65f8c95e46
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>
50 lines
1.6 KiB
Text
50 lines
1.6 KiB
Text
config PSTORE
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bool "Persistent store support"
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default n
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help
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This option enables generic access to platform level
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persistent storage via "pstore" filesystem that can
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be mounted as /dev/pstore. Only useful if you have
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a platform level driver that registers with pstore to
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provide the data, so you probably should just go say "Y"
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(or "M") to a platform specific persistent store driver
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(e.g. ACPI_APEI on X86) which will select this for you.
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If you don't have a platform persistent store driver,
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say N.
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config PSTORE_CONSOLE
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bool "Log kernel console messages"
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depends on PSTORE
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help
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When the option is enabled, pstore will log all kernel
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messages, even if no oops or panic happened.
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config PSTORE_FTRACE
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bool "Persistent function tracer"
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depends on PSTORE
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depends on FUNCTION_TRACER
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depends on DEBUG_FS
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help
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With this option kernel traces function calls into a persistent
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ram buffer that can be decoded and dumped after reboot through
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pstore filesystem. It can be used to determine what function
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was last called before a reset or panic.
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If unsure, say N.
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config PSTORE_RAM
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tristate "Log panic/oops to a RAM buffer"
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depends on PSTORE
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depends on HAS_IOMEM
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depends on HAVE_MEMBLOCK
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select REED_SOLOMON
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select REED_SOLOMON_ENC8
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select REED_SOLOMON_DEC8
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help
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This enables panic and oops messages to be logged to a circular
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buffer in RAM where it can be read back at some later point.
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Note that for historical reasons, the module will be named
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"ramoops.ko".
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For more information, see Documentation/ramoops.txt.
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