1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Extensible Firmware Interface 4 * 5 * Based on Extensible Firmware Interface Specification version 1.0 6 * 7 * Copyright (C) 1999 VA Linux Systems 8 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com> 9 * Copyright (C) 1999-2002 Hewlett-Packard Co. 10 * David Mosberger-Tang <davidm@hpl.hp.com> 11 * Stephane Eranian <eranian@hpl.hp.com> 12 * 13 * All EFI Runtime Services are not implemented yet as EFI only 14 * supports physical mode addressing on SoftSDV. This is to be fixed 15 * in a future version. --drummond 1999-07-20 16 * 17 * Implemented EFI runtime services and virtual mode calls. --davidm 18 * 19 * Goutham Rao: <goutham.rao@intel.com> 20 * Skip non-WB memory and ignore empty memory ranges. 21 */ 22 23 #include <linux/kernel.h> 24 #include <linux/types.h> 25 #include <linux/ioport.h> 26 #include <linux/efi.h> 27 28 #include <asm/io.h> 29 #include <asm/desc.h> 30 #include <asm/page.h> 31 #include <asm/pgtable.h> 32 #include <asm/tlbflush.h> 33 #include <asm/efi.h> 34 35 /* 36 * To make EFI call EFI runtime service in physical addressing mode we need 37 * prolog/epilog before/after the invocation to claim the EFI runtime service 38 * handler exclusively and to duplicate a memory mapping in low memory space, 39 * say 0 - 3G. 40 */ 41 42 int __init efi_alloc_page_tables(void) 43 { 44 return 0; 45 } 46 47 void efi_sync_low_kernel_mappings(void) {} 48 49 void __init efi_dump_pagetable(void) 50 { 51 #ifdef CONFIG_EFI_PGT_DUMP 52 ptdump_walk_pgd_level(NULL, swapper_pg_dir); 53 #endif 54 } 55 56 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) 57 { 58 return 0; 59 } 60 61 void __init efi_map_region(efi_memory_desc_t *md) 62 { 63 old_map_region(md); 64 } 65 66 void __init efi_map_region_fixed(efi_memory_desc_t *md) {} 67 void __init parse_efi_setup(u64 phys_addr, u32 data_len) {} 68 69 pgd_t * __init efi_call_phys_prolog(void) 70 { 71 struct desc_ptr gdt_descr; 72 pgd_t *save_pgd; 73 74 /* Current pgd is swapper_pg_dir, we'll restore it later: */ 75 save_pgd = swapper_pg_dir; 76 load_cr3(initial_page_table); 77 __flush_tlb_all(); 78 79 gdt_descr.address = get_cpu_gdt_paddr(0); 80 gdt_descr.size = GDT_SIZE - 1; 81 load_gdt(&gdt_descr); 82 83 return save_pgd; 84 } 85 86 void __init efi_call_phys_epilog(pgd_t *save_pgd) 87 { 88 load_fixmap_gdt(0); 89 load_cr3(save_pgd); 90 __flush_tlb_all(); 91 } 92 93 void __init efi_runtime_update_mappings(void) 94 { 95 if (__supported_pte_mask & _PAGE_NX) 96 runtime_code_page_mkexec(); 97 } 98