Milton Miller wrote:
On Oct 23, 2008, at 10:15 AM, Mohan Kumar M wrote:
Hi Milton,
My suggestions:
Milton Miller wrote:
i.e.,
[code snip 1]
lwz r7,__run_at_load-_stext(r26)
cmplwi cr0,r7,1 /* kdump kernel ? - stay where we are */
bne 1f
add r25,r25,r26
lwz r7,__run_at_load-_stext(r26)
cmplwi cr0,r7,1
bne 3f
kexec-tools
[code snip 2]
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
skip:
lwz 7,0(4) # get the first instruction that we stole
stw 7,0(0) # and put it in the slave loop at 0
# skip cache flush, do we care?
[code snip 3]
if (info->kexec_flags & KEXEC_ON_CRASH) {
....
elf_rel_set_symbol(&info->rhdr, "run_at_load",
&my_run_at_load,
sizeof(my_run_at_load));
}
This elf_rel_set_symbol sets the copy in purgatory,
after we have copied the code from the kernel. It
is this copy that gets copied to address 0.
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?
However this information is not in the code that
is at the start of the kernel. We don't have any
symbols for the kernel itself, it might be stripped.
So we can't use the elf_set_symbol api. (The kernel
may not be relocatable either).
Regards,
Mohan.
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