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    Subject[PATCH v4 1/2] ftrace: cleanup ftrace_graph_caller enable and disable
    Date
    The ftrace_[enable,disable]_ftrace_graph_caller() are used to do
    special hooks for graph tracer, which are not needed on some ARCHs
    that use graph_ops:func function to install return_hooker.

    So introduce the weak version in ftrace core code to cleanup
    in x86.

    Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
    ---
    v4:
    - put weak ftrace_enable,disable_ftrace_graph_caller() in
    fgraph.c instead of ftrace.c as suggested by Steve.

    v3:
    - consolidate two #if into a single #if, suggested by Steve. Thanks.
    ---
    arch/x86/kernel/ftrace.c | 17 ++---------------
    kernel/trace/fgraph.c | 18 ++++++++++++++++++
    2 files changed, 20 insertions(+), 15 deletions(-)

    diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
    index 1e31c7d21597..b09d73c2ba89 100644
    --- a/arch/x86/kernel/ftrace.c
    +++ b/arch/x86/kernel/ftrace.c
    @@ -579,9 +579,7 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)

    #ifdef CONFIG_FUNCTION_GRAPH_TRACER

    -#ifdef CONFIG_DYNAMIC_FTRACE
    -
    -#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
    +#if defined(CONFIG_DYNAMIC_FTRACE) && !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS)
    extern void ftrace_graph_call(void);
    static const char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
    {
    @@ -610,18 +608,7 @@ int ftrace_disable_ftrace_graph_caller(void)

    return ftrace_mod_jmp(ip, &ftrace_stub);
    }
    -#else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
    -int ftrace_enable_ftrace_graph_caller(void)
    -{
    - return 0;
    -}
    -
    -int ftrace_disable_ftrace_graph_caller(void)
    -{
    - return 0;
    -}
    -#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
    -#endif /* !CONFIG_DYNAMIC_FTRACE */
    +#endif /* CONFIG_DYNAMIC_FTRACE && !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */

    /*
    * Hook the return address and push it in the stack of return addrs
    diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
    index 8f4fb328133a..289311680c29 100644
    --- a/kernel/trace/fgraph.c
    +++ b/kernel/trace/fgraph.c
    @@ -30,6 +30,24 @@ int ftrace_graph_active;
    /* Both enabled by default (can be cleared by function_graph tracer flags */
    static bool fgraph_sleep_time = true;

    +/*
    + * archs can override this function if they must do something
    + * to enable hook for graph tracer.
    + */
    +int __weak ftrace_enable_ftrace_graph_caller(void)
    +{
    + return 0;
    +}
    +
    +/*
    + * archs can override this function if they must do something
    + * to disable hook for graph tracer.
    + */
    +int __weak ftrace_disable_ftrace_graph_caller(void)
    +{
    + return 0;
    +}
    +
    /**
    * ftrace_graph_stop - set to permanently disable function graph tracing
    *
    --
    2.35.1
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