On Mon, Dec 23, 2019 at 7:23 AM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > The EFI mixed mode entry code goes through the ordinary startup_32() > routine before jumping into the kernel's EFI boot code in 64-bit > mode. The 32-bit startup code must be entered with paging disabled, > but this is not documented as a requirement for the EFI handover > protocol, and so we should disable paging explicitly when entering > the kernel from 32-bit EFI firmware. Does this mean that EFI is allowed to call the kernel with paging on but the text identity-mapped? Have you seen this happen in practice? If the kernel is entered with paging on and the text not identity-mapped, this is going to blow up badly. --Andy
