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[MTD] mtdoops: Add a magic number to logged kernel oops 

Add a magic number to logged kernel oops messages so that they
can be more accurately detected rather than just having to rely
on the sequence number. This also allows easier detection of
saved crashes by userspace.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Richard Purdie 2008-07-26 09:22:45 +01:00 committed by David Woodhouse
parent ecd5b31023
commit f0482ee366
1 changed files with 18 additions and 14 deletions
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32
drivers/mtd/mtdoops.c
View File

@ -33,6 +33,7 @@
#include <linux/interrupt.h>
#include <linux/mtd/mtd.h>
#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
#define OOPS_PAGE_SIZE 4096
static struct mtdoops_context {
@ -224,31 +225,33 @@ static void find_next_position(struct mtdoops_context *cxt)
{
struct mtd_info *mtd = cxt->mtd;
int ret, page, maxpos = 0;
u32 count, maxcount = 0xffffffff;
u32 count[2], maxcount = 0xffffffff;
size_t retlen;
for (page = 0; page < cxt->oops_pages; page++) {
ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]);
if ((retlen != 8) || ((ret < 0) && (ret != -EUCLEAN))) {
printk(KERN_ERR "mtdoops: Read failure at %d (%td of 8 read)"
", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
continue;
}
if (count == 0xffffffff)
if (count[1] != MTDOOPS_KERNMSG_MAGIC)
continue;
if (count[0] == 0xffffffff)
continue;
if (maxcount == 0xffffffff) {
maxcount = count;
maxcount = count[0];
maxpos = page;
} else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
maxcount = count;
} else if ((count[0] < 0x40000000) && (maxcount > 0xc0000000)) {
maxcount = count[0];
maxpos = page;
} else if ((count > maxcount) && (count < 0xc0000000)) {
maxcount = count;
} else if ((count[0] > maxcount) && (count[0] < 0xc0000000)) {
maxcount = count[0];
maxpos = page;
} else if ((count > maxcount) && (count > 0xc0000000)
} else if ((count[0] > maxcount) && (count[0] > 0xc0000000)
&& (maxcount > 0x80000000)) {
maxcount = count;
maxcount = count[0];
maxpos = page;
}
}
@ -358,8 +361,9 @@ mtdoops_console_write(struct console *co, const char *s, unsigned int count)
if (cxt->writecount == 0) {
u32 *stamp = cxt->oops_buf;
*stamp = cxt->nextcount;
cxt->writecount = 4;
*stamp++ = cxt->nextcount;
*stamp = MTDOOPS_KERNMSG_MAGIC;
cxt->writecount = 8;
}
if ((count + cxt->writecount) > OOPS_PAGE_SIZE)