[RFC PATCH v2 0/2] selftests/x86: sysret_rip update for FRED system

[Ammar Faizi]

From: Ammar Faizi <ammarfaizi2@xxxxxxxxxxx>

This is an RFC patchset v2.

Xin Li reported sysret_rip test fails at:

        assert(ctx->uc_mcontext.gregs[REG_EFL] ==
               ctx->uc_mcontext.gregs[REG_R11]);

in a FRED system. Handle the FRED system scenario too. There are two
patches in this series. Comments welcome...

Note: This patchset is only tested for 'syscall' sets %rcx=%rip and
%r11=%rflags case. I don't have a FRED system to test it.

How to test this:

  $ make -C tools/testing/selftests/x86
  $ tools/testing/selftests/x86/sysret_rip_64

Link: https://lore.kernel.org/lkml/5d4ad3e3-034f-c7da-d141-9c001c2343af@xxxxxxxxx
Signed-off-by: Ammar Faizi <ammarfaizi2@xxxxxxxxxxx>
---

## Changelog v2:

   - Use "+r"(rsp) as the right way to avoid redzone problems
     per Andrew's comment (hpa).
     (Ref: https://lore.kernel.org/lkml/8f5c24df-514d-5d89-f58f-ec8c3eb1e049@xxxxxxxxx )

---

Ammar Faizi (2):
  selftests/x86: sysret_rip: Handle syscall in a FRED system
  selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11`

 tools/testing/selftests/x86/sysret_rip.c | 105 ++++++++++++++++++++++-
 1 file changed, 104 insertions(+), 1 deletion(-)


base-commit: e12ad468c22065a2826b2fc4c11d2113a7975301
-- 
Ammar Faizi