Messages in this thread | | | Subject | Re: [PATCH] watchdog: dw_wdt: dont build for avr32 | From | Guenter Roeck <> | Date | Sun, 1 May 2016 07:09:20 -0700 |
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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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