kselftest/arm64: Include larger SVE and SME VLs in signal tests

Now that the core utilities for signal testing support handling data in
EXTRA_CONTEXT blocks we can test larger SVE and SME VLs which spill over
the limits in the base signal context. This is done by defining storage
for the context as a union with a ucontext_t and a buffer together with
some helpers for getting relevant sizes and offsets like we do for
fake_sigframe, this isn't the most lovely code ever but is fairly
straightforward to implement and much less invasive to the somewhat
unclear and indistinct layers of abstraction in the signal handling test
code.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220829160703.874492-11-broonie@kernel.orgSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

tools/testing/selftests/arm64/signal/testcases/ssve_regs.c

@@ -13,7 +13,10 @@
 #include "test_signals_utils.h"
 #include "testcases.h"
 
-struct fake_sigframe sf;
+static union {
+	ucontext_t uc;
+	char buf[1024 * 64];
+} context;
 static unsigned int vls[SVE_VQ_MAX];
 unsigned int nvls = 0;
 
@@ -55,8 +58,8 @@ static void setup_ssve_regs(void)
 static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
 			 unsigned int vl)
 {
-	size_t resv_sz, offset;
-	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
+	size_t offset;
+	struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context);
 	struct sve_context *ssve;
 	int ret;
 
@@ -73,11 +76,11 @@ static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
 	 * in it.
 	 */
 	setup_ssve_regs();
-	if (!get_current_context(td, &sf.uc, sizeof(sf.uc)))
+	if (!get_current_context(td, &context.uc, sizeof(context)))
 		return 1;
 
-	resv_sz = GET_SF_RESV_SIZE(sf);
-	head = get_header(head, SVE_MAGIC, resv_sz, &offset);
+	head = get_header(head, SVE_MAGIC, GET_BUF_RESV_SIZE(context),
+			  &offset);
 	if (!head) {
 		fprintf(stderr, "No SVE context\n");
 		return 1;
@@ -101,16 +104,6 @@ static int sme_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
 	int i;
 
 	for (i = 0; i < nvls; i++) {
-		/*
-		 * TODO: the signal test helpers can't currently cope
-		 * with signal frames bigger than struct sigcontext,
-		 * skip VLs that will trigger that.
-		 */
-		if (vls[i] > 64) {
-			printf("Skipping VL %u due to stack size\n", vls[i]);
-			continue;
-		}
-
 		if (do_one_sme_vl(td, si, uc, vls[i]))
 			return 1;
 	}

tools/testing/selftests/arm64/signal/testcases/sve_regs.c

@@ -13,7 +13,10 @@
 #include "test_signals_utils.h"
 #include "testcases.h"
 
-struct fake_sigframe sf;
+static union {
+	ucontext_t uc;
+	char buf[1024 * 64];
+} context;
 static unsigned int vls[SVE_VQ_MAX];
 unsigned int nvls = 0;
 
@@ -55,8 +58,8 @@ static void setup_sve_regs(void)
 static int do_one_sve_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
 			 unsigned int vl)
 {
-	size_t resv_sz, offset;
-	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
+	size_t offset;
+	struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context);
 	struct sve_context *sve;
 
 	fprintf(stderr, "Testing VL %d\n", vl);
@@ -71,11 +74,11 @@ static int do_one_sve_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
 	 * in it.
 	 */
 	setup_sve_regs();
-	if (!get_current_context(td, &sf.uc, sizeof(sf.uc)))
+	if (!get_current_context(td, &context.uc, sizeof(context)))
 		return 1;
 
-	resv_sz = GET_SF_RESV_SIZE(sf);
-	head = get_header(head, SVE_MAGIC, resv_sz, &offset);
+	head = get_header(head, SVE_MAGIC, GET_BUF_RESV_SIZE(context),
+			  &offset);
 	if (!head) {
 		fprintf(stderr, "No SVE context\n");
 		return 1;
@@ -99,14 +102,6 @@ static int sve_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
 	int i;
 
 	for (i = 0; i < nvls; i++) {
-		/*
-		 * TODO: the signal test helpers can't currently cope
-		 * with signal frames bigger than struct sigcontext,
-		 * skip VLs that will trigger that.
-		 */
-		if (vls[i] > 64)
-			continue;
-
 		if (do_one_sve_vl(td, si, uc, vls[i]))
 			return 1;
 	}

tools/testing/selftests/arm64/signal/testcases/testcases.h

@@ -30,6 +30,13 @@
 #define GET_SF_RESV_SIZE(sf) \
 	sizeof((sf).uc.uc_mcontext.__reserved)
 
+#define GET_BUF_RESV_HEAD(buf) \
+	(struct _aarch64_ctx *)(&(buf).uc.uc_mcontext.__reserved)
+
+#define GET_BUF_RESV_SIZE(buf) \
+	(sizeof(buf) - sizeof(buf.uc) +	\
+	 sizeof((buf).uc.uc_mcontext.__reserved))
+
 #define GET_UCP_RESV_SIZE(ucp) \
 	sizeof((ucp)->uc_mcontext.__reserved)
 

tools/testing/selftests/arm64/signal/testcases/za_regs.c

@@ -13,7 +13,10 @@
 #include "test_signals_utils.h"
 #include "testcases.h"
 
-struct fake_sigframe sf;
+static union {
+	ucontext_t uc;
+	char buf[1024 * 128];
+} context;
 static unsigned int vls[SVE_VQ_MAX];
 unsigned int nvls = 0;
 
@@ -57,8 +60,8 @@ static char zeros[ZA_SIG_REGS_SIZE(SVE_VQ_MAX)];
 static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
 			 unsigned int vl)
 {
-	size_t resv_sz, offset;
-	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
+	size_t offset;
+	struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context);
 	struct za_context *za;
 
 	fprintf(stderr, "Testing VL %d\n", vl);
@@ -73,11 +76,10 @@ static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
 	 * in it.
 	 */
 	setup_za_regs();
-	if (!get_current_context(td, &sf.uc, sizeof(sf.uc)))
+	if (!get_current_context(td, &context.uc, sizeof(context)))
 		return 1;
 
-	resv_sz = GET_SF_RESV_SIZE(sf);
-	head = get_header(head, ZA_MAGIC, resv_sz, &offset);
+	head = get_header(head, ZA_MAGIC, GET_BUF_RESV_SIZE(context), &offset);
 	if (!head) {
 		fprintf(stderr, "No ZA context\n");
 		return 1;
@@ -113,16 +115,6 @@ static int sme_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
 	int i;
 
 	for (i = 0; i < nvls; i++) {
-		/*
-		 * TODO: the signal test helpers can't currently cope
-		 * with signal frames bigger than struct sigcontext,
-		 * skip VLs that will trigger that.
-		 */
-		if (vls[i] > 32) {
-			printf("Skipping VL %u due to stack size\n", vls[i]);
-			continue;
-		}
-
 		if (do_one_sme_vl(td, si, uc, vls[i]))
 			return 1;
 	}