From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from kirsty.vergenet.net ([202.4.237.240]) by bombadil.infradead.org with esmtp (Exim 4.69 #1 (Red Hat Linux)) id 1MbVZM-0005XX-7O for kexec@lists.infradead.org; Thu, 13 Aug 2009 08:22:01 +0000 Date: Thu, 13 Aug 2009 18:21:51 +1000 From: Simon Horman Subject: Re: [PATCH] Increase kernel text size for x86_64 Message-ID: <20090813082151.GA6502@verge.net.au> References: <4A827223.8090907@suse.de> <20090813004013.GB23310@verge.net.au> <4A83CAF5.6080004@suse.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4A83CAF5.6080004@suse.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Hannes Reinecke Cc: kexec mailing list On Thu, Aug 13, 2009 at 10:12:37AM +0200, Hannes Reinecke wrote: > Simon Horman wrote: > > On Wed, Aug 12, 2009 at 09:41:23AM +0200, Hannes Reinecke wrote: > >> Hi all, > >> > >> I cannot load a x86_64 kernel with kexec on 2.6.31; the error message is: > >> > >> Can't find kernel text map area from kcore > >> Cannot load /boot/vmlinuz > >> > >> Digging through the source I found a mismatch between the assumed > >> kernel text size; kexec has: > >> > >> #define KERNEL_TEXT_SIZE (40UL*1024*1024) > >> > >> but on the kernel side we have: > >> > >> include/asm/page_64_types.h: > >> #define KERNEL_IMAGE_SIZE (512 * 1024 * 1024) > >> > >> And, indeed, changing the definition in kexec-tools to the kernel one > >> fixed the problem. > >> > >> Not sure if this has been reported before, if so please ignore > >> the noise. > > > > Hi, > > > > I'm wondering what effect this would have when using > > kexec-tools with older kernels, which presumably have > > a smaller value for KERNEL_IMAGE_SIZE. > > > >> diff --git a/kexec/arch/x86_64/crashdump-x86_64.h b/kexec/arch/x86_64/crashdump-x86_64.h > >> index 9f4dee9..0e83527 100644 > >> --- a/kexec/arch/x86_64/crashdump-x86_64.h > >> +++ b/kexec/arch/x86_64/crashdump-x86_64.h > >> @@ -11,7 +11,7 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline, > >> #define MAXMEM 0x3fffffffffffUL > >> > >> /* Kernel text size */ > >> -#define KERNEL_TEXT_SIZE (40UL*1024*1024) > >> +#define KERNEL_TEXT_SIZE (512UL*1024*1024) > >> > >> #define CRASH_MAX_MEMMAP_NR (KEXEC_MAX_SEGMENTS + 1) > >> #define CRASH_MAX_MEMORY_RANGES (MAX_MEMORY_RANGES + 2) > > > Well, the actual point of failure is in kexec/arch/x86_64/crashdump-x86_64.c:125 > > /* Look for kernel text mapping header. */ > if ((saddr >= __START_KERNEL_map) && > (eaddr <= __START_KERNEL_map + KERNEL_TEXT_SIZE)) { > saddr = (saddr) & (~(KERN_VADDR_ALIGN - 1)); > info->kern_vaddr_start = saddr; > size = eaddr - saddr; > > which basically should look for a ELF header into which the kernel fits. As we're > effectively just moving the upper limit I fail to see any harm to older kernels. > > Hmm. Haven't checked for other occurrences of KERNEL_TEXT_SIZE, though. > > Would be nice we could be getting these values off somewhere; rely on > some kernel defines is going to break now and then. Agreed, but I think that your patch is worth having in the mean time. I will apply it. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec