diff mbox series

kselftest/arm64: signal: fix/refactor SVE vector length enumeration

Message ID 20240812140924.2100643-1-andre.przywara@arm.com (mailing list archive)
State New, archived
Headers show
Series kselftest/arm64: signal: fix/refactor SVE vector length enumeration | expand

Commit Message

Andre Przywara Aug. 12, 2024, 2:09 p.m. UTC
Currently a number of SVE/SME related tests have almost identical
functions to enumerate all supported vector lengths. However over time
the copy&pasted code has diverged, allowing some bugs to creep in:
- fake_sigreturn_sme_change_vl reports a failure, not a SKIP if only
  one vector length is supported (but the SVE version is fine)
- fake_sigreturn_sme_change_vl tries to set the SVE vector length, not
  the SME one (but the other SME tests are fine)
- za_no_regs keeps iterating forever if only one vector length is
  supported (but za_regs is correct)

Since those bugs seem to be mostly copy&paste ones, let's consolidate
the enumeration loop into one shared function, and just call that from
each test. That should fix the above bugs, and prevent similar issues
from happening again.

Fixes: 4963aeb35a9e ("kselftest/arm64: signal: Add SME signal handling tests")
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
Hi,

this fixes at least the three bugs mentioned, with a refactoring. Please
let me know if you want those bugs to be fixed separately, using the old
code, to simplify backports, or if it's not worth it.

Cheers,
Andre

 tools/testing/selftests/arm64/signal/Makefile |  2 +-
 .../selftests/arm64/signal/sve_helpers.c      | 48 +++++++++++++++++++
 .../selftests/arm64/signal/sve_helpers.h      | 21 ++++++++
 .../testcases/fake_sigreturn_sme_change_vl.c  | 31 +++---------
 .../testcases/fake_sigreturn_sve_change_vl.c  | 30 +++---------
 .../arm64/signal/testcases/ssve_regs.c        | 36 ++++----------
 .../arm64/signal/testcases/ssve_za_regs.c     | 36 ++++----------
 .../arm64/signal/testcases/sve_regs.c         | 32 ++++---------
 .../arm64/signal/testcases/za_no_regs.c       | 32 ++++---------
 .../arm64/signal/testcases/za_regs.c          | 36 ++++----------
 10 files changed, 123 insertions(+), 181 deletions(-)
 create mode 100644 tools/testing/selftests/arm64/signal/sve_helpers.c
 create mode 100644 tools/testing/selftests/arm64/signal/sve_helpers.h

Comments

Mark Brown Aug. 13, 2024, 11 a.m. UTC | #1
On Mon, Aug 12, 2024 at 03:09:24PM +0100, Andre Przywara wrote:

> +		/* Did we find the lowest supported VL? */
> +		if (use_sme && vq < sve_vq_from_vl(vl))
> +			break;

We don't need the use_sme check here, SVE is just architecturally
guaranteed to never trip the && case.  Unless you add a warning for
broken implementations I'd just skip it.
Andre Przywara Aug. 13, 2024, 12:55 p.m. UTC | #2
On Tue, 13 Aug 2024 12:00:06 +0100
Mark Brown <broonie@kernel.org> wrote:

Hi broonie,

> On Mon, Aug 12, 2024 at 03:09:24PM +0100, Andre Przywara wrote:
> 
> > +		/* Did we find the lowest supported VL? */
> > +		if (use_sme && vq < sve_vq_from_vl(vl))
> > +			break;  
> 
> We don't need the use_sme check here, SVE is just architecturally
> guaranteed to never trip the && case.  Unless you add a warning for
> broken implementations I'd just skip it.

Ah, thanks, I wasn't sure about that, and wanted to mimic the existing
code as close as possible. Will surely just drop it.

