From: William Tambe <tambewilliam@gmail.com>
To: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
Cc: Kernel Newbies <kernelnewbies@kernelnewbies.org>
Subject: Re: make vmlinux .bss PROGBITS
Date: Tue, 6 Oct 2020 13:56:11 -0500 [thread overview]
Message-ID: <CAF8i9mNR1Xggu1SMn-gu4wDxYCbqMQ3KoK88sogX+zgwcNW35w@mail.gmail.com> (raw)
In-Reply-To: <123123.1602007865@turing-police>
On Tue, Oct 6, 2020 at 1:11 PM Valdis Klētnieks <valdis.kletnieks@vt.edu> wrote:
>
> On Tue, 06 Oct 2020 08:17:44 -0500, William Tambe said:
> > How can I modify Makefile such that when vmlinux is created, following
> > command is run on vmlinux to make section .bss PROGBITS:
> > objcopy --set-section-flags .bss=alloc,load,contents
>
> Remember - vmlinux isn't going to be loaded by the userspace loader,
> but rather by a bootstrap loader. So those flags probably don't actually
> do what you think they do.
We have a loader that loads vmlinux.bin (created from vmlinux using
objcopy -O binary), however if section .bss is not PROGBITS,
vmlinux.bin does not include that space, which the loader will not
reserve; by allocating that space in vmlinux.bin the loader also
reserves that space.
To solve the problem we are looking to make section .bss PROBGITS
using objcopy --set-section-flags .bss=alloc,load,contents , but it is
not trivial how to modify the Linux Makefile to achieve that.
>
> For that matter, what *do* you think they do, and what problem are you
> trying to solve with them?
>
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next prev parent reply other threads:[~2020-10-06 18:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 13:17 make vmlinux .bss PROGBITS William Tambe
2020-10-06 18:11 ` Valdis Klētnieks
2020-10-06 18:56 ` William Tambe [this message]
2020-10-06 23:52 ` Valdis Klētnieks
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