Commit b7564127 authored by Kristina Martsenko's avatar Kristina Martsenko Committed by Catalin Marinas
Browse files

arm64: mops: detect and enable FEAT_MOPS 



The Arm v8.8/9.3 FEAT_MOPS feature provides new instructions that
perform a memory copy or set. Wire up the cpufeature code to detect the
presence of FEAT_MOPS and enable it.

Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarKristina Martsenko <kristina.martsenko@arm.com>
Link: https://lore.kernel.org/r/20230509142235.3284028-10-kristina.martsenko@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 8cd076a6

Documentation/arm64/cpu-feature-registers.rst

+2 −0
Original line number Diff line number Diff line
@@ -288,6 +288,8 @@ infrastructure: 
     +------------------------------+---------+---------+

     | Name                         |  bits   | visible |

     +------------------------------+---------+---------+

     | MOPS                         | [19-16] |    y    |

     +------------------------------+---------+---------+

     | RPRES                        | [7-4]   |    y    |

     +------------------------------+---------+---------+

     | WFXT                         | [3-0]   |    y    |

Documentation/arm64/elf_hwcaps.rst

+3 −0
Original line number Diff line number Diff line
@@ -302,6 +302,9 @@ HWCAP2_SMEB16B16 
HWCAP2_SMEF16F16

    Functionality implied by ID_AA64SMFR0_EL1.F16F16 == 0b1



HWCAP2_MOPS

    Functionality implied by ID_AA64ISAR2_EL1.MOPS == 0b0001.



4. Unused AT_HWCAP bits

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

arch/arm64/include/asm/hwcap.h

+1 −0
Original line number Diff line number Diff line
@@ -137,6 +137,7 @@ 
#define KERNEL_HWCAP_SME_BI32I32	__khwcap2_feature(SME_BI32I32)

#define KERNEL_HWCAP_SME_B16B16		__khwcap2_feature(SME_B16B16)

#define KERNEL_HWCAP_SME_F16F16		__khwcap2_feature(SME_F16F16)

#define KERNEL_HWCAP_MOPS		__khwcap2_feature(MOPS)



/*

 * 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
@@ -102,5 +102,6 @@ 
#define HWCAP2_SME_BI32I32	(1UL << 40)

#define HWCAP2_SME_B16B16	(1UL << 41)

#define HWCAP2_SME_F16F16	(1UL << 42)

#define HWCAP2_MOPS		(1UL << 43)



#endif /* _UAPI__ASM_HWCAP_H */

arch/arm64/kernel/cpufeature.c

+15 −0
Original line number Diff line number Diff line
@@ -223,6 +223,7 @@ 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_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_RPRFM_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, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_MOPS_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),

	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
@@ -2187,6 +2188,11 @@ static void cpu_enable_dit(const struct arm64_cpu_capabilities *__unused) 
	set_pstate_dit(1);

}



static void cpu_enable_mops(const struct arm64_cpu_capabilities *__unused)

{

	sysreg_clear_set(sctlr_el1, 0, SCTLR_EL1_MSCEn);

}



/* Internal helper functions to match cpu capability type */

static bool

cpucap_late_cpu_optional(const struct arm64_cpu_capabilities *cap)
@@ -2649,6 +2655,14 @@ static const struct arm64_cpu_capabilities arm64_features[] = { 
		.cpu_enable = cpu_enable_dit,

		ARM64_CPUID_FIELDS(ID_AA64PFR0_EL1, DIT, IMP)

	},

	{

		.desc = "Memory Copy and Memory Set instructions",

		.capability = ARM64_HAS_MOPS,

		.type = ARM64_CPUCAP_SYSTEM_FEATURE,

		.matches = has_cpuid_feature,

		.cpu_enable = cpu_enable_mops,

		ARM64_CPUID_FIELDS(ID_AA64ISAR2_EL1, MOPS, IMP)

	},

	{},

};
@@ -2777,6 +2791,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { 
	HWCAP_CAP(ID_AA64ISAR2_EL1, RPRFM, IMP, CAP_HWCAP, KERNEL_HWCAP_RPRFM),

	HWCAP_CAP(ID_AA64ISAR2_EL1, RPRES, IMP, CAP_HWCAP, KERNEL_HWCAP_RPRES),

	HWCAP_CAP(ID_AA64ISAR2_EL1, WFxT, IMP, CAP_HWCAP, KERNEL_HWCAP_WFXT),

	HWCAP_CAP(ID_AA64ISAR2_EL1, MOPS, IMP, CAP_HWCAP, KERNEL_HWCAP_MOPS),

#ifdef CONFIG_ARM64_SME

	HWCAP_CAP(ID_AA64PFR1_EL1, SME, IMP, CAP_HWCAP, KERNEL_HWCAP_SME),

	HWCAP_CAP(ID_AA64SMFR0_EL1, FA64, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_FA64),