Hi all,
There are currently two competing debug facilities to store kernel messages in a persistent storage: a generic pstore and Google's persistent_ram. Not so long ago (https://lkml.org/lkml/2012/3/8/252), it was decided that we should fix this situation.
Recently ramoops has switched to pstore, which basically means that it became a RAM backend for the pstore framework.
persistent_ram+ram_console and ramoops+pstore have almost the same features, except:
1. Ramoops doesn't support ECC. Having ECC is useful when a hardware reset was used to bring the machine back to life (i.e. a watchdog triggered). In such cases, RAM may be somewhat corrupt, but usually it is restorable.
2. Pstore doesn't support logging kernel messages in run-time, it only dumps dmesg when kernel oopses/panics. This makes pstore useless for debugging hangs caused by HW issues or improper use of HW (e.g. weird device inserted -> driver tried to write a reserved bits -> SoC hanged. In that case we don't get any messages in the pstore.
These patches solve the first issue, plus move things to their proper places. Patches that will fix the second issue are pending.
Thanks,
--- drivers/char/Kconfig | 9 - drivers/char/Makefile | 1 - drivers/char/ramoops.c | 362 -------------------- drivers/staging/android/Kconfig | 10 +- drivers/staging/android/persistent_ram.c | 473 -------------------------- drivers/staging/android/persistent_ram.h | 78 ----- drivers/staging/android/ram_console.c | 2 +- fs/pstore/Kconfig | 12 + fs/pstore/Makefile | 1 + fs/pstore/ram.c | 384 ++++++++++++++++++++++ fs/pstore/ram_core.c | 530 ++++++++++++++++++++++++++++++ include/linux/pstore_ram.h | 99 ++++++ include/linux/ramoops.h | 17 - 13 files changed, 1028 insertions(+), 950 deletions(-)