Handout

kernel/boot/multiboot/data.cc

@@ -0,0 +1,160 @@
+#include "./data.h"
+
+/*! \brief Multiboot Information Structure according to Specification
+ * \see [Multiboot Specification]{@ref multiboot}
+ */
+struct multiboot_info {
+	/*! \brief Helper Structure
+	 */
+	struct Array {
+		uint32_t size;	///< Length
+		uint32_t addr;	///< Begin (physical address)
+	} __attribute__((packed));
+
+	enum Flag : uint32_t {
+		Memory = 1 << 0,   ///< is there basic lower/upper memory information?
+		BootDev = 1 << 1,  ///< is there a boot device set?
+		CmdLine = 1 << 2,  ///< is the command-line defined?
+		Modules = 1 << 3,  ///< are there modules to do something with?
+		/* These next two are mutually exclusive */
+		SymbolTable = 1 << 4,	 ///< is there an a.out symbol table loaded?
+		SectionHeader = 1 << 5,	 ///< is there an ELF section header table?
+
+		MemoryMap = 1 << 6,		  ///< is there a full memory map?
+		DriveInfo = 1 << 7,		  ///< Is there drive info?
+		ConfigTable = 1 << 8,	  ///< Is there a config table?
+		BootLoaderName = 1 << 9,  ///< Is there a boot loader name?
+		ApmTable = 1 << 10,		  ///< Is there a APM table?
+
+		// Is there video information?
+		VbeInfo = 1 << 11,		   ///< Vesa bios extension
+		FramebufferInfo = 1 << 12  ///< Framebuffer
+	} flags;
+
+	/*! \brief Available memory retrieved from BIOS
+	 */
+	struct {
+		uint32_t lower;	 ///< Amount of memory below 1 MiB in kilobytes
+		uint32_t upper;	 ///< Amount of memory above 1 MiB in kilobytes
+	} mem __attribute__((packed));
+	uint32_t boot_device;  ///< "root" partition
+	uint32_t cmdline;	   ///< Kernel command line
+	Array mods;			   ///< List of boot modules
+	union {
+		/*! \brief Symbol table for kernel in a.out format
+		 */
+		struct {
+			uint32_t tabsize;
+			uint32_t strsize;
+			uint32_t addr;
+			uint32_t reserved;
+		} aout_symbol_table __attribute__((packed));
+
+		/*! \brief Section header table for kernel in ELF
+		 */
+		struct {
+			uint32_t num;	 ///< Number of entries
+			uint32_t size;	 ///< Size per entry
+			uint32_t addr;	 ///< Start of the header table
+			uint32_t shndx;	 ///< String table index
+		} elf_section_header_table __attribute__((packed));
+	};
+
+	struct Array mmap;			///< Memory Map
+	struct Array drives;		///< Drive Information
+	uint32_t config_table;		///< ROM configuration table
+	uint32_t boot_loader_name;	///< Boot Loader Name
+	uint32_t apm_table;			///< APM table
+
+	struct Multiboot::VBE vbe;					///< VBE Information
+	struct Multiboot::Framebuffer framebuffer;	///< Framebuffer information
+
+	/*! \brief Check if setting is available
+	 * \param flag Flag to check
+	 * \return `true` if available
+	 */
+	bool has(enum Flag flag) const { return (flags & flag) != 0; }
+} __attribute__((packed));
+assert_size(multiboot_info, 116);
+
+/*! \brief The pointer to the multiboot structures will be assigned in the
+ * assembler startup code (multiboot.inc)
+ */
+struct multiboot_info *multiboot_addr = 0;
+
+namespace Multiboot {
+Module *getModule(unsigned i) {
+	if (multiboot_addr != nullptr &&
+		multiboot_addr->has(multiboot_info::Flag::Modules) &&
+		i < multiboot_addr->mods.size) {
+		return i + reinterpret_cast<Module *>(
+					   static_cast<uintptr_t>(multiboot_addr->mods.addr));
+	} else {
+		return nullptr;
+	}
+}
+
+unsigned getModuleCount() { return multiboot_addr->mods.size; }
+
+void *Memory::getStartAddress() const {
+	return reinterpret_cast<void *>(static_cast<uintptr_t>(addr));
+}
+
+void *Memory::getEndAddress() const {
+	uint64_t end = addr + len;
+	return reinterpret_cast<void *>(static_cast<uintptr_t>(end));
+}
+
+bool Memory::isAvailable() const { return type == AVAILABLE; }
+
+Memory *Memory::getNext() const {
+	if (multiboot_addr != nullptr &&
+		multiboot_addr->has(multiboot_info::Flag::MemoryMap)) {
+		uintptr_t next =
+			reinterpret_cast<uintptr_t>(this) + size + sizeof(size);
+		if (next < multiboot_addr->mmap.addr + multiboot_addr->mmap.size) {
+			return reinterpret_cast<Memory *>(next);
+		}
+	}
+	return nullptr;
+}
+
+Memory *getMemoryMap() {
+	if (multiboot_addr != nullptr &&
+		multiboot_addr->has(multiboot_info::Flag::MemoryMap) &&
+		multiboot_addr->mmap.size > 0) {
+		return reinterpret_cast<Memory *>(
+			static_cast<uintptr_t>(multiboot_addr->mmap.addr));
+	} else {
+		return nullptr;
+	}
+}
+
+char *getCommandLine() {
+	return reinterpret_cast<char *>(
+		static_cast<uintptr_t>(multiboot_addr->cmdline));
+}
+
+char *getBootLoader() {
+	return reinterpret_cast<char *>(
+		static_cast<uintptr_t>(multiboot_addr->boot_loader_name));
+}
+
+VBE *getVesaBiosExtensionInfo() {
+	if (multiboot_addr != nullptr &&
+		multiboot_addr->has(multiboot_info::Flag::VbeInfo)) {
+		return &(multiboot_addr->vbe);
+	} else {
+		return nullptr;
+	}
+}
+
+Framebuffer *getFramebufferInfo() {
+	if (multiboot_addr != nullptr &&
+		multiboot_addr->has(multiboot_info::Flag::FramebufferInfo)) {
+		return &(multiboot_addr->framebuffer);
+	} else {
+		return nullptr;
+	}
+}
+}  // namespace Multiboot