releases/5.1.6/drm-nouveau-bar-nv50-ensure-bar-is-mapped.patch

From c09c44958a4aab5397e26de647adb30e9f4a85fe Mon Sep 17 00:00:00 2001
From: Jon Derrick <jonathan.derrick@intel.com>
Date: Fri, 15 Mar 2019 18:05:16 -0600
Subject: drm/nouveau/bar/nv50: ensure BAR is mapped

[ Upstream commit f10b83de1fd49216a4c657816f48001437e4bdd5 ]

If the BAR is zero size, it indicates it was never successfully mapped.
Ensure that the BAR is valid during initialization before attempting to
use it.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/bar/nv50.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/nv50.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/nv50.c
index 157b076a12723..38c9c086754b6 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/nv50.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/nv50.c
@@ -109,7 +109,7 @@ nv50_bar_oneinit(struct nvkm_bar *base)
 	struct nvkm_device *device = bar->base.subdev.device;
 	static struct lock_class_key bar1_lock;
 	static struct lock_class_key bar2_lock;
-	u64 start, limit;
+	u64 start, limit, size;
 	int ret;
 
 	ret = nvkm_gpuobj_new(device, 0x20000, 0, false, NULL, &bar->mem);
@@ -127,7 +127,10 @@ nv50_bar_oneinit(struct nvkm_bar *base)
 
 	/* BAR2 */
 	start = 0x0100000000ULL;
-	limit = start + device->func->resource_size(device, 3);
+	size = device->func->resource_size(device, 3);
+	if (!size)
+		return -ENOMEM;
+	limit = start + size;
 
 	ret = nvkm_vmm_new(device, start, limit-- - start, NULL, 0,
 			   &bar2_lock, "bar2", &bar->bar2_vmm);
@@ -164,7 +167,10 @@ nv50_bar_oneinit(struct nvkm_bar *base)
 
 	/* BAR1 */
 	start = 0x0000000000ULL;
-	limit = start + device->func->resource_size(device, 1);
+	size = device->func->resource_size(device, 1);
+	if (!size)
+		return -ENOMEM;
+	limit = start + size;
 
 	ret = nvkm_vmm_new(device, start, limit-- - start, NULL, 0,
 			   &bar1_lock, "bar1", &bar->bar1_vmm);
-- 
2.20.1