lkml.org 
[lkml]   [2018]   [Jan]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC] selftests/x86: Add test_vsyscall
From
Date

> On Jan 5, 2018, at 11:28 AM, Borislav Petkov <bp@alien8.de> wrote:
>
>> On Fri, Jan 05, 2018 at 11:22:21AM -0800, Andy Lutomirski wrote:
>> It's emulated! We catch the page fault and fake the whole thing :)
>
> Then I'm really confused. It says "ro" above, which means _PAGE_RW is
> not set so page is read-only.
>
> I must be missing something...
>

It's meant to be read-only, user-acccessible, NX as far as the CPU is concerned. When user code calls it, we get an instruction fetch fault, and the kernel fixes it up.

> --
> Regards/Gruss,
> Boris.
>
> Good mailing practices for 400: avoid top-posting and trim the reply.

\
 
 \ /
  Last update: 2018-01-05 21:11    [W:0.033 / U:0.428 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site