1 files changed, 127 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/signal/sigreturn_vdso.c b/tools/testing/selftests/powerpc/signal/sigreturn_vdso.c
new file mode 100644
index 000000000000..e282fff0fe25
--- /dev/null
+++ b/tools/testing/selftests/powerpc/signal/sigreturn_vdso.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test that we can take signals with and without the VDSO mapped, which trigger
+ * different paths in the signal handling code.
+ *
+ * See handle_rt_signal64() and setup_trampoline() in signal_64.c
+ */
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <stdio.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+// Ensure assert() is not compiled out
+#undef NDEBUG
+#include <assert.h>
+
+#include "utils.h"
+
+static int search_proc_maps(char *needle, unsigned long *low, unsigned long *high)
+{
+	unsigned long start, end;
+	static char buf[4096];
+	char name[128];
+	FILE *f;
+	int rc = -1;
+
+	f = fopen("/proc/self/maps", "r");
+	if (!f) {
+		perror("fopen");
+		return -1;
+	}
+
+	while (fgets(buf, sizeof(buf), f)) {
+		rc = sscanf(buf, "%lx-%lx %*c%*c%*c%*c %*x %*d:%*d %*d %127s\n",
+			    &start, &end, name);
+		if (rc == 2)
+			continue;
+
+		if (rc != 3) {
+			printf("sscanf errored\n");
+			rc = -1;
+			break;
+		}
+
+		if (strstr(name, needle)) {
+			*low = start;
+			*high = end - 1;
+			rc = 0;
+			break;
+		}
+	}
+
+	fclose(f);
+
+	return rc;
+}
+
+static volatile sig_atomic_t took_signal = 0;
+
+static void sigusr1_handler(int sig)
+{
+	took_signal++;
+}
+
+int test_sigreturn_vdso(void)
+{
+	unsigned long low, high, size;
+	struct sigaction act;
+	char *p;
+
+	act.sa_handler = sigusr1_handler;
+	act.sa_flags = 0;
+	sigemptyset(&act.sa_mask);
+
+	assert(sigaction(SIGUSR1, &act, NULL) == 0);
+
+	// Confirm the VDSO is mapped, and work out where it is
+	assert(search_proc_maps("[vdso]", &low, &high) == 0);
+	size = high - low + 1;
+	printf("VDSO is at 0x%lx-0x%lx (%lu bytes)\n", low, high, size);
+
+	kill(getpid(), SIGUSR1);
+	assert(took_signal == 1);
+	printf("Signal delivered OK with VDSO mapped\n");
+
+	// Remap the VDSO somewhere else
+	p = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+	assert(p != MAP_FAILED);
+	assert(mremap((void *)low, size, size, MREMAP_MAYMOVE|MREMAP_FIXED, p) != MAP_FAILED);
+	assert(search_proc_maps("[vdso]", &low, &high) == 0);
+	size = high - low + 1;
+	printf("VDSO moved to 0x%lx-0x%lx (%lu bytes)\n", low, high, size);
+
+	kill(getpid(), SIGUSR1);
+	assert(took_signal == 2);
+	printf("Signal delivered OK with VDSO moved\n");
+
+	assert(munmap((void *)low, size) == 0);
+	printf("Unmapped VDSO\n");
+
+	// Confirm the VDSO is not mapped anymore
+	assert(search_proc_maps("[vdso]", &low, &high) != 0);
+
+	// Make the stack executable
+	assert(search_proc_maps("[stack]", &low, &high) == 0);
+	size = high - low + 1;
+	mprotect((void *)low, size, PROT_READ|PROT_WRITE|PROT_EXEC);
+	printf("Remapped the stack executable\n");
+
+	kill(getpid(), SIGUSR1);
+	assert(took_signal == 3);
+	printf("Signal delivered OK with VDSO unmapped\n");
+
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(test_sigreturn_vdso, "sigreturn_vdso");
+}