linux-kernel - Re: [PATCH] gpu/drm: Replace "%p" with "%pK"

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Message-ID: <d29e6b5d-da4d-fde3-dd85-80e69bb5e497@amd.com>
Date:   Tue, 30 Jun 2020 15:01:56 +0200
From:   Christian König <christian.koenig@....com>
To:     Tiezhu Yang <yangtiezhu@...ngson.cn>,
        Alex Deucher <alexander.deucher@....com>
Cc:     amd-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] gpu/drm: Replace "%p" with "%pK"

Am 30.06.20 um 14:14 schrieb Tiezhu Yang:
> On 06/30/2020 04:05 PM, Christian König wrote:
>> Am 30.06.20 um 09:36 schrieb Tiezhu Yang:
>>> When I update the latest kernel, I see the following 
>>> "____ptrval____" boot
>>> messages. Use "%pK" instead of "%p" so that the cpu address can be 
>>> printed
>>> when the kptr_restrict sysctl is set to 1.
>>>
>>> Both radeon_fence_driver_start_ring() and 
>>> amdgpu_fence_driver_start_ring()
>>> have this similar issue, fix them.
>>>
>>> [    1.872600] radeon 0000:01:05.0: fence driver on ring 0 use gpu 
>>> addr 0x0000000048000c00 and cpu addr 0x(____ptrval____)
>>> [    1.879095] radeon 0000:01:05.0: fence driver on ring 5 use gpu 
>>> addr 0x0000000040056038 and cpu addr 0x(____ptrval____)
>>
>> We can probably just completely drop the CPU address here.
>
> OK, maybe the CPU address is not much useful. If nobody has any 
> objections,
> I will send v2 to remove the debug info about CPU address.

The CPU address was useful in the past, but isn't any more. We now have 
a debugfs file to read the current fence values.

Please go ahead and send a patch to just remove printing them.

Thanks,
Christian.

>
> Thanks,
> Tiezhu
>
>>
>> Christian.
>>
>>>
>>> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 5 ++---
>>>   drivers/gpu/drm/radeon/radeon_fence.c     | 2 +-
>>>   2 files changed, 3 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> index d878fe7..d4d1e8c 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> @@ -422,9 +422,8 @@ int amdgpu_fence_driver_start_ring(struct 
>>> amdgpu_ring *ring,
>>>       ring->fence_drv.irq_type = irq_type;
>>>       ring->fence_drv.initialized = true;
>>>   -    DRM_DEV_DEBUG(adev->dev, "fence driver on ring %s use gpu addr "
>>> -              "0x%016llx, cpu addr 0x%p\n", ring->name,
>>> -              ring->fence_drv.gpu_addr, ring->fence_drv.cpu_addr);
>>> +    DRM_DEV_DEBUG(adev->dev, "fence driver on ring %s use gpu addr 
>>> 0x%016llx, cpu addr 0x%pK\n",
>>> +              ring->name, ring->fence_drv.gpu_addr, 
>>> ring->fence_drv.cpu_addr);
>>>       return 0;
>>>   }
>>>   diff --git a/drivers/gpu/drm/radeon/radeon_fence.c 
>>> b/drivers/gpu/drm/radeon/radeon_fence.c
>>> index 43f2f93..c51b094 100644
>>> --- a/drivers/gpu/drm/radeon/radeon_fence.c
>>> +++ b/drivers/gpu/drm/radeon/radeon_fence.c
>>> @@ -865,7 +865,7 @@ int radeon_fence_driver_start_ring(struct 
>>> radeon_device *rdev, int ring)
>>>       }
>>>       radeon_fence_write(rdev, 
>>> atomic64_read(&rdev->fence_drv[ring].last_seq), ring);
>>>       rdev->fence_drv[ring].initialized = true;
>>> -    dev_info(rdev->dev, "fence driver on ring %d use gpu addr 
>>> 0x%016llx and cpu addr 0x%p\n",
>>> +    dev_info(rdev->dev, "fence driver on ring %d use gpu addr 
>>> 0x%016llx and cpu addr 0x%pK\n",
>>>            ring, rdev->fence_drv[ring].gpu_addr, 
>>> rdev->fence_drv[ring].cpu_addr);
>>>       return 0;
>>>   }
>