kdb: core for kgdb back end (2 of 2)

This patch contains the hooks and instrumentation into kernel which
live outside the kernel/debug directory, which the kdb core
will call to run commands like lsmod, dmesg, bt etc...

CC: linux-arch@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Martin Hicks <mort@sgi.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index 75077ad0b537..9213b8b5bb4f 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -413,6 +413,22 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
         return do_syslog(type, buf, len, SYSLOG_FROM_CALL);
 }
 
+#ifdef  CONFIG_KGDB_KDB
+/* kdb dmesg command needs access to the syslog buffer.  do_syslog()
+ * uses locks so it cannot be used during debugging.  Just tell kdb
+ * where the start and end of the physical and logical logs are.  This
+ * is equivalent to do_syslog(3).
+ */
+void kdb_syslog_data(char *syslog_data[4])
+{
+        syslog_data[0] = log_buf;
+        syslog_data[1] = log_buf + log_buf_len;
+        syslog_data[2] = log_buf + log_end -
+                (logged_chars < log_buf_len ? logged_chars : log_buf_len);
+        syslog_data[3] = log_buf + log_end;
+}
+#endif  /* CONFIG_KGDB_KDB */
+
 /*
  * Call the console drivers on a range of log_buf
  */