x86/multiboot: add multiboot header

Unfortunately, GNU AS doesn't perform GCC-like preprocessing. So, to
include the multiboot header in the assembly code, we should parse
and format it to GAS-style.

3 files changed, 300 insertions, 6 deletions

diff --git a/arch/x86/boot/multiboot/Makefile b/arch/x86/boot/multiboot/Makefile
new file mode 100644
index 0000000..995237d
--- /dev/null
+++ b/arch/x86/boot/multiboot/Makefile
@@ -0,0 +1,25 @@
+# If you want run this makefile immediately, then set environment
+# variables (CC, LD, AS, OBJDUMP) to path of your cross-compiler.
+#
+# The best way to build multiboot header is to run the corresponding
+# target in the main Makefile, which is in the root of the
+# project (.../path/to/os/Makefile)
+
+MULTIBOOT_HEADER = $(ARCH_INCLUDE)/multiboot.h
+BARE_MULTIBOOT_HEADER = bare_multiboot.h
+
+.PHONY: all clean
+
+all: $(BARE_MULTIBOOT_HEADER)
+
+$(BARE_MULTIBOOT_HEADER): $(MULTIBOOT_HEADER)
+	$(CC) -E -dM -undef -fsyntax-only $(MULTIBOOT_HEADER) > $(BARE_MULTIBOOT_HEADER)
+# Delete all defines that have double underscore
+	sed -i '/__/d' $(BARE_MULTIBOOT_HEADER)
+# Replace "#define" with ".set" on each line
+	sed -i 's/#define/.set/g' $(BARE_MULTIBOOT_HEADER)
+# Put a comma after the macro name
+	sed -i 's/\>/,/2' $(BARE_MULTIBOOT_HEADER)
+
+clean:
+	rm $(BARE_MULTIBOOT_HEADER)
diff --git a/arch/x86/boot/multiboot/multiboot.s b/arch/x86/boot/multiboot/multiboot.s
index 33e54f1..e6e8c21 100644
--- a/arch/x86/boot/multiboot/multiboot.s
+++ b/arch/x86/boot/multiboot/multiboot.s
@@ -1,13 +1,12 @@
 # https://www.gnu.org/software/grub/manual/multiboot/multiboot.html
 
+.include "bare_multiboot.h" # the file is auto-generated
+
 /*
 Declare constants for the multiboot header.
 */
-.set ALIGN,		1 << 0				# align loaded modules on page boundaries
-.set MEMINFO,	1 << 1				# provide memory map
-.set FLAGS,		ALIGN | MEMINFO		# this is the Multiboot 'flag' field
-.set MAGIC,		0x1BADB002			# 'magic number' lets bootloader find the header
-.set CHECKSUM,	-(MAGIC + FLAGS)	# checksum of above, to prove we are multiboot
+.set FLAGS,	MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO	# this is the Multiboot 'flag' field
+.set CHECKSUM,	-(MULTIBOOT_HEADER_MAGIC + FLAGS)		# checksum of above, to prove we are multiboot
 
 /*
 Declare a multiboot header that marks the program as a kernel.
@@ -19,7 +18,7 @@ its own section so the header can be forced to be within the first
 */
 .section .multiboot
 .align 4
-.long MAGIC
+.long MULTIBOOT_HEADER_MAGIC
 .long FLAGS
 .long CHECKSUM
 
