kselftest: arm64: fake_sigreturn_misaligned_sp

Add a simple fake_sigreturn testcase which places a valid sigframe on a
non-16 bytes aligned SP. Expects a SIGSEGV on test PASS.

Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c
new file mode 100644 (file)
index 0000000..1e089e6
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Place a fake sigframe on the stack at a misaligned SP: on sigreturn
+ * Kernel must spot this attempt and the test case is expected to be
+ * terminated via SEGV.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+
+static int fake_sigreturn_misaligned_run(struct tdescr *td,
+                                        siginfo_t *si, ucontext_t *uc)
+{
+       /* just to fill the ucontext_t with something real */
+       if (!get_current_context(td, &sf.uc))
+               return 1;
+
+       /* Forcing sigframe on misaligned SP (16 + 3) */
+       fake_sigreturn(&sf, sizeof(sf), 3);
+
+       return 1;
+}
+
+struct tdescr tde = {
+               .name = "FAKE_SIGRETURN_MISALIGNED_SP",
+               .descr = "Triggers a sigreturn with a misaligned sigframe",
+               .sig_ok = SIGSEGV,
+               .timeout = 3,
+               .run = fake_sigreturn_misaligned_run,
+};