1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * EFI hello world 4 * 5 * Copyright (c) 2016 Google, Inc 6 * Written by Simon Glass <sjg@chromium.org> 7 * 8 * This program demonstrates calling a boottime service. 9 * It writes a greeting and the load options to the console. 10 */ 11 12 #include <common.h> 13 #include <efi_api.h> 14 15 static const efi_guid_t loaded_image_guid = LOADED_IMAGE_GUID; 16 static const efi_guid_t fdt_guid = EFI_FDT_GUID; 17 static const efi_guid_t smbios_guid = SMBIOS_TABLE_GUID; 18 19 static int hw_memcmp(const void *buf1, const void *buf2, size_t length) 20 { 21 const u8 *pos1 = buf1; 22 const u8 *pos2 = buf2; 23 24 for (; length; --length) { 25 if (*pos1 != *pos2) 26 return *pos1 - *pos2; 27 ++pos1; 28 ++pos2; 29 } 30 return 0; 31 } 32 33 /* 34 * Entry point of the EFI application. 35 * 36 * @handle handle of the loaded image 37 * @systable system table 38 * @return status code 39 */ 40 efi_status_t EFIAPI efi_main(efi_handle_t handle, 41 struct efi_system_table *systable) 42 { 43 struct efi_simple_text_output_protocol *con_out = systable->con_out; 44 struct efi_boot_services *boottime = systable->boottime; 45 struct efi_loaded_image *loaded_image; 46 efi_status_t ret; 47 efi_uintn_t i; 48 u16 rev[] = L"0.0.0"; 49 50 con_out->output_string(con_out, L"Hello, world!\n"); 51 52 /* Print the revision number */ 53 rev[0] = (systable->hdr.revision >> 16) + '0'; 54 rev[4] = systable->hdr.revision & 0xffff; 55 for (; rev[4] >= 10;) { 56 rev[4] -= 10; 57 ++rev[2]; 58 } 59 /* Third digit is only to be shown if non-zero */ 60 if (rev[4]) 61 rev[4] += '0'; 62 else 63 rev[3] = 0; 64 65 con_out->output_string(con_out, L"Running on UEFI "); 66 con_out->output_string(con_out, rev); 67 con_out->output_string(con_out, L"\n"); 68 69 /* Get the loaded image protocol */ 70 ret = boottime->handle_protocol(handle, &loaded_image_guid, 71 (void **)&loaded_image); 72 if (ret != EFI_SUCCESS) { 73 con_out->output_string(con_out, 74 L"Cannot open loaded image protocol\n"); 75 goto out; 76 } 77 /* Find configuration tables */ 78 for (i = 0; i < systable->nr_tables; ++i) { 79 if (!hw_memcmp(&systable->tables[i].guid, &fdt_guid, 80 sizeof(efi_guid_t))) 81 con_out->output_string(con_out, L"Have device tree\n"); 82 if (!hw_memcmp(&systable->tables[i].guid, &smbios_guid, 83 sizeof(efi_guid_t))) 84 con_out->output_string(con_out, L"Have SMBIOS table\n"); 85 } 86 /* Output the load options */ 87 con_out->output_string(con_out, L"Load options: "); 88 if (loaded_image->load_options_size && loaded_image->load_options) 89 con_out->output_string(con_out, 90 (u16 *)loaded_image->load_options); 91 else 92 con_out->output_string(con_out, L"<none>"); 93 con_out->output_string(con_out, L"\n"); 94 95 out: 96 boottime->exit(handle, ret, 0, NULL); 97 98 /* We should never arrive here */ 99 return ret; 100 } 101