linux-kernel - Re: [PATCH 12/20] x86_64: 64bit ACPI wakeup trampoline

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Message-ID: <20070307224508.GE5956@elf.ucw.cz>
Date:	Wed, 7 Mar 2007 23:45:08 +0100
From:	Pavel Machek <pavel@....cz>
To:	Vivek Goyal <vgoyal@...ibm.com>
Cc:	linux kernel mailing list <linux-kernel@...r.kernel.org>,
	Reloc Kernel List <fastboot@...ts.osdl.org>,
	ebiederm@...ssion.com, akpm@...ux-foundation.org, ak@...e.de,
	hpa@...or.com, magnus.damm@...il.com, lwang@...hat.com,
	dzickus@...hat.com, rjw@...k.pl
Subject: Re: [PATCH 12/20] x86_64: 64bit ACPI wakeup trampoline

Hi!

> o Moved wakeup_level4_pgt into the wakeup routine so we can
>   run the kernel above 4G.
> 
> o Now we first go to 64bit mode and continue to run from trampoline and
>   then then start accessing kernel symbols and restore processor context.
>   This enables us to resume even in relocatable kernel context when 
>   kernel might not be loaded at physical addr it has been compiled for.
> 
> o Removed the need for modifying any existing kernel page table.
> 
> o Increased the size of the wakeup routine to 8K. This is required as
>   wake page tables are on trampoline itself and they got to be at 4K
>   boundary, hence one page is not sufficient.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com>
> Signed-off-by: Vivek Goyal <vgoyal@...ibm.com>

> +	if ((&wakeup_end - &wakeup_start) > (PAGE_SIZE*2))
>  		printk(KERN_CRIT
> -		       "ACPI: Wakeup code way too big, will crash on attempt to suspend\n");
> +		       "ACPI: Wakeup code way too big, will crash on attempt"
> +		       " to suspend\n");

Hmm, if you split it like
		printk(KERN_CRIT "ACPI: Wakeup code way too big, will crash"
			"on attempt to suspend\n");

...you'll still keep 80-column rule while keeping it readable.

> @@ -159,11 +159,11 @@ wakeup_32:
>  	 */
>  
>  	/* Finally jump in 64bit mode */
> -	ljmp	*(wakeup_long64_vector - __START_KERNEL_map)
> +        ljmp    *(wakeup_long64_vector - wakeup_code)(%esi)

spaces vs. tabs problem.

Otherwise looks good. ACK if it was tested.
									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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