From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ingo Molnar <mingo@kernel.org>
Date: Mon, 05 Jul 2021 07:03:19 +0000
Subject: Re: [PATCH -tip v8 03/13] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_han
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To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>, Josh Poimboeuf <jpoimboe@redhat.com>, X86 ML <x86@kernel.org>, Daniel Xu <dxu@dxuuu.xyz>, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com, ast@kernel.org, Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@alien8.de>, Peter Zijlstra <peterz@infradead.org>, kernel-team@fb.com, yhs@fb.com, linux-ia64@vger.kernel.org, Abhishek Sagar <sagar.abhishek@gmail.com>, Andrii Nakryiko <andrii.nakryiko@gmail.com>


* Masami Hiramatsu <mhiramat@kernel.org> wrote:

> --- a/include/linux/kprobes.h
> +++ b/include/linux/kprobes.h
> @@ -197,15 +197,23 @@ extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
>  				   struct pt_regs *regs);
>  extern int arch_trampoline_kprobe(struct kprobe *p);
>  
> +void kretprobe_trampoline(void);
> +/*
> + * Since some architecture uses structured function pointer,
> + * use dereference_function_descriptor() to get real function address.
> + */
> +static nokprobe_inline void *kretprobe_trampoline_addr(void)
> +{
> +	return dereference_kernel_function_descriptor(kretprobe_trampoline);
> +}

Could we please also make 'kretprobe_trampoline' harder to use 
accidentally, such by naming it appropriately?

__kretprobe_trampoline would be a good first step I guess.

Thanks,

	Ingo