src/boot/efi/linux.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <efi.h>
   4 #include <efilib.h>
   5
   6 #include "linux.h"
   7 #include "util.h"
   8
   9 #ifdef __x86_64__
  10 typedef VOID(*handover_f)(VOID *image, EFI_SYSTEM_TABLE *table, struct boot_params *params);
  11 static VOID linux_efi_handover(EFI_HANDLE image, struct boot_params *params) {
  12         handover_f handover;
  13
  14         asm volatile ("cli");
  15         handover = (handover_f)((UINTN)params->hdr.code32_start + 512 + params->hdr.handover_offset);
  16         handover(image, ST, params);
  17 }
  18 #else
  19 typedef VOID(*handover_f)(VOID *image, EFI_SYSTEM_TABLE *table, struct boot_params *params) __attribute__((regparm(0)));
  20 static VOID linux_efi_handover(EFI_HANDLE image, struct boot_params *params) {
  21         handover_f handover;
  22
  23         handover = (handover_f)((UINTN)params->hdr.code32_start + params->hdr.handover_offset);
  24         handover(image, ST, params);
  25 }
  26 #endif
  27
  28 EFI_STATUS linux_exec(EFI_HANDLE *image,
  29                       CHAR8 *cmdline, UINTN cmdline_len,
  30                       UINTN linux_addr,
  31                       UINTN initrd_addr, UINTN initrd_size) {
  32         struct boot_params *image_params;
  33         struct boot_params *boot_params;
  34         UINT8 setup_sectors;
  35         EFI_PHYSICAL_ADDRESS addr;
  36         EFI_STATUS err;
  37
  38         image_params = (struct boot_params *) linux_addr;
  39
  40         if (image_params->hdr.boot_flag != 0xAA55 ||
  41             image_params->hdr.header != SETUP_MAGIC ||
  42             image_params->hdr.version < 0x20b ||
  43             !image_params->hdr.relocatable_kernel)
  44                 return EFI_LOAD_ERROR;
  45
  46         boot_params = (struct boot_params *) 0xFFFFFFFF;
  47         err = uefi_call_wrapper(BS->AllocatePages, 4, AllocateMaxAddress, EfiLoaderData,
  48                                 EFI_SIZE_TO_PAGES(0x4000), (UINTN *) &boot_params);
  49         if (EFI_ERROR(err))
  50                 return err;
  51
  52         ZeroMem(boot_params, 0x4000);
  53         CopyMem(&boot_params->hdr, &image_params->hdr, sizeof(struct setup_header));
  54         boot_params->hdr.type_of_loader = 0xff;
  55         setup_sectors = image_params->hdr.setup_sects > 0 ? image_params->hdr.setup_sects : 4;
  56         boot_params->hdr.code32_start = (UINT32)linux_addr + (setup_sectors + 1) * 512;
  57
  58         if (cmdline) {
  59                 addr = 0xA0000;
  60                 err = uefi_call_wrapper(BS->AllocatePages, 4, AllocateMaxAddress, EfiLoaderData,
  61                                         EFI_SIZE_TO_PAGES(cmdline_len + 1), &addr);
  62                 if (EFI_ERROR(err))
  63                         return err;
  64                 CopyMem((VOID *)(UINTN)addr, cmdline, cmdline_len);
  65                 ((CHAR8 *)(UINTN)addr)[cmdline_len] = 0;
  66                 boot_params->hdr.cmd_line_ptr = (UINT32)addr;
  67         }
  68
  69         boot_params->hdr.ramdisk_image = (UINT32)initrd_addr;
  70         boot_params->hdr.ramdisk_size = (UINT32)initrd_size;
  71
  72         linux_efi_handover(image, boot_params);
  73         return EFI_LOAD_ERROR;
  74 }