feat: some clean up and validation of multiboot header

CMakeLists.txt

@@ -1,17 +1,12 @@
 cmake_minimum_required(VERSION 3.15)
 project(new_kernel C ASM)
-#set(CMAKE_VERBOSE_MAKEFILE ON)
+#SET(CMAKE_VERBOSE_MAKEFILE ON)
-set(CMAKE_C_FLAGS "-I/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/include -mno-sse -g -ffreestanding -Wall -Wextra -fno-exceptions -fno-stack-protector -nostdinc -nostdlib -fno-pie -m32")
+SET(GCC_INCLUDE_DIR "/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/include")
-#set(CMAKE_ASM_NASM_OBJECT_FORMAT "elf")
+SET(CMAKE_C_FLAGS "-I${GCC_INCLUDE_DIR} -mno-sse -g -ffreestanding -Wall -Wextra -fno-exceptions -fno-stack-protector -nostdinc -nostdlib -fno-pie -m32")
-set(CMAKE_ASM_FLAGS --32)
+SET(CMAKE_ASM_FLAGS "${CFLAGS} -m32 -x assembler-with-cpp" )
-#set(CMAKE_ASM-ATT_FLAGS --32)
+SET(CMAKE_EXE_LINKER_FLAGS "-T${CMAKE_CURRENT_LIST_DIR}/linker.ld -lgcc -ffreestanding -nostdlib -no-pie")
-SET(CMAKE_EXE_LINKER_FLAGS "-T${CMAKE_CURRENT_LIST_DIR}/linker.ld -lgcc -ffreestanding -nostdlib")
-set(CMAKE_ASM_COMPILER "/usr/bin/as")
-#ENABLE_LANGUAGE(ASM_NASM)
-#enable_language(ASM)
 
 include_directories(AFTER kernel boot)
-include_directories("/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/include")
 
 set(CMAKE_C_STANDARD 99)
 
@@ -19,7 +14,10 @@ FILE(GLOB_RECURSE kernel_src kernel/**.c)
 FILE(GLOB_RECURSE kernel_asm kernel/**.S)
 FILE(GLOB_RECURSE boot_asm boot/boot.S)
 
+# Run IDE in DMA mode if available (NYI)
 #add_compile_definitions(IDE_ENABLE_INTERRUPT)
+# Run the kernel shell as the main task
+add_compile_definitions(K_SHELL)
 
 add_executable(my-kernel.bin ${kernel_src} ${kernel_asm} ${boot_asm})
 set_source_files_properties(${kernel_src} PROPERTIES LANGUAGE C COMPILE_FLAGS "")

boot/boot.S

@@ -78,7 +78,9 @@ _start:
 	mov $stack_top, %esp
 
 	// store multiboot on stack
-	pushl %ebx
+	pushl 0
+	pushl %eax // MB code
+	pushl %ebx // MB structure
 
 	/*
 	This is a good place to initialize crucial processor state before the

kernel/kernel.c

@@ -49,7 +49,8 @@ void init_block_devices() {
     fat_register_block_driver();
 }
 
-void noreturn kmain(multiboot_info_t *multiboot_info) {
+void noreturn kmain(multiboot_info_t *multiboot_info, uint32_t mb_name) {
+    // early init
     isr_install();
     vga_clear_screen();
     vga_clear_screen(' ', VGA_WHITE | (VGA_GRAY << VGA_SHIFT_BG));
@@ -57,25 +58,42 @@ void noreturn kmain(multiboot_info_t *multiboot_info) {
     serial_init();
     kprint_register(serial_kprint);
 
+    // parse multiboot
+    if (mb_name != MULTIBOOT_BOOTLOADER_MAGIC) {
+        k_panics("Not booted by multiboot\n");
+    }
+
     store_bootloader_info(multiboot_info);
+
+    // initialize memory management
     init_mmap(multiboot_info);
 
+    // initialize kprint functionality
     kprint_init();
 
+    // identify cpu
     cpuidx_print_info();
 
-    // init done, enable interrupts
+    // enable interrupts
     __asm__ __volatile__("sti");
+    // start the timer
     init_timer(1000);
+    // initialize devices
     init_keyboard();
     init_pci_system();
+
+    // register block device drivers
     init_block_devices();
 
     printf("Booted successfully v%d.%d.%d\n", version_major, version_minor, version_patch);
 
