From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Brian Gerst <brgerst@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Nilay Vaish <nilayvaish@gmail.com>
Subject: Re: [PATCH 3/9] x86/entry/32: fix the end of the stack for newly forked tasks
Date: Tue, 20 Sep 2016 22:33:04 -0500 [thread overview]
Message-ID: <20160921033304.jm667dzgiftdv2ij@treble> (raw)
In-Reply-To: <20160921032516.ah3etafe4po4wfxu@treble>
On Tue, Sep 20, 2016 at 10:25:16PM -0500, Josh Poimboeuf wrote:
> On Tue, Sep 20, 2016 at 09:10:55PM -0400, Brian Gerst wrote:
> > Dropping asmlinkage from schedule_tail() would be a better option if possible.
>
> My understanding is that it's still needed for ia64. AFAICT, ia64
> relies on schedule_tail() having the syscall_linkage function attribute.
> From the gcc manual:
>
> This attribute is used to modify the IA64 calling convention by
> marking all input registers as live at all function exits. This makes
> it possible to restart a system call after an interrupt without having
> to save/restore the input registers. This also prevents kernel data
> from leaking into application code.
>
> And the ia64 entry code has some similar language:
>
> /*
> * Invoke schedule_tail(task) while preserving in0-in7, which may be needed
> * in case a system call gets restarted.
> */
> GLOBAL_ENTRY(ia64_invoke_schedule_tail)
> ...
(But I should note that I'm a complete ia64 neophyte, so I could be
misreading that...)
--
Josh
next prev parent reply other threads:[~2016-09-21 3:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-20 20:02 [PATCH 0/9] x86/entry/head: standardize the end of the stack Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 1/9] x86/entry/head/32: use local labels Josh Poimboeuf
2016-09-21 0:57 ` Andy Lutomirski
2016-09-21 2:52 ` Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 2/9] x86/entry/32: rename 'error_code' to 'common_exception' Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 3/9] x86/entry/32: fix the end of the stack for newly forked tasks Josh Poimboeuf
2016-09-21 1:10 ` Brian Gerst
2016-09-21 3:25 ` Josh Poimboeuf
2016-09-21 3:33 ` Josh Poimboeuf [this message]
2016-09-21 6:39 ` Andy Lutomirski
2016-09-21 11:35 ` Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 4/9] x86/head/32: fix the end of the stack for idle tasks Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 5/9] x86/smp: fix initial idle stack location on 32-bit Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 6/9] x86/asm/head: use a common function for starting CPUs Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 7/9] x86/head: put real return address on idle task stack Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 8/9] x86/head: fix the end of the stack for idle tasks Josh Poimboeuf
2016-09-20 20:02 ` [PATCH 9/9] x86: move _stext marker to before head code Josh Poimboeuf
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