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KVM: arm64: Simplify PtrAuth alternative patching

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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>
This commit is contained in:
Marc Zyngier 2020-06-15 21:03:30 +01:00
parent 655169cec7
commit 11ac16a429
1 changed files with 11 additions and 19 deletions
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30
arch/arm64/include/asm/kvm_ptrauth.h
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@ -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_if_not ARM64_HAS_ADDRESS_AUTH
b .L__skip_switch\@
alternative_else_nop_endif
alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
b 2001f
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 */