[PATCH v4 26/36] kselftest/arm64: Verify the GCS hwcap

[Mark Brown <broonie@kernel.org>]

Add coverage of the GCS hwcap to the hwcap selftest, using a read of
GCSPR_EL0 to generate SIGILL without having to worry about enabling GCS.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/abi/hwcap.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/tools/testing/selftests/arm64/abi/hwcap.c b/tools/testing/selftests/arm64/abi/hwcap.c
index d4ad813fed10..38844e4c5aae 100644
--- a/tools/testing/selftests/arm64/abi/hwcap.c
+++ b/tools/testing/selftests/arm64/abi/hwcap.c
@@ -39,6 +39,17 @@ static void cssc_sigill(void)
 	asm volatile(".inst 0xdac01c00" : : : "x0");
 }
 
+static void gcs_sigill(void)
+{
+	unsigned long *gcspr;
+
+	asm volatile(
+		"mrs	%0, S3_3_C2_C5_1"
+	: "=r" (gcspr)
+	:
+	: "cc");
+}
+
 static void mops_sigill(void)
 {
 	char dst[1], src[1];
@@ -223,6 +234,14 @@ static const struct hwcap_data {
 		.cpuinfo = "cssc",
 		.sigill_fn = cssc_sigill,
 	},
+	{
+		.name = "GCS",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_GCS,
+		.cpuinfo = "gcs",
+		.sigill_fn = gcs_sigill,
+		.sigill_reliable = true,
+	},
 	{
 		.name = "MOPS",
 		.at_hwcap = AT_HWCAP2,

-- 
2.30.2