On 11/20/2017 12:46 PM, Andy Lutomirski wrote: >>> + /* >>> + * 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.
I did this, but unfortunately it ends up having to individually map all four pieces of cpu_entry_area. They all need different permissions and while theoretically we could do TSS+exception-stacks in the same call, they're not next to each other: GDT: R/O TSS: R/W at least because of trampoline stack entry code: EXEC+R/O exception stacks: R/W
