MIPS: Add crc instruction support flag to elf_hwcap

Indicate that CRC32 and CRC32C instuctions are supported by the CPU
through elf_hwcap flags.

This will be used by a follow-up commit that introduces crc32(c) crypto
acceleration modules and is required by GENERIC_CPU_AUTOPROBE feature.

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@mips.com>
Signed-off-by: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18600/

arch/mips/include/asm/mipsregs.h

@@ -664,6 +664,7 @@
 #define MIPS_CONF5_FRE		(_ULCAST_(1) << 8)
 #define MIPS_CONF5_UFE		(_ULCAST_(1) << 9)
 #define MIPS_CONF5_CA2		(_ULCAST_(1) << 14)
+#define MIPS_CONF5_CRCP		(_ULCAST_(1) << 18)
 #define MIPS_CONF5_MSAEN	(_ULCAST_(1) << 27)
 #define MIPS_CONF5_EVA		(_ULCAST_(1) << 28)
 #define MIPS_CONF5_CV		(_ULCAST_(1) << 29)

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

@@ -5,5 +5,6 @@
 /* HWCAP flags */
 #define HWCAP_MIPS_R6		(1 << 0)
 #define HWCAP_MIPS_MSA		(1 << 1)
+#define HWCAP_MIPS_CRC32	(1 << 2)
 
 #endif /* _UAPI_ASM_HWCAP_H */

arch/mips/kernel/cpu-probe.c

@@ -848,6 +848,9 @@ static inline unsigned int decode_config5(struct cpuinfo_mips *c)
 	if (config5 & MIPS_CONF5_CA2)
 		c->ases |= MIPS_ASE_MIPS16E2;
 
+	if (config5 & MIPS_CONF5_CRCP)
+		elf_hwcap |= HWCAP_MIPS_CRC32;
+
 	return config5 & MIPS_CONF_M;
 }