From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Lutomirski <luto@kernel.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Kalle Valo <kvalo@codeaurora.org>, Peter Anvin <hpa@zytor.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Arnd Bergmann <arnd@arndb.de>,
Peter Zijlstra <peterz@infradead.org>,
Brian Gerst <brgerst@gmail.com>,
"linux-tip-commits@vger.kernel.org"
<linux-tip-commits@vger.kernel.org>
Subject: Re: [tip:x86/urgent] x86/io: Mark target address as output in 'insb()' asm
Date: Wed, 12 Jul 2017 21:24:22 +0200 [thread overview]
Message-ID: <20170712192421.cpuucr2a233xcovl@gmail.com> (raw)
In-Reply-To: <CA+55aFzrMBzQO4jDhaG2tbgWpFGqfK+-VXehG_tSCrFZTx4D5Q@mail.gmail.com>
* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Wed, Jul 12, 2017 at 6:10 AM, tip-bot for Arnd Bergmann
> <tipbot@zytor.com> wrote:
> >
> > Apparently the assember constraints are slightly off here, as marking the
> > 'addr' argument as a memory output seems appropriate here and gets rid
> > of the warning. For consistency I'm also adding it as input for outsb().
>
> The new constraints look very questionable to me.
Ok, I've removed the commit.
> The real fix is probably to just mark them as "clobbers memory" (ie
> just add "memory" to the clobber list).
>
> If you want to be fancy, you can try to do what <asm/uaccess.h> does,
> which is a disgusting hack, but has traditionally worked;
>
> struct __large_struct { unsigned long buf[100]; };
> #define __m(x) (*(struct __large_struct __user *)(x))
>
> and then use your approach with "m" and "=m".
Arnd, could you please try Linus's suggestions?
Thanks,
Ingo
next prev parent reply other threads:[~2017-07-12 19:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-10 14:44 [RFC 1/2] x86: mark target address as output in 'insb' asm Arnd Bergmann
2017-07-10 14:44 ` [RFC 2/2] wl3501_cs: reduce stack size for KASAN Arnd Bergmann
2017-07-25 12:52 ` Kalle Valo
2017-07-25 14:50 ` Arnd Bergmann
2017-07-12 13:10 ` [tip:x86/urgent] x86/io: Mark target address as output in 'insb()' asm tip-bot for Arnd Bergmann
2017-07-12 16:57 ` Linus Torvalds
2017-07-12 19:24 ` Ingo Molnar [this message]
2017-07-12 21:47 ` Arnd Bergmann
2017-07-12 22:43 ` Linus Torvalds
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