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    Subject[RFC PATCH 7/7] events: Use early task context tracking if available
    Date
    Use the early task context tracking to detect the current context,
    if the arch supports it.

    Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>
    Cc: Romulo Silva de Oliveira <romulo.deoliveira@ufsc.br>
    Cc: Clark Williams <williams@redhat.com>
    Cc: linux-kernel@vger.kernel.org
    Cc: x86@kernel.org
    ---
    kernel/events/internal.h | 13 +++++++++++++
    1 file changed, 13 insertions(+)

    diff --git a/kernel/events/internal.h b/kernel/events/internal.h
    index 241a2318bfdc..8e4215f8cb93 100644
    --- a/kernel/events/internal.h
    +++ b/kernel/events/internal.h
    @@ -219,6 +219,18 @@ enum {
    TRACE_CTX_MAX
    };

    +#ifdef ARCH_HAS_TASK_CONTEXT
    +static __always_inline int trace_get_context_bit(void)
    +{
    + unsigned long tc = this_cpu_read(task_context);
    +
    + if (tc)
    + return tc & TASK_CTX_NMI ? TRACE_CTX_NMI :
    + tc & TASK_CTX_IRQ ? TRACE_CTX_IRQ : TRACE_CTX_SOFTIRQ;
    + else
    + return TRACE_CTX_NORMAL;
    +}
    +#else /* ARCH_HAS_TASK_CONTEXT */
    static __always_inline int trace_get_context_bit(void)
    {
    unsigned long pc = preempt_count();
    @@ -229,6 +241,7 @@ static __always_inline int trace_get_context_bit(void)
    else
    return TRACE_CTX_NORMAL;
    }
    +#endif /* ARCH_HAS_TASK_CONTEXT */

    static inline int get_recursion_context(int *recursion)
    {
    --
    2.20.1
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