linux.git/fs/pstore/pmsg.c, branch v4.11

pstore/pmsg: drop bounce buffer

2016-09-08T22:01:10+00:00

Removing a bounce buffer copy operation in the pmsg driver path is
always better. We also gain in overall performance by not requesting
a vmalloc on every write as this can cause precious RT tasks, such
as user facing media operation, to stall while memory is being
reclaimed. Added a write_buf_user to the pstore functions, a backup
platform write_buf_user that uses the small buffer that is part of
the instance, and implemented a ramoops write_buf_user that only
supports PSTORE_TYPE_PMSG.

Signed-off-by: Mark Salyzyn 
Signed-off-by: Kees Cook

pstore: add pstore unregister

2015-10-22T15:59:18+00:00

pstore doesn't support unregistering yet. It was marked as TODO.
This patch adds some code to fix it:
 1) Add functions to unregister kmsg/console/ftrace/pmsg.
 2) Add a function to free compression buffer.
 3) Unmap the memory and free it.
 4) Add a function to unregister pstore filesystem.

Signed-off-by: Geliang Tang 
Acked-by: Kees Cook 
[Removed __exit annotation from ramoops_remove(). Reported by Arnd Bergmann]
Signed-off-by: Tony Luck

pstore: add vmalloc error check

2015-10-21T16:27:10+00:00

If vmalloc fails, make write_pmsg return -ENOMEM.

Signed-off-by: Geliang Tang 
Acked-by: Kees Cook 
Signed-off-by: Tony Luck

pstore: Add pmsg - user-space accessible pstore object

2015-01-17T00:01:10+00:00

A secured user-space accessible pstore object. Writes
to /dev/pmsg0 are appended to the buffer, on reboot
the persistent contents are available in
/sys/fs/pstore/pmsg-ramoops-[ID].

One possible use is syslogd, or other daemon, can
write messages, then on reboot provides a means to
triage user-space activities leading up to a panic
as a companion to the pstore dmesg or console logs.

Signed-off-by: Mark Salyzyn 
Acked-by: Kees Cook 
Signed-off-by: Tony Luck