Re: [v8] misc: pci_endpoint_test: Fix overflow of bar_size

Hans Zhang
2025-01-07T15:44:52Z

On 2025/1/7 19:47, Niklas Cassel wrote:

Hi Niklas,

> The error:
> drivers/misc/pci_endpoint_test.c:315: undefined reference to `__udivmoddi4'
> sounds like the compiler is using a specialized instruction to do both div
> and mod in one. By removing the mod in patch 1/2, I expect that patch 2/2
> will no longer get this error.

The __udivmoddi4 may be the way div and mod are combined.

Delete remain's patch 1/2 according to your suggestion. I compiled it as
a KO module for an experiment.

There are still __udivdi3 errors, so the do_div API must be used.

zhb@zhb:/media/zhb/hans/code/kernel_org/hans$ make
make -C /media/zhb/hans/code/kernel_org/linux/
M=/media/zhb/hans/code/kernel_org/hans modules
make[1]: Entering directory '/media/zhb/hans/code/kernel_org/linux'
make[2]: Entering directory '/media/zhb/hans/code/kernel_org/hans'
CC [M] pci_endpoint_test.o
MODPOST Module.symvers
ERROR: modpost: "__udivdi3" [pci_endpoint_test.ko] undefined!
make[4]: ***
[/media/zhb/hans/code/kernel_org/linux/scripts/Makefile.modpost:145:
Module.symvers] Error 1
make[3]: *** [/media/zhb/hans/code/kernel_org/linux/Makefile:1939:
modpost] Error 2
make[2]: *** [/media/zhb/hans/code/kernel_org/linux/Makefile:251:
__sub-make] Error 2
make[2]: Leaving directory '/media/zhb/hans/code/kernel_org/hans'
make[1]: *** [Makefile:251: __sub-make] Error 2
make[1]: Leaving directory '/media/zhb/hans/code/kernel_org/linux'
make: *** [Makefile:10: kernel_modules] Error 2

Best regards
Hans