On Tue, Dec 12, 2017 at 10:36:59PM +0800, Dongjiu Geng wrote: > ARM v8.4 extensions add new neon instructions for performing a > multiplication of each FP16 element of one vector with the corresponding > FP16 element of a second vector, and to add or subtract this without an > intermediate rounding to the corresponding FP32 element in a third vector. > > This patch detects this feature and let the userspace know about it via a > HWCAP bit and MRS emulation. > > Cc: Dave Martin <dave.mar...@arm.com> > Cc: Suzuki K Poulose <suzuki.poul...@arm.com> > Signed-off-by: Dongjiu Geng <gengdong...@huawei.com> > --- > Change since v1: > 1. Address Dave and Suzuki's comments to update the commit message. > 2. Address Dave's comments to update Documentation/arm64/elf_hwcaps.txt. > --- > Documentation/arm64/cpu-feature-registers.txt | 4 +++- > Documentation/arm64/elf_hwcaps.txt | 4 ++++ > 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 + > 6 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/Documentation/arm64/cpu-feature-registers.txt > b/Documentation/arm64/cpu-feature-registers.txt > index bd9b3fa..a70090b 100644 > --- a/Documentation/arm64/cpu-feature-registers.txt > +++ b/Documentation/arm64/cpu-feature-registers.txt > @@ -110,7 +110,9 @@ infrastructure: > x--------------------------------------------------x > | Name | bits | visible | > |--------------------------------------------------| > - | RES0 | [63-48] | n | > + | RES0 | [63-52] | n | > + |--------------------------------------------------| > + | FHM | [51-48] | y | > |--------------------------------------------------| > | DP | [47-44] | y | > |--------------------------------------------------| > diff --git a/Documentation/arm64/elf_hwcaps.txt > b/Documentation/arm64/elf_hwcaps.txt > index 89edba1..987c40e 100644 > --- a/Documentation/arm64/elf_hwcaps.txt > +++ b/Documentation/arm64/elf_hwcaps.txt > @@ -158,3 +158,7 @@ HWCAP_SHA512 > HWCAP_SVE > > Functionality implied by ID_AA64PFR0_EL1.SVE == 0b0001. > + > +HWCAP_FHM
This needs to match the name of the #define in hwcap.h. With that change, Reviewed-by: Dave Martin <dave.mar...@arm.com> Cheers ---Dave > + > + Functionality implied by ID_AA64ISAR0_EL1.FHM == 0b0001. > diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h > index 08cc885..1818077 100644 > --- a/arch/arm64/include/asm/sysreg.h > +++ b/arch/arm64/include/asm/sysreg.h > @@ -419,6 +419,7 @@ > #define SCTLR_EL1_CP15BEN (1 << 5) > > /* id_aa64isar0 */ > +#define ID_AA64ISAR0_FHM_SHIFT 48 > #define ID_AA64ISAR0_DP_SHIFT 44 > #define ID_AA64ISAR0_SM4_SHIFT 40 > #define ID_AA64ISAR0_SM3_SHIFT 36 > diff --git a/arch/arm64/include/uapi/asm/hwcap.h > b/arch/arm64/include/uapi/asm/hwcap.h > index cda76fa..f018c3d 100644 > --- a/arch/arm64/include/uapi/asm/hwcap.h > +++ b/arch/arm64/include/uapi/asm/hwcap.h > @@ -43,5 +43,6 @@ > #define HWCAP_ASIMDDP (1 << 20) > #define HWCAP_SHA512 (1 << 21) > #define HWCAP_SVE (1 << 22) > +#define HWCAP_ASIMDFHM (1 << 23) > > #endif /* _UAPI__ASM_HWCAP_H */ > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index c5ba009..bc7e707 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -123,6 +123,7 @@ static int __init register_cpu_hwcaps_dumper(void) > * sync with the documentation of the CPU feature register ABI. > */ > static const struct arm64_ftr_bits ftr_id_aa64isar0[] = { > + ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, > ID_AA64ISAR0_FHM_SHIFT, 4, 0), > ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, > ID_AA64ISAR0_DP_SHIFT, 4, 0), > ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, > ID_AA64ISAR0_SM4_SHIFT, 4, 0), > ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, > ID_AA64ISAR0_SM3_SHIFT, 4, 0), > @@ -991,6 +992,7 @@ static bool has_no_fpsimd(const struct > arm64_cpu_capabilities *entry, int __unus > HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM3_SHIFT, FTR_UNSIGNED, > 1, CAP_HWCAP, HWCAP_SM3), > HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM4_SHIFT, FTR_UNSIGNED, > 1, CAP_HWCAP, HWCAP_SM4), > HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_DP_SHIFT, FTR_UNSIGNED, 1, > CAP_HWCAP, HWCAP_ASIMDDP), > + HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_FHM_SHIFT, FTR_UNSIGNED, > 1, CAP_HWCAP, HWCAP_ASIMDFHM), > HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 0, > CAP_HWCAP, HWCAP_FP), > HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 1, > CAP_HWCAP, HWCAP_FPHP), > HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 0, > CAP_HWCAP, HWCAP_ASIMD), > diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c > index 1e25545..7f94623 100644 > --- a/arch/arm64/kernel/cpuinfo.c > +++ b/arch/arm64/kernel/cpuinfo.c > @@ -76,6 +76,7 @@ > "asimddp", > "sha512", > "sve", > + "asimdfhm", > NULL > }; > > -- > 1.9.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-ker...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel