[bootwrapper PATCH] aarch64: Recognize PAuth QARMA3

Vladimir Murzin
2022-01-28T16:09:53Z

QARMA3 is relaxed version of the QARMA5 algorithm which expected to
reduce the latency of calculation while still delivering a suitable
level of security.

Support for QARMA3 can be discovered via ID_AA64ISAR2_EL1 [1]

APA3, bits [15:12] Indicates whether the QARMA3 algorithm is
implemented in the PE for address authentication in
AArch64 state.

GPA3, bits [11:8] Indicates whether the QARMA3 algorithm is
implemented in the PE for generic code
authentication in AArch64 state.

[1] https://developer.arm.com/documentation/ddi0601/2021-12/AArch64-Registers/ID-AA64ISAR2-EL1--AArch64-Instruction-Set-Attribute-Register-2?lang=en

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
arch/aarch64/include/asm/cpu.h | 5 +++++
arch/aarch64/init.c | 14 +++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/arch/aarch64/include/asm/cpu.h b/arch/aarch64/include/asm/cpu.h
index 1be2d54..ce80b6e 100644
--- a/arch/aarch64/include/asm/cpu.h
+++ b/arch/aarch64/include/asm/cpu.h
@@ -63,6 +63,9 @@
#define ID_AA64ISAR1_EL1_GPA BITS(27, 24)
#define ID_AA64ISAR1_EL1_GPI BITS(31, 28)

+#define ID_AA64ISAR2_EL1_GPA3 BITS(11, 8)
+#define ID_AA64ISAR2_EL1_APA3 BITS(15, 12)
+
#define ID_AA64MMFR0_EL1_FGT BITS(59, 56)
#define ID_AA64MMFR0_EL1_ECV BITS(63, 60)

@@ -104,6 +107,8 @@
#define ZCR_EL3 s3_6_c1_c2_0
#define ZCR_EL3_LEN_MAX 0xf

+#define ID_AA64ISAR2_EL1 s3_0_c0_c6_2
+
#define SCTLR_EL1_CP15BEN (1 << 5)

#ifdef KERNEL_32
diff --git a/arch/aarch64/init.c b/arch/aarch64/init.c
index 6677f2b..aa58567 100644
--- a/arch/aarch64/init.c
+++ b/arch/aarch64/init.c
@@ -30,12 +30,16 @@ static inline bool kernel_is_32bit(void)

static inline bool cpu_has_pauth(void)
{
- const unsigned long id_pauth = ID_AA64ISAR1_EL1_APA |
- ID_AA64ISAR1_EL1_API |
- ID_AA64ISAR1_EL1_GPA |
- ID_AA64ISAR1_EL1_GPI;
+ const unsigned long isar1_pauth = ID_AA64ISAR1_EL1_APA |
+ ID_AA64ISAR1_EL1_API |
+ ID_AA64ISAR1_EL1_GPA |
+ ID_AA64ISAR1_EL1_GPI;

- return mrs(ID_AA64ISAR1_EL1) & id_pauth;
+ const unsigned long isar2_pauth = ID_AA64ISAR2_EL1_APA3 |
+ ID_AA64ISAR2_EL1_GPA3;
+
+ return (mrs(ID_AA64ISAR1_EL1) & isar1_pauth) ||
+ (mrs(ID_AA64ISAR2_EL1) & isar2_pauth);
}

void cpu_init_el3(void)
--
2.7.4

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