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Subject: Re: [PATCH] ARC: uaccess: get_user to zero out dest in cause of fault
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Mon, 22 Aug 2016 16:51:28 -0700
To: Linus Torvalds <torvalds@linux-foundation.org>
CC: Al Viro <viro@zeniv.linux.org.uk>, Jakub Jelinek <jakub@redhat.com>,
        Vineet Gupta <Vineet.Gupta1@synopsys.com>,
        "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@redhat.com>
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On August 22, 2016 4:48:00 PM PDT, Linus Torvalds <torvalds@linux-foundation.org> wrote:
>On Mon, Aug 22, 2016 at 4:12 PM, H. Peter Anvin <hpa@zytor.com> wrote:
>>
>> How about the gcc native __builtin_setjmp stuff which is supposedly
>better?
>
>How new is it? The whole point was that we'd not have to worry and
>wait for gcc features..
>
>glibc doesn't use it, which worries me a bit. Has it ever gotten any
>use/testing?
>
>But yes, the compiler could do better. If we can rely on it, and it
>doesn't do stupid things (like have signal state etc crap - glibc
>seems to just alias "setjmp" to "sigsetjmp" with a "didn't save
>signals" flag)
>
>             Linus

We can always fall back on the classic implementation for older gcc, just like we do for so many other features.
-- 
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