I know there are some Unix specs that say that page size is reported via runtime interfaces, but I suspect that eg on x86 if you built a Linux kernel that gave

I know there are some Unix specs that say that page size is reported via runtime interfaces, but I suspect that eg on x86 if you built a Linux kernel that gave userspace a 2MB page size, and started returning that from the sysconf(_SC_PAGESIZE) interface, many (most?) apps would break and shrugging that away with "those apps are just broken" would be a nonstarter. But maybe just counts as a a de facto user expectation and is not documented anywhere architecture in Linux ABIs?