Messages in this thread | | | From | (Eric W. Biederman) | Date | Thu, 15 May 2008 19:25:00 -0700 | Subject | Re: [PATCH] kexec based hibernation: a prototype of kexec multi-stage load |
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"Huang, Ying" <ying.huang@intel.com> writes:
> On Thu, 2008-05-15 at 11:39 -0700, Eric W. Biederman wrote: > [...] >> 2) After we figure out our address read the stack pointer from >> a fixed location and simply set it. (This is my preference) > > Just for confirmation (My English is poor). > > Do you mean that kernel A just read the stack top as re-entry point, > regardless of whether it is return address or argument 1?
What I was thinking was:
In kernel A()
relocate_new_kernel:
...
call *%eax
kexec_jump_back_entry: /* This code should be PIC so figure out where we are */ call 1f 1: popl %edi subl $(1b - relocate_kernel), %edi
/* Setup a safe stack */ leal PAGE_SIZE(%edi), %esp ...
Then in purgatory we can read the address of kexec_jump_back_entry by examining 0(%esp) and export it in whatever fashion is sane.
However we reach kexec_jump_back_entry we should be fine.
Eric
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