src/boot/efi/linux.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify it
   3  * under the terms of the GNU Lesser General Public License as published by
   4  * the Free Software Foundation; either version 2.1 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful, but
   8  * WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10  * Lesser General Public License for more details.
  11  *
  12  * Copyright (C) 2015 Kay Sievers <kay@vrfy.org>
  13  */
  14
  15 #include <efi.h>
  16 #include <efilib.h>
  17
  18 #include "linux.h"
  19 #include "util.h"
  20
  21 #define SETUP_MAGIC             0x53726448      /* "HdrS" */
  22 struct SetupHeader {
  23         UINT8 boot_sector[0x01f1];
  24         UINT8 setup_secs;
  25         UINT16 root_flags;
  26         UINT32 sys_size;
  27         UINT16 ram_size;
  28         UINT16 video_mode;
  29         UINT16 root_dev;
  30         UINT16 signature;
  31         UINT16 jump;
  32         UINT32 header;
  33         UINT16 version;
  34         UINT16 su_switch;
  35         UINT16 setup_seg;
  36         UINT16 start_sys;
  37         UINT16 kernel_ver;
  38         UINT8 loader_id;
  39         UINT8 load_flags;
  40         UINT16 movesize;
  41         UINT32 code32_start;
  42         UINT32 ramdisk_start;
  43         UINT32 ramdisk_len;
  44         UINT32 bootsect_kludge;
  45         UINT16 heap_end;
  46         UINT8 ext_loader_ver;
  47         UINT8 ext_loader_type;
  48         UINT32 cmd_line_ptr;
  49         UINT32 ramdisk_max;
  50         UINT32 kernel_alignment;
  51         UINT8 relocatable_kernel;
  52         UINT8 min_alignment;
  53         UINT16 xloadflags;
  54         UINT32 cmdline_size;
  55         UINT32 hardware_subarch;
  56         UINT64 hardware_subarch_data;
  57         UINT32 payload_offset;
  58         UINT32 payload_length;
  59         UINT64 setup_data;
  60         UINT64 pref_address;
  61         UINT32 init_size;
  62         UINT32 handover_offset;
  63 } __attribute__((packed));
  64
  65 #ifdef __x86_64__
  66 typedef VOID(*handover_f)(VOID *image, EFI_SYSTEM_TABLE *table, struct SetupHeader *setup);
  67 static inline VOID linux_efi_handover(EFI_HANDLE image, struct SetupHeader *setup) {
  68         handover_f handover;
  69
  70         asm volatile ("cli");
  71         handover = (handover_f)((UINTN)setup->code32_start + 512 + setup->handover_offset);
  72         handover(image, ST, setup);
  73 }
  74 #else
  75 typedef VOID(*handover_f)(VOID *image, EFI_SYSTEM_TABLE *table, struct SetupHeader *setup) __attribute__((regparm(0)));
  76 static inline VOID linux_efi_handover(EFI_HANDLE image, struct SetupHeader *setup) {
  77         handover_f handover;
  78
  79         handover = (handover_f)((UINTN)setup->code32_start + setup->handover_offset);
  80         handover(image, ST, setup);
  81 }
  82 #endif
  83
  84 EFI_STATUS linux_exec(EFI_HANDLE *image,
  85                       CHAR8 *cmdline, UINTN cmdline_len,
  86                       UINTN linux_addr,
  87                       UINTN initrd_addr, UINTN initrd_size) {
  88         struct SetupHeader *image_setup;
  89         struct SetupHeader *boot_setup;
  90         EFI_PHYSICAL_ADDRESS addr;
  91         EFI_STATUS err;
  92
  93         image_setup = (struct SetupHeader *)(linux_addr);
  94         if (image_setup->signature != 0xAA55 || image_setup->header != SETUP_MAGIC)
  95                 return EFI_LOAD_ERROR;
  96
  97         if (image_setup->version < 0x20b || !image_setup->relocatable_kernel)
  98                 return EFI_LOAD_ERROR;
  99
 100         addr = 0x3fffffff;
 101         err = uefi_call_wrapper(BS->AllocatePages, 4, AllocateMaxAddress, EfiLoaderData,
 102                                 EFI_SIZE_TO_PAGES(0x4000), &addr);
 103         if (EFI_ERROR(err))
 104                 return err;
 105         boot_setup = (struct SetupHeader *)(UINTN)addr;
 106         ZeroMem(boot_setup, 0x4000);
 107         CopyMem(boot_setup, image_setup, sizeof(struct SetupHeader));
 108         boot_setup->loader_id = 0xff;
 109
 110         boot_setup->code32_start = (UINT32)linux_addr + (image_setup->setup_secs+1) * 512;
 111
 112         if (cmdline) {
 113                 addr = 0xA0000;
 114                 err = uefi_call_wrapper(BS->AllocatePages, 4, AllocateMaxAddress, EfiLoaderData,
 115                                         EFI_SIZE_TO_PAGES(cmdline_len + 1), &addr);
 116                 if (EFI_ERROR(err))
 117                         return err;
 118                 CopyMem((VOID *)(UINTN)addr, cmdline, cmdline_len);
 119                 ((CHAR8 *)addr)[cmdline_len] = 0;
 120                 boot_setup->cmd_line_ptr = (UINT32)addr;
 121         }
 122
 123         boot_setup->ramdisk_start = (UINT32)initrd_addr;
 124         boot_setup->ramdisk_len = (UINT32)initrd_size;
 125
 126         linux_efi_handover(image, boot_setup);
 127         return EFI_LOAD_ERROR;
 128 }