arch/x86/platform/efi/efi_32.c

   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 #include <linux/pgtable.h>
  28
  29 #include <asm/io.h>
  30 #include <asm/desc.h>
  31 #include <asm/page.h>
  32 #include <asm/set_memory.h>
  33 #include <asm/tlbflush.h>
  34 #include <asm/efi.h>
  35
  36 void __init efi_map_region(efi_memory_desc_t *md)
  37 {
  38         u64 start_pfn, end_pfn, end;
  39         unsigned long size;
  40         void *va;
  41
  42         start_pfn       = PFN_DOWN(md->phys_addr);
  43         size            = md->num_pages << PAGE_SHIFT;
  44         end             = md->phys_addr + size;
  45         end_pfn         = PFN_UP(end);
  46
  47         if (pfn_range_is_mapped(start_pfn, end_pfn)) {
  48                 va = __va(md->phys_addr);
  49
  50                 if (!(md->attribute & EFI_MEMORY_WB))
  51                         set_memory_uc((unsigned long)va, md->num_pages);
  52         } else {
  53                 va = ioremap_cache(md->phys_addr, size);
  54         }
  55
  56         md->virt_addr = (unsigned long)va;
  57         if (!va)
  58                 pr_err("ioremap of 0x%llX failed!\n", md->phys_addr);
  59 }
  60
  61 /*
  62  * To make EFI call EFI runtime service in physical addressing mode we need
  63  * prolog/epilog before/after the invocation to claim the EFI runtime service
  64  * handler exclusively and to duplicate a memory mapping in low memory space,
  65  * say 0 - 3G.
  66  */
  67
  68 int __init efi_alloc_page_tables(void)
  69 {
  70         return 0;
  71 }
  72
  73 void efi_sync_low_kernel_mappings(void) {}
  74
  75 void __init efi_dump_pagetable(void)
  76 {
  77 #ifdef CONFIG_EFI_PGT_DUMP
  78         ptdump_walk_pgd_level(NULL, &init_mm);
  79 #endif
  80 }
  81
  82 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
  83 {
  84         return 0;
  85 }
  86
  87 void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
  88 void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}
  89
  90 efi_status_t efi_call_svam(efi_runtime_services_t * const *,
  91                            u32, u32, u32, void *, u32);
  92
  93 efi_status_t __init efi_set_virtual_address_map(unsigned long memory_map_size,
  94                                                 unsigned long descriptor_size,
  95                                                 u32 descriptor_version,
  96                                                 efi_memory_desc_t *virtual_map,
  97                                                 unsigned long systab_phys)
  98 {
  99         const efi_system_table_t *systab = (efi_system_table_t *)systab_phys;
 100         struct desc_ptr gdt_descr;
 101         efi_status_t status;
 102         unsigned long flags;
 103         pgd_t *save_pgd;
 104
 105         /* Current pgd is swapper_pg_dir, we'll restore it later: */
 106         save_pgd = swapper_pg_dir;
 107         load_cr3(initial_page_table);
 108         __flush_tlb_all();
 109
 110         gdt_descr.address = get_cpu_gdt_paddr(0);
 111         gdt_descr.size = GDT_SIZE - 1;
 112         load_gdt(&gdt_descr);
 113
 114         /* Disable interrupts around EFI calls: */
 115         local_irq_save(flags);
 116         status = efi_call_svam(&systab->runtime,
 117                                memory_map_size, descriptor_size,
 118                                descriptor_version, virtual_map,
 119                                __pa(&efi.runtime));
 120         local_irq_restore(flags);
 121
 122         load_fixmap_gdt(0);
 123         load_cr3(save_pgd);
 124         __flush_tlb_all();
 125
 126         return status;
 127 }
 128
 129 void __init efi_runtime_update_mappings(void)
 130 {
 131         if (__supported_pte_mask & _PAGE_NX) {
 132                 efi_memory_desc_t *md;
 133
 134                 /* Make EFI runtime service code area executable */
 135                 for_each_efi_memory_desc(md) {
 136                         if (md->type != EFI_RUNTIME_SERVICES_CODE)
 137                                 continue;
 138
 139                         set_memory_x(md->virt_addr, md->num_pages);
 140                 }
 141         }
 142 }