From: Joey Gouly Date: Fri, 10 Dec 2021 16:54:32 +0000 (+0000) Subject: arm64: cpufeature: add HWCAP for FEAT_RPRES X-Git-Tag: accepted/tizen/unified/20230118.172025~1748 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e38b3c0d245b87835138296fd9b57d2a56721461;p=platform%2Fkernel%2Flinux-rpi.git arm64: cpufeature: add HWCAP for FEAT_RPRES commit 1175011a7d0030d49dc9c10bde36f08f26d0a8ee upstream. Add a new HWCAP to detect the Increased precision of Reciprocal Estimate and Reciprocal Square Root Estimate feature (FEAT_RPRES), introduced in Armv8.7. Also expose this to userspace in the ID_AA64ISAR2_EL1 feature register. Signed-off-by: Joey Gouly Cc: Will Deacon Cc: Jonathan Corbet Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20211210165432.8106-4-joey.gouly@arm.com Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst index 1b19d20..749ae97 100644 --- a/Documentation/arm64/cpu-feature-registers.rst +++ b/Documentation/arm64/cpu-feature-registers.rst @@ -283,6 +283,14 @@ infrastructure: | AFP | [47-44] | y | +------------------------------+---------+---------+ + 9) ID_AA64ISAR2_EL1 - Instruction set attribute register 2 + + +------------------------------+---------+---------+ + | Name | bits | visible | + +------------------------------+---------+---------+ + | RPRES | [7-4] | y | + +------------------------------+---------+---------+ + Appendix I: Example ------------------- diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst index 247728d..b72ff17 100644 --- a/Documentation/arm64/elf_hwcaps.rst +++ b/Documentation/arm64/elf_hwcaps.rst @@ -255,6 +255,10 @@ HWCAP2_AFP Functionality implied by ID_AA64MFR1_EL1.AFP == 0b0001. +HWCAP2_RPRES + + Functionality implied by ID_AA64ISAR2_EL1.RPRES == 0b0001. + 4. Unused AT_HWCAP bits ----------------------- diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h index 2809df2..f68fbb2 100644 --- a/arch/arm64/include/asm/hwcap.h +++ b/arch/arm64/include/asm/hwcap.h @@ -107,6 +107,7 @@ #define KERNEL_HWCAP_MTE __khwcap2_feature(MTE) #define KERNEL_HWCAP_ECV __khwcap2_feature(ECV) #define KERNEL_HWCAP_AFP __khwcap2_feature(AFP) +#define KERNEL_HWCAP_RPRES __khwcap2_feature(RPRES) /* * 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 180da73..f037318 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -77,5 +77,6 @@ #define HWCAP2_MTE (1 << 18) #define HWCAP2_ECV (1 << 19) #define HWCAP2_AFP (1 << 20) +#define HWCAP2_RPRES (1 << 21) #endif /* _UAPI__ASM_HWCAP_H */ diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index e184831..f07b41f 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -226,6 +226,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar1[] = { }; static const struct arm64_ftr_bits ftr_id_aa64isar2[] = { + ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_RPRES_SHIFT, 4, 0), ARM64_FTR_END, }; @@ -2467,6 +2468,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { #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), + HWCAP_CAP(SYS_ID_AA64ISAR2_EL1, ID_AA64ISAR2_RPRES_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_RPRES), {}, }; diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index f2f8fe0..591c18a 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -96,6 +96,7 @@ static const char *const hwcap_str[] = { [KERNEL_HWCAP_MTE] = "mte", [KERNEL_HWCAP_ECV] = "ecv", [KERNEL_HWCAP_AFP] = "afp", + [KERNEL_HWCAP_RPRES] = "rpres", }; #ifdef CONFIG_COMPAT