]> git.karo-electronics.de Git - karo-tx-linux.git/commit
tracing, x86: add low level support for ftrace return tracing
authorFrederic Weisbecker <fweisbec@gmail.com>
Tue, 11 Nov 2008 06:03:45 +0000 (07:03 +0100)
committerIngo Molnar <mingo@elte.hu>
Tue, 11 Nov 2008 09:29:11 +0000 (10:29 +0100)
commitcaf4b323b02a16c92fba449952ac6515ddc76d7a
tree6fc234d00faca192248344996a168afb253e5f40
parentd844222a54c33a960755b44b934cd1b01b05dceb
tracing, x86: add low level support for ftrace return tracing

Impact: add infrastructure for function-return tracing

Add low level support for ftrace return tracing.

This plug-in stores return addresses on the thread_info structure of
the current task.

The index of the current return address is initialized when the task
is the first one (init) and when a process forks (the child). It is
not needed when a task does a sys_execve because after this syscall,
it still needs to return on the kernel functions it called.

Note that the code of return_to_handler has been suggested by Steven
Rostedt as almost all of the ideas of improvements in this V3.

For purpose of security, arch/x86/kernel/process_32.c is not traced
because __switch_to() changes the current task during its execution.
That could cause inconsistency in the stored return address of this
function even if I didn't have any crash after testing with tracing on
this function enabled.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/Kconfig
arch/x86/include/asm/ftrace.h
arch/x86/include/asm/thread_info.h
arch/x86/kernel/Makefile
arch/x86/kernel/entry_32.S
arch/x86/kernel/ftrace.c
include/linux/ftrace.h
include/linux/ftrace_irq.h
include/linux/sched.h
kernel/Makefile