From: Sudip Mukherjee <sudipm.mukherjee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
Cc: Andy Shevchenko
<andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Wim Van Sebroeck <wim-IQzOog9fTRqzQB+pC5nmwQ@public.gmane.org>,
Haavard Skinnemoen
<hskinnemoen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Hans-Christian Egtvedt
<egtvedt-BrfabpQBY5qlHtIdYg32fQ@public.gmane.org>,
"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-watchdog-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Chris Mason <clm-b10kYP2dOMg@public.gmane.org>
Subject: Re: [PATCH] watchdog: dw_wdt: dont build for avr32
Date: Sun, 01 May 2016 17:30:26 +0100 [thread overview]
Message-ID: <57262F22.9040708@gmail.com> (raw)
In-Reply-To: <57260E10.5050601-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
On Sunday 01 May 2016 03:09 PM, Guenter Roeck wrote:
> On 05/01/2016 02:04 AM, Sudip Mukherjee wrote:
>> On Sunday 01 May 2016 02:13 AM, Guenter Roeck wrote:
>>> On Sat, Apr 30, 2016 at 05:36:51PM -0700, Guenter Roeck wrote:
>>>> On Sat, Apr 30, 2016 at 07:38:28PM +0100, Sudip Mukherjee wrote:
>>>>> On Tue, Apr 12, 2016 at 11:01:28AM -0700, Guenter Roeck wrote:
>>>>>> On Tue, Apr 12, 2016 at 05:58:20PM +0300, Andy Shevchenko wrote:
>>>>>>> On Tue, Apr 12, 2016 at 4:39 PM, Sudip Mukherjee
>>>>>>> <sudipm.mukherjee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>>>>>>>> On Tuesday 12 April 2016 06:36 PM, Guenter Roeck wrote:
>>>>>>>>>
>>>>>>>>> On 04/11/2016 10:51 PM, Sudip Mukherjee wrote:
>>>>>>>>>>
>>>>>>>>>> The build of avr32 allmodconfig fails with the error:
>>>>>>>>>> ERROR: "__avr32_udiv64" [drivers/watchdog/kempld_wdt.ko]
>>>>>>>>>> undefined!
>>>>>>>>>>
>>>>>>>>> This means there is a direct 64 bit divide operation in the
>>>>>>>>> driver,
>>>>>>>>> which we should identify and fix.
>>>>>>>
>>>>>>> This driver will quite likely never be used on AVR32. Do we need to
>>>>>>> fix this due to some other architectures?
>>>>>>>
>>>>>>>> yes, there is.
>>>>>>>>
>>>>>>>> in function: kempld_wdt_set_stage_timeout()
>>>>>>>> remainder = do_div(stage_timeout64, prescaler);
>>>>>>>
>>>>>>>> Any idea how to fix it?
>>>>>>>
>>>>>>> Not easy, however, prescaler value is ((1 << 21) - 1) which someone
>>>>>>> might consider as (1 << 21) with lost in precision.
>>>>>>>
>>>>>>> Thus, shift on 20 bits right, add last bit to the value and shift
>>>>>>> on 1
>>>>>>> bit right more.
>>>>>>>
>>>>>> Sorry, I am missing something. do_div() should work fine with any
>>>>>> 32 bit value
>>>>>> as divisor, no matter what that value is. Why does it fail here ?
>>>>>> And why does
>>>>>> it work if I pass 0x1fffff as second parameter to do_div() directly ?
>>>>>
>>>>> Please let me know what i can do here to help solve the problem.
>>>>> linux-next continues to fail for avr32, and to make matters worse we
>>>>> also have the similar problem in btrfs.
>>>>>
>>>>> ERROR: "__avr32_udiv64" [fs/btrfs/btrfs.ko] undefined!
>>>>> ERROR: "__avr32_udiv64" [drivers/watchdog/kempld_wdt.ko] undefined!
>>>>>
>>>>> Adding Chris to CC if he has some idea how to solve this error for
>>>>> btrfs.
>>>>> Build log for next-20160429 is at:
>>>>> https://travis-ci.org/sudipm-mukherjee/parport/jobs/126581065
>>>>>
>>>>
>>>> Try the patch below.
>>>>
>>>> Guenter
>>>>
>>> Sorry, patch wasn't complete.
