* esp register value after jump to linux
@ 2014-12-24 18:59 Alexander Kuleshov
2014-12-26 18:35 ` Andrei Borzenkov
0 siblings, 1 reply; 2+ messages in thread
From: Alexander Kuleshov @ 2014-12-24 18:59 UTC (permalink / raw)
To: grub-devel
Hello all,
I see that grub setups registers before jump to linux kernel at
grub/grub-core/loader/i386/pc/linux.c:
grub_linux16_boot (void)
{
...
state.gs = state.fs = state.es = state.Tds = state.ss = segment;
state.sp = GRUB_LINUX_SETUP_STACK;
state.cs = segment + 0x20;
state.ip = 0;
...
}
I see in gdb that: ss, ds, and other segment registers are 0x1000, and
cs is 0x1020. It is good. But why esp is 0xf7f4? I see that
GRUB_LINUX_SETUP_STACK is 0x9000.
Thank you.
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: esp register value after jump to linux
2014-12-24 18:59 esp register value after jump to linux Alexander Kuleshov
@ 2014-12-26 18:35 ` Andrei Borzenkov
0 siblings, 0 replies; 2+ messages in thread
From: Andrei Borzenkov @ 2014-12-26 18:35 UTC (permalink / raw)
To: Alexander Kuleshov; +Cc: grub-devel
В Thu, 25 Dec 2014 00:59:36 +0600
Alexander Kuleshov <kuleshovmail@gmail.com> пишет:
> Hello all,
>
> I see that grub setups registers before jump to linux kernel at
> grub/grub-core/loader/i386/pc/linux.c:
>
> grub_linux16_boot (void)
>
> {
>
> ...
>
> state.gs = state.fs = state.es = state.Tds = state.ss = segment;
>
> state.sp = GRUB_LINUX_SETUP_STACK;
>
> state.cs = segment + 0x20;
>
> state.ip = 0;
>
> ...
>
> }
>
> I see in gdb that: ss, ds, and other segment registers are 0x1000, and
> cs is 0x1020. It is good. But why esp is 0xf7f4? I see that
> GRUB_LINUX_SETUP_STACK is 0x9000.
>
It is absolutely unclear at which point, where and how you get content
of ESP.
^ permalink raw reply [flat|nested] 2+ messages in thread
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