+    // initialize tasking
     task_init();
     kprint_start_task();
     block_dev_start_task();
+#ifdef K_SHELL
     task_spawn(main_loop, NULL);
+#endif
+    // switch to tasking
     syscall_start_scheduler();
 }

kernel/libk/kprint.c

@@ -50,6 +50,10 @@ void kprint_internal(const char *msg) {
     }
 }
 
+void kprint_sync(const char* msg) {
+    kprint_internal(msg);
+}
+
 void kprint_init() {
     kprint_stream = stream_create(STREAM_SIZE);
 }

kernel/libk/kprint.h

@@ -15,6 +15,8 @@ void kprint_register(kprint_handler);
 
 void kprint(const char *msg);
 
+void kprint_sync(const char* msg);
+
 void kprint_init();
 
 void kprint_start_task();

kernel/libk/libk.c

@@ -17,12 +17,12 @@ void k_wait_for_interrupt() {
 
 void noreturn k_panics(const char *msg) {
     // todo this is not printed
-    kprint(msg);
+    kprint_sync(msg);
     k_panic();
 }
 
 void noreturn k_panic() {
-    kprint("PANIC!");
+    kprint_sync("PANIC!");
     while (true) {
         __asm__ __volatile__("cli;"
                              "hlt;");

kernel/multiboot2.h

@@ -0,0 +1,380 @@
+/*   multiboot2.h - Multiboot 2 header file. */
+/*   Copyright (C) 1999,2003,2007,2008,2009,2010  Free Software Foundation, Inc.
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to
+ *  deal in the Software without restriction, including without limitation the
+ *  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ *  sell copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL ANY
+ *  DEVELOPER OR DISTRIBUTOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+ *  IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef MULTIBOOT_HEADER
+#define MULTIBOOT_HEADER 1
+
+/*  How many bytes from the start of the file we search for the header. */
+#define MULTIBOOT_SEARCH                        32768
+#define MULTIBOOT_HEADER_ALIGN                  8
+
+/*  The magic field should contain this. */
+#define MULTIBOOT2_HEADER_MAGIC                 0xe85250d6
+
+/*  This should be in %eax. */
+#define MULTIBOOT2_BOOTLOADER_MAGIC             0x36d76289
+
+/*  Alignment of multiboot modules. */
+#define MULTIBOOT_MOD_ALIGN                     0x00001000
+
+/*  Alignment of the multiboot info structure. */
+#define MULTIBOOT_INFO_ALIGN                    0x00000008
+
+/*  Flags set in the ’flags’ member of the multiboot header. */
+
+#define MULTIBOOT_TAG_ALIGN                  8
+#define MULTIBOOT_TAG_TYPE_END               0
+#define MULTIBOOT_TAG_TYPE_CMDLINE           1
+#define MULTIBOOT_TAG_TYPE_BOOT_LOADER_NAME  2
+#define MULTIBOOT_TAG_TYPE_MODULE            3
+#define MULTIBOOT_TAG_TYPE_BASIC_MEMINFO     4
+#define MULTIBOOT_TAG_TYPE_BOOTDEV           5
+#define MULTIBOOT_TAG_TYPE_MMAP              6
+#define MULTIBOOT_TAG_TYPE_VBE               7
+#define MULTIBOOT_TAG_TYPE_FRAMEBUFFER       8
+#define MULTIBOOT_TAG_TYPE_ELF_SECTIONS      9
+#define MULTIBOOT_TAG_TYPE_APM               10
+#define MULTIBOOT_TAG_TYPE_EFI32             11
+#define MULTIBOOT_TAG_TYPE_EFI64             12
+#define MULTIBOOT_TAG_TYPE_SMBIOS            13
+#define MULTIBOOT_TAG_TYPE_ACPI_OLD          14
+#define MULTIBOOT_TAG_TYPE_ACPI_NEW          15
+#define MULTIBOOT_TAG_TYPE_NETWORK           16
+#define MULTIBOOT_TAG_TYPE_EFI_MMAP          17
+#define MULTIBOOT_TAG_TYPE_EFI_BS            18
+#define MULTIBOOT_TAG_TYPE_EFI32_IH          19
+#define MULTIBOOT_TAG_TYPE_EFI64_IH          20
+#define MULTIBOOT_TAG_TYPE_LOAD_BASE_ADDR    21
+
+#define MULTIBOOT_HEADER_TAG_END  0
+#define MULTIBOOT_HEADER_TAG_INFORMATION_REQUEST  1
+#define MULTIBOOT_HEADER_TAG_ADDRESS  2
+#define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS  3
+#define MULTIBOOT_HEADER_TAG_CONSOLE_FLAGS  4
+#define MULTIBOOT_HEADER_TAG_FRAMEBUFFER  5
+#define MULTIBOOT_HEADER_TAG_MODULE_ALIGN  6
+#define MULTIBOOT_HEADER_TAG_EFI_BS        7
+#define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS_EFI32  8
