linux-kernel - [PATCH 3/3] arm64: v8.3: Support for weaker release consistency

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Message-Id: <1489515207-9233-4-git-send-email-suzuki.poulose@arm.com>
Date:   Tue, 14 Mar 2017 18:13:27 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, will.deacon@....com,
        catalin.marinas@....com, mark.rutland@....com,
        Suzuki K Poulose <suzuki.poulose@....com>
Subject: [PATCH 3/3] arm64: v8.3: Support for weaker release consistency

ARMv8.3 adds new instructions to support Release Consistent
processor consistent (RCpc) model, which is weaker than the
RCsc model.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
---
 Documentation/arm64/cpu-feature-registers.txt | 2 ++
 arch/arm64/include/asm/sysreg.h               | 1 +
 arch/arm64/include/uapi/asm/hwcap.h           | 1 +
 arch/arm64/kernel/cpufeature.c                | 2 ++
 arch/arm64/kernel/cpuinfo.c                   | 1 +
 5 files changed, 7 insertions(+)

diff --git a/Documentation/arm64/cpu-feature-registers.txt b/Documentation/arm64/cpu-feature-registers.txt
index 0ce0a40..d1c97f9 100644
--- a/Documentation/arm64/cpu-feature-registers.txt
+++ b/Documentation/arm64/cpu-feature-registers.txt
@@ -174,6 +174,8 @@ infrastructure:
      x--------------------------------------------------x
      | Name                         |  bits   | visible |
      |--------------------------------------------------|
+     | LRCPC                        | [23-20] |    y    |
+     |--------------------------------------------------|
      | FCMA                         | [19-16] |    y    |
      |--------------------------------------------------|
      | JSCVT                        | [15-12] |    y    |
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 69af995..c776bde 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -157,6 +157,7 @@
 #define ID_AA64ISAR0_AES_SHIFT		4
 
 /* id_aa64isar1 */
+#define ID_AA64ISAR1_LRCPC_SHIFT	20
 #define ID_AA64ISAR1_FCMA_SHIFT		16
 #define ID_AA64ISAR1_JSCVT_SHIFT	12
 
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 85841a4..4e187ce 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -34,5 +34,6 @@
 #define HWCAP_ASIMDRDM		(1 << 12)
 #define HWCAP_JSCVT		(1 << 13)
 #define HWCAP_FCMA		(1 << 14)
+#define HWCAP_LRCPC		(1 << 15)
 
 #endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index a5ff8ae..b05de6b 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -98,6 +98,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar0[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64isar1[] = {
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_FCMA_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0),
 	ARM64_FTR_END,
@@ -896,6 +897,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, HWCAP_ASIMDHP),
 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_JSCVT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_JSCVT),
 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FCMA_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_FCMA),
+	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_LRCPC),
 	{},
 };
 
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index e6afed8..e8de218 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -67,6 +67,7 @@ static const char *const hwcap_str[] = {
 	"asimdrdm",
 	"jscvt",
 	"fcma",
+	"lrcpc",
 	NULL
 };
 
-- 
2.7.4