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authorLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 10:23:43 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 10:23:43 -0800
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 b5ac4d99c667..1ded8e7dd19b 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -34,6 +34,7 @@
#include <linux/syscalls.h>
#include <linux/kexec.h>
#include <linux/ratelimit.h>
+#include <linux/kmsg_dump.h>
#include <asm/uaccess.h>
@@ -1405,4 +1406,122 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies,
return false;
}
EXPORT_SYMBOL(printk_timed_ratelimit);
+
+static DEFINE_SPINLOCK(dump_list_lock);
+static LIST_HEAD(dump_list);
+
+/**
+ * kmsg_dump_register - register a kernel log dumper.
+ * @dump: pointer to the kmsg_dumper structure
+ *
+ * Adds a kernel log dumper to the system. The dump callback in the
+ * structure will be called when the kernel oopses or panics and must be
+ * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
+ */
+int kmsg_dump_register(struct kmsg_dumper *dumper)
+{
+ unsigned long flags;
+ int err = -EBUSY;
+
+ /* The dump callback needs to be set */
+ if (!dumper->dump)
+ return -EINVAL;
+
+ spin_lock_irqsave(&dump_list_lock, flags);
+ /* Don't allow registering multiple times */
+ if (!dumper->registered) {
+ dumper->registered = 1;
+ list_add_tail(&dumper->list, &dump_list);
+ err = 0;
+ }
+ spin_unlock_irqrestore(&dump_list_lock, flags);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_register);
+
+/**
+ * kmsg_dump_unregister - unregister a kmsg dumper.
+ * @dump: pointer to the kmsg_dumper structure
+ *
+ * Removes a dump device from the system. Returns zero on success and
+ * %-EINVAL otherwise.
+ */
+int kmsg_dump_unregister(struct kmsg_dumper *dumper)
+{
+ unsigned long flags;
+ int err = -EINVAL;
+
+ spin_lock_irqsave(&dump_list_lock, flags);
+ if (dumper->registered) {
+ dumper->registered = 0;
+ list_del(&dumper->list);
+ err = 0;
+ }
+ spin_unlock_irqrestore(&dump_list_lock, flags);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
+
+static const char const *kmsg_reasons[] = {
+ [KMSG_DUMP_OOPS] = "oops",
+ [KMSG_DUMP_PANIC] = "panic",
+};
+
+static const char *kmsg_to_str(enum kmsg_dump_reason reason)
+{
+ if (reason >= ARRAY_SIZE(kmsg_reasons) || reason < 0)
+ return "unknown";
+
+ return kmsg_reasons[reason];
+}
+
+/**
+ * kmsg_dump - dump kernel log to kernel message dumpers.
+ * @reason: the reason (oops, panic etc) for dumping
+ *
+ * Iterate through each of the dump devices and call the oops/panic
+ * callbacks with the log buffer.
+ */
+void kmsg_dump(enum kmsg_dump_reason reason)
+{
+ unsigned long end;
+ unsigned chars;
+ struct kmsg_dumper *dumper;
+ const char *s1, *s2;
+ unsigned long l1, l2;
+ unsigned long flags;
+
+ /* Theoretically, the log could move on after we do this, but
+ there's not a lot we can do about that. The new messages
+ will overwrite the start of what we dump. */
+ spin_lock_irqsave(&logbuf_lock, flags);
+ end = log_end & LOG_BUF_MASK;
+ chars = logged_chars;
+ spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ if (logged_chars > end) {
+ s1 = log_buf + log_buf_len - logged_chars + end;
+ l1 = logged_chars - end;
+
+ s2 = log_buf;
+ l2 = end;
+ } else {
+ s1 = "";
+ l1 = 0;
+
+ s2 = log_buf + end - logged_chars;
+ l2 = logged_chars;
+ }
+
+ if (!spin_trylock_irqsave(&dump_list_lock, flags)) {
+ printk(KERN_ERR "dump_kmsg: dump list lock is held during %s, skipping dump\n",
+ kmsg_to_str(reason));
+ return;
+ }
+ list_for_each_entry(dumper, &dump_list, list)
+ dumper->dump(dumper, reason, s1, l1, s2, l2);
+ spin_unlock_irqrestore(&dump_list_lock, flags);
+}
#endif