Commit 95aa6860 authored by Mark Brown's avatar Mark Brown Committed by Will Deacon
Browse files

arm64/hwcap: Add support for FEAT_CSSC 



FEAT_CSSC adds a number of new instructions usable to optimise common short
sequences of instructions, add a hwcap indicating that the feature is
available and can be used by userspace.

Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20221017152520.1039165-2-broonie@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 01ab991f

Documentation/arm64/elf_hwcaps.rst

+3 −0
Original line number Diff line number Diff line
@@ -275,6 +275,9 @@ HWCAP2_EBF16 
HWCAP2_SVE_EBF16

    Functionality implied by ID_AA64ZFR0_EL1.BF16 == 0b0010.



HWCAP2_CSSC

    Functionality implied by ID_AA64ISAR2_EL1.CSSC == 0b0001.



4. Unused AT_HWCAP bits

-----------------------

arch/arm64/include/asm/hwcap.h

+1 −0
Original line number Diff line number Diff line
@@ -120,6 +120,7 @@ 
#define KERNEL_HWCAP_WFXT		__khwcap2_feature(WFXT)

#define KERNEL_HWCAP_EBF16		__khwcap2_feature(EBF16)

#define KERNEL_HWCAP_SVE_EBF16		__khwcap2_feature(SVE_EBF16)

#define KERNEL_HWCAP_CSSC		__khwcap2_feature(CSSC)



/*

 * This yields a mask that user programs can use to figure out what

arch/arm64/include/uapi/asm/hwcap.h

+1 −0
Original line number Diff line number Diff line
@@ -93,5 +93,6 @@ 
#define HWCAP2_WFXT		(1UL << 31)

#define HWCAP2_EBF16		(1UL << 32)

#define HWCAP2_SVE_EBF16	(1UL << 33)

#define HWCAP2_CSSC		(1UL << 34)



#endif /* _UAPI__ASM_HWCAP_H */

arch/arm64/kernel/cpufeature.c

+2 −0
Original line number Diff line number Diff line
@@ -212,6 +212,7 @@ 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_EL1_CSSC_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_HIGHER_SAFE, ID_AA64ISAR2_EL1_BC_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),

		       FTR_STRICT, FTR_EXACT, ID_AA64ISAR2_EL1_APA3_SHIFT, 4, 0),
@@ -2815,6 +2816,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { 
#endif /* CONFIG_ARM64_MTE */

	HWCAP_CAP(SYS_ID_AA64MMFR0_EL1, ID_AA64MMFR0_EL1_ECV_SHIFT, 4, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ECV),

	HWCAP_CAP(SYS_ID_AA64MMFR1_EL1, ID_AA64MMFR1_EL1_AFP_SHIFT, 4, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_AFP),

	HWCAP_CAP(SYS_ID_AA64ISAR2_EL1, ID_AA64ISAR2_EL1_CSSC_SHIFT, 4, FTR_UNSIGNED, ID_AA64ISAR2_EL1_CSSC_IMP, CAP_HWCAP, KERNEL_HWCAP_CSSC),

	HWCAP_CAP(SYS_ID_AA64ISAR2_EL1, ID_AA64ISAR2_EL1_RPRES_SHIFT, 4, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_RPRES),

	HWCAP_CAP(SYS_ID_AA64ISAR2_EL1, ID_AA64ISAR2_EL1_WFxT_SHIFT, 4, FTR_UNSIGNED, ID_AA64ISAR2_EL1_WFxT_IMP, CAP_HWCAP, KERNEL_HWCAP_WFXT),

#ifdef CONFIG_ARM64_SME

arch/arm64/kernel/cpuinfo.c

+1 −0
Original line number Diff line number Diff line
@@ -116,6 +116,7 @@ static const char *const hwcap_str[] = { 
	[KERNEL_HWCAP_WFXT]		= "wfxt",

	[KERNEL_HWCAP_EBF16]		= "ebf16",

	[KERNEL_HWCAP_SVE_EBF16]	= "sveebf16",

	[KERNEL_HWCAP_CSSC]		= "cssc",

};



#ifdef CONFIG_COMPAT