From: Cao jin <caoj.fnst@cn.fujitsu.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: <x86@kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-doc@vger.kernel.org>, <tglx@linutronix.de>,
<mingo@redhat.com>, <bp@alien8.de>, <hpa@zytor.com>,
<corbet@lwn.net>
Subject: Re: [RFC PATCH] x86/doc/boot_protocol: Correct the description of "reloc"
Date: Thu, 26 Sep 2019 15:55:51 +0800 [thread overview]
Message-ID: <faabfe47-ba3e-5a92-af65-dc26e8e2ecb9@cn.fujitsu.com> (raw)
In-Reply-To: <20190926060139.GA100481@gmail.com>
On 9/26/19 2:01 PM, Ingo Molnar wrote:
> * Cao jin <caoj.fnst@cn.fujitsu.com> wrote:
>
>> The fields marked with (reloc) actually are not dedicated for writing,
>> but communicating info for relocatable kernel with boot loaders. For
>> example:
>>
>> ============ ============
>> Field name: pref_address
>> Type: read (reloc)
>> Offset/size: 0x258/8
>> Protocol: 2.10+
>> ============ ============
>>
>> ============ ========================
>> Field name: code32_start
>> Type: modify (optional, reloc)
>> Offset/size: 0x214/4
>> Protocol: 2.00+
>> ============ ========================
>>
>> Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
>> ---
>> Unless I have incorrect non-native understanding for "fill in", I think
>> this is inaccurate.
>>
>> Documentation/x86/boot.rst | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/Documentation/x86/boot.rst b/Documentation/x86/boot.rst
>> index 08a2f100c0e6..a611bf04492d 100644
>> --- a/Documentation/x86/boot.rst
>> +++ b/Documentation/x86/boot.rst
>> @@ -243,7 +243,7 @@ bootloader ("modify").
>>
>> All general purpose boot loaders should write the fields marked
>> (obligatory). Boot loaders who want to load the kernel at a
>> -nonstandard address should fill in the fields marked (reloc); other
>> +nonstandard address should consult with the fields marked (reloc); other
>> boot loaders can ignore those fields.
>>
>> The byte order of all fields is littleendian (this is x86, after all.)
>
> Well, this documentation is written from the point of view of a
> *bootloader*, not the kernel. So the 'fill in' says that the bootloader
> should write those fields - which is correct, right?
>
Take pref_address or relocatable_kernel for example, they have type:
read (reloc), does boot loader need to write them? I don't see grub does
this at least.
--
Sincerely,
Cao jin
next prev parent reply other threads:[~2019-09-26 7:55 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 4:21 [RFC PATCH] x86/doc/boot_protocol: Correct the description of "reloc" Cao jin
2019-09-26 6:01 ` Ingo Molnar
2019-09-26 6:03 ` hpa
2019-09-26 7:55 ` Cao jin [this message]
2019-09-26 7:58 ` hpa
2019-09-26 8:20 ` Cao jin
2019-09-26 19:18 ` hpa
2019-09-27 2:09 ` Cao jin
2019-09-26 15:20 ` Randy Dunlap
2019-09-26 19:17 ` hpa
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