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From: "H. Peter Anvin" <hpa@zytor.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Linux-pm mailing list <linux-pm@lists.osdl.org>,
	kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [rft] s2ram wakeup moves to .c, could fix few machines
Date: Thu, 07 Feb 2008 14:34:26 -0800	[thread overview]
Message-ID: <47AB8772.4010709@zytor.com> (raw)
In-Reply-To: <20080207222833.GA23004@uranus.ravnborg.org>

Sam Ravnborg wrote:
>> +
>> +	. = 0;
>> +	.text		: { *(.text*) }
>> +
>> +	. = ALIGN(16);
> Why?

It's good practice to have at least paragraph (segment boundary) 
alignment between different types of data.  In the case of the .bss, it 
also allows cleaning with rep;movsl.

It's technically not all that necessary (except for 4-byte alignment for 
the .bss), but it makes things easier to debug on the assembly level.

>> +	/* Adjust this as appropriate */
>> +	/* This allows 4 pages (16K) */
>> +	. = ASSERT(_end <= 0x4000, "Wakeup too big!");
> PAGE_SIZE * 4?

Not really, because it's not at all related to the kernel page size; the 
reference to pages there is informal.  If we go to a larger virtual page 
size we do NOT want this to change.

	-hpa

WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, Pavel Machek <pavel@ucw.cz>,
	kernel list <linux-kernel@vger.kernel.org>,
	Linux-pm mailing list <linux-pm@lists.osdl.org>
Subject: Re: [rft] s2ram wakeup moves to .c, could fix few machines
Date: Thu, 07 Feb 2008 14:34:26 -0800	[thread overview]
Message-ID: <47AB8772.4010709@zytor.com> (raw)
In-Reply-To: <20080207222833.GA23004@uranus.ravnborg.org>

Sam Ravnborg wrote:
>> +
>> +	. = 0;
>> +	.text		: { *(.text*) }
>> +
>> +	. = ALIGN(16);
> Why?

It's good practice to have at least paragraph (segment boundary) 
alignment between different types of data.  In the case of the .bss, it 
also allows cleaning with rep;movsl.

It's technically not all that necessary (except for 4-byte alignment for 
the .bss), but it makes things easier to debug on the assembly level.

>> +	/* Adjust this as appropriate */
>> +	/* This allows 4 pages (16K) */
>> +	. = ASSERT(_end <= 0x4000, "Wakeup too big!");
> PAGE_SIZE * 4?

Not really, because it's not at all related to the kernel page size; the 
reference to pages there is informal.  If we go to a larger virtual page 
size we do NOT want this to change.

	-hpa

  reply	other threads:[~2008-02-07 22:34 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-05 19:06 [rft] s2ram wakeup moves to .c, could fix few machines Pavel Machek
2008-02-06  1:27 ` Rafael J. Wysocki
2008-02-06  1:36   ` H. Peter Anvin
2008-02-06  1:42     ` Rafael J. Wysocki
2008-02-06  1:51       ` H. Peter Anvin
2008-02-06  1:56         ` Rafael J. Wysocki
2008-02-06 11:29         ` Pavel Machek
2008-02-14  2:54         ` Bill Davidsen
2008-02-06 23:48   ` Rafael J. Wysocki
2008-02-07 22:12     ` Rafael J. Wysocki
2008-02-07 22:28       ` Sam Ravnborg
2008-02-07 22:34         ` H. Peter Anvin [this message]
2008-02-07 22:34           ` H. Peter Anvin
2008-02-08 21:31         ` Pavel Machek
2008-02-08 21:34         ` Pavel Machek
2008-02-08 21:41         ` Pavel Machek
2008-02-08 21:47           ` Sam Ravnborg
2008-02-08 21:49         ` Pavel Machek
2008-02-07 22:28       ` Pavel Machek
2008-02-07 22:40         ` Rafael J. Wysocki
2008-02-07 22:44           ` H. Peter Anvin
2008-02-07 22:53             ` Rafael J. Wysocki
2008-02-07 22:45           ` H. Peter Anvin
2008-02-07 22:49             ` Pavel Machek
2008-02-08 21:13           ` Pavel Machek
2008-02-08 21:41             ` Maxim Levitsky
2008-02-08 21:41               ` Maxim Levitsky
2008-02-08 21:51               ` Pavel Machek
2008-02-07 22:46         ` H. Peter Anvin
2008-02-07 22:51           ` Pavel Machek
2008-02-07 23:09             ` Rafael J. Wysocki
2008-02-07 22:57           ` Rafael J. Wysocki
2008-02-07 23:14             ` H. Peter Anvin
2008-02-07 23:14               ` H. Peter Anvin
2008-02-08 21:35               ` Pavel Machek
2008-02-07 22:38       ` H. Peter Anvin
2008-02-07 23:06         ` Rafael J. Wysocki
2008-02-07 23:13           ` H. Peter Anvin
2008-02-07 23:35           ` Pavel Machek
2008-02-07 23:36             ` Rafael J. Wysocki
2008-02-07 23:41               ` Pavel Machek
2008-02-07 23:42             ` H. Peter Anvin
2008-02-08  7:04               ` Pavel Machek
2008-02-08  7:40                 ` H. Peter Anvin
2008-02-08 16:23                 ` Rafael J. Wysocki
2008-02-08 21:00                   ` Pavel Machek
2008-02-08 21:02                     ` H. Peter Anvin
2008-02-08 21:02                       ` H. Peter Anvin
2008-02-08 21:09                       ` Pavel Machek
2008-02-08 21:18                         ` H. Peter Anvin
2008-02-08 21:20                     ` [linux-pm] " Alan Stern
2008-02-08 21:23                       ` Pavel Machek
2008-02-08 21:27                         ` H. Peter Anvin
2008-02-08 21:31                           ` Pavel Machek
2008-02-08 21:56                             ` Rafael J. Wysocki
2008-02-08 21:59                               ` Pavel Machek
2008-02-08 21:56         ` Pavel Machek
2008-02-08 21:58         ` Pavel Machek
2008-02-08 22:01           ` Rafael J. Wysocki
2008-02-08 22:08             ` Pavel Machek
2008-02-09  0:18               ` Rafael J. Wysocki
2008-02-09  0:32                 ` H. Peter Anvin
2008-02-09 13:48                   ` Rafael J. Wysocki
2008-02-10 21:14                   ` Pavel Machek
2008-02-10 21:21                     ` Sam Ravnborg
2008-02-06 23:37 ` Rafael J. Wysocki

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