From: Dave Hansen <dave@sr71.net>
To: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
dave.hansen@linux.intel.com, hpa@zytor.com, fenghua.yu@intel.com,
yu-cheng.yu@intel.com
Subject: Re: [PATCH 1/5] x86: fix early command-line parsing when matching at end
Date: Tue, 5 Jan 2016 10:51:05 -0800 [thread overview]
Message-ID: <568C1099.5000100@sr71.net> (raw)
In-Reply-To: <20160105183542.GD4617@pd.tnic>
On 01/05/2016 10:35 AM, Borislav Petkov wrote:
> On Tue, Dec 22, 2015 at 02:52:38PM -0800, Dave Hansen wrote:
>> From: Dave Hansen <dave.hansen@linux.intel.com>
>> The x86 early command line parsing in cmdline_find_option_bool()
>> is buggy. If it matches a specified 'option' all the way to
>> the end of the command-line, it will consider it a match.
>>
>> For instance,
>>
>> cmdline = "foo";
>> cmdline_find_option_bool(cmdline, "fool");
>>
>> will return 1. This is particularly annoying since we have
>> actual FPU options like "noxsave" and "noxsaves" So,
>> command-line "foo bar noxsave" will match *BOTH* a "noxsave" and
>> "noxsaves". (This turns out not to be an actual problem because
>> "noxsave" implies "noxsaves", but it's still confusing.)
>
> So I booted a guest with this command line:
>
> [ 0.000000] Kernel command line: root=/dev/sda1 resume=/dev/sdb1 debug ignore_loglevel log_buf_len=16M earlyprintk=ttyS0,115200 console=ttyS0,115200 console=tty0 noxsave
>
> after applying the debug hunk below. However, the only debug output I
> got is this:
>
> [ 0.000000] x86_noxsave_setup
>
> If I supply "noxsaves", I get, as expected
>
> [ 0.000000] x86_noxsaves_setup
>
> only. Ditto for "noxsaveopt".
>
> So what am I missing?
The current code uses __setup() which uses different parsing than
cmdline_find_option_bool(). We're going to have to move the noxsave*
ones over to cmdline_find_option_bool() since we need the parsing
earlier than __setup() works.
The changelog should have been more clear on this, though.
next prev parent reply other threads:[~2016-01-05 18:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-22 22:52 [PATCH 0/5] x86: early command-line parsing fixes / tests (v2) Dave Hansen
2015-12-22 22:52 ` [PATCH 1/5] x86: fix early command-line parsing when matching at end Dave Hansen
2016-01-05 18:35 ` Borislav Petkov
2016-01-05 18:51 ` Dave Hansen [this message]
2016-01-06 17:10 ` Borislav Petkov
2016-01-06 17:57 ` Dave Hansen
2016-01-06 18:14 ` Borislav Petkov
2016-02-03 11:34 ` [tip:x86/boot] x86/boot: Fix " tip-bot for Dave Hansen
2015-12-22 22:52 ` [PATCH 2/5] x86: fix early command-line parsing, when partial word match Dave Hansen
2016-02-03 11:35 ` [tip:x86/boot] x86/boot: Fix early command-line parsing when partial word matches tip-bot for Dave Hansen
2015-12-22 22:52 ` [PATCH 3/5] x86: simplify early command line parsing Dave Hansen
2016-01-06 17:10 ` Borislav Petkov
2016-01-06 17:35 ` Dave Hansen
2016-01-06 17:37 ` Dave Hansen
2016-01-06 17:48 ` Borislav Petkov
2016-02-03 11:35 ` [tip:x86/boot] x86/boot: Simplify " tip-bot for Dave Hansen
2015-12-22 22:52 ` [PATCH 4/5] x86: pass in size to early cmdline parsing Dave Hansen
2016-02-03 11:36 ` [tip:x86/boot] x86/boot: Pass " tip-bot for Dave Hansen
2015-12-22 22:52 ` [PATCH 5/5] x86: test early command-line code Dave Hansen
2016-01-27 12:28 ` Borislav Petkov
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