From: Aruna Hewapathirane <aruna.hewapathirane@gmail.com>
To: ebashinskii <ebashinskii@proton.me>
Cc: "kernelnewbies@kernelnewbies.org" <kernelnewbies@kernelnewbies.org>
Subject: Re: Is arch/x86/boot/main.c main obsolete?
Date: Sat, 25 Jun 2022 22:05:40 -0400 [thread overview]
Message-ID: <CAFSeFg_-cXJQxK9NbucWDZ0mNcQuU-__j7ouwE6fbkbdBOjRRw@mail.gmail.com> (raw)
In-Reply-To: <zcMypU8DDYjLz2ODqB0N9Pbpv7OHc7PK8ncYNuNj1slaFnA1cGdy-TFKcpScWQs9xOVCcQljUtR94Ed3guRc9hpufe6DyqgvKRhAbR3hU7A=@proton.me>
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On Sat, Jun 25, 2022 at 7:35 PM ebashinskii <ebashinskii@proton.me> wrote:
> CPU: Intel x86 KabyLake. I'm using 5.17 Kernel built from upstream and
> GRUB 2.04
>
> When debugging the kernel initialization process I found out that there is
> a function *void main(void)* in the source file *arch/x86/boot/main.c* (source
> link:
> https://elixir.bootlin.com/linux/v5.17/source/arch/x86/boot/main.c#L134) which
> seems to be the entry point which the boot loader is supposed to jump into.
>
> But *objdump*-ing the Kernel image shows that there is no such symbol as
> *main*. GDB attached to QEMU does not know about this symbol either.
>
> The earliest stage of Kernel Initialization I could manage to catch with
> GDB is *x86_64_start_kernel* (source link:
> https://elixir.bootlin.com/linux/v5.17/source/arch/x86/kernel/head64.c#L467
> )
>
> The question is what function GRUB actually jump into passing control to
> the Kernel code and what is the purpose of *arch/x86/boot/main.c::main*?
>
This should answer most of the questions you may have about the kernel boot
process:
https://0xax.gitbooks.io/linux-insides/content/Booting/
:-)
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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next prev parent reply other threads:[~2022-06-26 2:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-25 23:35 Is arch/x86/boot/main.c main obsolete? ebashinskii
2022-06-26 2:05 ` Aruna Hewapathirane [this message]
2022-06-26 13:38 ` ebashinskii
2022-07-19 2:41 ` jim.cromie
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