lkml.org 
[lkml]   [2023]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [RFC PATCH v2 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11`
From


On 1/23/23 18:27, Ammar Faizi wrote:
> From: Ammar Faizi <ammarfaizi2@gnuweeb.org>
>
> Test that:
>
> - "syscall" in a FRED system doesn't clobber %rcx and %r11.
> - "syscall" in a non-FRED system sets %rcx=%rip and %r11=%rflags.
>
> Test them out with a trivial system call like __NR_getppid and friends
> which are extremely likely to return with SYSRET on an IDT system; check
> that it returns a nonnegative value and then save the result.
>

"Nonnegative" here should be "valid"; it is an implementation detail
that the error value is -1.

However, you are not checking that you don't get a mix of REGS_SAVED and
REGS_SYSRET, which is a major part of the point.

-hpa


\
 
 \ /
  Last update: 2023-03-26 23:53    [W:0.158 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site