Thanks,
Andre
Dave Martin Aug. 14, 2024, 1:27 p.m. UTC | #3
On Tue, Aug 13, 2024 at 01:55:46PM +0100, Andre Przywara wrote:
> On Tue, 13 Aug 2024 12:00:06 +0100
> Mark Brown <broonie@kernel.org> wrote:
> 
> Hi broonie,
> 
> > On Mon, Aug 12, 2024 at 03:09:24PM +0100, Andre Przywara wrote:
> > 
> > > +		/* Did we find the lowest supported VL? */
> > > +		if (use_sme && vq < sve_vq_from_vl(vl))
> > > +			break;  
> > 
> > We don't need the use_sme check here, SVE is just architecturally
> > guaranteed to never trip the && case.  Unless you add a warning for
> > broken implementations I'd just skip it.
> 
> Ah, thanks, I wasn't sure about that, and wanted to mimic the existing
> code as close as possible. Will surely just drop it.
> 
> Thanks,
> Andre

Maybe at least worth a comment?

I was looking at this code the other week, and this puzzled me until I
went and looked back at the architecture.

Cheers
---Dave
>
diff mbox series

Patch

diff --git a/tools/testing/selftests/arm64/signal/Makefile b/tools/testing/selftests/arm64/signal/Makefile
index 8f5febaf1a9a2..edb3613513b8a 100644
--- a/tools/testing/selftests/arm64/signal/Makefile
+++ b/tools/testing/selftests/arm64/signal/Makefile
@@ -23,7 +23,7 @@  $(TEST_GEN_PROGS): $(PROGS)
 # Common test-unit targets to build common-layout test-cases executables
 # Needs secondary expansion to properly include the testcase c-file in pre-reqs
 COMMON_SOURCES := test_signals.c test_signals_utils.c testcases/testcases.c \
-	signals.S
+	signals.S sve_helpers.c
 COMMON_HEADERS := test_signals.h test_signals_utils.h testcases/testcases.h
 
 .SECONDEXPANSION:
diff --git a/tools/testing/selftests/arm64/signal/sve_helpers.c b/tools/testing/selftests/arm64/signal/sve_helpers.c
new file mode 100644
index 0000000000000..a8f6dc0114451
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/sve_helpers.c
@@ -0,0 +1,48 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 ARM Limited
+ *
+ * Common helper functions for SVE and SME functionality.
+ */
+
+#include <stdbool.h>
+#include <kselftest.h>
+#include <asm/sigcontext.h>
+#include <sys/prctl.h>
+
+unsigned int vls[SVE_VQ_MAX];
+unsigned int nvls;
+
+int sve_fill_vls(bool use_sme, int min_vls)
+{
+	int vq, vl;
+	int option = use_sme ? PR_SME_SET_VL : PR_SVE_SET_VL;
+	int len_mask = use_sme ? PR_SME_VL_LEN_MASK : PR_SVE_VL_LEN_MASK;
+
+	/*
+	 * Enumerate up to SVE_VQ_MAX vector lengths
+	 */
+	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
+		vl = prctl(option, vq * 16);
+		if (vl == -1)
+			return KSFT_FAIL;
+
+		vl &= len_mask;
+
+		/* Did we find the lowest supported VL? */
+		if (use_sme && vq < sve_vq_from_vl(vl))
+			break;
+
+		/* Skip missing VLs */
+		vq = sve_vq_from_vl(vl);
+
+		vls[nvls++] = vl;
+	}
+
+	if (nvls < min_vls) {
+		fprintf(stderr, "Only %d VL supported\n", nvls);
+		return KSFT_SKIP;
+	}
+
+	return KSFT_PASS;
+}
diff --git a/tools/testing/selftests/arm64/signal/sve_helpers.h b/tools/testing/selftests/arm64/signal/sve_helpers.h
new file mode 100644
index 0000000000000..50948ce471cc6
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/sve_helpers.h
@@ -0,0 +1,21 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 ARM Limited
+ *
+ * Common helper functions for SVE and SME functionality.
+ */
+
+#ifndef __SVE_HELPERS_H__
+#define __SVE_HELPERS_H__
+
+#include <stdbool.h>
+
+#define VLS_USE_SVE	false
+#define VLS_USE_SME	true
+
+extern unsigned int vls[];
+extern unsigned int nvls;
+
+int sve_fill_vls(bool use_sme, int min_vls);
+
+#endif
diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sme_change_vl.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sme_change_vl.c
index ebd5815b54bba..bc10585062d57 100644
--- a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sme_change_vl.c
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sme_change_vl.c
@@ -11,39 +11,22 @@ 
 #include <sys/prctl.h>
 
