From: gangchen@rdamicro.com (Chen Gang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/1] ARM : missing corrupted reg in __do_div_asm
Date: Wed, 10 Jun 2015 17:53:24 +0800 [thread overview]
Message-ID: <20150610095324.GA29556@localhost.rdamicro.com.cn> (raw)
__xl (R0 in little endian system, or R1 in big endian system) is corrupted
after calling __do_div64 and compiler is not informed about this in
macro __do_div_asm. If n is used again afterwards, __xl won't be
reloaded and n will contain incorrect value.
Signed-off-by: Chen Gang <gangchen@rdamicro.com>
---
arch/arm/include/asm/div64.h | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h
index 662c7bd..fa9489e 100644
--- a/arch/arm/include/asm/div64.h
+++ b/arch/arm/include/asm/div64.h
@@ -34,12 +34,14 @@
register unsigned long long __n asm("r0") = n; \
register unsigned long long __res asm("r2"); \
register unsigned int __rem asm(__xh); \
+ register unsigned int __clobber asm(__xl); \
asm( __asmeq("%0", __xh) \
- __asmeq("%1", "r2") \
- __asmeq("%2", "r0") \
- __asmeq("%3", "r4") \
+ __asmeq("%1", __xl) \
+ __asmeq("%2", "r2") \
+ __asmeq("%3", "r0") \
+ __asmeq("%4", "r4") \
"bl __do_div64" \
- : "=r" (__rem), "=r" (__res) \
+ : "=r" (__rem), "=r" (__clobber), "=r" (__res) \
: "r" (__n), "r" (__base) \
: "ip", "lr", "cc"); \
n = __res; \
--
2.4.2
next reply other threads:[~2015-06-10 9:53 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-10 9:53 Chen Gang [this message]
-- strict thread matches above, loose matches on Subject: below --
2015-06-09 13:09 [PATCH 1/1] ARM : missing corrupted reg in __do_div_asm Russell King - ARM Linux
2015-06-19 11:28 ` [PATCH v2 " Chen Gang
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