From: "H. Peter Anvin" <hpa@zytor.com>
To: Andy Lutomirski <luto@amacapital.net>,
Thomas Gleixner <tglx@linutronix.de>, X86 ML <x86@kernel.org>,
Ingo Molnar <mingo@redhat.com>
Cc: Sebastian Lackner <sebastian@fds-team.de>,
Anish Bhatt <anish@chelsio.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Chuck Ebbert <cebbert.lkml@gmail.com>
Subject: Re: [PATCH v3 2/2] x86_64: Don't save flags on context switch
Date: Wed, 01 Oct 2014 11:35:27 -0700 [thread overview]
Message-ID: <542C496F.80003@zytor.com> (raw)
In-Reply-To: <bf6fb790787eb95b922157838f52712c25dda157.1412187233.git.luto@amacapital.net>
On 10/01/2014 11:28 AM, Andy Lutomirski wrote:
>
> #define __EXTRA_CLOBBER \
> , "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \
> - "r12", "r13", "r14", "r15"
> + "r12", "r13", "r14", "r15", "flags"
>
I was under the impression that gcc *always* assumes the flags were
clobbered for an asm statement. Otherwise I think we'd have a lot of
problems.
-hpa
next prev parent reply other threads:[~2014-10-01 18:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-01 18:28 [PATCH v3 0/2] x86_64,entry: Clear NT on entry and speed up switch_to Andy Lutomirski
2014-10-01 18:28 ` [PATCH v3 1/2] x86_64,entry: Filter RFLAGS.NT on entry from userspace Andy Lutomirski
2014-10-01 18:28 ` [PATCH v3 2/2] x86_64: Don't save flags on context switch Andy Lutomirski
2014-10-01 18:35 ` H. Peter Anvin [this message]
2014-10-01 18:44 ` Andy Lutomirski
2014-10-20 18:52 ` Andy Lutomirski
2014-10-28 11:14 ` [tip:x86/asm] sched/x86_64: " tip-bot for Andy Lutomirski
2014-11-03 21:11 ` Andy Lutomirski
2014-11-03 21:47 ` Oleg Nesterov
2014-11-03 21:58 ` Oleg Nesterov
2014-11-03 22:37 ` Andy Lutomirski
2014-11-03 22:57 ` Oleg Nesterov
2014-11-03 23:02 ` Andy Lutomirski
2014-11-03 23:10 ` Oleg Nesterov
2014-11-04 23:09 ` Oleg Nesterov
2014-11-03 22:17 ` H. Peter Anvin
2014-10-01 18:34 ` [PATCH v3 0/2] x86_64,entry: Clear NT on entry and speed up switch_to H. Peter Anvin
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