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authorArjan van de Ven <arjan@infradead.org>2008-01-30 13:34:08 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:34:08 +0100
commitedeed30589f5defe63ce6aaae56f2b7c855e4520 (patch)
treea49736ff74dcbd3feba3c8318b204fb2165f892d /arch/x86/kernel/test_rodata.c
parentadafdf6a4e45f2d1051e10aebe13025e89dbdf6d (diff)
x86: add testcases for RODATA and NX protections/attributes
Latest update; I now have 4 NX tests, but 2 fail so they're #if 0'd. I also cleaned up the NX test code quite a bit, and got rid of the ugly exception table sorting stuff. From: Arjan van de Ven <arjan@linux.intel.com> This patch adds testcases for the CONFIG_DEBUG_RODATA configuration option as well as the NX CPU feature/mappings. Both testcases can move to tests/ once that patch gets merged into mainline. (I'm half considering moving the rodata test into mm/init.c but I'll wait with that until init.c is unified) As part of this I had to fix a not-quite-right alignment in the vmlinux.lds.h for the RODATA sections, which lead to 1 page less being marked read only. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/test_rodata.c')
-rw-r--r--arch/x86/kernel/test_rodata.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/arch/x86/kernel/test_rodata.c b/arch/x86/kernel/test_rodata.c
new file mode 100644
index 00000000000..4c163772000
--- /dev/null
+++ b/arch/x86/kernel/test_rodata.c
@@ -0,0 +1,86 @@
+/*
+ * test_rodata.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/module.h>
+#include <asm/sections.h>
+extern int rodata_test_data;
+
+int rodata_test(void)
+{
+ unsigned long result;
+ unsigned long start, end;
+
+ /* test 1: read the value */
+ /* If this test fails, some previous testrun has clobbered the state */
+ if (!rodata_test_data) {
+ printk(KERN_ERR "rodata_test: test 1 fails (start data)\n");
+ return -ENODEV;
+ }
+
+ /* test 2: write to the variable; this should fault */
+ /*
+ * If this test fails, we managed to overwrite the data
+ *
+ * This is written in assembly to be able to catch the
+ * exception that is supposed to happen in the correct
+ * case
+ */
+
+ result = 1;
+ asm volatile(
+ "0: mov %[zero],(%[rodata_test])\n"
+ " mov %[zero], %[rslt]\n"
+ "1:\n"
+ ".section .fixup,\"ax\"\n"
+ "2: jmp 1b\n"
+ ".previous\n"
+ ".section __ex_table,\"a\"\n"
+ " .align 16\n"
+#ifdef CONFIG_X86_32
+ " .long 0b,2b\n"
+#else
+ " .quad 0b,2b\n"
+#endif
+ ".previous"
+ : [rslt] "=r" (result)
+ : [rodata_test] "r" (&rodata_test_data), [zero] "r" (0UL)
+ );
+
+
+ if (!result) {
+ printk(KERN_ERR "rodata_test: test data was not read only\n");
+ return -ENODEV;
+ }
+
+ /* test 3: check the value hasn't changed */
+ /* If this test fails, we managed to overwrite the data */
+ if (!rodata_test_data) {
+ printk(KERN_ERR "rodata_test: Test 3 failes (end data)\n");
+ return -ENODEV;
+ }
+ /* test 4: check if the rodata section is 4Kb aligned */
+ start = (unsigned long)__start_rodata;
+ end = (unsigned long)__end_rodata;
+ if (start & (PAGE_SIZE - 1)) {
+ printk(KERN_ERR "rodata_test: .rodata is not 4k aligned\n");
+ return -ENODEV;
+ }
+ if (end & (PAGE_SIZE - 1)) {
+ printk(KERN_ERR "rodata_test: .rodata end is not 4k aligned\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Testcase for the DEBUG_RODATA infrastructure");
+MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");