>>>
>>> Guenter
>>>
>>> ---
>>> From c684f2cf54ecb256007288af23c24bfcdb2bbace Mon Sep 17 00:00:00 2001
>>> From: Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
>>> Date: Sat, 30 Apr 2016 17:29:14 -0700
>>> Subject: [PATCH] avr32: __div64_const32 is not ok
>>>
>>> Building avr32 images may fail with errors such as
>>>
>>> ERROR: "__avr32_udiv64" [fs/btrfs/btrfs.ko] undefined!
>>> ERROR: "__avr32_udiv64" [drivers/watchdog/kempld_wdt.ko] undefined!
>>>
>>> gcc for avr32 generates those symbols for certain constants used
>>> as divisor in do_div(). The problem can be avoided by setting
>>> __div64_const32_is_OK to false for the architecture.
>>>
>>> Cc: Sudip Mukherjee <sudipm.mukherjee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>>> Signed-off-by: Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
>>> ---
>>> arch/avr32/include/asm/Kbuild | 1 -
>>> arch/avr32/include/asm/div64.h | 3 +++
>>> 2 files changed, 3 insertions(+), 1 deletion(-)
>>> create mode 100644 arch/avr32/include/asm/div64.h
>>>
>>> diff --git a/arch/avr32/include/asm/Kbuild
>>> b/arch/avr32/include/asm/Kbuild
>>> index 241b9b9729d8..d2be4688ac7b 100644
>>> --- a/arch/avr32/include/asm/Kbuild
>>> +++ b/arch/avr32/include/asm/Kbuild
>>> @@ -3,7 +3,6 @@ generic-y += clkdev.h
>>> generic-y += cputime.h
>>> generic-y += delay.h
>>> generic-y += device.h
>>> -generic-y += div64.h
>>> generic-y += emergency-restart.h
>>> generic-y += exec.h
>>> generic-y += futex.h
>>> diff --git a/arch/avr32/include/asm/div64.h
>>> b/arch/avr32/include/asm/div64.h
>>> new file mode 100644
>>> index 000000000000..1f3328e178df
>>> --- /dev/null
>>> +++ b/arch/avr32/include/asm/div64.h
>>> @@ -0,0 +1,3 @@
>>> +#define __div64_const32_is_OK false
>>> +
>>> +#include <asm-generic/div64.h>
>>>
>>
>> It looks like this patch has fixed about the error about the watchdog
>> but for some reason I am still getting the error about the btrfs.
>>
>> ERROR: "__avr32_udiv64" [fs/btrfs/btrfs.ko] undefined!
>>
>
> Are you sure that this failure is limited to avr32 ?
>
> Bisect for that problem points to commit "Btrfs: fix divide error upon
> chunk's stripe_len",
> which modified stripe_len in struct map_lookup to 64 bit.
> map->stripe_length is used
> at least once in a 64-bit divide operation, so I would expect to see
> more build failures.
>
> A quick check shows that i386:allmodconfig now fails to build as well
> due to a 64-bit
> divide operation in brtfs.
yes, i didn't get the time to monitor my build bot for last one week.
But now that i go and see the results:
i386, m68k, mips allmodconfig failed with:
ERROR: "__udivdi3" [fs/btrfs/btrfs.ko] undefined!
regards
sudip
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next prev parent reply other threads:[~2016-05-01 16:30 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-12 5:51 [PATCH] watchdog: dw_wdt: dont build for avr32 Sudip Mukherjee
[not found] ` <1460440303-20640-1-git-send-email-sudipm.mukherjee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-04-12 13:06 ` Guenter Roeck
[not found] ` <570CF2CB.2050200-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
2016-04-12 13:39 ` Sudip Mukherjee
[not found] ` <570CFA90.4060100-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-04-12 14:58 ` Andy Shevchenko
2016-04-12 15:29 ` Sudip Mukherjee
[not found] ` <CAHp75VcrmiP0GWR-zCBmqc7zA6uiC4dD8-HDikmWZxyEwXkRLw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-12 18:01 ` Guenter Roeck
[not found] ` <20160412180128.GA6965-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
2016-04-12 18:17 ` Andy Shevchenko
2016-04-30 18:38 ` Sudip Mukherjee
2016-05-01 0:04 ` Guenter Roeck
2016-05-01 0:36 ` Guenter Roeck
[not found] ` <20160501003651.GA28804-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
2016-05-01 1:13 ` Guenter Roeck
2016-05-01 9:04 ` Sudip Mukherjee
[not found] ` <5725C698.1090504-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-05-01 14:09 ` Guenter Roeck
[not found] ` <57260E10.5050601-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
2016-05-01 16:30 ` Sudip Mukherjee [this message]
2016-04-12 13:07 ` Guenter Roeck
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