diff --git a/arch/x86/include/multiboot.h b/arch/x86/include/multiboot.h
new file mode 100644
index 0000000..522a249
--- /dev/null
+++ b/arch/x86/include/multiboot.h
@@ -0,0 +1,270 @@
+/* multiboot.h - Multiboot 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			8192
+#define MULTIBOOT_HEADER_ALIGN			4
+
+/* The magic field should contain this. */
+#define MULTIBOOT_HEADER_MAGIC			0x1BADB002
+
+/* This should be in %eax. */
+#define MULTIBOOT_BOOTLOADER_MAGIC		0x2BADB002
+
+/* Alignment of multiboot modules. */
+#define MULTIBOOT_MOD_ALIGN			0x00001000
+
+/* Alignment of the multiboot info structure. */
+#define MULTIBOOT_INFO_ALIGN			0x00000004
+
+/* Flags set in the ’flags’ member of the multiboot header. */
+
+/* Align all boot modules on i386 page (4KB) boundaries. */
+#define MULTIBOOT_PAGE_ALIGN			0x00000001
+
+/* Must pass memory information to OS. */
+#define MULTIBOOT_MEMORY_INFO			0x00000002
+
+/* Must pass video information to OS. */
+#define MULTIBOOT_VIDEO_MODE			0x00000004
+
+/* This flag indicates the use of the address fields in the header. */
+#define MULTIBOOT_AOUT_KLUDGE			0x00010000
+
+/* Flags to be set in the ’flags’ member of the multiboot info structure. */
+
+/* is there basic lower/upper memory information? */
+#define MULTIBOOT_INFO_MEMORY			0x00000001
+/* is there a boot device set? */
+#define MULTIBOOT_INFO_BOOTDEV			0x00000002
+/* is the command-line defined? */
+#define MULTIBOOT_INFO_CMDLINE			0x00000004
+/* are there modules to do something with? */
+#define MULTIBOOT_INFO_MODS			0x00000008
+
+/* These next two are mutually exclusive */
+
+/* is there a symbol table loaded? */
+#define MULTIBOOT_INFO_AOUT_SYMS		0x00000010
+/* is there an ELF section header table? */
+#define MULTIBOOT_INFO_ELF_SHDR			0X00000020
+
+/* is there a full memory map? */
+#define MULTIBOOT_INFO_MEM_MAP			0x00000040
+
+/* Is there drive info? */
+#define MULTIBOOT_INFO_DRIVE_INFO		0x00000080
+
+/* Is there a config table? */
+#define MULTIBOOT_INFO_CONFIG_TABLE		0x00000100
+
+/* Is there a boot loader name? */
+#define MULTIBOOT_INFO_BOOT_LOADER_NAME		0x00000200
+
+/* Is there a APM table? */
+#define MULTIBOOT_INFO_APM_TABLE		0x00000400
+
+/* Is there video information? */
+#define MULTIBOOT_INFO_VBE_INFO			0x00000800
+#define MULTIBOOT_INFO_FRAMEBUFFER_INFO		0x00001000
+
+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;
+
+	/* Feature flags. */
+	multiboot_uint32_t flags;
+
+	/* The above fields plus this one must equal 0 mod 2^32. */
+	multiboot_uint32_t checksum;
+
+	/* These are only valid if MULTIBOOT_AOUT_KLUDGE is set. */
+	multiboot_uint32_t header_addr;
+	multiboot_uint32_t load_addr;
+	multiboot_uint32_t load_end_addr;
+	multiboot_uint32_t bss_end_addr;
+	multiboot_uint32_t entry_addr;
+
+	/* These are only valid if MULTIBOOT_VIDEO_MODE is set. */
+	multiboot_uint32_t mode_type;
+	multiboot_uint32_t width;
+	multiboot_uint32_t height;
+	multiboot_uint32_t depth;
+};
+
+/* The symbol table for a.out. */
+struct multiboot_aout_symbol_table
+{
+	multiboot_uint32_t tabsize;
+	multiboot_uint32_t strsize;
+	multiboot_uint32_t addr;
+	multiboot_uint32_t reserved;
+};
+typedef struct multiboot_aout_symbol_table multiboot_aout_symbol_table_t;
+
+/* The section header table for ELF. */
+struct multiboot_elf_section_header_table
+{
+	multiboot_uint32_t num;
+	multiboot_uint32_t size;
+	multiboot_uint32_t addr;
+	multiboot_uint32_t shndx;
+};
+typedef struct multiboot_elf_section_header_table multiboot_elf_section_header_table_t;
+
+struct multiboot_info
+{
+	/* Multiboot info version number */
+	multiboot_uint32_t flags;
+
+	/* Available memory from BIOS */
+	multiboot_uint32_t mem_lower;
+	multiboot_uint32_t mem_upper;
+
+	/* "root" partition */
+	multiboot_uint32_t boot_device;
+
+	/* Kernel command line */
+	multiboot_uint32_t cmdline;
+
+	/* Boot-Module list */
+	multiboot_uint32_t mods_count;
+	multiboot_uint32_t mods_addr;
+
+	union
+	{
+		multiboot_aout_symbol_table_t aout_sym;
+		multiboot_elf_section_header_table_t elf_sec;
+	} u;
+
+	/* Memory Mapping buffer */
+	multiboot_uint32_t mmap_length;
+	multiboot_uint32_t mmap_addr;
+
+	/* Drive Info buffer */
+	multiboot_uint32_t drives_length;
+	multiboot_uint32_t drives_addr;
+
+	/* ROM configuration table */
+	multiboot_uint32_t config_table;
+
+	/* Boot Loader Name */
+	multiboot_uint32_t boot_loader_name;
+
+	/* APM table */
+	multiboot_uint32_t apm_table;
+
+	/* Video */
+	multiboot_uint32_t vbe_control_info;
+	multiboot_uint32_t vbe_mode_info;
+	multiboot_uint16_t vbe_mode;
+	multiboot_uint16_t vbe_interface_seg;
+	multiboot_uint16_t vbe_interface_off;
+	multiboot_uint16_t vbe_interface_len;
+
+	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;
+	union
+	{
+		struct
+		{
+			multiboot_uint32_t framebuffer_palette_addr;
+			multiboot_uint16_t framebuffer_palette_num_colors;
+		};
+		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;
+		};
+	};
+};
+typedef struct multiboot_info multiboot_info_t;
+
+struct multiboot_color
+{
+	multiboot_uint8_t red;
+	multiboot_uint8_t green;
+	multiboot_uint8_t blue;
+};
+
+struct multiboot_mmap_entry
+{
+	multiboot_uint32_t size;
+	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;
+} __attribute__((packed));
+typedef struct multiboot_mmap_entry multiboot_memory_map_t;
+
+struct multiboot_mod_list
+{
+	/* the memory used goes from bytes ’mod_start’ to ’mod_end-1’ inclusive */
+	multiboot_uint32_t mod_start;
+	multiboot_uint32_t mod_end;
+
+	/* Module command line */
+	multiboot_uint32_t cmdline;
+
+	/* padding to take it to 16 bytes (must be zero) */
+	multiboot_uint32_t pad;
+};
+typedef struct multiboot_mod_list multiboot_module_t;
+
+/* APM BIOS info. */
+struct multiboot_apm_info
+{
+	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;
+};
+
+#endif /* ! MULTIBOOT_HEADER */