linux-kernel - RE: [PATCH 03/10] PCI: AMD SATA IDE mode quirk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Mon, 25 Feb 2008 16:00:48 +0800
From:	"Cai, Crane" <Crane.Cai@....com>
To:	"Grant Grundler" <grundler@...isc-linux.org>
Cc:	"Matthew Wilcox" <matthew@....cx>,
	"Greg Kroah-Hartman" <gregkh@...e.de>,
	<linux-pci@...ey.karlin.mff.cuni.cz>,
	<linux-kernel@...r.kernel.org>,
	"Linus Torvalds" <torvalds@...l.org>,
	"Andrew Morton" <akpm@...l.org>
Subject: RE: [PATCH 03/10] PCI: AMD SATA IDE mode quirk

> On Mon, Feb 25, 2008 at 09:43:59AM +0800, Cai, Crane wrote:
> > > On Fri, Feb 22, 2008 at 01:49:20PM +0800, Cai, Crane wrote:
> > > > > On Thu, Feb 21, 2008 at 03:47:33PM -0800, Greg
> > > Kroah-Hartman wrote:
> > > > > > +static void __devinit quirk_amd_ide_mode(struct pci_dev 
> > > > > > +*pdev)
> > > > > >  {
> > > > > > -	/* set sb600 sata to ahci mode */
> > > > > > -	if ((pdev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
> > > > > > -		u8 tmp;
> > > > > > +	/* set sb600/sb700/sb800 sata to ahci mode */
> > > > > > +	u8 tmp;
> > > > > >  
> > > > > > +	pci_read_config_byte(pdev, PCI_CLASS_DEVICE, &tmp);
> > > > > > +	if (tmp == 0x01) {
> > > > > >  		pci_read_config_byte(pdev, 0x40, &tmp);
> > > > > 
> > > > > This seems like a dis-improvement.  Why are we reading a
> > > config byte
> > > > > for something we already have in the pci_dev?
> > > > > Why are we now checking against 0x01 instead of a
> > > symbolic constant?  
> > > > > Why are we no longer checking that this is 
> PCI_BASE_CLASS_STORAGE?
> > > > It is a quirk. In pci_ids.h did have PCI_CLASS_STORAGE_IDE and 
> > > > PCI_BASE_CLASS_STORAGE, these can not represent the right
> > > situation we
> > > > want to check. 0x01 represents PCI_CLASS_STORAGE_IDE last 2
> > > bit. Also
> > > > because it is a quirk, I do not think we need to change
> > > pci_ids.h. So
> > > > 0x01 used.
> > > 
> > > You haven't explained what is wrong with the original code:
> > > 
> > > 	if ((pdev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
> > > 
> > 
> > When resume, this pdev->class is quirked, however BIOS has modified 
> > pci configuration too. Inconsistance occurs.
> 
> Can you update pdev->class from the quirk?
I think we can, there are many places where pdev->class is changed in quirks.c.
> It would be consistent then.
> That would leave the code as-is except it's re-reading the 
> field from config space.
> 
> hth,
> grant

> > > > > Nothing in the changelog entry suggests why we now need
> > > FIXUP_RESUME
> > > > > entries when we didn't before.
> > > > > 
> > > > PCI configuration space will be changed by BIOS and then in
> > > pci init
> > > > and restore. So resume also needed.
> > > 
> > > That information needed to be in the changelog.
> > 
> > This info, is a normal info. If maintainer need us to added 
> in source code. I preferred too. 
> > > --
> > > Intel are signing my paycheques ... these opinions are still mine 
> > > "Bill, look, we understand that you're interested in 
> selling us this 
> > > operating system, but compare it to ours.  We can't possibly take 
> > > such a retrograde step."
> > > 
> > > 
> > > 
> 
> 
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/