kselftest/arm64: Log SVCR when the SME tests barf

On failure we log the actual and expected value of the register we detect
a mismatch in. For SME one obvious potential source of corruption would be
if we had corrupted SVCR since changes in streaming mode will reset the
register values, log the value to aid in understanding issues.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231205-arm64-kselftest-log-svcr-v1-1-b77abd9ee7f3@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

tools/testing/selftests/arm64/fp/sve-test.S

@@ -515,6 +515,10 @@ function barf
 	mov	x11, x1	// actual data
 	mov	x12, x2	// data size
 
+#ifdef SSVE
+	mrs	x13, S3_3_C4_C2_2
+#endif
+
 	puts	"Mismatch: PID="
 	mov	x0, x20
 	bl	putdec
@@ -534,6 +538,12 @@ function barf
 	bl	dumphex
 	puts	"]\n"
 
+#ifdef SSVE
+	puts	"\tSVCR: "
+	mov	x0, x13
+	bl	putdecn
+#endif
+
 	mov	x8, #__NR_getpid
 	svc	#0
 // fpsimd.c acitivty log dump hack

tools/testing/selftests/arm64/fp/za-test.S

@@ -333,6 +333,9 @@ function barf
 //	mov	w8, #__NR_exit
 //	svc	#0
 // end hack
+
+	mrs	x13, S3_3_C4_C2_2
+
 	smstop
 	mov	x10, x0	// expected data
 	mov	x11, x1	// actual data
@@ -356,6 +359,9 @@ function barf
 	mov	x1, x12
 	bl	dumphex
 	puts	"]\n"
+	puts	"\tSVCR: "
+	mov	x0, x13
+	bl	putdecn
 
 	mov	x8, #__NR_getpid
 	svc	#0

tools/testing/selftests/arm64/fp/zt-test.S

@@ -267,6 +267,8 @@ function barf
 //	mov	w8, #__NR_exit
 //	svc	#0
 // end hack
+
+	mrs	x13, S3_3_C4_C2_2
 	smstop
 	mov	x10, x0	// expected data
 	mov	x11, x1	// actual data
@@ -287,6 +289,9 @@ function barf
 	mov	x1, x12
 	bl	dumphex
 	puts	"]\n"
+	puts	"\tSVCR: "
+	mov	x0, x13
+	bl	putdecn
 
 	mov	x8, #__NR_getpid
 	svc	#0