linux-kernel - Re: [patch 14/23] x86 microcode: dont check the size

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Date:	Mon, 04 Dec 2006 09:04:03 +0800
From:	Shaohua Li <shaohua.li@...el.com>
To:	Willy Tarreau <w@....eu>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [patch 14/23] x86 microcode: dont check the size

On Sat, 2006-12-02 at 07:44 +0100, Willy Tarreau wrote:
> Shaohua,
> 
> this one seems appropriate for 2.4 too. It is OK for you if I merge it ?
Yes, 2.4 and 2.6 use the same driver. It should be fine to merge it.

Thanks,
Shaohua

> On Wed, Nov 29, 2006 at 02:00:25PM -0800, Chris Wright wrote:
> > -stable review patch.  If anyone has any objections, please let us know.
> > ------------------
> > 
> > From: Shaohua Li <shaohua.li@...el.com>
> > 
> > IA32 manual says if micorcode update's size is 0, then the size is
> > default size (2048 bytes). But this doesn't suggest all microcode
> > update's size should be above 2048 bytes to me. We actually had a
> > microcode update whose size is 1024 bytes. The patch just removed the
> > check.
> > 
> > Backported to 2.6.18 by Daniel Drake.
> > 
> > Signed-off-by: Daniel Drake <dsd@...too.org>
> > Signed-off-by: Chris Wright <chrisw@...s-sol.org>
> > ---
> >  arch/i386/kernel/microcode.c |    9 ++-------
> >  1 file changed, 2 insertions(+), 7 deletions(-)
> > 
> > --- linux-2.6.18.4.orig/arch/i386/kernel/microcode.c
> > +++ linux-2.6.18.4/arch/i386/kernel/microcode.c
> > @@ -250,14 +250,14 @@ static int find_matching_ucodes (void) 
> >  		}
> >  
> >  		total_size = get_totalsize(&mc_header);
> > -		if ((cursor + total_size > user_buffer_size) || (total_size < DEFAULT_UCODE_TOTALSIZE)) {
> > +		if (cursor + total_size > user_buffer_size) {
> >  			printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
> >  			error = -EINVAL;
> >  			goto out;
> >  		}
> >  
> >  		data_size = get_datasize(&mc_header);
> > -		if ((data_size + MC_HEADER_SIZE > total_size) || (data_size < DEFAULT_UCODE_DATASIZE)) {
> > +		if (data_size + MC_HEADER_SIZE > total_size) {
> >  			printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
> >  			error = -EINVAL;
> >  			goto out;
> > @@ -460,11 +460,6 @@ static ssize_t microcode_write (struct f
> >  {
> >  	ssize_t ret;
> >  
> > -	if (len < DEFAULT_UCODE_TOTALSIZE) {
> > -		printk(KERN_ERR "microcode: not enough data\n"); 
> > -		return -EINVAL;
> > -	}
> > -
> >  	if ((len >> PAGE_SHIFT) > num_physpages) {
> >  		printk(KERN_ERR "microcode: too much data (max %ld pages)\n", num_physpages);
> >  		return -EINVAL;
> > 
> > --
> > -
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