 #include "test_signals_utils.h"
+#include "sve_helpers.h"
 #include "testcases.h"
 
 struct fake_sigframe sf;
-static unsigned int vls[SVE_VQ_MAX];
-unsigned int nvls = 0;
 
 static bool sme_get_vls(struct tdescr *td)
 {
-	int vq, vl;
+	int res = sve_fill_vls(VLS_USE_SME, 2);
 
-	/*
-	 * Enumerate up to SVE_VQ_MAX vector lengths
-	 */
-	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
-		vl = prctl(PR_SVE_SET_VL, vq * 16);
-		if (vl == -1)
-			return false;
+	if (!res)
+		return true;
 
-		vl &= PR_SME_VL_LEN_MASK;
+	if (res == KSFT_SKIP)
+		td->result = KSFT_SKIP;
 
-		/* Skip missing VLs */
-		vq = sve_vq_from_vl(vl);
-
-		vls[nvls++] = vl;
-	}
-
-	/* We need at least two VLs */
-	if (nvls < 2) {
-		fprintf(stderr, "Only %d VL supported\n", nvls);
-		return false;
-	}
-
-	return true;
+	return false;
 }
 
 static int fake_sigreturn_ssve_change_vl(struct tdescr *td,
diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c
index e2a452190511f..e1ccf8f85a70c 100644
--- a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c
@@ -12,40 +12,22 @@ 
 #include <sys/prctl.h>
 
 #include "test_signals_utils.h"
+#include "sve_helpers.h"
 #include "testcases.h"
 
 struct fake_sigframe sf;
-static unsigned int vls[SVE_VQ_MAX];
-unsigned int nvls = 0;
 
 static bool sve_get_vls(struct tdescr *td)
 {
-	int vq, vl;
+	int res = sve_fill_vls(VLS_USE_SVE, 2);
 
-	/*
-	 * Enumerate up to SVE_VQ_MAX vector lengths
-	 */
-	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
-		vl = prctl(PR_SVE_SET_VL, vq * 16);
-		if (vl == -1)
-			return false;
+	if (!res)
+		return true;
 
-		vl &= PR_SVE_VL_LEN_MASK;
-
-		/* Skip missing VLs */
-		vq = sve_vq_from_vl(vl);
-
-		vls[nvls++] = vl;
-	}
-
-	/* We need at least two VLs */
-	if (nvls < 2) {
-		fprintf(stderr, "Only %d VL supported\n", nvls);
+	if (res == KSFT_SKIP)
 		td->result = KSFT_SKIP;
-		return false;
-	}
 
-	return true;
+	return false;
 }
 
 static int fake_sigreturn_sve_change_vl(struct tdescr *td,
diff --git a/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c b/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c
index 3d37daafcff51..6dbe48cf8b09e 100644
--- a/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c
+++ b/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c
@@ -6,51 +6,31 @@ 
  * set up as expected.
  */
 
+#include <kselftest.h>
 #include <signal.h>
 #include <ucontext.h>
 #include <sys/prctl.h>
 
 #include "test_signals_utils.h"
+#include "sve_helpers.h"
 #include "testcases.h"
 
 static union {
 	ucontext_t uc;
 	char buf[1024 * 64];
 } context;
-static unsigned int vls[SVE_VQ_MAX];
-unsigned int nvls = 0;
 
 static bool sme_get_vls(struct tdescr *td)
 {
-	int vq, vl;
+	int res = sve_fill_vls(VLS_USE_SME, 1);
 
-	/*
-	 * Enumerate up to SVE_VQ_MAX vector lengths
-	 */
-	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
-		vl = prctl(PR_SME_SET_VL, vq * 16);
-		if (vl == -1)
-			return false;
-
-		vl &= PR_SME_VL_LEN_MASK;
-
-		/* Did we find the lowest supported VL? */
-		if (vq < sve_vq_from_vl(vl))
-			break;
+	if (!res)
+		return true;
 
