kselftest/arm64: Add hwcap test for RNG

Validate the RNG hwcap and make sure we don't generate a SIGILL reading
RNDR when it is reported.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220913141101.151400-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/tools/testing/selftests/arm64/abi/hwcap.c b/tools/testing/selftests/arm64/abi/hwcap.c
index 6c91b4a..d173e41 100644 (file)
--- a/tools/testing/selftests/arm64/abi/hwcap.c
+++ b/tools/testing/selftests/arm64/abi/hwcap.c
@@ -33,6 +33,11 @@
  */
 typedef void (*sigill_fn)(void);
 
+static void rng_sigill(void)
+{
+       asm volatile("mrs x0, S3_3_C2_C4_0" : : : "x0");
+}
+
 static void sme_sigill(void)
 {
        /* RDSVL x0, #0 */
@@ -114,6 +119,13 @@ static const struct hwcap_data {
        bool sigill_reliable;
 } hwcaps[] = {
        {
+               .name = "RNG",
+               .at_hwcap = AT_HWCAP2,
+               .hwcap_bit = HWCAP2_RNG,
+               .cpuinfo = "rng",
+               .sigill_fn = rng_sigill,
+       },
+       {
                .name = "SME",
                .at_hwcap = AT_HWCAP2,
                .hwcap_bit = HWCAP2_SME,