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authorIngo Molnar <mingo@elte.hu>2008-02-06 22:39:45 +0100
committerIngo Molnar <mingo@elte.hu>2008-02-06 22:39:45 +0100
commit971a52d66a3e87d4d2f5d3455e62680447cdb8e9 (patch)
treec55f87abe255ef85854ab36e7d081fd8e4d2aec1 /arch
parentf1fbabb312d657262322f4ce68b30a95f501945c (diff)
x86: delay CPA self-test and repeat it
delay the CPA self-test so that any impact (corruption) of user-space pagetables can be triggered. Repeat the test every 30 seconds. this would have prevented the bug fixed by 8cb2a7c1e95e472b5, at its source. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig.debug4
-rw-r--r--arch/x86/mm/pageattr-test.c65
2 files changed, 53 insertions, 16 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 2e1e3af28c3..fa555148823 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -220,9 +220,9 @@ config DEBUG_BOOT_PARAMS
This option will cause struct boot_params to be exported via debugfs.
config CPA_DEBUG
- bool "CPA self test code"
+ bool "CPA self-test code"
depends on DEBUG_KERNEL
help
- Do change_page_attr self tests at boot.
+ Do change_page_attr() self-tests every 30 seconds.
endmenu
diff --git a/arch/x86/mm/pageattr-test.c b/arch/x86/mm/pageattr-test.c
index 398f3a578dd..ed820160035 100644
--- a/arch/x86/mm/pageattr-test.c
+++ b/arch/x86/mm/pageattr-test.c
@@ -5,6 +5,7 @@
* and compares page tables forwards and afterwards.
*/
#include <linux/bootmem.h>
+#include <linux/kthread.h>
#include <linux/random.h>
#include <linux/kernel.h>
#include <linux/init.h>
@@ -14,8 +15,13 @@
#include <asm/pgtable.h>
#include <asm/kdebug.h>
+/*
+ * Only print the results of the first pass:
+ */
+static __read_mostly int print = 1;
+
enum {
- NTEST = 4000,
+ NTEST = 400,
#ifdef CONFIG_X86_64
LPS = (1 << PMD_SHIFT),
#elif defined(CONFIG_X86_PAE)
@@ -31,7 +37,7 @@ struct split_state {
long min_exec, max_exec;
};
-static __init int print_split(struct split_state *s)
+static int print_split(struct split_state *s)
{
long i, expected, missed = 0;
int printed = 0;
@@ -82,10 +88,13 @@ static __init int print_split(struct split_state *s)
s->max_exec = addr;
}
}
- printk(KERN_INFO
- "CPA mapping 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
- s->spg, s->lpg, s->gpg, s->exec,
- s->min_exec != ~0UL ? s->min_exec : 0, s->max_exec, missed);
+ if (print) {
+ printk(KERN_INFO
+ " 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
+ s->spg, s->lpg, s->gpg, s->exec,
+ s->min_exec != ~0UL ? s->min_exec : 0,
+ s->max_exec, missed);
+ }
expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
if (expected != i) {
@@ -96,11 +105,11 @@ static __init int print_split(struct split_state *s)
return err;
}
-static unsigned long __initdata addr[NTEST];
-static unsigned int __initdata len[NTEST];
+static unsigned long addr[NTEST];
+static unsigned int len[NTEST];
/* Change the global bit on random pages in the direct mapping */
-static __init int exercise_pageattr(void)
+static int pageattr_test(void)
{
struct split_state sa, sb, sc;
unsigned long *bm;
@@ -110,7 +119,8 @@ static __init int exercise_pageattr(void)
int i, k;
int err;
- printk(KERN_INFO "CPA exercising pageattr\n");
+ if (print)
+ printk(KERN_INFO "CPA self-test:\n");
bm = vmalloc((max_pfn_mapped + 7) / 8);
if (!bm) {
@@ -186,7 +196,6 @@ static __init int exercise_pageattr(void)
failed += print_split(&sb);
- printk(KERN_INFO "CPA reverting everything\n");
for (i = 0; i < NTEST; i++) {
if (!addr[i])
continue;
@@ -214,12 +223,40 @@ static __init int exercise_pageattr(void)
failed += print_split(&sc);
if (failed) {
- printk(KERN_ERR "CPA selftests NOT PASSED. Please report.\n");
+ printk(KERN_ERR "NOT PASSED. Please report.\n");
WARN_ON(1);
+ return -EINVAL;
} else {
- printk(KERN_INFO "CPA selftests PASSED\n");
+ if (print)
+ printk(KERN_INFO "ok.\n");
}
return 0;
}
-module_init(exercise_pageattr);
+
+static int do_pageattr_test(void *__unused)
+{
+ while (!kthread_should_stop()) {
+ schedule_timeout_interruptible(HZ*30);
+ if (pageattr_test() < 0)
+ break;
+ if (print)
+ print--;
+ }
+ return 0;
+}
+
+static int start_pageattr_test(void)
+{
+ struct task_struct *p;
+
+ p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
+ if (!IS_ERR(p))
+ wake_up_process(p);
+ else
+ WARN_ON(1);
+
+ return 0;
+}
+
+module_init(start_pageattr_test);