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 acpi_guid = EFI_ACPI_TABLE_GUID; 18 static const efi_guid_t smbios_guid = SMBIOS_TABLE_GUID; 19 20 static int hw_memcmp(const void *buf1, const void *buf2, size_t length) 21 { 22 const u8 *pos1 = buf1; 23 const u8 *pos2 = buf2; 24 25 for (; length; --length) { 26 if (*pos1 != *pos2) 27 return *pos1 - *pos2; 28 ++pos1; 29 ++pos2; 30 } 31 return 0; 32 } 33 34 /* 35 * Entry point of the EFI application. 36 * 37 * @handle handle of the loaded image 38 * @systable system table 39 * @return status code 40 */ 41 efi_status_t EFIAPI efi_main(efi_handle_t handle, 42 struct efi_system_table *systable) 43 { 44 struct efi_simple_text_output_protocol *con_out = systable->con_out; 45 struct efi_boot_services *boottime = systable->boottime; 46 struct efi_loaded_image *loaded_image; 47 efi_status_t ret; 48 efi_uintn_t i; 49 u16 rev[] = L"0.0.0"; 50 51 con_out->output_string(con_out, L"Hello, world!\n"); 52 53 /* Print the revision number */ 54 rev[0] = (systable->hdr.revision >> 16) + '0'; 55 rev[4] = systable->hdr.revision & 0xffff; 56 for (; rev[4] >= 10;) { 57 rev[4] -= 10; 58 ++rev[2]; 59 } 60 /* Third digit is only to be shown if non-zero */ 61 if (rev[4]) 62 rev[4] += '0'; 63 else 64 rev[3] = 0; 65 66 con_out->output_string(con_out, L"Running on UEFI "); 67 con_out->output_string(con_out, rev); 68 con_out->output_string(con_out, L"\n"); 69 70 /* Get the loaded image protocol */ 71 ret = boottime->handle_protocol(handle, &loaded_image_guid, 72 (void **)&loaded_image); 73 if (ret != EFI_SUCCESS) { 74 con_out->output_string(con_out, 75 L"Cannot open loaded image protocol\n"); 76 goto out; 77 } 78 /* Find configuration tables */ 79 for (i = 0; i < systable->nr_tables; ++i) { 80 if (!hw_memcmp(&systable->tables[i].guid, &fdt_guid, 81 sizeof(efi_guid_t))) 82 con_out->output_string(con_out, L"Have device tree\n"); 83 if (!hw_memcmp(&systable->tables[i].guid, &acpi_guid, 84 sizeof(efi_guid_t))) 85 con_out->output_string(con_out, L"Have ACPI 2.0 table\n"); 86 if (!hw_memcmp(&systable->tables[i].guid, &smbios_guid, 87 sizeof(efi_guid_t))) 88 con_out->output_string(con_out, L"Have SMBIOS table\n"); 89 } 90 /* Output the load options */ 91 con_out->output_string(con_out, L"Load options: "); 92 if (loaded_image->load_options_size && loaded_image->load_options) 93 con_out->output_string(con_out, 94 (u16 *)loaded_image->load_options); 95 else 96 con_out->output_string(con_out, L"<none>"); 97 con_out->output_string(con_out, L"\n"); 98 99 out: 100 boottime->exit(handle, ret, 0, NULL); 101 102 /* We should never arrive here */ 103 return ret; 104 } 105