On Fri, 10 Nov 2017, Dave Hansen wrote: > __set_fixmap(get_cpu_gdt_ro_index(cpu), get_cpu_gdt_paddr(cpu), prot); > + > + /* CPU 0's mapping is done in kaiser_init() */ > + if (cpu) { > + int ret; > + > + ret = kaiser_add_mapping((unsigned long) get_cpu_gdt_ro(cpu), > + PAGE_SIZE, __PAGE_KERNEL_RO); > + /* > + * We do not have a good way to fail CPU bringup. > + * Just WARN about it and hope we boot far enough > + * to get a good log out. > + */ The GDT fixmap can be set up before the CPU is started. There is no reason to do that in cpu_init(). > + > + /* > + * We could theoretically do this in setup_fixmap_gdt(). > + * But, we would need to rewrite the above page table > + * allocation code to use the bootmem allocator. The > + * buddy allocator is not available at the time that we > + * call setup_fixmap_gdt() for CPU 0. > + */ > + kaiser_add_user_map_early(get_cpu_gdt_ro(0), PAGE_SIZE, > + __PAGE_KERNEL_RO | _PAGE_GLOBAL); This one is needs to stay. Thanks, tglx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>