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From foo@baz Tue Mar 8 08:47:19 PM CET 2022 |
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From: Joey Gouly <joey.gouly@arm.com> |
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Date: Fri, 10 Dec 2021 16:54:30 +0000 |
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Subject: arm64: cpufeature: add HWCAP for FEAT_AFP |
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|
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From: Joey Gouly <joey.gouly@arm.com> |
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|
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commit 5c13f042e73200b50573ace63e1a6b94e2917616 upstream. |
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|
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Add a new HWCAP to detect the Alternate Floating-point Behaviour |
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feature (FEAT_AFP), introduced in Armv8.7. |
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|
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Also expose this to userspace in the ID_AA64MMFR1_EL1 feature register. |
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|
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Signed-off-by: Joey Gouly <joey.gouly@arm.com> |
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Cc: Will Deacon <will@kernel.org> |
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Acked-by: Marc Zyngier <maz@kernel.org> |
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Link: https://lore.kernel.org/r/20211210165432.8106-2-joey.gouly@arm.com |
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Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> |
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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--- |
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Documentation/arm64/cpu-feature-registers.rst | 9 +++++++++ |
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Documentation/arm64/elf_hwcaps.rst | 4 ++++ |
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arch/arm64/include/asm/hwcap.h | 1 + |
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arch/arm64/include/asm/sysreg.h | 1 + |
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arch/arm64/include/uapi/asm/hwcap.h | 1 + |
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arch/arm64/kernel/cpufeature.c | 2 ++ |
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arch/arm64/kernel/cpuinfo.c | 1 + |
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7 files changed, 19 insertions(+) |
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|
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--- a/Documentation/arm64/cpu-feature-registers.rst |
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+++ b/Documentation/arm64/cpu-feature-registers.rst |
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@@ -275,6 +275,15 @@ infrastructure: |
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| SVEVer | [3-0] | y | |
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+------------------------------+---------+---------+ |
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|
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+ 8) ID_AA64MMFR1_EL1 - Memory model feature register 1 |
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+ |
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+ +------------------------------+---------+---------+ |
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+ | Name | bits | visible | |
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+ +------------------------------+---------+---------+ |
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+ | AFP | [47-44] | y | |
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+ +------------------------------+---------+---------+ |
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+ |
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+ |
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Appendix I: Example |
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------------------- |
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|
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--- a/Documentation/arm64/elf_hwcaps.rst |
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+++ b/Documentation/arm64/elf_hwcaps.rst |
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@@ -251,6 +251,10 @@ HWCAP2_ECV |
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|
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Functionality implied by ID_AA64MMFR0_EL1.ECV == 0b0001. |
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|
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+HWCAP2_AFP |
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+ |
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+ Functionality implied by ID_AA64MFR1_EL1.AFP == 0b0001. |
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+ |
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4. Unused AT_HWCAP bits |
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----------------------- |
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|
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--- a/arch/arm64/include/asm/hwcap.h |
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+++ b/arch/arm64/include/asm/hwcap.h |
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@@ -106,6 +106,7 @@ |
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#define KERNEL_HWCAP_BTI __khwcap2_feature(BTI) |
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#define KERNEL_HWCAP_MTE __khwcap2_feature(MTE) |
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#define KERNEL_HWCAP_ECV __khwcap2_feature(ECV) |
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+#define KERNEL_HWCAP_AFP __khwcap2_feature(AFP) |
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|
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/* |
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* This yields a mask that user programs can use to figure out what |
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--- a/arch/arm64/include/asm/sysreg.h |
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+++ b/arch/arm64/include/asm/sysreg.h |
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@@ -896,6 +896,7 @@ |
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#endif |
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|
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/* id_aa64mmfr1 */ |
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+#define ID_AA64MMFR1_AFP_SHIFT 44 |
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#define ID_AA64MMFR1_ETS_SHIFT 36 |
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#define ID_AA64MMFR1_TWED_SHIFT 32 |
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#define ID_AA64MMFR1_XNX_SHIFT 28 |
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--- a/arch/arm64/include/uapi/asm/hwcap.h |
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+++ b/arch/arm64/include/uapi/asm/hwcap.h |
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@@ -76,5 +76,6 @@ |
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#define HWCAP2_BTI (1 << 17) |
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#define HWCAP2_MTE (1 << 18) |
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#define HWCAP2_ECV (1 << 19) |
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+#define HWCAP2_AFP (1 << 20) |
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|
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#endif /* _UAPI__ASM_HWCAP_H */ |
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--- a/arch/arm64/kernel/cpufeature.c |
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+++ b/arch/arm64/kernel/cpufeature.c |
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@@ -329,6 +329,7 @@ static const struct arm64_ftr_bits ftr_i |
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}; |
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|
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static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = { |
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+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_AFP_SHIFT, 4, 0), |
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ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_ETS_SHIFT, 4, 0), |
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ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_TWED_SHIFT, 4, 0), |
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ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_XNX_SHIFT, 4, 0), |
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@@ -2465,6 +2466,7 @@ static const struct arm64_cpu_capabiliti |
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HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_MTE_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_MTE, CAP_HWCAP, KERNEL_HWCAP_MTE), |
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#endif /* CONFIG_ARM64_MTE */ |
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HWCAP_CAP(SYS_ID_AA64MMFR0_EL1, ID_AA64MMFR0_ECV_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ECV), |
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+ HWCAP_CAP(SYS_ID_AA64MMFR1_EL1, ID_AA64MMFR1_AFP_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_AFP), |
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{}, |
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}; |
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|
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--- a/arch/arm64/kernel/cpuinfo.c |
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+++ b/arch/arm64/kernel/cpuinfo.c |
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@@ -95,6 +95,7 @@ static const char *const hwcap_str[] = { |
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[KERNEL_HWCAP_BTI] = "bti", |
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[KERNEL_HWCAP_MTE] = "mte", |
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[KERNEL_HWCAP_ECV] = "ecv", |
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+ [KERNEL_HWCAP_AFP] = "afp", |
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}; |
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|
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#ifdef CONFIG_COMPAT |
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