Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Catalin Marinas:

 - It turns out that the optimised string routines merged in 5.14 are
   not safe with in-kernel MTE (KASAN_HW_TAGS) because of reading beyond
   the end of a string (strcmp, strncmp). Such reading may go across a
   16 byte tag granule and cause a tag check fault. When KASAN_HW_TAGS
   is enabled, use the generic strcmp/strncmp C implementation.

 - An errata workaround for ThunderX relied on the CPU capabilities
   being enabled in a specific order. This disappeared with the
   automatic generation of the cpucaps.h file (sorted alphabetically).
   Fix it by checking the current CPU only rather than the system-wide
   capability.

 - Add system_supports_mte() checks on the kernel entry/exit path and
   thread switching to avoid unnecessary barriers and function calls on
   systems where MTE is not supported.

 - kselftests: skip arm64 tests if the required features are missing.

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Restore forced disabling of KPTI on ThunderX
  kselftest/arm64: signal: Skip tests if required features are missing
  arm64: Mitigate MTE issues with str{n}cmp()
  arm64: add MTE supported check to thread switching and syscall entry/exit

tools/testing/selftests/arm64/signal/test_signals_utils.c

@@ -266,16 +266,19 @@ int test_init(struct tdescr *td)
 			td->feats_supported |= FEAT_SSBS;
 		if (getauxval(AT_HWCAP) & HWCAP_SVE)
 			td->feats_supported |= FEAT_SVE;
-		if (feats_ok(td))
+		if (feats_ok(td)) {
 			fprintf(stderr,
 				"Required Features: [%s] supported\n",
 				feats_to_string(td->feats_required &
 						td->feats_supported));
-		else
+		} else {
 			fprintf(stderr,
 				"Required Features: [%s] NOT supported\n",
 				feats_to_string(td->feats_required &
 						~td->feats_supported));
+			td->result = KSFT_SKIP;
+			return 0;
+		}
 	}
 
 	/* Perform test specific additional initialization */