4.4-stable review patch. If anyone has any objections, please let me know.
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[ Backport of upstream commit b3669b1e1c09890d61109a1a8ece2c5b66804714 ]
To allow EL0 (and/or EL1) to use pointer authentication functionality, we must ensure that pointer authentication instructions and accesses to pointer authentication keys are not trapped to EL2.
This patch ensures that HCR_EL2 is configured appropriately when the kernel is booted at EL2. For non-VHE kernels we set HCR_EL2.{API,APK}, ensuring that EL1 can access keys and permit EL0 use of instructions. For VHE kernels host EL0 (TGE && E2H) is unaffected by these settings, and it doesn't matter how we configure HCR_EL2.{API,APK}, so we don't bother setting them.
This does not enable support for KVM guests, since KVM manages HCR_EL2 itself when running VMs.
Reviewed-by: Richard Henderson richard.henderson@linaro.org Signed-off-by: Mark Rutland mark.rutland@arm.com Acked-by: Christoffer Dall christoffer.dall@arm.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: Marc Zyngier marc.zyngier@arm.com Cc: Will Deacon will.deacon@arm.com Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Will Deacon will.deacon@arm.com [kristina: backport to 4.4.y: adjust context] Signed-off-by: Kristina Martsenko kristina.martsenko@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/include/asm/kvm_arm.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 013b7de45ee7..d7e7cf56e8d6 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -23,6 +23,8 @@ #include <asm/types.h>
/* Hyp Configuration Register (HCR) bits */ +#define HCR_API (UL(1) << 41) +#define HCR_APK (UL(1) << 40) #define HCR_ID (UL(1) << 33) #define HCR_CD (UL(1) << 32) #define HCR_RW_SHIFT 31 @@ -81,7 +83,7 @@ HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW) #define HCR_VIRT_EXCP_MASK (HCR_VA | HCR_VI | HCR_VF) #define HCR_INT_OVERRIDE (HCR_FMO | HCR_IMO) -#define HCR_HOST_NVHE_FLAGS (HCR_RW) +#define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK)
/* Hyp System Control Register (SCTLR_EL2) bits */