Re: [PATCH] MIPS: OCTEON: Changes to support readq()/writeq() usage.

[David Daney <ddaney@caviumnetworks.com>]

On 08/12/2016 02:38 PM, Aaro Koskinen wrote:
> Hi,
>
> On Fri, Jul 08, 2016 at 09:45:01PM -0500, Steven J. Hill wrote:
>> Update OCTEON port mangling code to support readq() and
>> writeq() functions to allow driver code to be more portable.
>> Updates also for word and long function pairs. We also
>> remove SWAP_IO_SPACE for OCTEON platforms as the function
>> macros are redundant with the new mangling code.
>>
>> Signed-off-by: Steven J. Hill <steven.hill@cavium.com>
>> Acked-by: David Daney <david.daney@cavium.com>
>
> [...]
>
>> +static inline bool __should_swizzle_bits(volatile void *a)
>> +{
>> +	extern const bool octeon_should_swizzle_table[];
>> +
>> +	unsigned long did = ((unsigned long)a >> 40) & 0xff;
>> +	return octeon_should_swizzle_table[did];
>> +}
>
> v4.8-rc1 OCTEON build is now broken with GCC 6.1 when support for 32-bit
> ABIs is enabled:

I don't get it.  The kernel is always 64-bit, so unsigned long will have 
a width of 64.

What kernel config are you using?

>
>    CC      arch/mips/vdso/gettimeofday-o32.o
> In file included from /home/aaro/los/work/shared/linux-v4.8-rc1/arch/mips/includ
> e/asm/io.h:32:0,
>                   from /home/aaro/los/work/shared/linux-v4.8-rc1/arch/mips/includ
> e/asm/page.h:194,
>                   from /home/aaro/los/work/shared/linux-v4.8-rc1/arch/mips/vdso/v
> dso.h:26,
>                   from /home/aaro/los/work/shared/linux-v4.8-rc1/arch/mips/vdso/g
> ettimeofday.c:11:
> /home/aaro/los/work/shared/linux-v4.8-rc1/arch/mips/include/asm/mach-cavium-octe
> on/mangle-port.h: In function '__should_swizzle_bits':
> /home/aaro/los/work/shared/linux-v4.8-rc1/arch/mips/include/asm/mach-cavium-octe
> on/mangle-port.h:19:40: error: right shift count >= width of type [-Werror=shift
> -count-overflow]
>    unsigned long did = ((unsigned long)a >> 40) & 0xff;
>
> A.
>