On Tue, Jan 24, 2023 at 12:59:23PM -0800, H. Peter Anvin wrote: > > > On 1/24/23 02:09, Ammar Faizi wrote: > > From: Ammar Faizi <ammarfaizi2@xxxxxxxxxxx> > > > > 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@xxxxxxxxx > > Co-developed-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> > > Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> > > Acked-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> > > Signed-off-by: Ammar Faizi <ammarfaizi2@xxxxxxxxxxx> > > 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. Added in v4. -- Ammar Faizi
