From: Tom St Denis <tom.stdenis@amd.com>
Date: Tue, 23 May 2017 15:35:22 +0000 (-0400)
Subject: drm/amd/amdgpu: Return error if initiating read out of range on vram
X-Git-Tag: archive/raspbian/4.9.51-1+rpi1~7^2~597
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=b85007c9114a05c696c46c2aac6da68aeaed7bbc;p=linux-4.9.git

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 dcaf691f56b5..264899df9bfc 100644
--- 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;