Re: [PATCH] drm/amdgpu: avoid integer overflow warning in amdgpu_device_resize_fb_bar()
From: Christian König
Date: Tue Jul 04 2023 - 02:54:15 EST
Am 03.07.23 um 14:35 schrieb Arnd Bergmann:
From: Arnd Bergmann <arnd@xxxxxxxx>
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)
~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
The compiler is right that this cannot happen in this configuration, which
is ok, so just add a cast to shut up the warning.
Well it doesn't make sense to compile that driver on systems with only
32bit phys_addr_t in the first place.
It might be cleaner to just not build the whole driver on such systems
or at least leave out this function.
Regards,
Christian
Fixes: 31b8adab3247e ("drm/amdgpu: require a root bus window above 4GB for BAR resize")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 7f069e1731fee..abd13942aac5d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1341,7 +1341,7 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
pci_bus_for_each_resource(root, res, i) {
if (res && res->flags & (IORESOURCE_MEM | IORESOURCE_MEM_64) &&
- res->start > 0x100000000ull)
+ (u64)res->start > 0x100000000ull)
break;
}