-		/* Skip missing VLs */
-		vq = sve_vq_from_vl(vl);
-
-		vls[nvls++] = vl;
-	}
-
-	/* We need at least one VL */
-	if (nvls < 1) {
-		fprintf(stderr, "Only %d VL supported\n", nvls);
-		return false;
-	}
+	if (res == KSFT_SKIP)
+		td->result = KSFT_SKIP;
 
-	return true;
+	return false;
 }
 
 static void setup_ssve_regs(void)
diff --git a/tools/testing/selftests/arm64/signal/testcases/ssve_za_regs.c b/tools/testing/selftests/arm64/signal/testcases/ssve_za_regs.c
index 9dc5f128bbc0d..5557e116e9736 100644
--- a/tools/testing/selftests/arm64/signal/testcases/ssve_za_regs.c
+++ b/tools/testing/selftests/arm64/signal/testcases/ssve_za_regs.c
@@ -6,51 +6,31 @@ 
  * signal frames is set up as expected when enabled simultaneously.
  */
 
+#include <kselftest.h>
 #include <signal.h>
 #include <ucontext.h>
 #include <sys/prctl.h>
 
 #include "test_signals_utils.h"
+#include "sve_helpers.h"
 #include "testcases.h"
 
 static union {
 	ucontext_t uc;
 	char buf[1024 * 128];
 } context;
-static unsigned int vls[SVE_VQ_MAX];
-unsigned int nvls = 0;
 
 static bool sme_get_vls(struct tdescr *td)
 {
-	int vq, vl;
+	int res = sve_fill_vls(VLS_USE_SME, 1);
 
-	/*
-	 * Enumerate up to SVE_VQ_MAX vector lengths
-	 */
-	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
-		vl = prctl(PR_SME_SET_VL, vq * 16);
-		if (vl == -1)
-			return false;
-
-		vl &= PR_SME_VL_LEN_MASK;
-
-		/* Did we find the lowest supported VL? */
-		if (vq < sve_vq_from_vl(vl))
-			break;
+	if (!res)
+		return true;
 
-		/* Skip missing VLs */
-		vq = sve_vq_from_vl(vl);
-
-		vls[nvls++] = vl;
-	}
-
-	/* We need at least one VL */
-	if (nvls < 1) {
-		fprintf(stderr, "Only %d VL supported\n", nvls);
-		return false;
-	}
+	if (res == KSFT_SKIP)
+		td->result = KSFT_SKIP;
 
-	return true;
+	return false;
 }
 
 static void setup_regs(void)
diff --git a/tools/testing/selftests/arm64/signal/testcases/sve_regs.c b/tools/testing/selftests/arm64/signal/testcases/sve_regs.c
index 8b16eabbb7697..8143eb1c58c18 100644
--- a/tools/testing/selftests/arm64/signal/testcases/sve_regs.c
+++ b/tools/testing/selftests/arm64/signal/testcases/sve_regs.c
@@ -6,47 +6,31 @@ 
  * expected.
  */
 
+#include <kselftest.h>
 #include <signal.h>
 #include <ucontext.h>
 #include <sys/prctl.h>
 
 #include "test_signals_utils.h"
+#include "sve_helpers.h"
 #include "testcases.h"
 
 static union {
 	ucontext_t uc;
 	char buf[1024 * 64];
 } context;
-static unsigned int vls[SVE_VQ_MAX];
-unsigned int nvls = 0;
 
 static bool sve_get_vls(struct tdescr *td)
 {
-	int vq, vl;
+	int res = sve_fill_vls(VLS_USE_SVE, 1);
 
-	/*
-	 * Enumerate up to SVE_VQ_MAX vector lengths
-	 */
-	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
-		vl = prctl(PR_SVE_SET_VL, vq * 16);
-		if (vl == -1)
-			return false;
-
-		vl &= PR_SVE_VL_LEN_MASK;
-
-		/* Skip missing VLs */
-		vq = sve_vq_from_vl(vl);
+	if (!res)
+		return true;
 
