Re: [PATCH 2/2] kprobes: compile out IPMODIFY support if ftrace doesn't support it

From: Masami Hiramatsu
Date: Wed Jan 14 2015 - 22:04:27 EST


(2015/01/14 17:48), Jiri Kosina wrote:
> If ftrace doesn't claim to support IPMODIFY support, there is no need to
> compile IPMODIFY support in kprobes either.
>

This looks good to me :)

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>

Thanks!

> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
> ---
> kernel/kprobes.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 06f5830..49a69d7 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -912,7 +912,7 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
> }
> #endif /* CONFIG_OPTPROBES */
>
> -#ifdef CONFIG_KPROBES_ON_FTRACE
> +#if defined(CONFIG_KPROBES_ON_FTRACE) && (ftrace_ipmodify_supported == 1)
> static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
> .func = kprobe_ftrace_handler,
> .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
> @@ -957,7 +957,7 @@ static void disarm_kprobe_ftrace(struct kprobe *p)
> (unsigned long)p->addr, 1, 0);
> WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
> }
> -#else /* !CONFIG_KPROBES_ON_FTRACE */
> +#else /* !CONFIG_KPROBES_ON_FTRACE || ftrace_ipmodify_supported == 0 */
> #define prepare_kprobe(p) arch_prepare_kprobe(p)
> #define arm_kprobe_ftrace(p) do {} while (0)
> #define disarm_kprobe_ftrace(p) do {} while (0)
> @@ -1416,12 +1416,12 @@ int __weak arch_check_ftrace_location(struct kprobe *p)
>
> ftrace_addr = ftrace_location((unsigned long)p->addr);
> if (ftrace_addr) {
> -#ifdef CONFIG_KPROBES_ON_FTRACE
> +#if defined(CONFIG_KPROBES_ON_FTRACE) && (ftrace_ipmodify_supported == 1)
> /* Given address is not on the instruction boundary */
> if ((unsigned long)p->addr != ftrace_addr)
> return -EILSEQ;
> p->flags |= KPROBE_FLAG_FTRACE;
> -#else /* !CONFIG_KPROBES_ON_FTRACE */
> +#else /* !CONFIG_KPROBES_ON_FTRACE || ftrace_ipmodify_supported == 0 */
> return -EINVAL;
> #endif
> }
>


--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx


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