linux-kernel - [PATCH] kselftest/arm64: Check that SVCR is 0 in signal handlers

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Message-Id: <20241106-arm64-fpmr-signal-test-v1-1-31fa34ce58fe@kernel.org>
Date: Wed, 06 Nov 2024 17:07:51 +0000
From: Mark Brown <broonie@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>, 
 Will Deacon <will@...nel.org>, Shuah Khan <shuah@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kselftest@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>
Subject: [PATCH] kselftest/arm64: Check that SVCR is 0 in signal handlers

We don't currently validate that we exit streaming mode and clear ZA when
we enter a signal handler. Add simple checks for this in the SSVE and ZA
tests.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 tools/testing/selftests/arm64/signal/sve_helpers.h         | 13 +++++++++++++
 tools/testing/selftests/arm64/signal/testcases/ssve_regs.c |  5 +++++
 tools/testing/selftests/arm64/signal/testcases/za_regs.c   |  5 +++++
 3 files changed, 23 insertions(+)

diff --git a/tools/testing/selftests/arm64/signal/sve_helpers.h b/tools/testing/selftests/arm64/signal/sve_helpers.h
index 50948ce471cc620118a0c7c8df70d66dbdfbb160..ca133b93375fa587b5e02cd76b2f2fcd92591723 100644
--- a/tools/testing/selftests/arm64/signal/sve_helpers.h
+++ b/tools/testing/selftests/arm64/signal/sve_helpers.h
@@ -18,4 +18,17 @@ extern unsigned int nvls;
 
 int sve_fill_vls(bool use_sme, int min_vls);
 
+static inline uint64_t get_svcr(void)
+{
+	uint64_t val;
+
+	asm volatile (
+		"mrs	%0, S3_3_C4_C2_2\n"
+		: "=r"(val)
+		:
+		: "cc");
+
+	return val;
+}
+
 #endif
diff --git a/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c b/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c
index 6dbe48cf8b09ed8b7a5ab47690bd87e39e18e1e6..3dee68fa36d1cf2716f54d5f328b3f4077493c3b 100644
--- a/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c
+++ b/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c
@@ -85,6 +85,11 @@ static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
 	fprintf(stderr, "Got expected size %u and VL %d\n",
 		head->size, ssve->vl);
 
+	if (get_svcr() != 0) {
+		fprintf(stderr, "Unexpected SVCR %llx\n", get_svcr());
+		return 1;
+	}
+
 	return 0;
 }
 
diff --git a/tools/testing/selftests/arm64/signal/testcases/za_regs.c b/tools/testing/selftests/arm64/signal/testcases/za_regs.c
index b9e13f27f1f9aaf55db2a5e391f360993561d0b7..9fff4c50030414d06157e0da0c29fd794f707309 100644
--- a/tools/testing/selftests/arm64/signal/testcases/za_regs.c
+++ b/tools/testing/selftests/arm64/signal/testcases/za_regs.c
@@ -91,6 +91,11 @@ static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
 		return 1;
 	}
 
+	if (get_svcr() != 0) {
+		fprintf(stderr, "Unexpected SVCR %llx\n", get_svcr());
+		return 1;
+	}
+
 	return 0;
 }
 

---
base-commit: 8e929cb546ee42c9a61d24fae60605e9e3192354
change-id: 20241106-arm64-fpmr-signal-test-c0a0c5bf0174

Best regards,
-- 
Mark Brown <broonie@...nel.org>