From: "H. Peter Anvin" <hpa@zytor.com>
To: Andy Lutomirski <andy@linux.luto.us>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC v2 PATCH 7/7] x86/entry: use int for syscall number; handle all invalid syscall nrs
Date: Thu, 13 May 2021 20:23:17 -0700 [thread overview]
Message-ID: <486B4C98-FFD1-40B9-B7AF-5323DE07A0FE@zytor.com> (raw)
In-Reply-To: <57bf2ff9-11ff-0907-975e-15177df72144@linux.luto.us>
Yeah. Also, x32 long is 32 bits...
On May 13, 2021 8:18:37 PM PDT, Andy Lutomirski <andy@linux.luto.us> wrote:
>On 5/13/21 5:38 PM, H. Peter Anvin wrote:
>> On 5/12/21 3:22 PM, Thomas Gleixner wrote:
>>>>
>>>> As far as this being a user ABI change, this is actually a revert
>to the
>>>> original x86-64 ABI; see my message to Ingo.
>>>
>>> I'm not against that change, but it has to be well justified and the
>>> reasoning wants to be in the changelog. You know the drill :)
>>>
>>
>> FYI:
>>
>> So in the process of breaking up and better document this patch, I
>have
>> looked at the syscall_numbering_64 (and have rewritten it to be more
>> complete.)
>>
>> I found that running it under strace fails, as strace (possibly
>ptrace,
>> possibly the strace binary) causes %rax = 2^32 to be clobbered to
>zero
>> already...
>>
>> More motivation, I guess.
>>
>
>Indeed.
>
>I would love to go back in time and switch to long, but there are
>plenty
>of things that use int now. I suppose we could try to make it long for
>real, but seccomp has u32 baked into its ABI.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
prev parent reply other threads:[~2021-05-14 3:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-10 18:53 [RFC v2 PATCH 0/6] x86/entry: cleanups and consistent syscall number handling H. Peter Anvin
2021-05-10 18:53 ` [RFC v2 PATCH 1/7] x86/entry: unify definitions from calling.h and ptrace-abi.h H. Peter Anvin
2021-05-12 9:23 ` [tip: x86/asm] x86/entry: Unify definitions from <asm/calling.h> and <asm/ptrace-abi.h> tip-bot2 for H. Peter Anvin (Intel)
2021-05-10 18:53 ` [RFC v2 PATCH 2/7] x86/entry: reverse arguments to do_syscall_64() H. Peter Anvin
2021-05-12 9:23 ` [tip: x86/asm] x86/entry: Reverse " tip-bot2 for H. Peter Anvin (Intel)
2021-05-10 18:53 ` [RFC v2 PATCH 3/7] x86/syscall: unconditionally prototype {ia32,x32}_sys_call_table[] H. Peter Anvin
2021-05-12 9:23 ` [tip: x86/asm] x86/syscall: Unconditionally " tip-bot2 for H. Peter Anvin (Intel)
2021-05-10 18:53 ` [RFC v2 PATCH 4/7] x86/syscall: maximize MSR_SYSCALL_MASK H. Peter Anvin
2021-05-12 9:23 ` [tip: x86/asm] x86/syscall: Maximize MSR_SYSCALL_MASK tip-bot2 for H. Peter Anvin (Intel)
2021-05-10 18:53 ` [RFC v2 PATCH 5/7] x86/entry: split PUSH_AND_CLEAR_REGS into two submacros H. Peter Anvin
2021-05-12 9:23 ` [tip: x86/asm] x86/entry: Split " tip-bot2 for H. Peter Anvin (Intel)
2021-05-10 18:53 ` [RFC v2 PATCH 6/7] x86/regs: syscall_get_nr() returns -1 for a non-system call H. Peter Anvin
2021-05-12 9:23 ` [tip: x86/asm] x86/regs: Syscall_get_nr() " tip-bot2 for H. Peter Anvin
2021-05-10 18:53 ` [RFC v2 PATCH 7/7] x86/entry: use int for syscall number; handle all invalid syscall nrs H. Peter Anvin
2021-05-12 8:51 ` Ingo Molnar
2021-05-12 17:50 ` H. Peter Anvin
2021-05-12 12:09 ` Thomas Gleixner
2021-05-12 18:21 ` H. Peter Anvin
2021-05-12 18:34 ` Thomas Gleixner
2021-05-12 22:09 ` H. Peter Anvin
2021-05-12 22:22 ` Thomas Gleixner
2021-05-12 22:24 ` H. Peter Anvin
2021-05-14 0:38 ` H. Peter Anvin
2021-05-14 3:18 ` Andy Lutomirski
2021-05-14 3:23 ` H. Peter Anvin [this message]
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