(2014/10/16 0:46), Heiko Carstens wrote:
> Allow architectures to implement handling of kprobes on function
> tracer call sites on their own, without depending on common code.
>
> This patch removes the kprobes check if a kprobe is being placed
> on a function tracer call site and therefore gives full responsibility
> of handling this correctly to the architecture.
>
> Signed-off-by: Heiko Carstens <heiko.carst...@de.ibm.com>
> ---
> arch/Kconfig | 8 ++++++++
> kernel/kprobes.c | 3 ++-
> 2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 05d7a8a458d5..e1a8e0edf03f 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -85,6 +85,14 @@ config KPROBES_ON_FTRACE
> passing of pt_regs to function tracing, then kprobes can
> optimize on top of function tracing.
>
> +config ARCH_HANDLES_KPROBES_ON_FTRACE
> + def_bool n
> + help
> + If an architecture can handle kprobes on function tracer call
> + sites on own, then this option should be selected. This option
> + removes the check which otherwise prevents to set kprobes on
> + function tracer call sites.
> +
> config UPROBES
> def_bool n
> select PERCPU_RWSEM
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 3995f546d0f3..4cc48aa67635 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1428,7 +1428,8 @@ static int check_kprobe_address_safe(struct kprobe *p,
> return -EILSEQ;
> p->flags |= KPROBE_FLAG_FTRACE;
> #else /* !CONFIG_KPROBES_ON_FTRACE */
> - return -EINVAL;
> + if (!IS_ENABLED(CONFIG_ARCH_HANDLES_KPROBES_ON_FTRACE))
> + return -EINVAL;
> #endif
> }
Hmm, this looks a bit not straight. Maybe we'd better introduce a local
check_ftrace_location() function which always returns 0 if
CONFIG_ARCH_HANDLES_KPROBES_ON_FTRACE(with a comment! :)) as below.
int check_ftrace_location(kp)
{
unsigned long ftrace_address;
/* If an architecture handles kprobes on ftrace, we don't check it */
if (IS_ENABLED(CONFIG_ARCH_HANDLES_KPROBES_ON_FTRACE))
return 0;
...
}
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
