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authorLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 13:23:43 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 13:23:43 -0500
commit60d9aa758c00f20ade0cb1951f6a934f628dd2d7 (patch)
treee3bdfa4ec0d3f9a29a822810b8b9188c7d613cbd /kernel/printk.c
parentb2adf0cbec4cf0934c63f48f893e0cebde380d0c (diff)
parent2e16cfca6e17ae37ae21feca080a6f2eca9087dc (diff)
Merge git://git.infradead.org/mtd-2.6
* git://git.infradead.org/mtd-2.6: (90 commits) jffs2: Fix long-standing bug with symlink garbage collection. mtd: OneNAND: Fix test of unsigned in onenand_otp_walk() mtd: cfi_cmdset_0002, fix lock imbalance Revert "mtd: move mxcnd_remove to .exit.text" mtd: m25p80: add support for Macronix MX25L4005A kmsg_dump: fix build for CONFIG_PRINTK=n mtd: nandsim: add support for 4KiB pages mtd: mtdoops: refactor as a kmsg_dumper mtd: mtdoops: make record size configurable mtd: mtdoops: limit the maximum mtd partition size mtd: mtdoops: keep track of used/unused pages in an array mtd: mtdoops: several minor cleanups core: Add kernel message dumper to call on oopses and panics mtd: add ARM pismo support mtd: pxa3xx_nand: Fix PIO data transfer mtd: nand: fix multi-chip suspend problem mtd: add support for switching old SST chips into QRY mode mtd: fix M29W800D dev_id and uaddr mtd: don't use PF_MEMALLOC mtd: Add bad block table overrides to Davinci NAND driver ... Fixed up conflicts (mostly trivial) in drivers/mtd/devices/m25p80.c drivers/mtd/maps/pcmciamtd.c drivers/mtd/nand/pxa3xx_nand.c kernel/printk.c
Diffstat (limited to 'kernel/printk.c')
-rw-r--r--kernel/printk.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index b5ac4d99c66..1ded8e7dd19 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -34,6 +34,7 @@
34#include <linux/syscalls.h> 34#include <linux/syscalls.h>
35#include <linux/kexec.h> 35#include <linux/kexec.h>
36#include <linux/ratelimit.h> 36#include <linux/ratelimit.h>
37#include <linux/kmsg_dump.h>
37 38
38#include <asm/uaccess.h> 39#include <asm/uaccess.h>
39 40
@@ -1405,4 +1406,122 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies,
1405 return false; 1406 return false;
1406} 1407}
1407EXPORT_SYMBOL(printk_timed_ratelimit); 1408EXPORT_SYMBOL(printk_timed_ratelimit);
1409
1410static DEFINE_SPINLOCK(dump_list_lock);
1411static LIST_HEAD(dump_list);
1412
1413/**
1414 * kmsg_dump_register - register a kernel log dumper.
1415 * @dump: pointer to the kmsg_dumper structure
1416 *
1417 * Adds a kernel log dumper to the system. The dump callback in the
1418 * structure will be called when the kernel oopses or panics and must be
1419 * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
1420 */
1421int kmsg_dump_register(struct kmsg_dumper *dumper)
1422{
1423 unsigned long flags;
1424 int err = -EBUSY;
1425
1426 /* The dump callback needs to be set */
1427 if (!dumper->dump)
1428 return -EINVAL;
1429
1430 spin_lock_irqsave(&dump_list_lock, flags);
1431 /* Don't allow registering multiple times */
1432 if (!dumper->registered) {
1433 dumper->registered = 1;
1434 list_add_tail(&dumper->list, &dump_list);
1435 err = 0;
1436 }
1437 spin_unlock_irqrestore(&dump_list_lock, flags);
1438
1439 return err;
1440}
1441EXPORT_SYMBOL_GPL(kmsg_dump_register);
1442
1443/**
1444 * kmsg_dump_unregister - unregister a kmsg dumper.
1445 * @dump: pointer to the kmsg_dumper structure
1446 *
1447 * Removes a dump device from the system. Returns zero on success and
1448 * %-EINVAL otherwise.
1449 */
1450int kmsg_dump_unregister(struct kmsg_dumper *dumper)
1451{
1452 unsigned long flags;
1453 int err = -EINVAL;
1454
1455 spin_lock_irqsave(&dump_list_lock, flags);
1456 if (dumper->registered) {
1457 dumper->registered = 0;
1458 list_del(&dumper->list);
1459 err = 0;
1460 }
1461 spin_unlock_irqrestore(&dump_list_lock, flags);
1462
1463 return err;
1464}
1465EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
1466
1467static const char const *kmsg_reasons[] = {
1468 [KMSG_DUMP_OOPS] = "oops",
1469 [KMSG_DUMP_PANIC] = "panic",
1470};
1471
1472static const char *kmsg_to_str(enum kmsg_dump_reason reason)
1473{
1474 if (reason >= ARRAY_SIZE(kmsg_reasons) || reason < 0)
1475 return "unknown";
1476
1477 return kmsg_reasons[reason];
1478}
1479
1480/**
1481 * kmsg_dump - dump kernel log to kernel message dumpers.
1482 * @reason: the reason (oops, panic etc) for dumping
1483 *
1484 * Iterate through each of the dump devices and call the oops/panic
1485 * callbacks with the log buffer.
1486 */
1487void kmsg_dump(enum kmsg_dump_reason reason)
1488{
1489 unsigned long end;
1490 unsigned chars;
1491 struct kmsg_dumper *dumper;
1492 const char *s1, *s2;
1493 unsigned long l1, l2;
1494 unsigned long flags;
1495
1496 /* Theoretically, the log could move on after we do this, but
1497 there's not a lot we can do about that. The new messages
1498 will overwrite the start of what we dump. */
1499 spin_lock_irqsave(&logbuf_lock, flags);
1500 end = log_end & LOG_BUF_MASK;
1501 chars = logged_chars;
1502 spin_unlock_irqrestore(&logbuf_lock, flags);
1503
1504 if (logged_chars > end) {
1505 s1 = log_buf + log_buf_len - logged_chars + end;
1506 l1 = logged_chars - end;
1507
1508 s2 = log_buf;
1509 l2 = end;
1510 } else {
1511 s1 = "";
1512 l1 = 0;
1513
1514 s2 = log_buf + end - logged_chars;
1515 l2 = logged_chars;
1516 }
1517
1518 if (!spin_trylock_irqsave(&dump_list_lock, flags)) {
1519 printk(KERN_ERR "dump_kmsg: dump list lock is held during %s, skipping dump\n",
1520 kmsg_to_str(reason));
1521 return;
1522 }
1523 list_for_each_entry(dumper, &dump_list, list)
1524 dumper->dump(dumper, reason, s1, l1, s2, l2);
1525 spin_unlock_irqrestore(&dump_list_lock, flags);
1526}
1408#endif 1527#endif