Revert "arm64: Mitigate MTE issues with str{n}cmp()"

This reverts commit 59a68d4138.

Now that the str{n}cmp functions have been updated to handle MTE
properly, the workaround to use the generic functions is no longer
needed.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220301101435.19327-4-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arch/arm64/include/asm/assembler.h

@@ -535,11 +535,6 @@ alternative_endif
 #define EXPORT_SYMBOL_NOKASAN(name)	EXPORT_SYMBOL(name)
 #endif
 
-#ifdef CONFIG_KASAN_HW_TAGS
-#define EXPORT_SYMBOL_NOHWKASAN(name)
-#else
-#define EXPORT_SYMBOL_NOHWKASAN(name)	EXPORT_SYMBOL_NOKASAN(name)
-#endif
 	/*
 	 * Emit a 64-bit absolute little endian symbol reference in a way that
 	 * ensures that it will be resolved at build time, even when building a

arch/arm64/include/asm/string.h

@@ -12,13 +12,11 @@ extern char *strrchr(const char *, int c);
 #define __HAVE_ARCH_STRCHR
 extern char *strchr(const char *, int c);
 
-#ifndef CONFIG_KASAN_HW_TAGS
 #define __HAVE_ARCH_STRCMP
 extern int strcmp(const char *, const char *);
 
 #define __HAVE_ARCH_STRNCMP
 extern int strncmp(const char *, const char *, __kernel_size_t);
-#endif
 
 #define __HAVE_ARCH_STRLEN
 extern __kernel_size_t strlen(const char *);

arch/arm64/lib/strcmp.S

@@ -187,4 +187,4 @@ L(done):
 	ret
 
 SYM_FUNC_END_PI(strcmp)
-EXPORT_SYMBOL_NOHWKASAN(strcmp)
+EXPORT_SYMBOL_NOKASAN(strcmp)

arch/arm64/lib/strncmp.S

@@ -306,4 +306,4 @@ L(ret0):
 	mov	result, #0
 	ret
 SYM_FUNC_END_PI(strncmp)
-EXPORT_SYMBOL_NOHWKASAN(strncmp)
+EXPORT_SYMBOL_NOKASAN(strncmp)