linux-kernel - Re: [PATCH v3 11/12] x86, boot: add fields to support load bzImage and ramdisk high

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Message-ID: <50B14AFB.3040500@zytor.com>
Date:	Sat, 24 Nov 2012 14:32:27 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Yinghai Lu <yinghai@...nel.org>
CC:	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	Rob Landley <rob@...dley.net>,
	Matt Fleming <matt.fleming@...el.com>
Subject: Re: [PATCH v3 11/12] x86, boot: add fields to support load bzImage
 and ramdisk high

On 11/24/2012 02:18 PM, Yinghai Lu wrote:
>>
>> Careful... consider the people who use a kexec-based solution as
>> bootloaders.
>
> yes, those may not update kexec in the flash...
>
> then, may need to use another bit in xloadflags to tell new kernel if
> need to check ext_...
>
> Field name:     xloadflags
> Type:           modify (obligatory)
> Offset/size:    0x236/2
> Protocol:       2.12+
>
>    This field is a bitmask.
>
>    Bit 0 (read): CAN_BE_LOADED_ABOVE_4G
>          - If 1, kernel/boot_params/cmdline/ramdisk can be above 4g,
>                  set by kernel.
>
>    Bit 1 (write): LOADED_ABOVE_4G
>          - If 1, kernel/boot_params/cmdline/ramdisk is loaded above 4g,
>                  set by bootloader, and kernel will check ext_ramdisk_image,
>                  ext_ramdisk_size and ext_cmd_line_ptr.
>

Well, that solves the problem for *this specific instance* but I fear 
therein lies madness in the general case.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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