src/boot/efi/linux.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /*
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License as published by
   6  * the Free Software Foundation; either version 2.1 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * Copyright (C) 2015 Kay Sievers <kay@vrfy.org>
  15  */
  16
  17 #include <efi.h>
  18 #include <efilib.h>
  19
  20 #include "util.h"
  21 #include "linux.h"
  22
  23 #define SETUP_MAGIC             0x53726448      /* "HdrS" */
  24 struct SetupHeader {
  25         UINT8 boot_sector[0x01f1];
  26         UINT8 setup_secs;
  27         UINT16 root_flags;
  28         UINT32 sys_size;
  29         UINT16 ram_size;
  30         UINT16 video_mode;
  31         UINT16 root_dev;
  32         UINT16 signature;
  33         UINT16 jump;
  34         UINT32 header;
  35         UINT16 version;
  36         UINT16 su_switch;
  37         UINT16 setup_seg;
  38         UINT16 start_sys;
  39         UINT16 kernel_ver;
  40         UINT8 loader_id;
  41         UINT8 load_flags;
  42         UINT16 movesize;
  43         UINT32 code32_start;
  44         UINT32 ramdisk_start;
  45         UINT32 ramdisk_len;
  46         UINT32 bootsect_kludge;
  47         UINT16 heap_end;
  48         UINT8 ext_loader_ver;
  49         UINT8 ext_loader_type;
  50         UINT32 cmd_line_ptr;
  51         UINT32 ramdisk_max;
  52         UINT32 kernel_alignment;
  53         UINT8 relocatable_kernel;
  54         UINT8 min_alignment;
  55         UINT16 xloadflags;
  56         UINT32 cmdline_size;
  57         UINT32 hardware_subarch;
  58         UINT64 hardware_subarch_data;
  59         UINT32 payload_offset;
  60         UINT32 payload_length;
  61         UINT64 setup_data;
  62         UINT64 pref_address;
  63         UINT32 init_size;
  64         UINT32 handover_offset;
  65 } __attribute__((packed));
  66
  67 #ifdef __x86_64__
  68 typedef VOID(*handover_f)(VOID *image, EFI_SYSTEM_TABLE *table, struct SetupHeader *setup);
  69 static inline VOID linux_efi_handover(EFI_HANDLE image, struct SetupHeader *setup) {
  70         handover_f handover;
  71
  72         asm volatile ("cli");
  73         handover = (handover_f)((UINTN)setup->code32_start + 512 + setup->handover_offset);
  74         handover(image, ST, setup);
  75 }
  76 #else
  77 typedef VOID(*handover_f)(VOID *image, EFI_SYSTEM_TABLE *table, struct SetupHeader *setup) __attribute__((regparm(0)));
  78 static inline VOID linux_efi_handover(EFI_HANDLE image, struct SetupHeader *setup) {
  79         handover_f handover;
  80
  81         handover = (handover_f)((UINTN)setup->code32_start + setup->handover_offset);
  82         handover(image, ST, setup);
  83 }
  84 #endif
  85
  86 EFI_STATUS linux_exec(EFI_HANDLE *image,
  87                       CHAR8 *cmdline, UINTN cmdline_len,
  88                       UINTN linux_addr,
  89                       UINTN initrd_addr, UINTN initrd_size) {
  90         struct SetupHeader *image_setup;
  91         struct SetupHeader *boot_setup;
  92         EFI_PHYSICAL_ADDRESS addr;
  93         EFI_STATUS err;
  94
  95         image_setup = (struct SetupHeader *)(linux_addr);
  96         if (image_setup->signature != 0xAA55 || image_setup->header != SETUP_MAGIC)
  97                 return EFI_LOAD_ERROR;
  98
  99         if (image_setup->version < 0x20b || !image_setup->relocatable_kernel)
 100                 return EFI_LOAD_ERROR;
 101
 102         addr = 0x3fffffff;
 103         err = uefi_call_wrapper(BS->AllocatePages, 4, AllocateMaxAddress, EfiLoaderData,
 104                                 EFI_SIZE_TO_PAGES(0x4000), &addr);
 105         if (EFI_ERROR(err))
 106                 return err;
 107         boot_setup = (struct SetupHeader *)(UINTN)addr;
 108         ZeroMem(boot_setup, 0x4000);
 109         CopyMem(boot_setup, image_setup, sizeof(struct SetupHeader));
 110         boot_setup->loader_id = 0xff;
 111
 112         boot_setup->code32_start = (UINT32)linux_addr + (image_setup->setup_secs+1) * 512;
 113
 114         if (cmdline) {
 115                 addr = 0xA0000;
 116                 err = uefi_call_wrapper(BS->AllocatePages, 4, AllocateMaxAddress, EfiLoaderData,
 117                                         EFI_SIZE_TO_PAGES(cmdline_len + 1), &addr);
 118                 if (EFI_ERROR(err))
 119                         return err;
 120                 CopyMem((VOID *)(UINTN)addr, cmdline, cmdline_len);
 121                 ((CHAR8 *)addr)[cmdline_len] = 0;
 122                 boot_setup->cmd_line_ptr = (UINT32)addr;
 123         }
 124
 125         boot_setup->ramdisk_start = (UINT32)initrd_addr;
 126         boot_setup->ramdisk_len = (UINT32)initrd_size;
 127
 128         linux_efi_handover(image, boot_setup);
 129         return EFI_LOAD_ERROR;
 130 }