Commit 3bda6d88 authored by Amit Daniel Kachhap's avatar Amit Daniel Kachhap Committed by Russell King (Oracle)
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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: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarAmit Daniel Kachhap <amit.kachhap@arm.com>
Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
parent 956ca3a4

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

+1 −0
Original line number Diff line number Diff line
@@ -43,5 +43,6 @@ 
#define HWCAP2_SHA1	(1 << 2)

#define HWCAP2_SHA2	(1 << 3)

#define HWCAP2_CRC32	(1 << 4)

#define HWCAP2_SB	(1 << 5)



#endif /* _UAPI__ASMARM_HWCAP_H */

arch/arm/kernel/setup.c

+8 −0
Original line number Diff line number Diff line
@@ -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

};