Date: Sat, 5 Dec 2015 18:12:57 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Li Bin <huawei.libin@huawei.com>
cc: rostedt@goodmis.org, mingo@redhat.com, linux-kernel@vger.kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org
Subject: Re: [PATCH 5/5] x86: ftrace: fix the comments for
 ftrace_modify_code_direct
In-Reply-To: <1449214067-12177-6-git-send-email-huawei.libin@huawei.com>
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References: <1449214067-12177-1-git-send-email-huawei.libin@huawei.com> <1449214067-12177-6-git-send-email-huawei.libin@huawei.com>
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On Fri, 4 Dec 2015, Li Bin wrote:
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -106,13 +106,12 @@ ftrace_modify_code_direct(unsigned long ip, unsigned const char *old_code,
>  	unsigned char replaced[MCOUNT_INSN_SIZE];
>  
>  	/*
> -	 * Note: Due to modules and __init, code can
> -	 *  disappear and change, we need to protect against faulting
> -	 *  as well as code changing. We do this by using the
> -	 *  probe_kernel_* functions.
> -	 *
> -	 * No real locking needed, this code is run through
> -	 * kstop_machine, or before SMP starts.
> +	 * Note:
> +	 * We are paranoid about modifying text, as if a bug were to happen, it
> +	 * could cause us to read or write to someplace that could cause harm.
> +	 * Carefully read and modify the code with aarch64_insn_*() which uses

aarch64_insn_() is related to x86 in which way?

Thanks,

	tglx
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