kselftest/arm64: Add a test for signal frames with ZA disabled

When ZA is disabled there should be no register data in the ZA signal
frame, add a test case which confirms that this is the case.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220829155728.854947-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/tools/testing/selftests/arm64/signal/testcases/za_no_regs.c b/tools/testing/selftests/arm64/signal/testcases/za_no_regs.c
new file mode 100644 (file)
index 0000000..4d6f94b
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/za_no_regs.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 ARM Limited
+ *
+ * Verify that the ZA register context in signal frames is set up as
+ * expected.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+#include <sys/prctl.h>
+
+#include "test_signals_utils.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;
+
+       /*
+        * 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);
+
+               vls[nvls++] = vl;
+       }
+
+       /* We need at least one VL */
+       if (nvls < 1) {
+               fprintf(stderr, "Only %d VL supported\n", nvls);
+               return false;
+       }
+
+       return true;
+}
+
+static int do_one_sme_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
+                        unsigned int vl)
+{
+       size_t offset;
+       struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context);
+       struct za_context *za;
+
+       fprintf(stderr, "Testing VL %d\n", vl);
+
+       if (prctl(PR_SME_SET_VL, vl) != vl) {
+               fprintf(stderr, "Failed to set VL\n");
+               return 1;
+       }
+
+       /*
+        * Get a signal context which should have a SVE frame and registers
+        * in it.
+        */
+       if (!get_current_context(td, &context.uc, sizeof(context)))
+               return 1;
+
+       head = get_header(head, ZA_MAGIC, GET_BUF_RESV_SIZE(context), &offset);
+       if (!head) {
+               fprintf(stderr, "No ZA context\n");
+               return 1;
+       }
+
+       za = (struct za_context *)head;
+       if (za->vl != vl) {
+               fprintf(stderr, "Got VL %d, expected %d\n", za->vl, vl);
+               return 1;
+       }
+
+       if (head->size != ZA_SIG_REGS_OFFSET) {
+               fprintf(stderr, "Context size %u, expected %lu\n",
+                       head->size, ZA_SIG_REGS_OFFSET);
+               return 1;
+       }
+
+       /* The actual size validation is done in get_current_context() */
+       fprintf(stderr, "Got expected size %u and VL %d\n",
+               head->size, za->vl);
+
+       return 0;
+}
+
+static int sme_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
+{
+       int i;
+
+       for (i = 0; i < nvls; i++) {
+               if (do_one_sme_vl(td, si, uc, vls[i]))
+                       return 1;
+       }
+
+       td->pass = 1;
+
+       return 0;
+}
+
+struct tdescr tde = {
+       .name = "ZA registers - ZA disabled",
+       .descr = "Check ZA context with ZA disabled",
+       .feats_required = FEAT_SME,
+       .timeout = 3,
+       .init = sme_get_vls,
+       .run = sme_regs,
+};