4.20-stable review patch. If anyone has any objections, please let me know.
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[ 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 Signed-off-by: Kristina Martsenko kristina.martsenko@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 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 7b914c6fb855..bc2327d4a505 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -24,6 +24,8 @@
/* Hyp Configuration Register (HCR) bits */ #define HCR_FWB (UL(1) << 46) +#define HCR_API (UL(1) << 41) +#define HCR_APK (UL(1) << 40) #define HCR_TEA (UL(1) << 37) #define HCR_TERR (UL(1) << 36) #define HCR_TLOR (UL(1) << 35) @@ -87,7 +89,7 @@ HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \ HCR_FMO | HCR_IMO) #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF) -#define HCR_HOST_NVHE_FLAGS (HCR_RW) +#define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK) #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
/* TCR_EL2 Registers bits */