This is a note to let you know that I've just added the patch titled
drm/amdgpu: avoid integer overflow warning in amdgpu_device_resize_fb_bar()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amdgpu-avoid-integer-overflow-warning-in-amdgpu_.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 37a2ed8ca538c9e7472976ff7f283f90eb59a498
Author: Arnd Bergmann <arnd@xxxxxxxx>
Date: Fri Jul 7 13:11:51 2023 +0200
drm/amdgpu: avoid integer overflow warning in amdgpu_device_resize_fb_bar()
[ Upstream commit 822130b5e8834ab30ad410cf19a582e5014b9a85 ]
On 32-bit architectures comparing a resource against a value larger than
U32_MAX can cause a warning:
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:1344:18: error: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
res->start > 0x100000000ull)
~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
As gcc does not warn about this in dead code, add an IS_ENABLED() check at
the start of the function. This will always return success but not actually resize
the BAR on 32-bit architectures without high memory, which is exactly what
we want here, as the driver can fall back to bank switching the VRAM
access.
Fixes: 31b8adab3247 ("drm/amdgpu: require a root bus window above 4GB for BAR resize")
Reviewed-by: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 787cbeea8dc55..c84f475d4f136 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -735,6 +735,9 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
u16 cmd;
int r;
+ if (!IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT))
+ return 0;
+
/* Bypass for VF */
if (amdgpu_sriov_vf(adev))
return 0;
