kdump: fix dmesg gdbmacro to work with record based printk

Commit 7ff9554bb578 ("printk: convert byte-buffer to variable-length
record buffer") introduced a record based printk buffer.  Modify
gdbmacros.txt to parse this new structure so dmesg will work properly.

Link: http://lkml.kernel.org/r/1463515794-1599-1-git-send-email-minyard@acm.org
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/kdump/gdbmacros.txt b/Documentation/kdump/gdbmacros.txt
index 35f6a982a0d5fdc040cfb722a071c8d707c53123..220d0a80ca2c9f45ce7f0705be1952c34df4f1dd 100644 (file)
--- a/Documentation/kdump/gdbmacros.txt
+++ b/Documentation/kdump/gdbmacros.txt
@@ -170,21 +170,92 @@ document trapinfo
        address the kernel panicked.
 end
 
+define dump_log_idx
+       set $idx = $arg0
+       if ($argc > 1)
+               set $prev_flags = $arg1
+       else
+               set $prev_flags = 0
+       end
+       set $msg = ((struct printk_log *) (log_buf + $idx))
+       set $prefix = 1
+       set $newline = 1
+       set $log = log_buf + $idx + sizeof(*$msg)
 
-define dmesg
-       set $i = 0
-       set $end_idx = (log_end - 1) & (log_buf_len - 1)
+       # prev & LOG_CONT && !(msg->flags & LOG_PREIX)
+       if (($prev_flags & 8) && !($msg->flags & 4))
+               set $prefix = 0
+       end
+
+       # msg->flags & LOG_CONT
+       if ($msg->flags & 8)
+               # (prev & LOG_CONT && !(prev & LOG_NEWLINE))
+               if (($prev_flags & 8) && !($prev_flags & 2))
+                       set $prefix = 0
+               end
+               # (!(msg->flags & LOG_NEWLINE))
+               if (!($msg->flags & 2))
+                       set $newline = 0
+               end
+       end
+
+       if ($prefix)
+               printf "[%5lu.%06lu] ", $msg->ts_nsec / 1000000000, $msg->ts_nsec % 1000000000
+       end
+       if ($msg->text_len != 0)
+               eval "printf \"%%%d.%ds\", $log", $msg->text_len, $msg->text_len
+       end
+       if ($newline)
+               printf "\n"
+       end
+       if ($msg->dict_len > 0)
+               set $dict = $log + $msg->text_len
+               set $idx = 0
+               set $line = 1
+               while ($idx < $msg->dict_len)
+                       if ($line)
+                               printf " "
+                               set $line = 0
+                       end
+                       set $c = $dict[$idx]
+                       if ($c == '\0')
+                               printf "\n"
+                               set $line = 1
+                       else
+                               if ($c < ' ' || $c >= 127 || $c == '\\')
+                                       printf "\\x%02x", $c
+                               else
+                                       printf "%c", $c
+                               end
+                       end
+                       set $idx = $idx + 1
+               end
+               printf "\n"
+       end
+end
+document dump_log_idx
+       Dump a single log given its index in the log buffer.  The first
+       parameter is the index into log_buf, the second is optional and
+       specified the previous log buffer's flags, used for properly
+       formatting continued lines.
+end
 
-       while ($i < logged_chars)
-               set $idx = (log_end - 1 - logged_chars + $i) & (log_buf_len - 1)
+define dmesg
+       set $i = log_first_idx
+       set $end_idx = log_first_idx
+       set $prev_flags = 0
 
-               if ($idx + 100 <= $end_idx) || \
-                  ($end_idx <= $idx && $idx + 100 < log_buf_len)
-                       printf "%.100s", &log_buf[$idx]
-                       set $i = $i + 100
+       while (1)
+               set $msg = ((struct printk_log *) (log_buf + $i))
+               if ($msg->len == 0)
+                       set $i = 0
                else
-                       printf "%c", log_buf[$idx]
-                       set $i = $i + 1
+                       dump_log_idx $i $prev_flags
+                       set $i = $i + $msg->len
+                       set $prev_flags = $msg->flags
+               end
+               if ($i == $end_idx)
+                       loop_break
                end
        end
 end