From: Andy Lutomirski <andy@linux.luto.us>
To: "H. Peter Anvin" <hpa@zytor.com>,
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 20:18:37 -0700 [thread overview]
Message-ID: <57bf2ff9-11ff-0907-975e-15177df72144@linux.luto.us> (raw)
In-Reply-To: <b6f47bd3-3e4c-7200-befe-5e14fecf3da7@zytor.com>
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.
next prev parent reply other threads:[~2021-05-14 3:18 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 [this message]
2021-05-14 3:23 ` H. Peter Anvin
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