From: Peter Zijlstra <peterz@infradead.org>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: bp@alien8.de, brgerst@gmail.com, catalin.marinas@arm.com,
dvlasenk@redhat.com, hpa@zytor.com, james.morse@arm.com,
jpoimboe@redhat.com, julien.thierry@arm.com, luto@amacapital.net,
luto@kernel.org, mingo@kernel.org, tglx@linutronix.de,
torvalds@linux-foundation.org, valentin.schneider@arm.com,
will.deacon@arm.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/8] i915,uaccess: Fix redundant CLAC
Date: Thu, 28 Feb 2019 16:24:32 +0100 [thread overview]
Message-ID: <20190228152432.GC32494@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <155136664389.5847.6200085578174808757@skylake-alporthouse-com>
On Thu, Feb 28, 2019 at 03:10:44PM +0000, Chris Wilson wrote:
> Quoting Peter Zijlstra (2019-02-28 14:54:56)
> > drivers/gpu/drm/i915/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x3c: redundant UACCESS disable
> > drivers/gpu/drm/i915/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x66: redundant UACCESS disable
> >
> > AKA. you don't need user_access_end() if user_access_begin() fails.
>
> Cool, I had no idea if it was required or not. The closest to
> instructions on how to use user_access_begin() is in
> arch/x86/include/asm/uaccess.h ... which I guess is earlier in this
> series!
Ah, I don't think I put the rules in a comment; that would've been
useful I suppose ;-)
I did teach the rules to objtool though, and that is in the next patch:
https://lkml.kernel.org/r/20190228150152.635362492@infradead.org
so at least it will yell at you during compile time when you get it
wrong.
> > Cc: Chris Wilson <chris@chris-wilson.co.uk>
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Thanks!
next prev parent reply other threads:[~2019-02-28 15:24 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 14:54 [PATCH 0/8] objtool: UACCESS validation v2 Peter Zijlstra
2019-02-28 14:54 ` [PATCH 1/8] kasan,x86: Frob kasan_report() in an exception Peter Zijlstra
2019-02-28 15:22 ` Dmitry Vyukov
2019-02-28 15:45 ` Peter Zijlstra
2019-02-28 15:52 ` Dmitry Vyukov
2019-02-28 16:01 ` Andrey Ryabinin
2019-02-28 16:03 ` Dmitry Vyukov
2019-02-28 17:46 ` Peter Zijlstra
2019-02-28 18:18 ` Dmitry Vyukov
2019-03-01 14:45 ` Peter Zijlstra
2019-03-01 15:06 ` Dmitry Vyukov
2019-03-01 15:23 ` Peter Zijlstra
2019-03-06 13:13 ` Peter Zijlstra
2019-03-06 13:39 ` Dmitry Vyukov
2019-03-06 13:57 ` Peter Zijlstra
2019-03-06 14:01 ` Dmitry Vyukov
2019-03-06 14:12 ` Peter Zijlstra
2019-03-06 14:34 ` Peter Zijlstra
2019-03-06 14:40 ` Dmitry Vyukov
2019-03-06 14:41 ` Dmitry Vyukov
2019-03-06 14:55 ` Peter Zijlstra
2019-03-06 15:01 ` Dmitry Vyukov
2019-03-06 17:14 ` Peter Zijlstra
2019-03-06 17:27 ` Linus Torvalds
2019-03-06 17:37 ` Peter Zijlstra
2019-03-06 17:59 ` Linus Torvalds
2019-03-07 13:49 ` Peter Zijlstra
2019-02-28 14:54 ` [PATCH 2/8] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-02-28 14:54 ` [PATCH 3/8] objtool: Set insn->func for alternatives Peter Zijlstra
2019-02-28 14:54 ` [PATCH 4/8] objtool: Hande function aliases Peter Zijlstra
2019-02-28 14:54 ` [PATCH 5/8] objtool: Rewrite add_ignores() Peter Zijlstra
2019-02-28 14:54 ` [PATCH 6/8] i915,uaccess: Fix redundant CLAC Peter Zijlstra
2019-02-28 15:10 ` Chris Wilson
2019-02-28 15:24 ` Peter Zijlstra [this message]
2019-02-28 16:49 ` Linus Torvalds
2019-02-28 17:51 ` Peter Zijlstra
2019-02-28 18:01 ` Peter Zijlstra
2019-02-28 18:29 ` Linus Torvalds
2019-02-28 19:01 ` Peter Zijlstra
2019-03-01 10:34 ` Peter Zijlstra
2019-03-01 12:27 ` Peter Zijlstra
2019-03-01 12:57 ` Peter Zijlstra
2019-03-01 14:38 ` Peter Zijlstra
2019-03-01 15:27 ` Andy Lutomirski
2019-03-01 16:15 ` Linus Torvalds
2019-03-01 16:17 ` Linus Torvalds
2019-02-28 14:54 ` [PATCH 7/8] objtool: Add UACCESS validation Peter Zijlstra
2019-02-28 14:54 ` [PATCH 8/8] objtool: Add Direction Flag validation Peter Zijlstra
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