drivers/firmware/efi/libstub/efi-stub-entry.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include <linux/efi.h>
   4 #include <linux/screen_info.h>
   5
   6 #include <asm/efi.h>
   7
   8 #include "efistub.h"
   9
  10 static unsigned long screen_info_offset;
  11
  12 struct screen_info *alloc_screen_info(void)
  13 {
  14         if (IS_ENABLED(CONFIG_ARM))
  15                 return __alloc_screen_info();
  16         return (void *)&screen_info + screen_info_offset;
  17 }
  18
  19 /*
  20  * EFI entry point for the generic EFI stub used by ARM, arm64, RISC-V and
  21  * LoongArch. This is the entrypoint that is described in the PE/COFF header
  22  * of the core kernel.
  23  */
  24 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
  25                                    efi_system_table_t *systab)
  26 {
  27         efi_loaded_image_t *image;
  28         efi_status_t status;
  29         unsigned long image_addr;
  30         unsigned long image_size = 0;
  31         /* addr/point and size pairs for memory management*/
  32         char *cmdline_ptr = NULL;
  33         efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
  34         unsigned long reserve_addr = 0;
  35         unsigned long reserve_size = 0;
  36
  37         WRITE_ONCE(efi_system_table, systab);
  38
  39         /* Check if we were booted by the EFI firmware */
  40         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
  41                 return EFI_INVALID_PARAMETER;
  42
  43         /*
  44          * Get a handle to the loaded image protocol.  This is used to get
  45          * information about the running image, such as size and the command
  46          * line.
  47          */
  48         status = efi_bs_call(handle_protocol, handle, &loaded_image_proto,
  49                              (void *)&image);
  50         if (status != EFI_SUCCESS) {
  51                 efi_err("Failed to get loaded image protocol\n");
  52                 return status;
  53         }
  54
  55         status = efi_handle_cmdline(image, &cmdline_ptr);
  56         if (status != EFI_SUCCESS)
  57                 return status;
  58
  59         efi_info("Booting Linux Kernel...\n");
  60
  61         status = handle_kernel_image(&image_addr, &image_size,
  62                                      &reserve_addr,
  63                                      &reserve_size,
  64                                      image, handle);
  65         if (status != EFI_SUCCESS) {
  66                 efi_err("Failed to relocate kernel\n");
  67                 return status;
  68         }
  69
  70         screen_info_offset = image_addr - (unsigned long)image->image_base;
  71
  72         status = efi_stub_common(handle, image, image_addr, cmdline_ptr);
  73
  74         efi_free(image_size, image_addr);
  75         efi_free(reserve_size, reserve_addr);
  76
  77         return status;
  78 }