From edeed30589f5defe63ce6aaae56f2b7c855e4520 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Wed, 30 Jan 2008 13:34:08 +0100 Subject: 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 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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/test_rodata.c | 86 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 arch/x86/kernel/test_rodata.c (limited to 'arch/x86/kernel/test_rodata.c') diff --git a/arch/x86/kernel/test_rodata.c b/arch/x86/kernel/test_rodata.c new file mode 100644 index 000000000000..4c163772000e --- /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 + * + * 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 +#include +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 "); -- cgit v1.2.3-59-g8ed1b