linux-kernel - [PATCH 3/4] kselftest/arm64: Expand the set of ZA writes fp-ptrace does

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Message-Id: <20241107-arm64-fp-ptrace-fpmr-v1-3-3e5e0b6e3be9@kernel.org>
Date: Thu, 07 Nov 2024 01:38:06 +0000
From: Mark Brown <broonie@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>, 
 Will Deacon <will@...nel.org>, Shuah Khan <shuah@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>, 
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, Mark Brown <broonie@...nel.org>
Subject: [PATCH 3/4] kselftest/arm64: Expand the set of ZA writes fp-ptrace
 does

Currently our test for implementable ZA writes is written in a bit of a
convoluted fashion which excludes all changes where we clear SVCR.SM even
though we can actually support that since changing the vector length resets
SVCR. Make the logic more direct, enabling us to actually run these cases.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 tools/testing/selftests/arm64/fp/fp-ptrace.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c
index 22d52a75ac9687673c4354f66abcf7204ce17875..a35dc6d8f82af47bf6adedba7e69a6577ee9f7de 100644
--- a/tools/testing/selftests/arm64/fp/fp-ptrace.c
+++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c
@@ -1080,21 +1080,19 @@ static void sve_write(pid_t child, struct test_config *config)
 
 static bool za_write_supported(struct test_config *config)
 {
-	if (config->svcr_expected & SVCR_SM) {
-		if (!(config->svcr_in & SVCR_SM))
+	if (config->sme_vl_in != config->sme_vl_expected) {
+		/* Changing the SME VL exits streaming mode. */
+		if (config->svcr_expected & SVCR_SM) {
 			return false;
-
-		/* Changing the SME VL exits streaming mode */
-		if (config->sme_vl_in != config->sme_vl_expected) {
+		}
+	} else {
+		/* Otherwise we can't change streaming mode */
+		if ((config->svcr_in & SVCR_SM) !=
+		    (config->svcr_expected & SVCR_SM)) {
 			return false;
 		}
 	}
 
-	/* Can't disable SM outside a VL change */
-	if ((config->svcr_in & SVCR_SM) &&
-	    !(config->svcr_expected & SVCR_SM))
-		return false;
-
 	return true;
 }
 

-- 
2.39.2