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SubjectRe: [PATCH v3 1/2] kprobes: introduce weak arch_check_ftrace_location() helper function
(2014/10/21 17:30), Heiko Carstens wrote:
> Introduce weak arch_check_ftrace_location() helper function which
> architectures can override in order to implement handling of kprobes
> on function tracer call sites on their own, without depending on
> common code or implementing the KPROBES_ON_FTRACE feature.
>
> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

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

Thanks!

> ---
> include/linux/kprobes.h | 1 +
> kernel/kprobes.c | 18 +++++++++++-------
> 2 files changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
> index f7296e57d614..5297f9fa0ef2 100644
> --- a/include/linux/kprobes.h
> +++ b/include/linux/kprobes.h
> @@ -335,6 +335,7 @@ extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
> extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
> #endif
>
> +int arch_check_ftrace_location(struct kprobe *p);
>
> /* Get the kprobe at this addr (if any) - called with preemption disabled */
> struct kprobe *get_kprobe(void *addr);
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 3995f546d0f3..317eb8ad28dd 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1410,16 +1410,10 @@ static inline int check_kprobe_rereg(struct kprobe *p)
> return ret;
> }
>
> -static int check_kprobe_address_safe(struct kprobe *p,
> - struct module **probed_mod)
> +int __weak arch_check_ftrace_location(struct kprobe *p)
> {
> - int ret = 0;
> unsigned long ftrace_addr;
>
> - /*
> - * If the address is located on a ftrace nop, set the
> - * breakpoint to the following instruction.
> - */
> ftrace_addr = ftrace_location((unsigned long)p->addr);
> if (ftrace_addr) {
> #ifdef CONFIG_KPROBES_ON_FTRACE
> @@ -1431,7 +1425,17 @@ static int check_kprobe_address_safe(struct kprobe *p,
> return -EINVAL;
> #endif
> }
> + return 0;
> +}
>
> +static int check_kprobe_address_safe(struct kprobe *p,
> + struct module **probed_mod)
> +{
> + int ret;
> +
> + ret = arch_check_ftrace_location(p);
> + if (ret)
> + return ret;
> jump_label_lock();
> preempt_disable();
>
>


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




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