Re: [RFC V2] mm: Generalize notify_page_fault()

Matthew Wilcox
2019-06-04T21:53:26Z

On Tue, Jun 04, 2019 at 12:04:06PM +0530, Anshuman Khandual wrote:
> +++ b/arch/x86/mm/fault.c
> @@ -46,23 +46,6 @@ kmmio_fault(struct pt_regs *regs, unsigned long addr)
> return 0;
> }
>
> -static nokprobe_inline int kprobes_fault(struct pt_regs *regs)
> -{
...
> -}

> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 0e8834a..c5a8dcf 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1778,6 +1778,7 @@ static inline int pte_devmap(pte_t pte)
> }
> #endif
>
> +int notify_page_fault(struct pt_regs *regs, unsigned int trap);

Why is it now out-of-line?

> +++ b/mm/memory.c
> +int __kprobes notify_page_fault(struct pt_regs *regs, unsigned int trap)
> +{
> + int ret = 0;
> +
> + /*
> + * To be potentially processing a kprobe fault and to be allowed
> + * to call kprobe_running(), we have to be non-preemptible.
> + */
> + if (kprobes_built_in() && !preemptible() && !user_mode(regs)) {
> + if (kprobe_running() && kprobe_fault_handler(regs, trap))
> + ret = 1;
> + }
> + return ret;
> +}
> +

I would argue this should be in kprobes.h as a static nokprobe_inline.