From 9a7c348ba6a46f6270d4fe49577649dad5664fe7 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Fri, 19 Aug 2016 06:52:57 -0500 Subject: ftrace: Add return address pointer to ftrace_ret_stack Storing this value will help prevent unwinders from getting out of sync with the function graph tracer ret_stack. Now instead of needing a stateful iterator, they can compare the return address pointer to find the right ret_stack entry. Note that an array of 50 ftrace_ret_stack structs is allocated for every task. So when an arch implements this, it will add either 200 or 400 bytes of memory usage per task (depending on whether it's a 32-bit or 64-bit platform). Signed-off-by: Josh Poimboeuf Acked-by: Steven Rostedt Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Byungchul Park Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/a95cfcc39e8f26b89a430c56926af0bb217bc0a1.1471607358.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- include/linux/ftrace.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 4ad9ccc60e38..483e02a50d37 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -798,6 +798,9 @@ struct ftrace_ret_stack { #ifdef HAVE_FUNCTION_GRAPH_FP_TEST unsigned long fp; #endif +#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR + unsigned long *retp; +#endif }; /* @@ -809,7 +812,7 @@ extern void return_to_handler(void); extern int ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, - unsigned long frame_pointer); + unsigned long frame_pointer, unsigned long *retp); /* * Sometimes we don't want to trace a function with the function -- cgit v1.2.3-59-g8ed1b