[PATCH v2 23/24] kselftest/arm64: fp-ptrace: Adjust to new VL change behaviour

[Mark Rutland]

In order to fix an ABI problem, we recently changed the way that
changing the SVE/SME vector length affects PSTATE.SM. Historically,
changing the SME vector length would clear PSTATE.SM. Now, changing the
SME vector length preserves PSTATE.SM.

Update the fp-ptrace test for the new behaviour.

Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: David Spickett <david.spickett at arm.com>
Cc: Luis Machado <luis.machado at arm.com>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Mark Brown <broonie at kernel.org>
Cc: Will Deacon <will at kernel.org>
---
 tools/testing/selftests/arm64/fp/fp-ptrace.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c
index 762048eb354ff..c2882a5a5cc0a 100644
--- a/tools/testing/selftests/arm64/fp/fp-ptrace.c
+++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c
@@ -1183,18 +1183,8 @@ static void sve_write(pid_t child, struct test_config *config)
 
 static bool za_write_supported(struct test_config *config)
 {
-	if (config->sme_vl_in != config->sme_vl_expected) {
-		/* Changing the SME VL exits streaming mode. */
-		if (config->svcr_expected & SVCR_SM) {
-			return false;
-		}
-	} else {
-		/* Otherwise we can't change streaming mode */
-		if ((config->svcr_in & SVCR_SM) !=
-		    (config->svcr_expected & SVCR_SM)) {
-			return false;
-		}
-	}
+	if ((config->svcr_in & SVCR_SM) != (config->svcr_expected & SVCR_SM))
+		return false;
 
 	return true;
 }
@@ -1212,10 +1202,8 @@ static void za_write_expected(struct test_config *config)
 		memset(zt_expected, 0, sizeof(zt_expected));
 	}
 
-	/* Changing the SME VL flushes ZT, SVE state and exits SM */
+	/* Changing the SME VL flushes ZT, SVE state */
 	if (config->sme_vl_in != config->sme_vl_expected) {
-		svcr_expected &= ~SVCR_SM;
-
 		sve_vq = __sve_vq_from_vl(vl_expected(config));
 		memset(z_expected, 0, __SVE_ZREGS_SIZE(sve_vq));
 		memset(p_expected, 0, __SVE_PREGS_SIZE(sve_vq));
-- 
2.30.2