From 949552d025a5968b3fd3e8d0ab399c9a85232def Mon Sep 17 00:00:00 2001 From: Konstantin Aladyshev Date: Sat, 19 Jun 2021 21:03:52 +0300 Subject: Rename lesson numbers to XX notation With XX notation lessons would be placed in a folder from first to last. --- Lesson_3/README.md | 168 ----------------------------------------------------- 1 file changed, 168 deletions(-) delete mode 100644 Lesson_3/README.md (limited to 'Lesson_3/README.md') diff --git a/Lesson_3/README.md b/Lesson_3/README.md deleted file mode 100644 index f0aef2e..0000000 --- a/Lesson_3/README.md +++ /dev/null @@ -1,168 +0,0 @@ -Finally we are ready to write our "Hello World" app. - -First we create a new edk2 module in our package directory similar to the our `SimplestApp` module: -``` -$ mkdir UefiLessonsPkg/HelloWorld -$ vi UefiLessonsPkg/HelloWorld/HelloWorld.inf -[Defines] - INF_VERSION = 1.25 - BASE_NAME = HelloWorld - FILE_GUID = 2e55fa38-f148-42d3-af90-1be247323e30 - MODULE_TYPE = UEFI_APPLICATION - VERSION_STRING = 1.0 - ENTRY_POINT = UefiMain - -[Sources] - HelloWorld.c - -[Packages] - MdePkg/MdePkg.dec - -[LibraryClasses] - UefiApplicationEntryPoint -``` -Don't forget to add our newly created app to the `Components` section of the package DSC file -``` -[Components] - UefiLessonsPkg/SimplestApp/SimplestApp.inf -+ UefiLessonsPkg/HelloWorld/HelloWorld.inf -``` -Next we need to write the source code file. Let's remember the code for our SimplestApp: -``` -EFI_STATUS -EFIAPI -UefiMain ( - IN EFI_HANDLE ImageHandle, - IN EFI_SYSTEM_TABLE *SystemTable - ) -{ - return EFI_SUCCESS; -} -``` -To print something to the console ("Hello World" message in our case) we need to use services from the `EFI_SYSTEM_TABLE` that is passed to the entry point of our app. - -The description of the `EFI_SYSTEM_TABLE` can be found in the UEFI specification (https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf). - -EFI_SYSTEM_TABLE is a struct that was populated by the UEFI firmware and contains pointers to the runtime and boot services tables. -``` -typedef struct { - EFI_TABLE_HEADER Hdr; - CHAR16 *FirmwareVendor; - UINT32 FirmwareRevision; - EFI_HANDLE ConsoleInHandle; - EFI_SIMPLE_TEXT_INPUT_PROTOCOL *ConIn; - EFI_HANDLE ConsoleOutHandle; - EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL *ConOut; - EFI_HANDLE StandardErrorHandle; - EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL *StdErr; - EFI_RUNTIME_SERVICES *RuntimeServices; - EFI_BOOT_SERVICES *BootServices; - UINTN NumberOfTableEntries; - EFI_CONFIGURATION_TABLE *ConfigurationTable; -} EFI_SYSTEM_TABLE; -``` -We are interested in the `ConOut` field. `ConOut` is abbreviaton for "Console Output" and according to the UEFI spec it is a pointer to the `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL` interface that is associated with `ConsoleOutHandle`. - -If we keep digging into UEFI spec we can find description of the `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL`. -According to the spec `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL` defines the minimum requirements for a text-based ConsoleOut device. - -As everything in UEFI it has GUID: -``` -#define EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL_GUID \ - {0x387477c2,0x69c7,0x11d2,\ - {0x8e,0x39,0x00,0xa0,0xc9,0x69,0x72,0x3b}} -``` - -And the interface description is: -``` -typedef struct _EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL { - EFI_TEXT_RESET Reset; - EFI_TEXT_STRING OutputString; - EFI_TEXT_TEST_STRING TestString; - EFI_TEXT_QUERY_MODE QueryMode; - EFI_TEXT_SET_MODE SetMode; - EFI_TEXT_SET_ATTRIBUTE SetAttribute; - EFI_TEXT_CLEAR_SCREEN ClearScreen; - EFI_TEXT_SET_CURSOR_POSITION SetCursorPosition; - EFI_TEXT_ENABLE_CURSOR EnableCursor; - SIMPLE_TEXT_OUTPUT_MODE *Mode; -} EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL; -``` -Right now we are interested in a `OutputString` method: -``` -OutputString Displays the string on the device at the current cursor location. -``` -This is what we need. Let's look at the function description: -``` -EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL.OutputString() - -Summary -Writes a string to the output device. - -Prototype -typedef -EFI_STATUS -(EFIAPI *EFI_TEXT_STRING) ( - IN EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL *This, - IN CHAR16 *String - ); - -Parameters -This A pointer to the EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL instance. -String The Null-terminated string to be displayed on the output device(s). -``` - -In edk2 `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL` is defined in the header file: -https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Protocol/SimpleTextOut.h - - -With all this knowledge we can write our source code file `UefiLessonsPkg/HelloWorld/HelloWorld.c`: -``` -EFI_STATUS -EFIAPI -UefiMain ( - IN EFI_HANDLE ImageHandle, - IN EFI_SYSTEM_TABLE *SystemTable - ) -{ - SystemTable->ConOut->OutputString(SystemTable->ConOut, L"Hello World!\n"); - return EFI_SUCCESS; -} -``` - -The `L""` signifies that the string is composed from CHAR16 symbols, as was required in spec. - -Let's compile our edk2 module: -``` -$ build --platform=UefiLessonsPkg/UefiLessonsPkg.dsc \ - --module=UefiLessonsPkg/HelloWorld/HelloWorld.inf \ - --arch=X64 \ - --buildtarget=RELEASE --tagname=GCC5 -``` - -Copy the app to our `UEFI_disk` folder and run OVMF: -``` -$ cp Build/UefiLessonsPkg/RELEASE_GCC5/X64/HelloWorld.efi ~/UEFI_disk/ -$ qemu-system-x86_64 -drive if=pflash,format=raw,file=Build/OvmfX64/RELEASE_GCC5/FV/OVMF.fd \ - -drive format=raw,file=fat:rw:~/UEFI_disk \ - -nographic \ - -net none -``` - -``` -UEFI Interactive Shell v2.2 -EDK II -UEFI v2.70 (EDK II, 0x00010000) -Mapping table - FS0: Alias(s):HD0a1:;BLK1: - PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)/HD(1,MBR,0xBE1AFDFA,0x3F,0xFBFC1) - BLK0: Alias(s): - PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0) - BLK2: Alias(s): - PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0) -Press ESC in 4 seconds to skip startup.nsh or any other key to continue. -Shell> fs0: -FS0:\> HelloWorld.efi -Hello World! -FS0:\> -``` -- cgit v1.2.3-18-g5258