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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Joey Gouly <joey.gouly@arm.com>,
	kernel-team@android.com
Subject: [PATCH v2 08/10] arm64: Add HWCAP advertising FEAT_WFXT
Date: Tue, 19 Apr 2022 19:27:53 +0100	[thread overview]
Message-ID: <20220419182755.601427-9-maz@kernel.org> (raw)
In-Reply-To: <20220419182755.601427-1-maz@kernel.org>

In order to allow userspace to enjoy WFET, add a new HWCAP that
advertises it when available.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 Documentation/arm64/cpu-feature-registers.rst | 2 ++
 Documentation/arm64/elf_hwcaps.rst            | 4 ++++
 arch/arm64/include/asm/hwcap.h                | 1 +
 arch/arm64/include/uapi/asm/hwcap.h           | 1 +
 arch/arm64/kernel/cpufeature.c                | 3 ++-
 arch/arm64/kernel/cpuinfo.c                   | 1 +
 6 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst
index 749ae970c319..04ba83e1965f 100644
--- a/Documentation/arm64/cpu-feature-registers.rst
+++ b/Documentation/arm64/cpu-feature-registers.rst
@@ -290,6 +290,8 @@ infrastructure:
      +------------------------------+---------+---------+
      | RPRES                        | [7-4]   |    y    |
      +------------------------------+---------+---------+
+     | WFXT                         | [3-0]   |    y    |
+     +------------------------------+---------+---------+
 
 
 Appendix I: Example
diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst
index a8f30963e550..af3ab524e826 100644
--- a/Documentation/arm64/elf_hwcaps.rst
+++ b/Documentation/arm64/elf_hwcaps.rst
@@ -264,6 +264,10 @@ HWCAP2_MTE3
     Functionality implied by ID_AA64PFR1_EL1.MTE == 0b0011, as described
     by Documentation/arm64/memory-tagging-extension.rst.
 
+HWCAP2_WFXT
+
+    Functionality implied by ID_AA64ISAR2_EL1.WFXT == 0b0010.
+
 4. Unused AT_HWCAP bits
 -----------------------
 
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 8db5ec0089db..909337b50e1f 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -109,6 +109,7 @@
 #define KERNEL_HWCAP_AFP		__khwcap2_feature(AFP)
 #define KERNEL_HWCAP_RPRES		__khwcap2_feature(RPRES)
 #define KERNEL_HWCAP_MTE3		__khwcap2_feature(MTE3)
+#define KERNEL_HWCAP_WFXT		__khwcap2_feature(WFXT)
 
 /*
  * This yields a mask that user programs can use to figure out what
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 99cb5d383048..9dddde1d046c 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -79,5 +79,6 @@
 #define HWCAP2_AFP		(1 << 20)
 #define HWCAP2_RPRES		(1 << 21)
 #define HWCAP2_MTE3		(1 << 22)
+#define HWCAP2_WFXT		(1 << 23)
 
 #endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index db6d9ab685e5..945190ebadd5 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -237,7 +237,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
 		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_GPA3_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_RPRES_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_WFXT_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_WFXT_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
 
@@ -2587,6 +2587,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 	HWCAP_CAP(SYS_ID_AA64MMFR0_EL1, ID_AA64MMFR0_ECV_SHIFT, 4, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ECV),
 	HWCAP_CAP(SYS_ID_AA64MMFR1_EL1, ID_AA64MMFR1_AFP_SHIFT, 4, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_AFP),
 	HWCAP_CAP(SYS_ID_AA64ISAR2_EL1, ID_AA64ISAR2_RPRES_SHIFT, 4, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_RPRES),
+	HWCAP_CAP(SYS_ID_AA64ISAR2_EL1, ID_AA64ISAR2_WFXT_SHIFT, 4, FTR_UNSIGNED, ID_AA64ISAR2_WFXT_SUPPORTED, CAP_HWCAP, KERNEL_HWCAP_WFXT),
 	{},
 };
 
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 330b92ea863a..781eab314794 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -98,6 +98,7 @@ static const char *const hwcap_str[] = {
 	[KERNEL_HWCAP_AFP]		= "afp",
 	[KERNEL_HWCAP_RPRES]		= "rpres",
 	[KERNEL_HWCAP_MTE3]		= "mte3",
+	[KERNEL_HWCAP_WFXT]		= "wfxt",
 };
 
 #ifdef CONFIG_COMPAT
-- 
2.34.1


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  parent reply	other threads:[~2022-04-19 18:39 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-19 18:27 [PATCH v2 00/10] arm64: Add initial support for FEAT_WFxT Marc Zyngier
2022-04-19 18:27 ` [PATCH v2 01/10] arm64: Expand ESR_ELx_WFx_ISS_TI to match its ARMv8.7 definition Marc Zyngier
2022-04-20 17:24   ` Catalin Marinas
2022-04-19 18:27 ` [PATCH v2 02/10] arm64: Add RV and RN fields for ESR_ELx_WFx_ISS Marc Zyngier
2022-04-20 17:25   ` Catalin Marinas
2022-04-19 18:27 ` [PATCH v2 03/10] KVM: arm64: Simplify kvm_cpu_has_pending_timer() Marc Zyngier
2022-04-19 18:27 ` [PATCH v2 04/10] KVM: arm64: Introduce kvm_counter_compute_delta() helper Marc Zyngier
2022-04-19 18:27 ` [PATCH v2 05/10] KVM: arm64: Handle blocking WFIT instruction Marc Zyngier
2022-04-19 18:27 ` [PATCH v2 06/10] KVM: arm64: Offer early resume for non-blocking WFxT instructions Marc Zyngier
2022-04-19 18:27 ` [PATCH v2 07/10] KVM: arm64: Expose the WFXT feature to guests Marc Zyngier
2022-04-20 17:46   ` Catalin Marinas
2022-04-19 18:27 ` Marc Zyngier [this message]
2022-04-20 17:27   ` [PATCH v2 08/10] arm64: Add HWCAP advertising FEAT_WFXT Catalin Marinas
2022-04-20 18:39     ` Marc Zyngier
2022-04-19 18:27 ` [PATCH v2 09/10] arm64: Add wfet()/wfit() helpers Marc Zyngier
2022-04-20 17:28   ` Catalin Marinas
2022-04-19 18:27 ` [PATCH v2 10/10] arm64: Use WFxT for __delay() when possible Marc Zyngier
2022-04-20 17:44   ` Catalin Marinas
2022-04-20 18:35     ` Marc Zyngier
2022-04-20 17:24 ` [PATCH v2 00/10] arm64: Add initial support for FEAT_WFxT Catalin Marinas
2022-04-20 18:50   ` Marc Zyngier

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