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Subject[PATCH next v3 8/8] scripts/gdb: support printk finalized records
Date
With commit ("printk: ringbuffer: add finalization/extension support")
a new state bit for finalized records was added. This not only changed
the bit representation of committed records, but also reduced the size
for record IDs.

Update the gdb scripts to correctly interpret the state variable.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
Documentation/admin-guide/kdump/gdbmacros.txt | 10 +++++++---
scripts/gdb/linux/dmesg.py | 10 ++++++----
2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/Documentation/admin-guide/kdump/gdbmacros.txt b/Documentation/admin-guide/kdump/gdbmacros.txt
index 7adece30237e..bcb78368b381 100644
--- a/Documentation/admin-guide/kdump/gdbmacros.txt
+++ b/Documentation/admin-guide/kdump/gdbmacros.txt
@@ -295,8 +295,11 @@ document dump_record
end

define dmesg
- set var $desc_committed = 1UL << ((sizeof(long) * 8) - 1)
- set var $flags_mask = 3UL << ((sizeof(long) * 8) - 2)
+ # definitions from kernel/printk/printk_ringbuffer.h
+ set var $desc_commit = 1UL << ((sizeof(long) * 8) - 1)
+ set var $desc_final = 1UL << ((sizeof(long) * 8) - 2)
+ set var $desc_reuse = 1UL << ((sizeof(long) * 8) - 3)
+ set var $flags_mask = $desc_commit | $desc_final | $desc_reuse
set var $id_mask = ~$flags_mask

set var $desc_count = 1U << prb->desc_ring.count_bits
@@ -309,7 +312,8 @@ define dmesg
set var $desc = &prb->desc_ring.descs[$id % $desc_count]

# skip non-committed record
- if (($desc->state_var.counter & $flags_mask) == $desc_committed)
+ # (note that commit+!final records will be displayed)
+ if (($desc->state_var.counter & $desc_commit) == $desc_commit)
dump_record $desc $prev_flags
set var $prev_flags = $desc->info.flags
end
diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py
index 6c6022012ea8..367523c5c270 100644
--- a/scripts/gdb/linux/dmesg.py
+++ b/scripts/gdb/linux/dmesg.py
@@ -79,9 +79,10 @@ class LxDmesg(gdb.Command):

# definitions from kernel/printk/printk_ringbuffer.h
desc_sv_bits = utils.get_long_type().sizeof * 8
- desc_committed_mask = 1 << (desc_sv_bits - 1)
- desc_reuse_mask = 1 << (desc_sv_bits - 2)
- desc_flags_mask = desc_committed_mask | desc_reuse_mask
+ desc_commit_mask = 1 << (desc_sv_bits - 1)
+ desc_final_mask = 1 << (desc_sv_bits - 2)
+ desc_reuse_mask = 1 << (desc_sv_bits - 3)
+ desc_flags_mask = desc_commit_mask | desc_final_mask | desc_reuse_mask
desc_id_mask = ~desc_flags_mask

# read in tail and head descriptor ids
@@ -96,8 +97,9 @@ class LxDmesg(gdb.Command):
desc_off = desc_sz * ind

# skip non-committed record
+ # (note that commit+!final records will be displayed)
state = utils.read_u64(descs, desc_off + sv_off + counter_off) & desc_flags_mask
- if state != desc_committed_mask:
+ if state & desc_commit_mask != desc_commit_mask:
if did == head_id:
break
did = (did + 1) & desc_id_mask
--
2.20.1
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