From: "H. Peter Anvin" <hpa@zytor.com>
To: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Cc: Xin Li <xin3.li@intel.com>, Dave Hansen <dave.hansen@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Cooper <Andrew.Cooper3@citrix.com>,
Brian Gerst <brgerst@gmail.com>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Shuah Khan <shuah@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
x86 Mailing List <x86@kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Linux Kselftest Mailing List <linux-kselftest@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v5 1/2] selftests/x86: sysret_rip: Handle syscall in a FRED system
Date: Wed, 25 Jan 2023 02:17:41 -0800 [thread overview]
Message-ID: <A7DAB159-7C02-412D-9CFB-5C3C3760DECB@zytor.com> (raw)
In-Reply-To: <Y9D8++DxphJS1oc4@biznet-home.integral.gnuweeb.org>
On January 25, 2023 1:57:15 AM PST, Ammar Faizi <ammarfaizi2@gnuweeb.org> wrote:
>On Wed, Jan 25, 2023 at 12:39:26AM -0800, H. Peter Anvin wrote:
>> > /* Set IP and CX to match so that SYSRET can happen. */
>> > ctx->uc_mcontext.gregs[REG_RIP] = rip;
>> > ctx->uc_mcontext.gregs[REG_RCX] = rip;
>>
>> It would be interesting to have the syscall handler try both with and
>> without this (so it would end up doing both IRET and SYSCALL on legacy.)
>> Perhaps SIGUSR1 versus SIGUSR2...
>
>Just to clarify this more so I am sure I understand it correctly.
>
>Did you mean to have the same signal handler without modifiying
>'REG_RCX' but still change 'REG_RIP'?
>
>IOW, we want to only *remove*:
>
> ctx->uc_mcontext.gregs[REG_RCX] = rip;
>
>and *keep*:
>
> ctx->uc_mcontext.gregs[REG_RIP] = rip;
>
>for the SIGUSR2 handler. Thus, inside the entry64 we will jump to the
>iret path because %rcx != %r11 upon rt_sigreturn()?
>
I guess it would depend on what they "normally" are. My #1 impulse would be to leave them both unchanged.
next prev parent reply other threads:[~2023-01-25 10:20 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <SA1PR11MB6734FA9139B9C9F6CC2ED123A8C59@SA1PR11MB6734.namprd11.prod.outlook.com>
[not found] ` <5d4ad3e3-034f-c7da-d141-9c001c2343af@intel.com>
[not found] ` <18B5DB6D-AEBD-4A67-A7B3-CE64940819B7@zytor.com>
[not found] ` <SA1PR11MB673498933098295BFC7C2900A8CB9@SA1PR11MB6734.namprd11.prod.outlook.com>
[not found] ` <b6e36a5c-6f5e-eda6-54ad-a0c20eb00402@intel.com>
[not found] ` <25b96960-a07e-a952-5c23-786b55054126@zytor.com>
[not found] ` <fb1cab9f-a373-38e6-92e6-456332010653@gnuweeb.org>
[not found] ` <F554C5FE-5074-410A-B0B5-EFE983D57946@zytor.com>
[not found] ` <Y88bhrDoPw5tOyKu@biznet-home.integral.gnuweeb.org>
[not found] ` <509443c8-e0fd-935f-63d8-7264f5dd3c05@zytor.com>
2023-01-24 0:26 ` [RFC PATCH v1 0/2] selftests/x86: sysret_rip update for FRED system Ammar Faizi
2023-01-24 0:26 ` [RFC PATCH v1 1/2] selftests/x86: sysret_rip: Handle syscall in a " Ammar Faizi
2023-01-24 1:40 ` H. Peter Anvin
2023-01-24 2:31 ` Ammar Faizi
2023-01-26 20:08 ` Ammar Faizi
2023-02-15 9:17 ` Andrew Cooper
2023-02-15 10:29 ` Andrew Cooper
2023-02-15 10:44 ` Ammar Faizi
2023-02-15 10:42 ` Ammar Faizi
2023-01-26 20:16 ` Ammar Faizi
2023-01-24 0:26 ` [RFC PATCH v1 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
[not found] ` <6cd0db14-c9e2-3598-fd10-4b473d78c373@citrix.com>
