Re: [PATCH 3/3] powerpc/ppc64/kdump: better flag for running relocatable

Milton Miller
2008-11-11T16:03:14Z

On Nov 10, 2008, at 9:22 AM, Mohan Kumar M wrote:
> Yes, elf_ret_symbol sets the copy in purgatory. But the following code
> in purgatory (to be introduced)
>
> LOADADDR(6,run_at_load)
> ld 18,0(6)
> cmpd 18,1
> bne skip
> li 7,1
> stw 7,92(4) # mark __run_at_load flag at kernel
>
> will set the __run_at_load in the kernel image (ie where ever kernel
> is loaded + 0x5c(92). Or am I missing some thing?

That would work, but I prefer to keep the change in the userspace side.
Partly because I don't want to link setting the relocatable flag to
purgatory starting a dump kernel, and partly because I think
kexec-tools should be verifying that the loaded kernel will run where
it expects, either by it finding the relcatable flag, inspecting the
elf header for the linked address, or some other method (like elf type
is dynamic for some platforms). Oh, and its more readable in C.

If someone adds mmap instead of read files to the common code, then we
will just have to make sure they use MMAP_PRIVATE instead of
MMAP_SHARED. Today its not an issue.

milton