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Message-Id: <20230125032240.728463-1-ammarfaizi2@gnuweeb.org>
Date: Wed, 25 Jan 2023 10:22:38 +0700
From: Ammar Faizi <ammarfaizi2@...weeb.org>
To: "H. Peter Anvin" <hpa@...or.com>, Xin Li <xin3.li@...el.com>
Cc: Ammar Faizi <ammarfaizi2@...weeb.org>,
Dave Hansen <dave.hansen@...el.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Cooper <Andrew.Cooper3@...rix.com>,
Brian Gerst <brgerst@...il.com>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Peter Zijlstra <peterz@...radead.org>,
Shuah Khan <shuah@...nel.org>, Ingo Molnar <mingo@...nel.org>,
Andy Lutomirski <luto@...nel.org>,
x86 Mailing List <x86@...nel.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Linux Kselftest Mailing List
<linux-kselftest@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH v4 0/2] sysret_rip update for the Intel FRED architecture
From: Ammar Faizi <ammarfaizi2@...weeb.org>
This is an RFC patchset v4. There are two patches in this series.
Xin Li reported that the sysret_rip test fails at:
assert(ctx->uc_mcontext.gregs[REG_EFL] ==
ctx->uc_mcontext.gregs[REG_R11]);
on the Intel FRED architecture. Let's handle the FRED system scenario
too. The 'syscall' instruction in a FRED system doesn't set %rcx=%rip
and %r11=%rflags.
Syscall and sysenter in a FRED system are treated equivalently to
software interrupts, e.g. INT 0x80. They do not modify any registers.
Link: https://lore.kernel.org/lkml/5d4ad3e3-034f-c7da-d141-9c001c2343af@intel.com
#### Changelog v4:
- Fix the assertion condition inside the SIGUSR1 handler (Xin Li).
- Explain the purpose of patch #2 in the commit message (HPA).
- Update commit message (Ammar).
- Repeat test_syscall_rcx_r11_consistent() 32 times to be more sure
that the result is really consistent (Ammar).
#### Changelog v3:
- Test that we don't get a mix of REGS_SAVED and REGS_SYSRET,
which is a major part of the point (HPA).
#### Changelog v2:
- Use "+r"(rsp) as the right way to avoid redzone problems
per Andrew's comment (HPA).
Co-developed-by: H. Peter Anvin (Intel) <hpa@...or.com>
Signed-off-by: H. Peter Anvin (Intel) <hpa@...or.com>
Signed-off-by: Ammar Faizi <ammarfaizi2@...weeb.org>
---
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 | 147 +++++++++++++++++++++--
1 file changed, 138 insertions(+), 9 deletions(-)
base-commit: e12ad468c22065a2826b2fc4c11d2113a7975301
--
Ammar Faizi
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