-		vls[nvls++] = vl;
-	}
-
-	/* We need at least one VL */
-	if (nvls < 1) {
-		fprintf(stderr, "Only %d VL supported\n", nvls);
-		return false;
-	}
+	if (res == KSFT_SKIP)
+		td->result = KSFT_SKIP;
 
-	return true;
+	return false;
 }
 
 static void setup_sve_regs(void)
diff --git a/tools/testing/selftests/arm64/signal/testcases/za_no_regs.c b/tools/testing/selftests/arm64/signal/testcases/za_no_regs.c
index 4d6f94b6178f3..ce26e9c2fa5e3 100644
--- a/tools/testing/selftests/arm64/signal/testcases/za_no_regs.c
+++ b/tools/testing/selftests/arm64/signal/testcases/za_no_regs.c
@@ -6,47 +6,31 @@ 
  * expected.
  */
 
+#include <kselftest.h>
 #include <signal.h>
 #include <ucontext.h>
 #include <sys/prctl.h>
 
 #include "test_signals_utils.h"
+#include "sve_helpers.h"
 #include "testcases.h"
 
 static union {
 	ucontext_t uc;
 	char buf[1024 * 128];
 } context;
-static unsigned int vls[SVE_VQ_MAX];
-unsigned int nvls = 0;
 
 static bool sme_get_vls(struct tdescr *td)
 {
-	int vq, vl;
+	int res = sve_fill_vls(VLS_USE_SME, 1);
 
-	/*
-	 * Enumerate up to SME_VQ_MAX vector lengths
-	 */
-	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
-		vl = prctl(PR_SME_SET_VL, vq * 16);
-		if (vl == -1)
-			return false;
-
-		vl &= PR_SME_VL_LEN_MASK;
-
-		/* Skip missing VLs */
-		vq = sve_vq_from_vl(vl);
+	if (!res)
+		return true;
 
-		vls[nvls++] = vl;
-	}
-
-	/* We need at least one VL */
-	if (nvls < 1) {
-		fprintf(stderr, "Only %d VL supported\n", nvls);
-		return false;
-	}
+	if (res == KSFT_SKIP)
+		td->result = KSFT_SKIP;
 
-	return true;
+	return false;
 }
 
 static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
diff --git a/tools/testing/selftests/arm64/signal/testcases/za_regs.c b/tools/testing/selftests/arm64/signal/testcases/za_regs.c
index 174ad66566964..b9e13f27f1f9a 100644
--- a/tools/testing/selftests/arm64/signal/testcases/za_regs.c
+++ b/tools/testing/selftests/arm64/signal/testcases/za_regs.c
@@ -6,51 +6,31 @@ 
  * expected.
  */
 
+#include <kselftest.h>
 #include <signal.h>
 #include <ucontext.h>
 #include <sys/prctl.h>
 
 #include "test_signals_utils.h"
+#include "sve_helpers.h"
 #include "testcases.h"
 
 static union {
 	ucontext_t uc;
 	char buf[1024 * 128];
 } context;
-static unsigned int vls[SVE_VQ_MAX];
-unsigned int nvls = 0;
 
 static bool sme_get_vls(struct tdescr *td)
 {
-	int vq, vl;
+	int res = sve_fill_vls(VLS_USE_SME, 1);
 
-	/*
-	 * Enumerate up to SME_VQ_MAX vector lengths
-	 */
-	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
-		vl = prctl(PR_SME_SET_VL, vq * 16);
-		if (vl == -1)
-			return false;
-
-		vl &= PR_SME_VL_LEN_MASK;
-
-		/* Did we find the lowest supported VL? */
-		if (vq < sve_vq_from_vl(vl))
-			break;
+	if (!res)
+		return true;
 
-		/* Skip missing VLs */
-		vq = sve_vq_from_vl(vl);
-
-		vls[nvls++] = vl;
-	}
-
-	/* We need at least one VL */
-	if (nvls < 1) {
-		fprintf(stderr, "Only %d VL supported\n", nvls);
-		return false;
-	}
+	if (res == KSFT_SKIP)
+		td->result = KSFT_SKIP;
 
-	return true;
+	return false;
 }
 
 static void setup_za_regs(void)