From: gangchen@rdamicro•com (陈刚(Gangchen))
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V4 1/1] ARM : missing corrupted reg in __div64_32
Date: Fri, 1 Apr 2016 11:35:13 +0000 [thread overview]
Message-ID: <56FE5CF0.3020205@rdamicro.com> (raw)
In-Reply-To: <20160401110315.GK3701@e103592.cambridge.arm.com>
On 04/01/2016 07:03 PM, Dave Martin wrote:
> On Fri, Apr 01, 2016 at 06:28:49PM +0800, chengang wrote:
>> __xl(R0 in little endian system, or R1 in big endian system) is corrupted
>> by the call to __do_div64i(). The compiler is not aware of this, so if
> Should that be "__do_div64", not "__do_div64i"?
>
>> n is used afterwards __xl won't be reloaded and n will contain incorrect value.
>>
>> Mark 64bits variable __n as inputi/output to inform compiler both r0 and r1
> Typo: "inputi"
>
>> are changed by the funciton call.
>>
>> Signed-off-by: Chen Gang <gangchen@rdamicro•com>
>> Signed-off-by: Chen Gang <changeang.beijing@outlook•com>
>> ---
>> arch/arm/include/asm/div64.h | 22 ++++++++--------------
>> 1 file changed, 8 insertions(+), 14 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h
>> index e1f0776..1153e6d 100644
>> --- a/arch/arm/include/asm/div64.h
>> +++ b/arch/arm/include/asm/div64.h
>> @@ -21,30 +21,24 @@
>> * for arguments and results (beware).
>> */
>>
>> -#ifdef __ARMEB__
>> -#define __xh "r0"
>> -#define __xl "r1"
>> -#else
>> -#define __xl "r0"
>> -#define __xh "r1"
>> -#endif
>>
>> static inline uint32_t __div64_32(uint64_t *n, uint32_t base)
>> {
>> register unsigned int __base asm("r4") = base;
>> register unsigned long long __n asm("r0") = *n;
>> register unsigned long long __res asm("r2");
>> - register unsigned int __rem asm(__xh);
>> - asm( __asmeq("%0", __xh)
>> + asm( __asmeq("%0", "r0")
>> __asmeq("%1", "r2")
>> - __asmeq("%2", "r0")
>> - __asmeq("%3", "r4")
>> + __asmeq("%2", "r4")
>> "bl __do_div64"
>> - : "=r" (__rem), "=r" (__res)
>> - : "r" (__n), "r" (__base)
>> + : "+r" (__n), "=r" (__res)
>> + : "r" (__base)
>> : "ip", "lr", "cc");
>> *n = __res;
>> - return __rem;
>> + /*
>> + * __do_div64 returns the remainder in the upper word of __n
>> + */
> Minor nit: ^ this is short enough to be a one-line comment
>
>> + return __n >> 32;
>> }
>> #define __div64_32 __div64_32
> With those changes,
>
> Reviewed-by: Dave Martin <Dave.Martin@arm•com>
Thanks a lot , especially for your patience! I just sent V5, cheers!
>
> Cheers
> ---Dave
next prev parent reply other threads:[~2016-04-01 11:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-28 4:19 [PATCH 1/1] ARM : missing corrupted reg in __do_div_asm Chen Gang
2016-03-29 10:19 ` Arnd Bergmann
2016-03-29 10:26 ` Dave Martin
2016-03-29 10:34 ` Russell King - ARM Linux
2016-03-29 10:56 ` Dave Martin
2016-03-30 3:27 ` 陈刚(Gangchen)
2016-03-30 14:07 ` Dave Martin
2016-03-31 7:56 ` 陈刚(Gangchen)
2016-03-31 10:30 ` Dave Martin
2016-03-31 11:20 ` 陈刚(Gangchen)
2016-03-31 11:41 ` Dave Martin
2016-04-01 4:22 ` [PATCH V3 1/1] ARM : missing corrupted reg in __div64_32 chengang
2016-04-01 8:56 ` Dave Martin
2016-04-01 10:28 ` [PATCH V4 " chengang
2016-04-01 11:03 ` Dave Martin
2016-04-01 11:25 ` [PATCH V5 " chengang
2016-04-01 11:34 ` Dave P Martin
2016-04-01 11:35 ` 陈刚(Gangchen) [this message]
2016-03-31 11:41 ` [PATCH v2 " Chen Gang
2016-03-29 10:58 ` [PATCH 1/1] ARM : missing corrupted reg in __do_div_asm 陈刚(Gangchen)
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