From: dhylands@gmail.com (Dave Hylands)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Query on linker scripts
Date: Mon, 26 Mar 2012 08:14:05 -0700 [thread overview]
Message-ID: <CABi1daErCC1iTTQgc42Nw_8x_hMasv9VFW6tNNmHVfFn3yhzOA@mail.gmail.com> (raw)
In-Reply-To: <CAKuUYSyiE2TfLwxu60z95rZDvk_bLWW5PAEcFZnCAEmPqdfF4g@mail.gmail.com>
Hi Vaibhav Jain,
On Mon, Mar 26, 2012 at 4:01 AM, Vaibhav Jain <vjoss197@gmail.com> wrote:
> Thanks a lot for the explanation and the link!! I have just one more
> question about
> linker scripts. I am not clear about alignment of sections. Is it necessary
> to align sections?
> Can the alignment be different from 4096?
> In the script that I provided the text and data sections are aligned while
> the bss section is not. Is there
> a reason for it ?
The reason for using page alignments is so that the kernel can enforce
different access types to the various sections. This is tyically done
using the MMU, which would require page alignment.
So, for example, the text section would allow executable code, and
should be read-only. The .rodata section should not allow executable
code and be read-only, and the .data section should not allow
executable code, and should allow writes.
By having the sections page aligned, it allows the kernel to enforce
these using the MMU.
--
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com
next prev parent reply other threads:[~2012-03-26 15:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-24 18:45 Query on linker scripts Pranay Kumar Srivastava
[not found] ` <CAKuUYSwPiuGTa+8r6O+-GMLu9e6dXOXNfDHu4UBx2yvrHcQyvw@mail.gmail.com>
2012-03-26 6:41 ` Pranay Kumar Srivastava
2012-03-26 11:01 ` Vaibhav Jain
2012-03-26 11:54 ` Pranay Kumar Srivastava
2012-03-27 1:38 ` Vaibhav Jain
2012-03-27 11:00 ` Pranay Kumar Srivastava
2012-03-26 15:14 ` Dave Hylands [this message]
-- strict thread matches above, loose matches on Subject: below --
2012-03-24 4:43 Vaibhav Jain
2012-03-24 15:26 ` Carlo Caione
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