From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linux-kernel@vger.kernel.org, npiggin@gmail.com,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v4 1/2] powerpc/uaccess: Implement unsafe_put_user() using 'asm goto'
Date: Wed, 6 May 2020 17:18:01 -0500 [thread overview]
Message-ID: <20200506221801.GW31009@gate.crashing.org> (raw)
In-Reply-To: <bd336b0f-9cf7-e2ce-e0a8-1891599638d1@csgroup.eu>
On Wed, May 06, 2020 at 08:10:57PM +0200, Christophe Leroy wrote:
> Le 06/05/2020 à 19:58, Segher Boessenkool a écrit :
> >> #define __put_user_asm_goto(x, addr, label, op) \
> >> asm volatile goto( \
> >>- "1: " op "%U1%X1 %0,%1 # put_user\n" \
> >>+ "1: " op "%X1 %0,%1 # put_user\n" \
> >> EX_TABLE(1b, %l2) \
> >> : \
> >>- : "r" (x), "m<>" (*addr) \
> >>+ : "r" (x), "m" (*addr) \
> >> : \
> >> : label)
> >
> >Like that. But you will have to do that to *all* places we use the "<>"
> >constraints, or wait for more stuff to fail? And, there probably are
> >places we *do* want update form insns used (they do help in some loops,
> >for example)?
> >
>
> AFAICT, git grep "m<>" provides no result.
Ah, okay.
> However many places have %Ux:
<snip>
Yes, all of those are from when "m" still meant what "m<>" is now. For
seeing how many update form insns can be generated (and how much that
matters), these all should be fixed, at a minimum.
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
npiggin@gmail.com, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v4 1/2] powerpc/uaccess: Implement unsafe_put_user() using 'asm goto'
Date: Wed, 6 May 2020 17:18:01 -0500 [thread overview]
Message-ID: <20200506221801.GW31009@gate.crashing.org> (raw)
In-Reply-To: <bd336b0f-9cf7-e2ce-e0a8-1891599638d1@csgroup.eu>
On Wed, May 06, 2020 at 08:10:57PM +0200, Christophe Leroy wrote:
> Le 06/05/2020 à 19:58, Segher Boessenkool a écrit :
> >> #define __put_user_asm_goto(x, addr, label, op) \
> >> asm volatile goto( \
> >>- "1: " op "%U1%X1 %0,%1 # put_user\n" \
> >>+ "1: " op "%X1 %0,%1 # put_user\n" \
> >> EX_TABLE(1b, %l2) \
> >> : \
> >>- : "r" (x), "m<>" (*addr) \
> >>+ : "r" (x), "m" (*addr) \
> >> : \
> >> : label)
> >
> >Like that. But you will have to do that to *all* places we use the "<>"
> >constraints, or wait for more stuff to fail? And, there probably are
> >places we *do* want update form insns used (they do help in some loops,
> >for example)?
> >
>
> AFAICT, git grep "m<>" provides no result.
Ah, okay.
> However many places have %Ux:
<snip>
Yes, all of those are from when "m" still meant what "m<>" is now. For
seeing how many update form insns can be generated (and how much that
matters), these all should be fixed, at a minimum.
Segher
next prev parent reply other threads:[~2020-05-06 22:21 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-17 17:08 [PATCH v4 1/2] powerpc/uaccess: Implement unsafe_put_user() using 'asm goto' Christophe Leroy
2020-04-17 17:08 ` Christophe Leroy
2020-04-17 17:08 ` [PATCH v4 2/2] powerpc/uaccess: Implement unsafe_copy_to_user() as a simple loop Christophe Leroy
2020-04-17 17:08 ` Christophe Leroy
2020-05-29 4:24 ` Michael Ellerman
2020-05-05 14:27 ` [PATCH v4 1/2] powerpc/uaccess: Implement unsafe_put_user() using 'asm goto' Michael Ellerman
2020-05-05 14:27 ` Michael Ellerman
2020-05-05 15:32 ` Segher Boessenkool
2020-05-05 15:32 ` Segher Boessenkool
2020-05-06 0:58 ` Michael Ellerman
2020-05-06 0:58 ` Michael Ellerman
2020-05-06 17:58 ` Segher Boessenkool
2020-05-06 17:58 ` Segher Boessenkool
2020-05-06 18:10 ` Christophe Leroy
2020-05-06 18:10 ` Christophe Leroy
2020-05-06 22:18 ` Segher Boessenkool [this message]
2020-05-06 22:18 ` Segher Boessenkool
2020-05-05 15:40 ` Christophe Leroy
2020-05-05 15:40 ` Christophe Leroy
2020-05-05 15:59 ` Segher Boessenkool
2020-05-05 15:59 ` Segher Boessenkool
2020-05-06 1:36 ` Michael Ellerman
2020-05-06 1:36 ` Michael Ellerman
2020-05-06 18:09 ` Segher Boessenkool
2020-05-06 18:09 ` Segher Boessenkool
2020-05-29 4:24 ` Michael Ellerman
2020-06-11 22:43 ` Nick Desaulniers
2020-06-11 22:43 ` Nick Desaulniers
2020-06-11 23:52 ` Segher Boessenkool
2020-06-11 23:52 ` Segher Boessenkool
2020-06-12 21:33 ` Nick Desaulniers
2020-06-12 21:33 ` Nick Desaulniers
2020-06-13 1:08 ` Segher Boessenkool
2020-06-13 1:08 ` Segher Boessenkool
2020-06-13 6:46 ` Christophe Leroy
2020-06-13 6:46 ` Christophe Leroy
2020-06-13 10:47 ` Michael Ellerman
2020-06-13 10:47 ` Michael Ellerman
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