From e60768311af854734ce2bbfc50f24cff67b54a91 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Fri, 14 Aug 2020 23:31:25 +0206 Subject: scripts/gdb: update for lockless printk ringbuffer With the introduction of the lockless printk ringbuffer, the data structure for the kernel log buffer was changed. Update the gdb scripts to be able to parse/print the new log buffer structure. Fixes: 896fbe20b4e2333fb55 ("printk: use the lockless ringbuffer") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reported-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Petr Mladek <pmladek@suse.com> [akpm@linux-foundation.org: A typo fix.] Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20200814212525.6118-3-john.ogness@linutronix.de --- Documentation/admin-guide/kdump/gdbmacros.txt | 153 ++++++++++++++++++-------- 1 file changed, 107 insertions(+), 46 deletions(-) (limited to 'Documentation/admin-guide/kdump') diff --git a/Documentation/admin-guide/kdump/gdbmacros.txt b/Documentation/admin-guide/kdump/gdbmacros.txt index 220d0a80ca2c..7adece30237e 100644 --- a/Documentation/admin-guide/kdump/gdbmacros.txt +++ b/Documentation/admin-guide/kdump/gdbmacros.txt @@ -170,57 +170,111 @@ document trapinfo address the kernel panicked. end -define dump_log_idx - set $idx = $arg0 +define dump_record + set var $desc = $arg0 if ($argc > 1) - set $prev_flags = $arg1 + set var $prev_flags = $arg1 else - set $prev_flags = 0 + set var $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) - - # prev & LOG_CONT && !(msg->flags & LOG_PREIX) - if (($prev_flags & 8) && !($msg->flags & 4)) - set $prefix = 0 + + set var $info = &$desc->info + set var $prefix = 1 + set var $newline = 1 + + set var $begin = $desc->text_blk_lpos.begin % (1U << prb->text_data_ring.size_bits) + set var $next = $desc->text_blk_lpos.next % (1U << prb->text_data_ring.size_bits) + + # handle data-less record + if ($begin & 1) + set var $text_len = 0 + set var $log = "" + else + # handle wrapping data block + if ($begin > $next) + set var $begin = 0 + end + + # skip over descriptor id + set var $begin = $begin + sizeof(long) + + # handle truncated message + if ($next - $begin < $info->text_len) + set var $text_len = $next - $begin + else + set var $text_len = $info->text_len + end + + set var $log = &prb->text_data_ring.data[$begin] + end + + # prev & LOG_CONT && !(info->flags & LOG_PREIX) + if (($prev_flags & 8) && !($info->flags & 4)) + set var $prefix = 0 end - # msg->flags & LOG_CONT - if ($msg->flags & 8) + # info->flags & LOG_CONT + if ($info->flags & 8) # (prev & LOG_CONT && !(prev & LOG_NEWLINE)) if (($prev_flags & 8) && !($prev_flags & 2)) - set $prefix = 0 + set var $prefix = 0 end - # (!(msg->flags & LOG_NEWLINE)) - if (!($msg->flags & 2)) - set $newline = 0 + # (!(info->flags & LOG_NEWLINE)) + if (!($info->flags & 2)) + set var $newline = 0 end end if ($prefix) - printf "[%5lu.%06lu] ", $msg->ts_nsec / 1000000000, $msg->ts_nsec % 1000000000 + printf "[%5lu.%06lu] ", $info->ts_nsec / 1000000000, $info->ts_nsec % 1000000000 end - if ($msg->text_len != 0) - eval "printf \"%%%d.%ds\", $log", $msg->text_len, $msg->text_len + if ($text_len) + eval "printf \"%%%d.%ds\", $log", $text_len, $text_len end if ($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) + + # handle dictionary data + + set var $begin = $desc->dict_blk_lpos.begin % (1U << prb->dict_data_ring.size_bits) + set var $next = $desc->dict_blk_lpos.next % (1U << prb->dict_data_ring.size_bits) + + # handle data-less record + if ($begin & 1) + set var $dict_len = 0 + set var $dict = "" + else + # handle wrapping data block + if ($begin > $next) + set var $begin = 0 + end + + # skip over descriptor id + set var $begin = $begin + sizeof(long) + + # handle truncated message + if ($next - $begin < $info->dict_len) + set var $dict_len = $next - $begin + else + set var $dict_len = $info->dict_len + end + + set var $dict = &prb->dict_data_ring.data[$begin] + end + + if ($dict_len > 0) + set var $idx = 0 + set var $line = 1 + while ($idx < $dict_len) if ($line) printf " " - set $line = 0 + set var $line = 0 end - set $c = $dict[$idx] + set var $c = $dict[$idx] if ($c == '\0') printf "\n" - set $line = 1 + set var $line = 1 else if ($c < ' ' || $c >= 127 || $c == '\\') printf "\\x%02x", $c @@ -228,33 +282,40 @@ define dump_log_idx printf "%c", $c end end - set $idx = $idx + 1 + set var $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. +document dump_record + Dump a single record. The first parameter is the descriptor + sequence number, the second is optional and specifies the + previous record's flags, used for properly formatting + continued lines. end define dmesg - set $i = log_first_idx - set $end_idx = log_first_idx - set $prev_flags = 0 + set var $desc_committed = 1UL << ((sizeof(long) * 8) - 1) + set var $flags_mask = 3UL << ((sizeof(long) * 8) - 2) + set var $id_mask = ~$flags_mask + + set var $desc_count = 1U << prb->desc_ring.count_bits + set var $prev_flags = 0 + + set var $id = prb->desc_ring.tail_id.counter + set var $end_id = prb->desc_ring.head_id.counter while (1) - set $msg = ((struct printk_log *) (log_buf + $i)) - if ($msg->len == 0) - set $i = 0 - else - dump_log_idx $i $prev_flags - set $i = $i + $msg->len - set $prev_flags = $msg->flags + set var $desc = &prb->desc_ring.descs[$id % $desc_count] + + # skip non-committed record + if (($desc->state_var.counter & $flags_mask) == $desc_committed) + dump_record $desc $prev_flags + set var $prev_flags = $desc->info.flags end - if ($i == $end_idx) + + set var $id = ($id + 1) & $id_mask + if ($id == $end_id) loop_break end end -- cgit v1.2.3