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arm64/sysreg: Add hwcap for SVE EBF16

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SVE has a separate identification register indicating support for BFloat16
operations. Add a hwcap identifying support for EBF16 in this register,
mirroring what we did for the non-SVE case.

While there is currently an architectural requirement for BF16 support to
be the same in SVE and non-SVE contexts there are separate identification
registers this separate hwcap helps avoid issues if that requirement were
to be relaxed in the future, we have already chosen to have a separate
capability for base BF16 support.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220829154815.832347-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Brown 2022-08-29 16:48:15 +01:00 committed by Catalin Marinas
parent b90cb10531
commit 81ff692ad9
5 changed files with 7 additions and 0 deletions
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3
Documentation/arm64/elf_hwcaps.rst
View File

@ -272,6 +272,9 @@ HWCAP2_WFXT
HWCAP2_EBF16
Functionality implied by ID_AA64ISAR1_EL1.BF16 == 0b0010.
HWCAP2_SVE_EBF16
Functionality implied by ID_AA64ZFR0_EL1.BF16 == 0b0010.
4. Unused AT_HWCAP bits
-----------------------

1
arch/arm64/include/asm/hwcap.h
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@ -119,6 +119,7 @@
#define KERNEL_HWCAP_SME_FA64 __khwcap2_feature(SME_FA64)
#define KERNEL_HWCAP_WFXT __khwcap2_feature(WFXT)
#define KERNEL_HWCAP_EBF16 __khwcap2_feature(EBF16)
#define KERNEL_HWCAP_SVE_EBF16 __khwcap2_feature(SVE_EBF16)
/*
* This yields a mask that user programs can use to figure out what

1
arch/arm64/include/uapi/asm/hwcap.h
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@ -92,5 +92,6 @@
#define HWCAP2_SME_FA64 (1 << 30)
#define HWCAP2_WFXT (1UL << 31)
#define HWCAP2_EBF16 (1UL << 32)
#define HWCAP2_SVE_EBF16 (1UL << 33)
#endif /* _UAPI__ASM_HWCAP_H */

1
arch/arm64/kernel/cpufeature.c
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@ -2733,6 +2733,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_EL1_AES_SHIFT, 4, FTR_UNSIGNED, ID_AA64ZFR0_EL1_AES_PMULL128, CAP_HWCAP, KERNEL_HWCAP_SVEPMULL),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_EL1_BitPerm_SHIFT, 4, FTR_UNSIGNED, ID_AA64ZFR0_EL1_BitPerm_IMP, CAP_HWCAP, KERNEL_HWCAP_SVEBITPERM),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_EL1_BF16_SHIFT, 4, FTR_UNSIGNED, ID_AA64ZFR0_EL1_BF16_IMP, CAP_HWCAP, KERNEL_HWCAP_SVEBF16),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_EL1_BF16_SHIFT, 4, FTR_UNSIGNED, ID_AA64ZFR0_EL1_BF16_EBF16, CAP_HWCAP, KERNEL_HWCAP_SVE_EBF16),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_EL1_SHA3_SHIFT, 4, FTR_UNSIGNED, ID_AA64ZFR0_EL1_SHA3_IMP, CAP_HWCAP, KERNEL_HWCAP_SVESHA3),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_EL1_SM4_SHIFT, 4, FTR_UNSIGNED, ID_AA64ZFR0_EL1_SM4_IMP, CAP_HWCAP, KERNEL_HWCAP_SVESM4),
HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_EL1_I8MM_SHIFT, 4, FTR_UNSIGNED, ID_AA64ZFR0_EL1_I8MM_IMP, CAP_HWCAP, KERNEL_HWCAP_SVEI8MM),

1
arch/arm64/kernel/cpuinfo.c
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@ -115,6 +115,7 @@ static const char *const hwcap_str[] = {
[KERNEL_HWCAP_SME_FA64] = "smefa64",
[KERNEL_HWCAP_WFXT] = "wfxt",
[KERNEL_HWCAP_EBF16] = "ebf16",
[KERNEL_HWCAP_SVE_EBF16] = "sveebf16",
};
#ifdef CONFIG_COMPAT