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Retrieve multiboot information from bootloader

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This commit is contained in:
Mathieu Maret 2018-08-05 15:09:32 +02:00
parent 89837e03bf
commit d51fff2d9d
4 changed files with 313 additions and 1 deletions
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10
boot.asm
View File

@ -73,6 +73,16 @@ _start:
; stack since (pushed 0 bytes so far) and the alignment is thus
; preserved and the call is well defined.
; note, that if you are building on Windows, C functions may have "_" prefix in assembly: _kernel_main
; Reset EFLAGS.
push dword 0
popf
; Push the pointer to the Multiboot information structure.
push ebx
; Push the magic value.
push eax
extern kmain
call kmain

9
boot.s
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@ -77,6 +77,11 @@ _start:
runtime support to work as well.
*/
/* Reset EFLAGS. */
pushl $0
popf
/*
Enter the high-level kernel. The ABI requires the stack is 16-byte
aligned at the time of the call instruction (which afterwards pushes
@ -85,6 +90,10 @@ _start:
stack since (pushed 0 bytes so far) and the alignment is thus
preserved and the call is well defined.
*/
/* Push the pointer to the Multiboot information structure. */
pushl %ebx
/* Push the magic value. */
pushl %eax
call kmain
/*

32
core/main.c
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@ -4,16 +4,20 @@
#include "interrupt.h"
#include "io.h"
#include "irq.h"
#include "multiboot.h"
#include "pit.h"
#include "types.h"
#include "vga.h"
#define CHECK_FLAG(flags,bit) ((flags) & (1 << (bit)))
void cpuid(int code, uint32_t *a, uint32_t *d)
{
asm volatile("cpuid" : "=a"(*a), "=d"(*d) : "0"(code) : "ebx", "ecx");
}
void kmain()
// Multiboot information available here : https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#kernel_002ec
void kmain(unsigned long magic, unsigned long addr)
{
initVGA(BLACK, GREEN);
printString("Setting up IDT\n");
@ -22,6 +26,32 @@ void kmain()
irqSetup();
initPit(100);
if (magic == MULTIBOOT_BOOTLOADER_MAGIC) { // Get loaded by Grub wuth mutliboot version 1
multiboot_info_t *mbi = (multiboot_info_t *)addr;
/* Are mem_* valid? */
if (CHECK_FLAG(mbi->flags, 0)){
printString("mem_lower = ");
printInt((unsigned)mbi->mem_lower);
printString("KB mem_upper = ");
printInt((unsigned)mbi->mem_upper);
printString("KB\n");
}
/* Is boot_device valid? */
if (CHECK_FLAG(mbi->flags, 1)){
printString("boot_device = ");
printInt((unsigned)mbi->boot_device);
printString("\n");
}
/* Is the command line passed? */
if (CHECK_FLAG(mbi->flags, 2)){
printString("cmdline = ");
printString((char *)mbi->cmdline);
printString("\n");
}
}
printString("Setting up IRQ handlers\n");
irqSetRoutine(IRQ_KEYBOARD, keyboard_handler);
irqSetRoutine(IRQ_TIMER, timer_handler);

263
core/multiboot.h Normal file
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@ -0,0 +1,263 @@
// Taken from https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#multiboot_002eh
/* 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
#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;
/* 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 /* ! ASM_FILE */
#endif /* ! MULTIBOOT_HEADER */