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    Subject[tip:perf/core] hw-breakpoints: Check the breakpoint params from perf tools
    Commit-ID:  fdf6bc95229821e3d9405eba28925b76e92b74d0
    Gitweb: http://git.kernel.org/tip/fdf6bc95229821e3d9405eba28925b76e92b74d0
    Author: Frederic Weisbecker <fweisbec@gmail.com>
    AuthorDate: Mon, 23 Nov 2009 15:42:33 +0100
    Committer: Ingo Molnar <mingo@elte.hu>
    CommitDate: Mon, 23 Nov 2009 18:18:30 +0100

    hw-breakpoints: Check the breakpoint params from perf tools

    Perf tools create perf events as disabled in the beginning.
    Breakpoints are then considered like ptrace temporary
    breakpoints, only meant to reserve a breakpoint slot until we
    get all the necessary informations from the user.

    In this case, we don't check the address that is breakpointed as
    it is NULL in the ptrace case.

    But perf tools don't have the same purpose, events are created
    disabled to wait for all events to be created before enabling
    all of them. We want to check the breakpoint parameters in this
    case.

    Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Prasad <prasad@linux.vnet.ibm.com>
    LKML-Reference: <1258987355-8751-2-git-send-email-fweisbec@gmail.com>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    ---
    kernel/hw_breakpoint.c | 11 ++++++++++-
    1 files changed, 10 insertions(+), 1 deletions(-)

    diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
    index c166622..06d372f 100644
    --- a/kernel/hw_breakpoint.c
    +++ b/kernel/hw_breakpoint.c
    @@ -267,7 +267,16 @@ int __register_perf_hw_breakpoint(struct perf_event *bp)
    if (ret)
    return ret;

    - if (!bp->attr.disabled)
    + /*
    + * Ptrace breakpoints can be temporary perf events only
    + * meant to reserve a slot. In this case, it is created disabled and
    + * we don't want to check the params right now (as we put a null addr)
    + * But perf tools create events as disabled and we want to check
    + * the params for them.
    + * This is a quick hack that will be removed soon, once we remove
    + * the tmp breakpoints from ptrace
    + */
    + if (!bp->attr.disabled || bp->callback == perf_bp_event)
    ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task);

    return ret;

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