From 3bda6d88489769fba5672dc66debdc1f5516c5fe Mon Sep 17 00:00:00 2001 From: Amit Daniel Kachhap Date: Thu, 17 Nov 2022 07:05:19 +0100 Subject: ARM: 9273/1: Add hwcap for Speculation Barrier(SB) Speculation Barrier(FEAT_SB) is a feature present in AArch32 state for Armv8 and is represented by ISAR6.SB identification register. This feature denotes the presence of SB instruction and hence adding a hwcap will enable the userspace to check it before trying to use this instruction. This commit adds the ID feature bit detection, and uses elf_hwcap2 accordingly. Reviewed-by: Linus Walleij Signed-off-by: Amit Daniel Kachhap Signed-off-by: Russell King (Oracle) --- arch/arm/kernel/setup.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'arch/arm/kernel/setup.c') diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 5807fa021785..979612add87a 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -450,6 +450,7 @@ static void __init cpuid_init_hwcaps(void) { int block; u32 isar5; + u32 isar6; if (cpu_architecture() < CPU_ARCH_ARMv7) return; @@ -485,6 +486,12 @@ static void __init cpuid_init_hwcaps(void) block = cpuid_feature_extract_field(isar5, 16); if (block >= 1) elf_hwcap2 |= HWCAP2_CRC32; + + /* Check for Speculation barrier instruction */ + isar6 = read_cpuid_ext(CPUID_EXT_ISAR6); + block = cpuid_feature_extract_field(isar6, 12); + if (block >= 1) + elf_hwcap2 |= HWCAP2_SB; } static void __init elf_hwcap_fixup(void) @@ -1264,6 +1271,7 @@ static const char *hwcap2_str[] = { "sha1", "sha2", "crc32", + "sb", NULL }; -- cgit v1.2.3