+#define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS_EFI64  9
+#define MULTIBOOT_HEADER_TAG_RELOCATABLE  10
+
+#define MULTIBOOT_ARCHITECTURE_I386  0
+#define MULTIBOOT_ARCHITECTURE_MIPS32  4
+#define MULTIBOOT_HEADER_TAG_OPTIONAL 1
+
+#define MULTIBOOT_LOAD_PREFERENCE_NONE 0
+#define MULTIBOOT_LOAD_PREFERENCE_LOW 1
+#define MULTIBOOT_LOAD_PREFERENCE_HIGH 2
+
+#define MULTIBOOT_CONSOLE_FLAGS_CONSOLE_REQUIRED 1
+#define MULTIBOOT_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED 2
+
+#ifndef ASM_FILE
+
+typedef unsigned char multiboot_uint8_t;
+typedef unsigned short multiboot_uint16_t;
+typedef unsigned int multiboot_uint32_t;
+typedef unsigned long long multiboot_uint64_t;
+
+struct multiboot_header {
+    /*  Must be MULTIBOOT_MAGIC - see above. */
+    multiboot_uint32_t magic;
+
+    /*  ISA */
+    multiboot_uint32_t architecture;
+
+    /*  Total header length. */
+    multiboot_uint32_t header_length;
+
+    /*  The above fields plus this one must equal 0 mod 2^32. */
+    multiboot_uint32_t checksum;
+};
+
+struct multiboot_header_tag {
+    multiboot_uint16_t type;
+    multiboot_uint16_t flags;
+    multiboot_uint32_t size;
+};
+
+struct multiboot_header_tag_information_request {
+    multiboot_uint16_t type;
+    multiboot_uint16_t flags;
+    multiboot_uint32_t size;
+    multiboot_uint32_t requests[0];
+};
+
+struct multiboot_header_tag_address {
+    multiboot_uint16_t type;
+    multiboot_uint16_t flags;
+    multiboot_uint32_t size;
+    multiboot_uint32_t header_addr;
+    multiboot_uint32_t load_addr;
+    multiboot_uint32_t load_end_addr;
+    multiboot_uint32_t bss_end_addr;
+};
+
+struct multiboot_header_tag_entry_address {
+    multiboot_uint16_t type;
+    multiboot_uint16_t flags;
+    multiboot_uint32_t size;
+    multiboot_uint32_t entry_addr;
+};
+
+struct multiboot_header_tag_console_flags {
+    multiboot_uint16_t type;
+    multiboot_uint16_t flags;
+    multiboot_uint32_t size;
+    multiboot_uint32_t console_flags;
+};
+
+struct multiboot_header_tag_framebuffer {
+    multiboot_uint16_t type;
+    multiboot_uint16_t flags;
+    multiboot_uint32_t size;
+    multiboot_uint32_t width;
+    multiboot_uint32_t height;
+    multiboot_uint32_t depth;
+};
+
+struct multiboot_header_tag_module_align {
+    multiboot_uint16_t type;
+    multiboot_uint16_t flags;
+    multiboot_uint32_t size;
+};
+
+struct multiboot_header_tag_relocatable {
+    multiboot_uint16_t type;
+    multiboot_uint16_t flags;
+    multiboot_uint32_t size;
+    multiboot_uint32_t min_addr;
+    multiboot_uint32_t max_addr;
+    multiboot_uint32_t align;
+    multiboot_uint32_t preference;
+};
+
+struct multiboot_color {
+    multiboot_uint8_t red;
+    multiboot_uint8_t green;
+    multiboot_uint8_t blue;
+};
+
+struct multiboot_mmap_entry {
+    multiboot_uint64_t addr;
+    multiboot_uint64_t len;
+#define MULTIBOOT_MEMORY_AVAILABLE              1
+#define MULTIBOOT_MEMORY_RESERVED               2
+#define MULTIBOOT_MEMORY_ACPI_RECLAIMABLE       3
+#define MULTIBOOT_MEMORY_NVS                    4
+#define MULTIBOOT_MEMORY_BADRAM                 5
+    multiboot_uint32_t type;
+    multiboot_uint32_t zero;
+};
+typedef struct multiboot_mmap_entry multiboot_memory_map_t;
+
+struct multiboot_tag {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+};
+
+struct multiboot_tag_string {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    char string[0];
+};
+
+struct multiboot_tag_module {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t mod_start;
+    multiboot_uint32_t mod_end;
+    char cmdline[0];
+};
+
+struct multiboot_tag_basic_meminfo {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t mem_lower;
+    multiboot_uint32_t mem_upper;
+};
+
+struct multiboot_tag_bootdev {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t biosdev;
+    multiboot_uint32_t slice;
