linux-kernel - [PATCH V4 08/17] arm64/cpufeature: Add remaining feature bits in ID

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Date:   Tue, 19 May 2020 15:10:45 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     catalin.marinas@....com, will@...nel.org, maz@...nel.org,
        mark.rutland@....com, suzuki.poulose@....com,
        Anshuman Khandual <anshuman.khandual@....com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH V4 08/17] arm64/cpufeature: Add remaining feature bits in ID_MMFR4 register

Enable all remaining feature bits like EVT, CCIDX, LSM, HPDS, CnP, XNX,
SpecSEI in ID_MMFR4 register per ARM DDI 0487F.a.

Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Suzuki K Poulose <suzuki.poulose@....com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org

Suggested-by: Mark Rutland <mark.rutland@....com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
 arch/arm64/include/asm/sysreg.h |  8 ++++++++
 arch/arm64/kernel/cpufeature.c  | 13 +++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 02b1246e7dbf..0a0cbb3add89 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -794,6 +794,14 @@
 #define ID_ISAR6_DP_SHIFT		4
 #define ID_ISAR6_JSCVT_SHIFT		0
 
+#define ID_MMFR4_EVT_SHIFT		28
+#define ID_MMFR4_CCIDX_SHIFT		24
+#define ID_MMFR4_LSM_SHIFT		20
+#define ID_MMFR4_HPDS_SHIFT		16
+#define ID_MMFR4_CNP_SHIFT		12
+#define ID_MMFR4_XNX_SHIFT		8
+#define ID_MMFR4_SPECSEI_SHIFT		0
+
 #define ID_MMFR5_ETS_SHIFT		0
 
 #define ID_PFR0_DIT_SHIFT		24
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index c929aed9fc4b..92186c40b817 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -392,7 +392,20 @@ static const struct arm64_ftr_bits ftr_id_isar5[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_mmfr4[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_EVT_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_CCIDX_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_LSM_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_HPDS_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_CNP_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_XNX_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),	/* ac2 */
+	/*
+	 * SpecSEI = 1 indicates that the PE might generate an SError on an
+	 * external abort on speculative read. It is safe to assume that an
+	 * SError might be generated than it will not be. Hence it has been
+	 * classified as FTR_HIGHER_SAFE.
+	 */
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_HIGHER_SAFE, ID_MMFR4_SPECSEI_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
 
-- 
2.20.1