drm/amd/amdgpu: Return error if initiating read out of range on vram

commit 9156e723301c0a7a7def4cde820e018ce791b842 upstream.

If you initiate a read that is out of the VRAM address space return
ENXIO instead of 0.

Reads that begin below that point will read upto the VRAM limit as
before.

Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index dcaf691..264899d 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1419,6 +1419,9 @@ static ssize_t amdgpu_ttm_vram_read(struct file *f, char __user *buf,
        if (size & 0x3 || *pos & 0x3)
                return -EINVAL;
 
+       if (*pos >= adev->mc.mc_vram_size)
+               return -ENXIO;
+
        while (size) {
                unsigned long flags;
                uint32_t value;