Subject: [PATCH 1/5] selftests/powerpc: Add exec() test to check for spr sanitisation

From: Cyril Bur <[email-masked]>
Date: Wed, 23 Mar 2016 16:47:01 +1100

Signed-off-by: Cyril Bur <[email-masked]>
---
 tools/testing/selftests/powerpc/syscalls/Makefile  |  3 +-
 .../testing/selftests/powerpc/syscalls/spr_exec.c  | 78 ++++++++++++++++++++++
 2 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/powerpc/syscalls/spr_exec.c

diff --git a/tools/testing/selftests/powerpc/syscalls/Makefile b/tools/testing/selftests/powerpc/syscalls/Makefile
index b35c794..291ba45 100644
--- a/tools/testing/selftests/powerpc/syscalls/Makefile
+++ b/tools/testing/selftests/powerpc/syscalls/Makefile
@@ -1,10 +1,11 @@
-TEST_PROGS := ipc_unmuxed
+TEST_PROGS := ipc_unmuxed spr_exec
 
 CFLAGS += -I../../../../../usr/include
 
 all: $(TEST_PROGS)
 
 $(TEST_PROGS): ../harness.c
+spr_exec: ../utils.c
 
 include ../../lib.mk
 
diff --git a/tools/testing/selftests/powerpc/syscalls/spr_exec.c b/tools/testing/selftests/powerpc/syscalls/spr_exec.c
new file mode 100644
index 0000000..5ecd6ca
--- /dev/null
+++ b/tools/testing/selftests/powerpc/syscalls/spr_exec.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2016, Cyril Bur, IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * This test checks that the TAR (an SPR) is correctly sanitised across
+ * execve()
+ */
+#include <asm/cputable.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/auxv.h>
+#include <unistd.h>
+
+#include "utils.h"
+
+static char *name;
+static int count;
+
+static int exec_spr(void)
+{
+	unsigned long tar;
+	char buffer[10];
+	char *args[3];
+
+	asm __volatile__(
+			"mfspr %[tar], 815"
+			: [tar] "=r" (tar)
+			);
+	/* Read TAR */
+	FAIL_IF(tar != 0);
+
+	tar = 1;
+	asm __volatile__(
+			"mtspr 815, %[tar]"
+			:
+			: [tar] "r" (tar)
+			);
+
+	FAIL_IF(sprintf(buffer, "%d", count + 1) == -1);
+	args[0] = name;
+	args[1] = buffer;
+	args[2] = NULL;
+	FAIL_IF(execve(name, args, NULL) == -1);
+
+	return 0;
+}
+
+static int exec_spr_check(void)
+{
+	unsigned long tar;
+
+	asm __volatile__(
+			"mfspr %[tar], 815;"
+			: [tar] "=r" (tar)
+			);
+	/* Read TAR */
+	FAIL_IF(tar != 0);
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_TAR));
+	name = argv[0];
+	/* Do this a few times to be sure isn't a false negative */
+	if (argc == 1 || atoi(argv[1]) < 10) {
+		if (argc > 1)
+			count = atoi(argv[1]);
+		return test_harness(exec_spr, "spr_exec");
+	} else {
+		return test_harness(exec_spr_check, "spr_exec_check");
+	}
+}
-- 
2.7.4