On Mon, Nov 20, 2017 at 12:22 PM, Thomas Gleixner <[email protected]> wrote: > 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.
When you rebase on to my latest version, this should change to mapping the entire cpu_entry_area. --Andy
