On 01/23/2012 02:04 PM, Dannie Stanley wrote:
> Regarding the source code for kernel version 2.6.38. In
> kernel/module.c the function defined as:
>
> SYSCALL_DEFINE3(init_module...)
>
> Calls set_section_ro_nx for core and init. My first question is this:
>
>Q1: Why doesn't the exit text/data get the RO/NX page protection?
>
I guess this is a trade off.
> In the set_section_ro_nx function the RO comment reads: "Do not
> protect last partial page" and the NX comment reads: "Do not protect
> first partial page." In the presence of mixed pages this makes sense.
> However, change_page_attr_set_clr seems to check for page alignment.
> So my second question is this:
>
>Q2: Does the RO/NX only apply to page aligned sections?
>
Most MMUs/TLBs deal only with page sized memory. They handle access
attributes in page sized memory.
> Thank you,
> Dannie
>
-Fredrick
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