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Re: [PATCH] watchdog: dw_wdt: dont build for avr32

Started bySudip Mukherjee <sudipm.mukherjee@gmail.com>
First post2016-04-30 20:40 +0200
Last post2016-05-01 18:40 +0200
Articles 7 — 2 participants

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  Re: [PATCH] watchdog: dw_wdt: dont build for avr32 Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2016-04-30 20:40 +0200
    Re: [PATCH] watchdog: dw_wdt: dont build for avr32 Guenter Roeck <linux@roeck-us.net> - 2016-05-01 02:10 +0200
    Re: [PATCH] watchdog: dw_wdt: dont build for avr32 Guenter Roeck <linux@roeck-us.net> - 2016-05-01 02:40 +0200
      Re: [PATCH] watchdog: dw_wdt: dont build for avr32 Guenter Roeck <linux@roeck-us.net> - 2016-05-01 03:20 +0200
        Re: [PATCH] watchdog: dw_wdt: dont build for avr32 Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2016-05-01 11:10 +0200
          Re: [PATCH] watchdog: dw_wdt: dont build for avr32 Guenter Roeck <linux@roeck-us.net> - 2016-05-01 16:10 +0200
            Re: [PATCH] watchdog: dw_wdt: dont build for avr32 Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2016-05-01 18:40 +0200

#1391653 — Re: [PATCH] watchdog: dw_wdt: dont build for avr32

FromSudip Mukherjee <sudipm.mukherjee@gmail.com>
Date2016-04-30 20:40 +0200
SubjectRe: [PATCH] watchdog: dw_wdt: dont build for avr32
Message-ID<rtHY6-3LI-19@gated-at.bofh.it>
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@gmail.com> 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

regards
sudip

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#1391723

FromGuenter Roeck <linux@roeck-us.net>
Date2016-05-01 02:10 +0200
Message-ID<rtN7r-8qI-1@gated-at.bofh.it>
In reply to#1391653
On 04/30/2016 11:38 AM, 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@gmail.com> 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!
>

Pretty much what I suspected would happen. Oddly enough, the symbol was defined
in early avr32 patch sets [1], but dropped in the final commit after some
discussion [2]. Makes me wonder if the problem was always known.

Guenter

> 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
>
> regards
> sudip
>
---
[1] https://kldp.org/files/linux-2.6.16.11-avr32-20060626.patch_.txt
[2] http://fa.linux.kernel.narkive.com/4UhaxiM4/avr32-architecture-patch-against-linux-2-6-18-rc1-available

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#1391725

FromGuenter Roeck <linux@roeck-us.net>
Date2016-05-01 02:40 +0200
Message-ID<rtNAt-fd-1@gated-at.bofh.it>
In reply to#1391653
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@gmail.com> 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

---
From d2f541c46ae2bf599d9aa3be0682cfac76742ebf Mon Sep 17 00:00:00 2001
From: Guenter Roeck <linux@roeck-us.net>
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@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 arch/avr32/include/asm/div64.h | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 arch/avr32/include/asm/div64.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>
-- 
2.5.0

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#1391732

FromGuenter Roeck <linux@roeck-us.net>
Date2016-05-01 03:20 +0200
Message-ID<rtOdb-Oj-3@gated-at.bofh.it>
In reply to#1391725
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@gmail.com> 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@roeck-us.net>
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@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 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>
-- 
2.5.0

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#1391777

FromSudip Mukherjee <sudipm.mukherjee@gmail.com>
Date2016-05-01 11:10 +0200
Message-ID<rtVy2-6Ve-9@gated-at.bofh.it>
In reply to#1391732
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@gmail.com> 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@roeck-us.net>
> 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@gmail.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>   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!

regards
sudip

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#1391823

FromGuenter Roeck <linux@roeck-us.net>
Date2016-05-01 16:10 +0200
Message-ID<ru0em-2ju-9@gated-at.bofh.it>
In reply to#1391777
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@gmail.com> 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@roeck-us.net>
>> 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@gmail.com>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> ---
>>   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.

Guenter

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#1391849

FromSudip Mukherjee <sudipm.mukherjee@gmail.com>
Date2016-05-01 18:40 +0200
Message-ID<ru2zw-40s-5@gated-at.bofh.it>
In reply to#1391823
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@gmail.com> 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@roeck-us.net>
>>> 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@gmail.com>
>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>>> ---
>>>   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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