From: Joey Gouly <joey.gouly@arm.com>
To: <linux-arm-kernel@lists.infradead.org>
Cc: <nd@arm.com>, <alexandru.elisei@arm.com>,
<catalin.marinas@arm.com>, <corbet@lwn.net>,
<james.morse@arm.com>, <joey.gouly@arm.com>, <maz@kernel.org>,
<reijiw@google.com>, <suzuki.poulose@arm.com>, <will@kernel.org>
Subject: [PATCH v3 1/3] arm64: cpufeature: add HWCAP for FEAT_AFP
Date: Fri, 10 Dec 2021 16:54:30 +0000 [thread overview]
Message-ID: <20211210165432.8106-2-joey.gouly@arm.com> (raw)
In-Reply-To: <20211210165432.8106-1-joey.gouly@arm.com>
Add a new HWCAP to detect the Alternate Floating-point Behaviour
feature (FEAT_AFP), introduced in Armv8.7.
Also expose this to userspace in the ID_AA64MMFR1_EL1 feature register.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
---
Documentation/arm64/cpu-feature-registers.rst | 9 +++++++++
Documentation/arm64/elf_hwcaps.rst | 4 ++++
arch/arm64/include/asm/hwcap.h | 1 +
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 +
7 files changed, 19 insertions(+)
diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst
index 9f9b8fd06089..1b19d20c2dbd 100644
--- a/Documentation/arm64/cpu-feature-registers.rst
+++ b/Documentation/arm64/cpu-feature-registers.rst
@@ -275,6 +275,15 @@ infrastructure:
| SVEVer | [3-0] | y |
+------------------------------+---------+---------+
+ 8) ID_AA64MMFR1_EL1 - Memory model feature register 1
+
+ +------------------------------+---------+---------+
+ | Name | bits | visible |
+ +------------------------------+---------+---------+
+ | AFP | [47-44] | y |
+ +------------------------------+---------+---------+
+
+
Appendix I: Example
-------------------
diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst
index af106af8e1c0..247728d37911 100644
--- a/Documentation/arm64/elf_hwcaps.rst
+++ b/Documentation/arm64/elf_hwcaps.rst
@@ -251,6 +251,10 @@ HWCAP2_ECV
Functionality implied by ID_AA64MMFR0_EL1.ECV == 0b0001.
+HWCAP2_AFP
+
+ Functionality implied by ID_AA64MFR1_EL1.AFP == 0b0001.
+
4. Unused AT_HWCAP bits
-----------------------
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index b100e0055eab..2809df2fdd63 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -106,6 +106,7 @@
#define KERNEL_HWCAP_BTI __khwcap2_feature(BTI)
#define KERNEL_HWCAP_MTE __khwcap2_feature(MTE)
#define KERNEL_HWCAP_ECV __khwcap2_feature(ECV)
+#define KERNEL_HWCAP_AFP __khwcap2_feature(AFP)
/*
* This yields a mask that user programs can use to figure out what
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 16b3f1a1d468..adcab9009f9d 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -889,6 +889,7 @@
#endif
/* id_aa64mmfr1 */
+#define ID_AA64MMFR1_AFP_SHIFT 44
#define ID_AA64MMFR1_ETS_SHIFT 36
#define ID_AA64MMFR1_TWED_SHIFT 32
#define ID_AA64MMFR1_XNX_SHIFT 28
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 7b23b16f21ce..180da7396549 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -76,5 +76,6 @@
#define HWCAP2_BTI (1 << 17)
#define HWCAP2_MTE (1 << 18)
#define HWCAP2_ECV (1 << 19)
+#define HWCAP2_AFP (1 << 20)
#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6f3e677d88f1..71ff5a4afb0f 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -325,6 +325,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
};
static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_AFP_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_ETS_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_TWED_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_XNX_SHIFT, 4, 0),
@@ -2476,6 +2477,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_MTE_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_MTE, CAP_HWCAP, KERNEL_HWCAP_MTE),
#endif /* CONFIG_ARM64_MTE */
HWCAP_CAP(SYS_ID_AA64MMFR0_EL1, ID_AA64MMFR0_ECV_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ECV),
+ HWCAP_CAP(SYS_ID_AA64MMFR1_EL1, ID_AA64MMFR1_AFP_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_AFP),
{},
};
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 6e27b759056a..0e52014019f6 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -95,6 +95,7 @@ static const char *const hwcap_str[] = {
[KERNEL_HWCAP_BTI] = "bti",
[KERNEL_HWCAP_MTE] = "mte",
[KERNEL_HWCAP_ECV] = "ecv",
+ [KERNEL_HWCAP_AFP] = "afp",
};
#ifdef CONFIG_COMPAT
--
2.17.1
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next prev parent reply other threads:[~2021-12-10 16:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-10 16:54 [PATCH v3 0/3] arm64: Add two HWCAPs for Arm v8.7 FP behaviour Joey Gouly
2021-12-10 16:54 ` Joey Gouly [this message]
2021-12-10 16:54 ` [PATCH v3 2/3] arm64: add ID_AA64ISAR2_EL1 sys register Joey Gouly
2021-12-10 16:54 ` [PATCH v3 3/3] arm64: cpufeature: add HWCAP for FEAT_RPRES Joey Gouly
2021-12-10 17:31 ` [PATCH v3 0/3] arm64: Add two HWCAPs for Arm v8.7 FP behaviour Marc Zyngier
2021-12-13 19:17 ` Catalin Marinas
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