From: Andy Lutomirski <luto@amacapital.net>
To: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Elvira Khabirova <lineprinter0@gmail.com>
Subject: Re: [PATCH] x86/signal: fix restart_syscall number for x32 tasks
Date: Thu, 17 Dec 2015 12:27:16 -0800 [thread overview]
Message-ID: <CALCETrUDmn_FoQXnQopO4H2c+N4P=Tv60w2T6G92c4L5_=soQA@mail.gmail.com> (raw)
In-Reply-To: <20151213034437.GA2392@altlinux.org>
On Sat, Dec 12, 2015 at 7:44 PM, Dmitry V. Levin <ldv@altlinux.org> wrote:
> On Mon, Dec 07, 2015 at 03:22:06PM -0800, Andy Lutomirski wrote:
>> [not real reply because I'm using a bad internet connection right now
>> and I'm not set up with my usual Gmane reply hack right now]
>>
>> The new code is (whitespace-damaged):
>>
>> static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
>> {
>> #if defined(CONFIG_X86_32) || !defined(CONFIG_X86_64)
>> return __NR_restart_syscall;
>> #else /* !CONFIG_X86_32 && CONFIG_X86_64 */
>> return test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall :
>> __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
>> #endif /* CONFIG_X86_32 || !CONFIG_X86_64 */
>> }
>>
>> This is IMO awful. This use of TIF_IA32 is wrong, and this is
>> otherwise gross. Can we do it for real:
>>
>> if (is_ia32_task())
>> return __NR_ia32_restart_syscall;
>> else
>> return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
>> /* preserve x32 bit */
>>
>> I'd send the patch myself, but you apparently have a good test case
>> for this, and I don't.
>
> Unfortunately, this won't compile on CONFIG_X86_32 because
> __NR_ia32_restart_syscall is defined for CONFIG_X86_64 only.
>
> Something like this should work:
>
> static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
> {
> #ifdef CONFIG_X86_64
> if (is_ia32_task())
> return __NR_ia32_restart_syscall;
> # ifdef CONFIG_X86_X32_ABI
> if (regs->orig_ax & __X32_SYSCALL_BIT)
> return __NR_restart_syscall | __X32_SYSCALL_BIT;
> # endif
> #endif
> return __NR_restart_syscall;
> }
Looks good to me. Want to send a patch?
--Andy
next prev parent reply other threads:[~2015-12-17 20:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-07 23:22 [PATCH] x86/signal: fix restart_syscall number for x32 tasks Andy Lutomirski
2015-12-13 3:44 ` Dmitry V. Levin
2015-12-17 20:27 ` Andy Lutomirski [this message]
2015-12-18 23:37 ` [PATCH] x86/signal: Cleanup get_nr_restart_syscall Dmitry V. Levin
2015-12-19 6:34 ` H. Peter Anvin
2015-12-19 14:43 ` [PATCH v2] " Dmitry V. Levin
2015-12-19 20:48 ` Andy Lutomirski
2016-01-11 14:55 ` [RESEND PATCH " Dmitry V. Levin
2016-01-19 13:39 ` [tip:x86/asm] x86/signal: Cleanup get_nr_restart_syscall() tip-bot for Dmitry V. Levin
-- strict thread matches above, loose matches on Subject: below --
2015-11-30 21:54 [PATCH] x86/signal: fix restart_syscall number for x32 tasks Dmitry V. Levin
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