armv8: Disable pointer authentication traps for EL1
The use of ARMv8.3 pointer authentication (PAuth) is governed by fields
in HCR_EL2, which trigger a 'trap to EL2' if not enabled. The reset
value of these fields is 'architecturally unknown' so we must ensure
that the fields are enabled (to disable the traps) if we are entering
the kernel at EL1.
The APK field disables PAuth instruction traps and the API field
disables PAuth register traps
Add code to disable the traps in armv8_switch_to_el1_m. Prior to doing
so, it checks fields in the ID_AA64ISAR1_EL1 register to ensure pointer
authentication is supported by the hardware.
The runtime checks require a second temporary register, so add this to
the EL1 transition macro signature and update 2 call sites.
Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 8b3a54e..77aa189 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -75,11 +75,26 @@
/*
* HCR_EL2 bits definitions
*/
+#define HCR_EL2_API (1 << 41) /* Trap pointer authentication
+ instructions */
+#define HCR_EL2_APK (1 << 40) /* Trap pointer authentication
+ key access */
#define HCR_EL2_RW_AARCH64 (1 << 31) /* EL1 is AArch64 */
#define HCR_EL2_RW_AARCH32 (0 << 31) /* Lower levels are AArch32 */
#define HCR_EL2_HCD_DIS (1 << 29) /* Hypervisor Call disabled */
/*
+ * ID_AA64ISAR1_EL1 bits definitions
+ */
+#define ID_AA64ISAR1_EL1_GPI (0xF << 28) /* Implementation-defined generic
+ code auth algorithm */
+#define ID_AA64ISAR1_EL1_GPA (0xF << 24) /* QARMA generic code auth
+ algorithm */
+#define ID_AA64ISAR1_EL1_API (0xF << 8) /* Implementation-defined address
+ auth algorithm */
+#define ID_AA64ISAR1_EL1_APA (0xF << 4) /* QARMA address auth algorithm */
+
+/*
* ID_AA64PFR0_EL1 bits definitions
*/
#define ID_AA64PFR0_EL1_EL3 (0xF << 12) /* EL3 implemented */