> -----Original Message----- > From: Horms [mailto:horms@xxxxxxxxxxxx] > Sent: 2007年2月14日 18:13 > To: Zou, Nanhai > Cc: Magnus Damm; vgoyal@xxxxxxxxxx; fastboot@xxxxxxxxxxxxxx; > linux-ia64@xxxxxxxxxxxxxxx > Subject: Re: Zero size /proc/vmcore on ia64 > > On Wed, Feb 14, 2007 at 05:57:58PM +0800, Zou, Nanhai wrote: > > > -----Original Message----- > > > From: Magnus Damm [mailto:magnus.damm@xxxxxxxxx] > > > Sent: 2007年2月14日 16:28 > > > To: vgoyal@xxxxxxxxxx > > > Cc: Horms; Zou, Nanhai; fastboot@xxxxxxxxxxxxxx; > linux-ia64@xxxxxxxxxxxxxxx > > > Subject: Re: Zero size /proc/vmcore on ia64 > > > > > > Vivek, everyone, > > > > > > On 2/8/07, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > > > I think we should not remove this check because even to parse the info > > > > passed in ELF headers, you need to first read the ELF headers from crashed > > > > kernel's memory. So if some programming error has passed wrong location > of > > > > ELF headers (elfcoreheader= invalid location) then we might try reading > the > > > > elf header from a non-existing physical page frame. > > > > > > Are you saying that the ELF header is located in the memory space of > > > the first kernel? > > > > > > The way I read the code the ELF header is put into the reserved memory > > > space for the secondary kernel. At least on ia64 that is true, and I > > > think the same goes for i386. > > > > > > And the fact that the ELF header is put in to the secondary kernel > > > brings me memory setup problems on ia64. > > > > > > Basically the ELF header is marked as EFI_UNUSABLE_MEMORY by the EFI > > > mangling code in purgatory. The secondary kernel detects this while > > > parsing the EFI tables and refuses to use/map the other memory present > > > in the same 16M granule. And in my case the initramfs happens to be > > > located in the same granule... boom! No good. =) > > > > > > So I'm wondering about the reason why we put the ELF header in the > > > secondary kernel. Can't we just put it in the first kernel and be done > > > with it? We still point it out using the kernel command line, don't > > > we? > > > > My first design is that putting data in second kernel is easy and > > safer. We could put it in the first kernel if we provide an interface > > to reserve this area at the time of kexec -p so that nobody will touch > > it even at the time of crash. > > > > Align that buffer to 16M will solve the issue but that seems to be a > > waste of the useful memory? Another way is append this elf header to > > command line in purgatory, like we append the ummy efi function, maybe > > this is too hacky? > > I think that the dummy efi function is already way to hacky. Yes it is. However the benefit of it is that you can kexec to an old kernel even a 2.4 based kernel. > I'd like to work out a (good) way to get rid of it. > For starters the PAGE_OFFSET is hardcoded at kexec-tools compile time - > which breaks xen as it has a different PAGE_OFFSET. > > -- > Horms > H: http://www.vergenet.net/~horms/ > W: http://www.valinux.co.jp/en/ - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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