From f29e5956aebafe63f81e80f972c44c4a666e5c7f Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Sat, 26 May 2012 06:20:19 -0700 Subject: pstore: Add console log messages support 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. Therefore, let's add a runtime logging support: PSTORE_TYPE_CONSOLE. Signed-off-by: Anton Vorontsov Acked-by: Kees Cook Acked-by: Colin Cross Signed-off-by: Greg Kroah-Hartman --- fs/pstore/Kconfig | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'fs/pstore/Kconfig') diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig index 23ade2680a4..d044de6ee30 100644 --- a/fs/pstore/Kconfig +++ b/fs/pstore/Kconfig @@ -12,6 +12,13 @@ config PSTORE 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_RAM tristate "Log panic/oops to a RAM buffer" depends on PSTORE -- cgit v1.2.3 From 060287b8c467bf49a594d8d669e1986c6d8d76b0 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Mon, 9 Jul 2012 17:10:41 -0700 Subject: pstore: Add persistent function tracing With this support kernel can save function call chain log 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. We store the log in a binary format and then decode it at read time. p.s. Mostly the code comes from trace_persistent.c driver found in the Android git tree, written by Colin Cross (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov Signed-off-by: Greg Kroah-Hartman --- fs/pstore/Kconfig | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'fs/pstore/Kconfig') diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig index d044de6ee30..d39bb5cce88 100644 --- a/fs/pstore/Kconfig +++ b/fs/pstore/Kconfig @@ -19,6 +19,18 @@ config PSTORE_CONSOLE 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 + 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 -- cgit v1.2.3 From 65f8c95e46a1827ae8bbc52a817ea308dd7d65ae Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Tue, 17 Jul 2012 14:26:15 -0700 Subject: 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 Signed-off-by: Anton Vorontsov --- fs/pstore/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/pstore/Kconfig') diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig index d39bb5cce88..ca71db69da0 100644 --- a/fs/pstore/Kconfig +++ b/fs/pstore/Kconfig @@ -23,6 +23,7 @@ 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 -- cgit v1.2.3