linux-kernel - Re: [PATCH v3 08/12] x86, boot: Don't check if cmd_line

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Date:	Wed, 21 Nov 2012 11:18:10 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 08/12] x86, boot: Don't check if cmd_line_ptr is
 accessible in misc/decompressor()

On Wed, Nov 21, 2012 at 9:21 AM, H. Peter Anvin <hpa@...or.com> wrote:
> On 11/20/2012 11:16 PM, Yinghai Lu wrote:
>>
>> At that stage, it is already in 32bit protected mode or 64bit mode.
>> so we do not need to check if ptr less 1M.
>>
>> When go from other boot loader (kexec) instead of boot/ code path.
>>
>> Move out accessible checking out __cmdline_find_option....
>>
>> So misc.c will parse cmdline and have debug print out.
>
>
> Your description doesn't seem to match the code, and is incredibly confusing
> to the reader.
>
> The reason why is because you leave out an essential piece of information:
> cmdline.c is included both in 16-bit code and in the decompressor (32/64-bit
> code), so you want to move the test out of the shared code.

updated change log to:

Subject: [PATCH] x86, boot: move checking of cmd_line_ptr out of common path

cmdline.c::__cmdline_find_option... are shared between
16-bit setup code and 32/64 bit decompressor code.

for 32/64 only path via kexec, we should not check if ptr less 1M.
as those cmdline could be put above 1M even 4G.

Move out accessible checking out of __cmdline_find_option....
So decompressor in misc.c can parse cmdline correctly.
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