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path: root/arch/loongarch/kernel/ftrace.c
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2022-12-14LoongArch/ftrace: Add basic supportQing Zhang
This patch contains basic ftrace support for LoongArch. Specifically, function tracer (HAVE_FUNCTION_TRACER), function graph tracer (HAVE_ FUNCTION_GRAPH_TRACER) are implemented following the instructions in Documentation/trace/ftrace-design.txt. Use `-pg` makes stub like a child function `void _mcount(void *ra)`. Thus, it can be seen store RA and alloc stack before `call _mcount`. Find `alloc stack` at first, and then find `store RA`. Note that the functions in both inst.c and time.c should not be hooked with the compiler's -pg option: to prevent infinite self-referencing for the former, and to ignore early setup stuff for the latter. Co-developed-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>