alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH - b 2000f -alternative_else_nop_endif -alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF - b 2001f +alternative_if_not ARM64_HAS_ADDRESS_AUTH + b .L__skip_switch\@ alternative_else_nop_endif -2000: mrs \reg1, hcr_el2 and \reg1, \reg1, #(HCR_API | HCR_APK) - cbz \reg1, 2001f + cbz \reg1, .L__skip_switch\@ add \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1 ptrauth_save_state \reg1, \reg2, \reg3 add \reg1, \h_ctxt, #CPU_APIAKEYLO_EL1 ptrauth_restore_state \reg1, \reg2, \reg3 isb -2001: +.L__skip_switch\@: .endm #else /* !CONFIG_ARM64_PTR_AUTH */
--
2.27.0
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