+    multiboot_uint32_t part;
+};
+
+struct multiboot_tag_mmap {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t entry_size;
+    multiboot_uint32_t entry_version;
+    struct multiboot_mmap_entry entries[0];
+};
+
+struct multiboot_vbe_info_block {
+    multiboot_uint8_t external_specification[512];
+};
+
+struct multiboot_vbe_mode_info_block {
+    multiboot_uint8_t external_specification[256];
+};
+
+struct multiboot_tag_vbe {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+
+    multiboot_uint16_t vbe_mode;
+    multiboot_uint16_t vbe_interface_seg;
+    multiboot_uint16_t vbe_interface_off;
+    multiboot_uint16_t vbe_interface_len;
+
+    struct multiboot_vbe_info_block vbe_control_info;
+    struct multiboot_vbe_mode_info_block vbe_mode_info;
+};
+
+struct multiboot_tag_framebuffer_common {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+
+    multiboot_uint64_t framebuffer_addr;
+    multiboot_uint32_t framebuffer_pitch;
+    multiboot_uint32_t framebuffer_width;
+    multiboot_uint32_t framebuffer_height;
+    multiboot_uint8_t framebuffer_bpp;
+#define MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED 0
+#define MULTIBOOT_FRAMEBUFFER_TYPE_RGB     1
+#define MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT     2
+    multiboot_uint8_t framebuffer_type;
+    multiboot_uint16_t reserved;
+};
+
+struct multiboot_tag_framebuffer {
+    struct multiboot_tag_framebuffer_common common;
+
+    union {
+        struct {
+            multiboot_uint16_t framebuffer_palette_num_colors;
+            struct multiboot_color framebuffer_palette[0];
+        };
+        struct {
+            multiboot_uint8_t framebuffer_red_field_position;
+            multiboot_uint8_t framebuffer_red_mask_size;
+            multiboot_uint8_t framebuffer_green_field_position;
+            multiboot_uint8_t framebuffer_green_mask_size;
+            multiboot_uint8_t framebuffer_blue_field_position;
+            multiboot_uint8_t framebuffer_blue_mask_size;
+        };
+    };
+};
+
+struct multiboot_tag_elf_sections {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t num;
+    multiboot_uint32_t entsize;
+    multiboot_uint32_t shndx;
+    char sections[0];
+};
+
+struct multiboot_tag_apm {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint16_t version;
+    multiboot_uint16_t cseg;
+    multiboot_uint32_t offset;
+    multiboot_uint16_t cseg_16;
+    multiboot_uint16_t dseg;
+    multiboot_uint16_t flags;
+    multiboot_uint16_t cseg_len;
+    multiboot_uint16_t cseg_16_len;
+    multiboot_uint16_t dseg_len;
+};
+
+struct multiboot_tag_efi32 {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t pointer;
+};
+
+struct multiboot_tag_efi64 {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint64_t pointer;
+};
+
+struct multiboot_tag_smbios {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint8_t major;
+    multiboot_uint8_t minor;
+    multiboot_uint8_t reserved[6];
+    multiboot_uint8_t tables[0];
+};
+
+struct multiboot_tag_old_acpi {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint8_t rsdp[0];
+};
+
+struct multiboot_tag_new_acpi {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint8_t rsdp[0];
+};
+
+struct multiboot_tag_network {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint8_t dhcpack[0];
+};
+
+struct multiboot_tag_efi_mmap {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t descr_size;
+    multiboot_uint32_t descr_vers;
+    multiboot_uint8_t efi_mmap[0];
+};
+
+struct multiboot_tag_efi32_ih {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t pointer;
+};
+
+struct multiboot_tag_efi64_ih {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint64_t pointer;
+};
+
+struct multiboot_tag_load_base_addr {
+    multiboot_uint32_t type;
+    multiboot_uint32_t size;
+    multiboot_uint32_t load_base_addr;
+};
+
+#endif /*  ! ASM_FILE */
+
+#endif /*  ! MULTIBOOT_HEADER */