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printk: ringbuffer: change representation of states

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Rather than deriving the state by evaluating bits within the flags
area of the state variable, assign the states explicit values and
set those values in the flags area. Introduce macros to make it
simple to read and write state values for the state variable.

Although the functionality is preserved, the binary representation
for the states is changed.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914123354.832-5-john.ogness@linutronix.de
This commit is contained in:
John Ogness
2020-09-14 14:39:52 +02:06
committed by Petr Mladek
parent cc5c7041c6
commit 10dcb06d40
4 changed files with 41 additions and 41 deletions
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11
scripts/gdb/linux/dmesg.py
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@@ -78,10 +78,10 @@ class LxDmesg(gdb.Command):
len_off = off + printk_info_type.get_type()['text_len'].bitpos // 8
# definitions from kernel/printk/printk_ringbuffer.h
desc_committed = 1
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_flags_shift = desc_sv_bits - 2
desc_flags_mask = 3 << desc_flags_shift
desc_id_mask = ~desc_flags_mask
# read in tail and head descriptor ids
@@ -96,8 +96,9 @@ class LxDmesg(gdb.Command):
desc_off = desc_sz * ind
# skip non-committed record
state = utils.read_u64(descs, desc_off + sv_off + counter_off) & desc_flags_mask
if state != desc_committed_mask:
state = 3 & (utils.read_u64(descs, desc_off + sv_off +
counter_off) >> desc_flags_shift)
if state != desc_committed:
if did == head_id:
break
did = (did + 1) & desc_id_mask