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    SubjectRe: utrace comments
    On Mon, Apr 30, 2007 at 10:45:10AM +0100, Russell King wrote:
    > For the sake of avoiding too much rehash, here's Roland's reply to my
    > initial forrey into utrace:
    >
    > http://marc.info/?l=linux-kernel&m=117309251916053&w=2

    In that mail Roland suggests keeping the singlestep code entirely
    in the arm ptrace code. After a brief look at the arm code this
    looks easily possible. From a brief look the arm software singlestep
    consist of the following pieces:

    - PTRACE_SINGLESTEP implementation. Sets the PT_SINGLESTEP flag,
    clears TIF_SYSCALL_TRACE, sets ->exit_code in the traced code
    to the singlestepping signal and wakes the traced process up.

    This can easily be implemented by putting alsmost equivalent code
    into arch_ptrace.
    - clearing PT_SINGLESTEP and cancelling the breakpoint in ptrace_disable.

    Equivalent code can go into tracehook_disable_single_step.

    - Various places in signal.c that check PT_SINGLESTEP to set/clear
    the special singlestep breakpoint. This can stay, it just needs
    a different place to store the singlestep flag.

    Do I miss something?

    -
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