From ab72a27da4c6c19b0e3d6d7556fdd4afb581c8ac Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Mon, 20 Jun 2016 14:36:51 +0100 Subject: [PATCH] x86/efi: Consolidate region mapping logic EFI regions are currently mapped in two separate places. The bulk of the work is done in efi_map_regions() but when CONFIG_EFI_MIXED is enabled the additional regions that are required when operating in mixed mode are mapping in efi_setup_page_tables(). Pull everything into efi_map_regions() and refactor the test for which regions should be mapped into a should_map_region() function. Generously sprinkle comments to clarify the different cases. Acked-by: Borislav Petkov Tested-by: Dave Young [kexec/kdump] Tested-by: Ard Biesheuvel [arm] Acked-by: Ard Biesheuvel Signed-off-by: Matt Fleming --- arch/x86/platform/efi/efi.c | 50 +++++++++++++++++++++++++++++----- arch/x86/platform/efi/efi_64.c | 20 -------------- 2 files changed, 43 insertions(+), 27 deletions(-) diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 1fbb408e2e72..625ec729b4e8 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -745,6 +745,46 @@ static void *efi_map_next_entry(void *entry) return entry; } +static bool should_map_region(efi_memory_desc_t *md) +{ + /* + * Runtime regions always require runtime mappings (obviously). + */ + if (md->attribute & EFI_MEMORY_RUNTIME) + return true; + + /* + * 32-bit EFI doesn't suffer from the bug that requires us to + * reserve boot services regions, and mixed mode support + * doesn't exist for 32-bit kernels. + */ + if (IS_ENABLED(CONFIG_X86_32)) + return false; + + /* + * Map all of RAM so that we can access arguments in the 1:1 + * mapping when making EFI runtime calls. + */ + if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_is_native()) { + if (md->type == EFI_CONVENTIONAL_MEMORY || + md->type == EFI_LOADER_DATA || + md->type == EFI_LOADER_CODE) + return true; + } + + /* + * Map boot services regions as a workaround for buggy + * firmware that accesses them even when they shouldn't. + * + * See efi_{reserve,free}_boot_services(). + */ + if (md->type == EFI_BOOT_SERVICES_CODE || + md->type == EFI_BOOT_SERVICES_DATA) + return true; + + return false; +} + /* * Map the efi memory ranges of the runtime services and update new_mmap with * virtual addresses. @@ -761,13 +801,9 @@ static void * __init efi_map_regions(int *count, int *pg_shift) p = NULL; while ((p = efi_map_next_entry(p))) { md = p; - if (!(md->attribute & EFI_MEMORY_RUNTIME)) { -#ifdef CONFIG_X86_64 - if (md->type != EFI_BOOT_SERVICES_CODE && - md->type != EFI_BOOT_SERVICES_DATA) -#endif - continue; - } + + if (!should_map_region(md)) + continue; efi_map_region(md); get_systab_virt_addr(md); diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 677e29e29473..45434ea345e9 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -214,7 +214,6 @@ void efi_sync_low_kernel_mappings(void) int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) { unsigned long pfn, text; - efi_memory_desc_t *md; struct page *page; unsigned npages; pgd_t *pgd; @@ -248,25 +247,6 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) if (!IS_ENABLED(CONFIG_EFI_MIXED)) return 0; - /* - * Map all of RAM so that we can access arguments in the 1:1 - * mapping when making EFI runtime calls. - */ - for_each_efi_memory_desc(md) { - if (md->type != EFI_CONVENTIONAL_MEMORY && - md->type != EFI_LOADER_DATA && - md->type != EFI_LOADER_CODE) - continue; - - pfn = md->phys_addr >> PAGE_SHIFT; - npages = md->num_pages; - - if (kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, npages, _PAGE_RW)) { - pr_err("Failed to map 1:1 memory\n"); - return 1; - } - } - page = alloc_page(GFP_KERNEL|__GFP_DMA32); if (!page) panic("Unable to allocate EFI runtime stack < 4GB\n"); -- 2.39.2