From: Antony Yu <swpenim@gmail.com>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: swpenim@gmail.com, Russell King <linux@armlinux.org.uk>,
LKML <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Nathan Chancellor <natechancellor@gmail.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: [PATCH v2] ARM: fix __div64_32() error when compiling with clang
Date: Mon, 30 Nov 2020 16:20:32 +0800 [thread overview]
Message-ID: <20201130082032.GA25739@penyung-VirtualBox> (raw)
In-Reply-To: <CAKwvOdkE5-OBWjmGwc8qUkj5wuqZTmtYxaMD3sz+4+aNiC2vLg@mail.gmail.com>
[-- Attachment #1: v2-0001-ARM-fix-__div64_32-error-when-compiling-with-clan.patch --]
[-- Type: text/x-diff, Size: 1327 bytes --]
From 3a4c19e09079324a625941ea3c16fe4b0df2ed86 Mon Sep 17 00:00:00 2001
From: Antony Yu <swpenim@gmail.com>
Date: Mon, 9 Nov 2020 17:31:52 +0800
Subject: [PATCH v2] ARM: fix __div64_32() error when compiling with clang
__do_div64 clobbers the input register r0 in little endian system.
According to the inline assembly document, if an input operand is
modified, it should be tied to a output operand. This patch can
prevent compilers from reusing r0 register after asm statements.
Signed-off-by: Antony Yu <swpenim@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
---
changed in v2
- add kernel-test-robot tag
- fix build failure on big endian
arch/arm/include/asm/div64.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h
index 898e9c78a7e7..961a129eb41f 100644
--- a/arch/arm/include/asm/div64.h
+++ b/arch/arm/include/asm/div64.h
@@ -39,9 +39,10 @@ static inline uint32_t __div64_32(uint64_t *n, uint32_t base)
asm( __asmeq("%0", __xh)
__asmeq("%1", "r2")
__asmeq("%2", "r0")
- __asmeq("%3", "r4")
+ __asmeq("%3", "r0")
+ __asmeq("%4", "r4")
"bl __do_div64"
- : "=r" (__rem), "=r" (__res)
+ : "=r" (__rem), "=r" (__res), "=r" (__xl)
: "r" (__n), "r" (__base)
: "ip", "lr", "cc");
*n = __res;
--
2.29.0
[-- Attachment #2: Type: text/plain, Size: 176 bytes --]
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-11-30 8:22 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-23 7:36 [RESEND,PATCH] ARM: fix __div64_32() error when compiling with clang Antony Yu
2020-11-23 18:16 ` Nathan Chancellor
[not found] ` <20201124074211.GA26157@penyung-VirtualBox>
2020-11-24 10:14 ` [RESEND, PATCH] " Antony Yu
2020-11-24 21:06 ` Nick Desaulniers
2020-11-30 8:20 ` Antony Yu [this message]
2020-11-24 23:16 ` [RESEND,PATCH] " kernel test robot
2020-11-30 10:11 ` [RESEND, PATCH] " Ard Biesheuvel
2020-11-30 10:12 ` Ard Biesheuvel
2020-11-30 10:21 ` [RESEND,PATCH] " Russell King - ARM Linux admin
2020-11-30 10:40 ` [RESEND, PATCH] " Ard Biesheuvel
2020-11-30 13:58 ` [RESEND,PATCH] " David Laight
2020-11-30 14:18 ` Russell King - ARM Linux admin
2020-11-30 15:50 ` Nicolas Pitre
2020-11-30 17:18 ` [RESEND, PATCH] " Ard Biesheuvel
2020-11-30 17:52 ` [RESEND,PATCH] " Nicolas Pitre
2020-11-30 18:08 ` [RESEND, PATCH] " Ard Biesheuvel
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=20201130082032.GA25739@penyung-VirtualBox \
--to=swpenim@gmail.com \
--cc=clang-built-linux@googlegroups.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=natechancellor@gmail.com \
--cc=ndesaulniers@google.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).