[PATCH] drm/amdkfd: Cast atomic64_read return value

[Felix Kuehling]

Am 2021-09-13 um 12:18 p.m. schrieb Michel Dänzer:
> On 2021-09-13 17:19, Felix Kuehling wrote:
>> Am 2021-09-13 um 10:19 a.m. schrieb Michel Dänzer:
>>> From: Michel Dänzer <mdaenzer at redhat.com>
>>>
>>> Avoids warning with -Wformat:
>>>
>>>   CC [M]  drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_smi_events.o
>>> ../drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_smi_events.c: In function ‘kfd_smi_event_update_thermal_throttling’:
>>> ../drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_smi_events.c:224:60: warning: format ‘%llx’ expects argument of type
>>>  ‘long long unsigned int’, but argument 6 has type ‘long int’ [-Wformat=]
>>>   224 |         len = snprintf(fifo_in, sizeof(fifo_in), "%x %x:%llx\n",
>>>       |                                                         ~~~^
>>>       |                                                            |
>>>       |                                                            long long unsigned int
>>>       |                                                         %lx
>>>   225 |                        KFD_SMI_EVENT_THERMAL_THROTTLE, throttle_bitmask,
>>>   226 |                        atomic64_read(&adev->smu.throttle_int_counter));
>>>       |                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>       |                        |
>>>       |                        long int
>> That's weird. As far as I can see, atomic64_read is defined to return
>> s64, which should be the same as long long. Which architecture are you
>> on?
> This was from a 64-bit powerpc build. atomic64_read returns long there.
>
>
This should be defined as s64:

./arch/powerpc/include/asm/atomic.h:static __inline__ s64 atomic64_read(const atomic64_t *v)

In arch/powerpc/include/uapi/asm/types.h I see this:

/*
 * This is here because we used to use l64 for 64bit powerpc
 * and we don't want to impact user mode with our change to ll64
 * in the kernel.
 *
 * However, some user programs are fine with this.  They can
 * flag __SANE_USERSPACE_TYPES__ to get int-ll64.h here.
 */
#if !defined(__SANE_USERSPACE_TYPES__) && defined(__powerpc64__) && !defined(__KERNEL__)
# include <asm-generic/int-l64.h>
#else
# include <asm-generic/int-ll64.h>
#endif


So in kernel mode it should be using int-ll64.h, which defines s64 as
long-long. The cast to u64 won't help either way. It's either
unnecessary or it's still unsigned long.

Regards,
  Felix