arm64: Add compat hwcap SB

This hwcap was added for 32-bit native arm kernel by commit
3bda6d8 ("ARM: 9273/1: Add hwcap for Speculation Barrier(SB)")
and hence the corresponding changes added in 32-bit compat arm64 kernel.

Speculation Barrier is a feature(FEAT_SB) present in both AArch32 and
AArch64 state. This hwcap is already advertised in native arm64 kernel.

Signed-off-by: Amit Daniel Kachhap <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

Author: amitdanielkachhap

arch/arm64/include/asm/hwcap.h

@@ -43,6 +43,7 @@
 #define COMPAT_HWCAP2_SHA1	(1 << 2)
 #define COMPAT_HWCAP2_SHA2	(1 << 3)
 #define COMPAT_HWCAP2_CRC32	(1 << 4)
+#define COMPAT_HWCAP2_SB	(1 << 5)
 
 #ifndef __ASSEMBLY__
 #include <linux/log2.h>

arch/arm64/kernel/cpufeature.c

@@ -532,7 +532,7 @@ static const struct arm64_ftr_bits ftr_id_isar6[] = {
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_EL1_I8MM_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_EL1_BF16_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_EL1_SPECRES_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_EL1_SB_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_EL1_SB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_EL1_FHM_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_EL1_DP_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_EL1_JSCVT_SHIFT, 4, 0),
@@ -2875,6 +2875,7 @@ static const struct arm64_cpu_capabilities compat_elf_hwcaps[] = {
 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_EL1_CRC32_SHIFT, 4, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_CRC32),
 	HWCAP_CAP(SYS_ID_ISAR6_EL1, ID_ISAR6_EL1_DP_SHIFT, 4, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP, COMPAT_HWCAP_ASIMDDP),
 	HWCAP_CAP(SYS_ID_ISAR6_EL1, ID_ISAR6_EL1_FHM_SHIFT, 4, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP, COMPAT_HWCAP_ASIMDFHM),
+	HWCAP_CAP(SYS_ID_ISAR6_EL1, ID_ISAR6_EL1_SB_SHIFT, 4, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SB),
 	HWCAP_CAP(SYS_ID_ISAR6_EL1, ID_ISAR6_EL1_BF16_SHIFT, 4, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP, COMPAT_HWCAP_ASIMDBF16),
 	HWCAP_CAP(SYS_ID_ISAR6_EL1, ID_ISAR6_EL1_I8MM_SHIFT, 4, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP, COMPAT_HWCAP_I8MM),
 #endif

arch/arm64/kernel/cpuinfo.c

@@ -161,6 +161,7 @@ static const char *const compat_hwcap2_str[] = {
 	[COMPAT_KERNEL_HWCAP2(SHA1)]	= "sha1",
 	[COMPAT_KERNEL_HWCAP2(SHA2)]	= "sha2",
 	[COMPAT_KERNEL_HWCAP2(CRC32)]	= "crc32",
+	[COMPAT_KERNEL_HWCAP2(SB)]	= "sb",
 };
 #endif /* CONFIG_COMPAT */