From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/1] ARM : missing corrupted reg in __do_div_asm
Date: Tue, 29 Mar 2016 12:19:49 +0200 [thread overview]
Message-ID: <3792990.eCI4tPEEyD@wuerfel> (raw)
In-Reply-To: <1459138743-10477-1-git-send-email-chengang.beijing@gmail.com>
On Monday 28 March 2016 12:19:03 Chen Gang wrote:
> __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>
> Signed-off-by: Chen Gang <chengang.beijing@gmail.com>
> ---
How did you find this? Did you run into this problem on a live system
or see it through inspection?
> arch/arm/include/asm/div64.h | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h
> index e1f0776..1a6e91a 100644
> --- a/arch/arm/include/asm/div64.h
> +++ b/arch/arm/include/asm/div64.h
> @@ -35,12 +35,14 @@ static inline uint32_t __div64_32(uint64_t *n, uint32_t base)
> 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("%3", "r0")
> + __asmeq("%4", "r4")
> __asmeq("%2", "r0")
> - __asmeq("%3", "r4")
> "bl __do_div64"
> - : "=r" (__rem), "=r" (__res)
> + : "=r" (__rem), "=r" (__res), "=r" (__clobber)
> : "r" (__n), "r" (__base)
> : "ip", "lr", "cc");
> *n = __res;
Doesn't the clobber normally go in the third line along with
"ip" and "lr"?
Arnd
next prev parent reply other threads:[~2016-03-29 10:19 UTC|newest]
Thread overview: 24+ 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 [this message]
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 ` [PATCH V4 " 陈刚(Gangchen)
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)
[not found] </home/gachen/Re: [PATCH 1_1] ARM:r0 is also corrupted after calling __do_div64..eml>
2015-06-02 6:13 ` Chen Gang
2015-06-08 5:30 ` Chen Gang
2015-06-09 13:09 ` Russell King - ARM Linux
2015-06-28 11:29 ` Chen Gang
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