On Tue, Jan 07, 2025 at 08:09:48PM +0800, Hans Zhang wrote: > Hi Niklas, > > The robot has been compiled with CONFIG_PHYS_ADDR_T_64BIT=y, so > resource_size_t=u64 > > > include/linux/types.h > > #ifdef CONFIG_PHYS_ADDR_T_64BIT > typedef u64 phys_addr_t; > #else > typedef u32 phys_addr_t; > #endif > > typedef phys_addr_t resource_size_t; > > > Is my understanding wrong? Could you correct me, please? Thank you very > much. I see. That is correct. > > config: i386-randconfig-003-20250101 (https://download.01.org/0day-ci/archive/20250101/202501011917.ugP1ywJV-lkp@xxxxxxxxx/config) > > > I compiled it as a KO module for an experiment. > __umoddi3 and __udivdi3 is similar to __udivmoddi4. > > u64 bar_size; > > iters = bar_size / buf_size; > remain = bar_size % buf_size; I think that I am an idiot (I'm the one who wrote this code). A BAR size is always a power of two. So I don't see how there can ever be a remainer... buf_size = min(SZ_1M, bar_size); If the BAR size is <= 1MB, there will be 1 iteration, no remainder. If the BAR size is > 1MB, there will be more than one iteration, but the size will always be evenly divisible by 1MB, so no remainder. This should probably be two patches: patch 1/2: @@ -316,12 +317,6 @@ static bool pci_endpoint_test_bar(struct pci_endpoint_test *test, write_buf, read_buf, buf_size)) return false; - remain = bar_size % buf_size; - if (remain) - if (pci_endpoint_test_bar_memcmp(test, barno, buf_size * iters, - write_buf, read_buf, remain)) - return false; - return true; } patch 2/2: @@ -283,10 +283,11 @@ static int pci_endpoint_test_bar_memcmp(struct pci_endpoint_test *test, static bool pci_endpoint_test_bar(struct pci_endpoint_test *test, enum pci_barno barno) { - int j, bar_size, buf_size, iters, remain; + int j, buf_size, iters; void *write_buf __free(kfree) = NULL; void *read_buf __free(kfree) = NULL; struct pci_dev *pdev = test->pdev; + resource_size_t bar_size; if (!test->bar[barno]) return false; The error: drivers/misc/pci_endpoint_test.c:315: undefined reference to `__udivmoddi4' sounds like the compiler is using a specialized instruction to do both div and mod in one. By removing the mod in patch 1/2, I expect that patch 2/2 will no longer get this error. Kind regards, Niklas
