Messages in this thread | | | Date | Tue, 24 Jan 2023 12:59:23 -0800 | Subject | Re: [RFC PATCH v3 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` | From | "H. Peter Anvin" <> |
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On 1/24/23 02:09, 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. > > Link: https://lore.kernel.org/lkml/25b96960-a07e-a952-5c23-786b55054126@zytor.com > Co-developed-by: H. Peter Anvin (Intel) <hpa@zytor.com> > Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> > Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com> > Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Add to the description that the purpose of this is to ensure that various system calls are *consistent*, as per the comment immediately below your code.
-hpa
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