From: Segher Boessenkool <segher@kernel.crashing.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: kbuild test robot <lkp@intel.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Paul Mackerras <paulus@samba.org>,
Nathan Chancellor <natechancellor@gmail.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] powerpc: fix inline asm constraints for dcbz
Date: Fri, 9 Aug 2019 17:10:52 -0500 [thread overview]
Message-ID: <20190809221052.GP31406@gate.crashing.org> (raw)
In-Reply-To: <CAK8P3a1AwmAe+PpHTRmN153fhG4ZkF_pb+240rj1ZAg-S6SKeg@mail.gmail.com>
On Fri, Aug 09, 2019 at 10:12:56PM +0200, Arnd Bergmann wrote:
> @@ -106,7 +106,7 @@ static inline u##size name(const volatile u##size
> __iomem *addr) \
> { \
> u##size ret; \
> __asm__ __volatile__("sync;"#insn" %0,%y1;twi 0,%0,0;isync" \
> - : "=r" (ret) : "Z" (*addr) : "memory"); \
> + : "=r" (ret) : "m" (*addr) : "memory"); \
> return ret; \
> }
That will no longer compile something like
u8 *p;
u16 x = in_le16(p + 12);
(you'll get something like "invalid %y value, try using the 'Z' constraint").
So then you remove the %y, but that makes you get something like
sync;lhbrx 3,12(3);twi 0,3,0;isync
which is completely wrong.
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Paul Mackerras <paulus@samba.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
kbuild test robot <lkp@intel.com>,
Nathan Chancellor <natechancellor@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH] powerpc: fix inline asm constraints for dcbz
Date: Fri, 9 Aug 2019 17:10:52 -0500 [thread overview]
Message-ID: <20190809221052.GP31406@gate.crashing.org> (raw)
In-Reply-To: <CAK8P3a1AwmAe+PpHTRmN153fhG4ZkF_pb+240rj1ZAg-S6SKeg@mail.gmail.com>
On Fri, Aug 09, 2019 at 10:12:56PM +0200, Arnd Bergmann wrote:
> @@ -106,7 +106,7 @@ static inline u##size name(const volatile u##size
> __iomem *addr) \
> { \
> u##size ret; \
> __asm__ __volatile__("sync;"#insn" %0,%y1;twi 0,%0,0;isync" \
> - : "=r" (ret) : "Z" (*addr) : "memory"); \
> + : "=r" (ret) : "m" (*addr) : "memory"); \
> return ret; \
> }
That will no longer compile something like
u8 *p;
u16 x = in_le16(p + 12);
(you'll get something like "invalid %y value, try using the 'Z' constraint").
So then you remove the %y, but that makes you get something like
sync;lhbrx 3,12(3);twi 0,3,0;isync
which is completely wrong.
Segher
next prev parent reply other threads:[~2019-08-09 22:13 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 20:25 [PATCH] powerpc: workaround clang codegen bug in dcbz Nick Desaulniers
2019-07-29 20:25 ` Nick Desaulniers
2019-07-29 20:32 ` Nathan Chancellor
2019-07-29 20:32 ` Nathan Chancellor
2019-07-29 20:45 ` Nick Desaulniers
2019-07-29 20:45 ` Nick Desaulniers
2019-07-29 20:47 ` Nathan Chancellor
2019-07-29 20:47 ` Nathan Chancellor
2019-07-29 20:49 ` Nick Desaulniers
2019-07-29 20:49 ` Nick Desaulniers
2019-07-29 21:52 ` Segher Boessenkool
2019-07-29 21:52 ` Segher Boessenkool
2019-07-30 7:34 ` Arnd Bergmann
2019-07-30 7:34 ` Arnd Bergmann
2019-07-30 11:17 ` Michael Ellerman
2019-07-30 11:17 ` Michael Ellerman
2019-08-09 18:21 ` [PATCH] powerpc: fix inline asm constraints for dcbz Nick Desaulniers
2019-08-09 18:21 ` Nick Desaulniers
2019-08-09 18:28 ` Arnd Bergmann
2019-08-09 18:28 ` Arnd Bergmann
2019-08-09 20:03 ` Christophe Leroy
2019-08-09 20:03 ` Christophe Leroy
2019-08-09 20:12 ` Arnd Bergmann
2019-08-09 20:12 ` Arnd Bergmann
2019-08-09 22:03 ` Nick Desaulniers
2019-08-09 22:03 ` Nick Desaulniers
2019-08-09 22:10 ` Segher Boessenkool [this message]
2019-08-09 22:10 ` Segher Boessenkool
2019-08-09 22:00 ` Segher Boessenkool
2019-08-09 22:00 ` Segher Boessenkool
2019-08-09 22:03 ` [PATCH v3] Revert "powerpc: slightly improve cache helpers" Nick Desaulniers
2019-08-09 22:03 ` Nick Desaulniers
2019-08-10 9:09 ` Michael Ellerman
2019-08-10 9:09 ` Michael Ellerman
2019-08-09 21:55 ` [PATCH] powerpc: fix inline asm constraints for dcbz Segher Boessenkool
2019-08-09 21:55 ` Segher Boessenkool
2019-08-09 20:36 ` Nathan Chancellor
2019-08-09 20:36 ` Nathan Chancellor
2019-07-30 13:48 ` [PATCH] powerpc: workaround clang codegen bug in dcbz Segher Boessenkool
2019-07-30 13:48 ` Segher Boessenkool
2019-07-30 14:30 ` Arnd Bergmann
2019-07-30 14:30 ` Arnd Bergmann
2019-07-30 16:16 ` Segher Boessenkool
2019-07-30 16:16 ` Segher Boessenkool
2019-07-30 17:07 ` Segher Boessenkool
2019-07-30 18:24 ` Arnd Bergmann
2019-07-30 18:24 ` Arnd Bergmann
2019-07-30 18:24 ` Arnd Bergmann
2019-07-30 19:35 ` Segher Boessenkool
2019-07-30 19:35 ` Segher Boessenkool
2019-07-30 5:31 ` Christophe Leroy
2019-07-30 5:31 ` Christophe Leroy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190809221052.GP31406@gate.crashing.org \
--to=segher@kernel.crashing.org \
--cc=arnd@arndb.de \
--cc=clang-built-linux@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=lkp@intel.com \
--cc=natechancellor@gmail.com \
--cc=ndesaulniers@google.com \
--cc=paulus@samba.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.