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From: Vladimir Murzin <vladimir.murzin@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: mark.rutland@arm.com
Subject: [bootwrapper PATCH] aarch64: Recognize PAuth QARMA3
Date: Fri, 28 Jan 2022 16:02:14 +0000	[thread overview]
Message-ID: <20220128160214.92297-1-vladimir.murzin@arm.com> (raw)

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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             reply	other threads:[~2022-01-28 16:09 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-28 16:02 Vladimir Murzin [this message]
2022-02-01 12:19 ` [bootwrapper PATCH] aarch64: Recognize PAuth QARMA3 Mark Rutland

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