drivers/gpu/drm/nouveau/nvkm/subdev/fb/gb100.c:19:37: warning: result of comparison of constant 4503599627370495 with expression of type 'dma_addr_t' (aka 'unsigned int') is always false

drivers/gpu/drm/nouveau/nvkm/subdev/fb/gb100.c:19:37: warning: result of comparison of constant 4503599627370495 with expression of type 'dma_addr_t' (aka 'unsigned int') is always false

[kernel test robot]

Hi Timur,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   cb8a75eec0877810b50aa1c5a833f929525cd2ee
commit: 31d3354f42c0da34415164a1f621a195caa1f1bc drm/nouveau: verify that hardware supports the flush page address
date:   9 months ago
config: i386-randconfig-007-20260820 (https://download.01.org/0day-ci/archive/20260820/202608202040.g0B7f22s-lkp@intel.com/config)
compiler: clang version 22.1.3 (https://github.com/llvm/llvm-project e9846648fd6183ee6d8cbdb4502213fcf902a211)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260820/202608202040.g0B7f22s-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Fixes: 31d3354f42c0 ("drm/nouveau: verify that hardware supports the flush page address")
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202608202040.g0B7f22s-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/nouveau/nvkm/subdev/fb/gb100.c:19:37: warning: result of comparison of constant 4503599627370495 with expression of type 'dma_addr_t' (aka 'unsigned int') is always false [-Wtautological-constant-out-of-range-compare]
      19 |         WARN_ON(fb->sysmem.flush_page_addr > DMA_BIT_MASK(52));
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
   include/asm-generic/bug.h:123:25: note: expanded from macro 'WARN_ON'
     123 |         int __ret_warn_on = !!(condition);                              \
         |                                ^~~~~~~~~
   1 warning generated.


vim +19 drivers/gpu/drm/nouveau/nvkm/subdev/fb/gb100.c

     9	
    10	static void
    11	gb100_fb_sysmem_flush_page_init(struct nvkm_fb *fb)
    12	{
    13		const u32 addr_hi = upper_32_bits(fb->sysmem.flush_page_addr);
    14		const u32 addr_lo = lower_32_bits(fb->sysmem.flush_page_addr);
    15		const u32 hshub = DRF_LO(NV_PFB_HSHUB0);
    16		struct nvkm_device *device = fb->subdev.device;
    17	
    18		// Ensure that the address is within hardware limits
  > 19		WARN_ON(fb->sysmem.flush_page_addr > DMA_BIT_MASK(52));
    20	
    21		nvkm_wr32(device, hshub + NV_PFB_HSHUB_PCIE_FLUSH_SYSMEM_ADDR_HI, addr_hi);
    22		nvkm_wr32(device, hshub + NV_PFB_HSHUB_PCIE_FLUSH_SYSMEM_ADDR_LO, addr_lo);
    23		nvkm_wr32(device, hshub + NV_PFB_HSHUB_EG_PCIE_FLUSH_SYSMEM_ADDR_HI, addr_hi);
    24		nvkm_wr32(device, hshub + NV_PFB_HSHUB_EG_PCIE_FLUSH_SYSMEM_ADDR_LO, addr_lo);
    25	}
    26	

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