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    Subject[RFC][PATCH 00/12] kprobes/ftrace: Making ftrace usable for kprobes
    This is an RFC of patches that allow ftrace to be used directly by

    The first set of patches modify the function tracer to:

    1) have ftrace_ops passed to all functions
    2) allow regs to be passed to all functions when requested

    The first change is not required by kprobes, but is a nice feature
    that people have asked for. You can now pass data to different
    functions. Well, you can pass the ftrace_ops that registered the function
    such that if two ftrace_ops register the same callback, the call back
    can do different things depending on what registered it.

    The second change adds a second mcount trampoline. That is,
    if you request to have pt_regs returned, it will call a different
    function that saves those registers. If nothing asks for regs, then
    the old way is performed, and there's no slow down in the performance,
    as not many functions would ever require regs passed to it.

    If an arch supports passing of ftrace ops, it must also pass regs.
    But it does not need to support passing all (or any) regs. By default
    an arch can just pass NULL. If it supports full regs, then
    it can allow tools like kprobes to ask for regs. Otherwise regs
    is either NULL or a subset of full regs.

    The second set is Masami's patches ported on top of these changes.

    Note, I just got these working and they could use more comments in
    the code. I plan on doing so and cleaning things up, but wanted to
    get these out in the "release early, release often" mentality.

    -- Steve

    These patches are in git and can be found at:


    Head SHA1: 80a5eca4e5d019c752ba580400f656afc5d8aca6

    Masami Hiramatsu (5):
    ftrace: add ftrace_set_filter_ip() for address based filter
    kprobes: cleanup to separate probe-able check
    kprobes: Move locks into appropriate functions
    kprobes: introduce ftrace based optimization
    kprobes/x86: ftrace based optimization for x86

    Steven Rostedt (7):
    ftrace: Pass ftrace_ops as third parameter to function trace callback
    ftrace: Consolidate arch dependent functions with 'list' function
    ftrace: Return pt_regs to function trace callback (x86_64 only so far)
    ftrace/x86_32: Push ftrace_ops in as 3rd parameter to function tracer
    ftrace/x86: Add separate function to save regs
    ftrace/x86: Add save_regs for i386 function calls
    kprobes: Inverse taking of module_mutex with kprobe_mutex

    arch/x86/include/asm/ftrace.h | 44 +++---
    arch/x86/include/asm/kprobes.h | 1 +
    arch/x86/kernel/entry_32.S | 56 ++++++++
    arch/x86/kernel/entry_64.S | 73 +++++++++-
    arch/x86/kernel/ftrace.c | 62 ++++++++-
    arch/x86/kernel/kprobes.c | 48 +++++++
    include/linux/ftrace.h | 89 +++++++++++-
    include/linux/kprobes.h | 27 ++++
    kernel/kprobes.c | 250 +++++++++++++++++++++++----------
    kernel/trace/ftrace.c | 273 ++++++++++++++++++++++++++-----------
    kernel/trace/trace_event_perf.c | 3 +-
    kernel/trace/trace_events.c | 3 +-
    kernel/trace/trace_functions.c | 10 +-
    kernel/trace/trace_irqsoff.c | 3 +-
    kernel/trace/trace_sched_wakeup.c | 3 +-
    kernel/trace/trace_selftest.c | 20 ++-
    kernel/trace/trace_stack.c | 3 +-
    17 files changed, 778 insertions(+), 190 deletions(-)

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