linux/fs/pstore/Kconfig
Anton Vorontsov 65f8c95e46 pstore/ftrace: Convert to its own enable/disable debugfs knob
With this patch we no longer reuse function tracer infrastructure, now
we register our own tracer back-end via a debugfs knob.

It's a bit more code, but that is the only downside. On the bright side we
have:

- Ability to make persistent_ram module removable (when needed, we can
  move ftrace_ops struct into a module). Note that persistent_ram is still
  not removable for other reasons, but with this patch it's just one
  thing less to worry about;

- Pstore part is more isolated from the generic function tracer. We tried
  it already by registering our own tracer in available_tracers, but that
  way we're loosing ability to see the traces while we record them to
  pstore. This solution is somewhere in the middle: we only register
  "internal ftracer" back-end, but not the "front-end";

- When there is only pstore tracing enabled, the kernel will only write
  to the pstore buffer, omitting function tracer buffer (which, of course,
  still can be enabled via 'echo function > current_tracer').

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-09-06 22:16:58 -07:00

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config PSTORE
bool "Persistent store support"
default n
help
This option enables generic access to platform level
persistent storage via "pstore" filesystem that can
be mounted as /dev/pstore. Only useful if you have
a platform level driver that registers with pstore to
provide the data, so you probably should just go say "Y"
(or "M") to a platform specific persistent store driver
(e.g. ACPI_APEI on X86) which will select this for you.
If you don't have a platform persistent store driver,
say N.
config PSTORE_CONSOLE
bool "Log kernel console messages"
depends on PSTORE
help
When the option is enabled, pstore will log all kernel
messages, even if no oops or panic happened.
config PSTORE_FTRACE
bool "Persistent function tracer"
depends on PSTORE
depends on FUNCTION_TRACER
depends on DEBUG_FS
help
With this option kernel traces function calls into a persistent
ram buffer that can be decoded and dumped after reboot through
pstore filesystem. It can be used to determine what function
was last called before a reset or panic.
If unsure, say N.
config PSTORE_RAM
tristate "Log panic/oops to a RAM buffer"
depends on PSTORE
depends on HAS_IOMEM
depends on HAVE_MEMBLOCK
select REED_SOLOMON
select REED_SOLOMON_ENC8
select REED_SOLOMON_DEC8
help
This enables panic and oops messages to be logged to a circular
buffer in RAM where it can be read back at some later point.
Note that for historical reasons, the module will be named
"ramoops.ko".
For more information, see Documentation/ramoops.txt.