Messages in this thread | | | Date | Mon, 11 May 2015 17:41:15 +0800 | From | Baoquan He <> | Subject | Re: [v2 1/5] arm64: kdump: reserve memory for crash dump kernel |
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On 05/11/15 at 05:17pm, AKASHI Takahiro wrote: > On 05/11/2015 04:54 PM, Baoquan He wrote: > >In this patch you reserve a separate memory region in 1st kernel to > >store elfcorehdr. I am wondering why you don't call add_buffer in > >kexec-tools directly. Like this you can get a region from reserved > >crashkernel region. Then you don't need reserve_elfcorehdr() to reserve > >memory for elfcorehdr specifically. Like other ARCHs do only one memory > >region is reserved in 1st kernel, that's crashkernel region. > > I think that you misunderstand somewhat. > * Kexec-tools only locates/identifies a small region for elfcore header within crash kernel's > memory region while 1st kernel is running. > * the data in elfcore header is filled up by kexec_load system call on 1st kernel. > * 1st kernel doesn't reserve any region for elfcore header because the kernel > commandline parameters don't contains "elfcorehdr=" parameter, then elfcorehdr_size=0. > * Crash dump kernel does reserve the region, as I said, because we don't want to > corrupt the info in elfcore header accidentally while crash kernel is running. > > Clear?
OK, got it now.
Then I am wondering why "elfcorehdr=" can't be contained in kernel cmdline as other ARCH does. Maybe I need go over all related threads then know why it is. Thanks for explanation.
Thanks Baoquan
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