Revert "kasan: Disable Software Tag-Based KASAN with GCC"

This reverts commit 7aed6a2.

Now that __no_sanitize_address attribute is fixed for KASAN_SW_TAGS with
GCC, allow re-enabling KASAN_SW_TAGS with GCC.

Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrew Pinski <pinskia@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/20241021120013.3209481-2-elver@google.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: melver

lib/Kconfig.kasan

@@ -22,11 +22,8 @@ config ARCH_DISABLE_KASAN_INLINE
 config CC_HAS_KASAN_GENERIC
 	def_bool $(cc-option, -fsanitize=kernel-address)
 
-# GCC appears to ignore no_sanitize_address when -fsanitize=kernel-hwaddress
-# is passed. See https://bugzilla.kernel.org/show_bug.cgi?id=218854 (and
-# the linked LKML thread) for more details.
 config CC_HAS_KASAN_SW_TAGS
-	def_bool !CC_IS_GCC && $(cc-option, -fsanitize=kernel-hwaddress)
+	def_bool $(cc-option, -fsanitize=kernel-hwaddress)
 
 # This option is only required for software KASAN modes.
 # Old GCC versions do not have proper support for no_sanitize_address.
@@ -101,7 +98,7 @@ config KASAN_SW_TAGS
 	help
 	  Enables Software Tag-Based KASAN.
 
-	  Requires Clang.
+	  Requires GCC 11+ or Clang.
 
 	  Supported only on arm64 CPUs and relies on Top Byte Ignore.