[not found] ` <5ecc383c-621b-57d9-7f6d-d63496fca3b3@zytor.com>
2023-01-24 2:27 ` [RFC PATCH v2 0/2] selftests/x86: sysret_rip update for FRED system Ammar Faizi
2023-01-24 2:27 ` [RFC PATCH v2 1/2] selftests/x86: sysret_rip: Handle syscall in a " Ammar Faizi
2023-01-24 5:44 ` H. Peter Anvin
2023-01-24 2:27 ` [RFC PATCH v2 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-24 6:16 ` H. Peter Anvin
2023-01-24 6:41 ` Ammar Faizi
2023-01-24 6:47 ` Ammar Faizi
2023-01-24 9:07 ` H. Peter Anvin
2023-01-24 9:12 ` Ammar Faizi
2023-01-24 10:09 ` [RFC PATCH v3 0/2] selftests/x86: sysret_rip update for FRED system Ammar Faizi
2023-01-24 10:09 ` [RFC PATCH v3 1/2] selftests/x86: sysret_rip: Handle syscall in a " Ammar Faizi
2023-01-24 10:09 ` [RFC PATCH v3 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-24 20:59 ` H. Peter Anvin
2023-01-25 3:29 ` Ammar Faizi
2023-01-24 21:32 ` [RFC PATCH v3 0/2] selftests/x86: sysret_rip update for FRED system Li, Xin3
2023-01-24 21:37 ` H. Peter Anvin
2023-01-24 23:20 ` Li, Xin3
2023-01-25 3:27 ` Ammar Faizi
2023-01-24 21:51 ` Andrew Cooper
2023-01-24 23:58 ` Li, Xin3
2023-01-25 3:22 ` [RFC PATCH v4 0/2] sysret_rip update for the Intel FRED architecture Ammar Faizi
2023-01-25 3:22 ` [RFC PATCH v4 1/2] selftests/x86: sysret_rip: Handle syscall in a FRED system Ammar Faizi
2023-01-25 3:37 ` Ammar Faizi
2023-01-25 3:44 ` Ammar Faizi
2023-01-25 3:22 ` [RFC PATCH v4 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-25 3:49 ` [RFC PATCH v5 0/2] sysret_rip update for the Intel FRED architecture Ammar Faizi
2023-01-25 3:49 ` [RFC PATCH v5 1/2] selftests/x86: sysret_rip: Handle syscall in a FRED system Ammar Faizi
2023-01-25 8:39 ` H. Peter Anvin
2023-01-25 8:53 ` Ammar Faizi
2023-01-25 9:57 ` Ammar Faizi
2023-01-25 10:01 ` Ammar Faizi
2023-01-25 10:17 ` H. Peter Anvin [this message]
2023-01-25 11:37 ` Ammar Faizi
2023-01-25 17:25 ` H. Peter Anvin
2023-01-25 3:49 ` [RFC PATCH v5 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-25 8:22 ` [RFC PATCH v5 0/2] sysret_rip update for the Intel FRED architecture Li, Xin3
2023-01-25 8:32 ` Ammar Faizi
2023-01-25 17:07 ` Li, Xin3
2023-01-25 17:24 ` H. Peter Anvin
2023-01-25 17:41 ` Ammar Faizi
2023-01-25 17:48 ` Li, Xin3
2023-02-15 7:42 ` Li, Xin3
2023-02-15 7:51 ` Ammar Faizi
2023-02-18 4:27 ` Ammar Faizi
2023-02-18 4:51 ` H. Peter Anvin
2023-01-25 21:17 ` [RFC PATCH v6 0/3] " Ammar Faizi
2023-01-25 21:17 ` [RFC PATCH v6 1/3] selftests/x86: sysret_rip: Handle syscall in a FRED system Ammar Faizi
2023-01-25 23:01 ` Ammar Faizi
2023-01-25 21:17 ` [RFC PATCH v6 2/3] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-25 21:17 ` [RFC PATCH v6 3/3] selftests/x86: sysret_rip: Test opportunistic SYSRET Ammar Faizi
2023-01-25 23:24 ` [RFC PATCH v7 0/3] sysret_rip update for the Intel FRED architecture Ammar Faizi
2023-01-25 23:24 ` [RFC PATCH v7 1/3] selftests/x86: sysret_rip: Handle syscall in a FRED system Ammar Faizi
2023-01-25 23:24 ` [RFC PATCH v7 2/3] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-25 23:24 ` [RFC PATCH v7 3/3] selftests/x86: sysret_rip: Test SYSRET with a signal handler Ammar Faizi
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