mm: add arch-independent testcases for RODATA
This patch makes arch-independent testcases for RODATA. Both x86 and
x86_64 already have testcases for RODATA, But they are arch-specific
because using inline assembly directly.
And cacheflush.h is not a suitable location for rodata-test related
things. Since they were in cacheflush.h, If someone change the state of
CONFIG_DEBUG_RODATA_TEST, It cause overhead of kernel build.
To solve the above issues, write arch-independent testcases and move it
to shared location.
[jinb.park7@gmail.com: fix config dependency]
Link: http://lkml.kernel.org/r/20170209131625.GA16954@pjb1027-Latitude-E5410
Link: http://lkml.kernel.org/r/20170129105436.GA9303@pjb1027-Latitude-E5410
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/rodata_test.c b/mm/rodata_test.c
new file mode 100644
index 0000000..0fd2167
--- /dev/null
+++ b/mm/rodata_test.c
@@ -0,0 +1,56 @@
+/*
+ * rodata_test.c: functional test for mark_rodata_ro function
+ *
+ * (C) Copyright 2008 Intel Corporation
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ *
+ * 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; version 2
+ * of the License.
+ */
+#include <linux/uaccess.h>
+#include <asm/sections.h>
+
+const int rodata_test_data = 0xC3;
+EXPORT_SYMBOL_GPL(rodata_test_data);
+
+void rodata_test(void)
+{
+ unsigned long start, end;
+ int zero = 0;
+
+ /* test 1: read the value */
+ /* If this test fails, some previous testrun has clobbered the state */
+ if (!rodata_test_data) {
+ pr_err("rodata_test: test 1 fails (start data)\n");
+ return;
+ }
+
+ /* test 2: write to the variable; this should fault */
+ if (!probe_kernel_write((void *)&rodata_test_data,
+ (void *)&zero, sizeof(zero))) {
+ pr_err("rodata_test: test data was not read only\n");
+ return;
+ }
+
+ /* test 3: check the value hasn't changed */
+ if (rodata_test_data == zero) {
+ pr_err("rodata_test: test data was changed\n");
+ return;
+ }
+
+ /* test 4: check if the rodata section is PAGE_SIZE aligned */
+ start = (unsigned long)__start_rodata;
+ end = (unsigned long)__end_rodata;
+ if (start & (PAGE_SIZE - 1)) {
+ pr_err("rodata_test: start of .rodata is not page size aligned\n");
+ return;
+ }
+ if (end & (PAGE_SIZE - 1)) {
+ pr_err("rodata_test: end of .rodata is not page size aligned\n");
+ return;
+ }
+
+ pr_info("rodata_test: all tests were successful\n");
+}