RE: [patch 3/3] IA64: verify the base address of crashkernel

From: Zou, Nanhai <nanhai.zou_at_intel.com>
Date: 2007-03-07 20:06:39
> -----Original Message-----
> From: Horms [mailto:horms@verge.net.au]
> Sent: 200737 15:55
> To: Zou, Nanhai
> Cc: Linux-IA64; fastboot@lists.osdl.org; Luck, Tony; Magnus Damm
> Subject: Re: [patch 3/3] IA64: verify the base address of crashkernel
> 
> On Wed, Mar 07, 2007 at 12:50:12PM +0800, Zou, Nanhai wrote:
> > On Wed, Mar 07, 2007 at 11:46, Horms wrote:
> > >
> > > I think that the manual option is also important because it
> > > maintains feature-compatibility with other architectures. I don't
> > > consider it a hack that might work purely for the purposes of
> > > debugging.
> >
> > I don't understand why we need to maintain compatibility with other
> > architectures here. Manfully choose may confuse user, XXX@16M may work
> > on one arch,but not on another arch. Other architectures need manually
> > choose crash kernel region simply because they do not support kernel
> > automatically choose feature.
> >
> > I keep the XXX@YYY format to just make kdump script compatible, do
> > that distributions does not need to maintain different kdump scripts
> > for different arches.
> 

> From my point of view, what you say in the paragraph immediately above
> Thanks, is this logic better?
> 
  Don't write code to improve a "no user will use" feature. 
  Let's keep kernel code clean.

> kdump_region_verify_rsvd_region (unsigned long base, unsigned long size,
>                                 struct rsvd_region *rsvd_regions, int n)
> {
> 	int i;
> 
> 	for (i = 0; i < n; i++) {
> 		/* Assume that start < end && size > 0 */
> 		if (__pa(rsvd_regions[i].start) >= base + size &&
> 		    __pa(rsvd_regions[i].end) < base)
> 			continue;
    This is much worse. Have you ever tested it?

> 		printk(KERN_WARNING "Kdump: crashkernel region 0x%lx-0x%lx "
> 		       "clashes with reserved region 0x%lx-0x%lx\n", base,
> 		       base + size - 1, __pa(rsvd_regions[i].start),
> 		       __pa(rsvd_regions[i].end));
> 		return 0;
> 	}
> 	return 1;
> }


> 
Zou Nan hai
> --
> Horms
>   H: http://www.vergenet.net/~horms/
>   W: http://www.valinux.co.jp/en/
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Received on Wed Mar 07 20:07:19 2007

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