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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Mon, 5 Jul 2021 09:03:19 +0200
From:   Ingo Molnar <mingo@kernel.org>
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,
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        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>
Subject: Re: [PATCH -tip v8 03/13] kprobes: treewide: Remove
 trampoline_address from kretprobe_trampoline_handler()
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References: <162399992186.506599.8457763707951687195.stgit@devnote2>
 <162399994996.506599.17672270294950096639.stgit@devnote2>
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* 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