src/boot/efi/linux.c

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