[RFC PATCH 1/7] arm64: cpufeature: Add API to report system support of HWDBM
From: Keqian Zhu <hidden>
Date: 2021-01-26 13:19:59
Also in:
kvm, kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Though we already has a cpu capability named ARM64_HW_DBM, it's a LOCAL_CPU cap and conditionally compiled by CONFIG_ARM64_HW_AFDBM. This reports the system wide support of HW_DBM. Signed-off-by: Keqian Zhu <redacted> --- arch/arm64/include/asm/cpufeature.h | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 9a555809b89c..dfded86c7684 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h@@ -664,6 +664,18 @@ static inline bool system_supports_mixed_endian(void) return val == 0x1; } +static inline bool system_supports_hw_dbm(void) +{ + u64 mmfr1; + u32 val; + + mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); + val = cpuid_feature_extract_unsigned_field(mmfr1, + ID_AA64MMFR1_HADBS_SHIFT); + + return val == 0x2; +} + static __always_inline bool system_supports_fpsimd(void) { return !cpus_have_const_cap(ARM64_HAS_NO_FPSIMD);
--
2.19.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel