diff options
Diffstat (limited to 'arch/x86/platform/efi/efi.c')
| -rw-r--r-- | arch/x86/platform/efi/efi.c | 39 |
1 files changed, 14 insertions, 25 deletions
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index ad28540..3c1f3cd 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -869,7 +869,7 @@ static void __init kexec_enter_virtual_mode(void) * This function will switch the EFI runtime services to virtual mode. * Essentially, we look through the EFI memmap and map every region that * has the runtime attribute bit set in its memory descriptor into the - * ->trampoline_pgd page table using a top-down VA allocation scheme. + * efi_pgd page table. * * The old method which used to update that memory descriptor with the * virtual address obtained from ioremap() is still supported when the @@ -879,8 +879,8 @@ static void __init kexec_enter_virtual_mode(void) * * The new method does a pagetable switch in a preemption-safe manner * so that we're in a different address space when calling a runtime - * function. For function arguments passing we do copy the PGDs of the - * kernel page table into ->trampoline_pgd prior to each call. + * function. For function arguments passing we do copy the PUDs of the + * kernel page table into efi_pgd prior to each call. * * Specially for kexec boot, efi runtime maps in previous kernel should * be passed in via setup_data. In that case runtime ranges will be mapped @@ -895,6 +895,12 @@ static void __init __efi_enter_virtual_mode(void) efi.systab = NULL; + if (efi_alloc_page_tables()) { + pr_err("Failed to allocate EFI page tables\n"); + clear_bit(EFI_RUNTIME_SERVICES, &efi.flags); + return; + } + efi_merge_regions(); new_memmap = efi_map_regions(&count, &pg_shift); if (!new_memmap) { @@ -954,28 +960,11 @@ static void __init __efi_enter_virtual_mode(void) efi_runtime_mkexec(); /* - * We mapped the descriptor array into the EFI pagetable above but we're - * not unmapping it here. Here's why: - * - * We're copying select PGDs from the kernel page table to the EFI page - * table and when we do so and make changes to those PGDs like unmapping - * stuff from them, those changes appear in the kernel page table and we - * go boom. - * - * From setup_real_mode(): - * - * ... - * trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd; - * - * In this particular case, our allocation is in PGD 0 of the EFI page - * table but we've copied that PGD from PGD[272] of the EFI page table: - * - * pgd_index(__PAGE_OFFSET = 0xffff880000000000) = 272 - * - * where the direct memory mapping in kernel space is. - * - * new_memmap's VA comes from that direct mapping and thus clearing it, - * it would get cleared in the kernel page table too. + * We mapped the descriptor array into the EFI pagetable above + * but we're not unmapping it here because if we're running in + * EFI mixed mode we need all of memory to be accessible when + * we pass parameters to the EFI runtime services in the + * thunking code. * * efi_cleanup_page_tables(__pa(new_memmap), 1 << pg_shift); */ |