feat(mbr): build mbr.bin separately

CMakeLists.txt

@@ -19,6 +19,12 @@ set(BOOTLOADER_SOURCES src/boot.s
 
 add_library(bootloader STATIC ${BOOTLOADER_SOURCES})
 
+add_custom_command(OUTPUT mbr.bin
+    DEPENDS ${PROJECT_SOURCE_DIR}/src/mbr.S ${PROJECT_SOURCE_DIR}/src/mbr.ld
+    COMMAND ${CMAKE_ASM_COMPILER} -m32 -c ${PROJECT_SOURCE_DIR}/src/mbr.S -o mbr.o
+    COMMAND ${CMAKE_LINKER} -T ${PROJECT_SOURCE_DIR}/src/mbr.ld mbr.o -o mbr.bin
+)
+
 add_custom_command(OUTPUT extracted_bootloader
     DEPENDS bootloader
     COMMAND ${CMAKE_AR} xf ${PROJECT_BINARY_DIR}/libbootloader.a --output=${EXTRACT_DIR}
@@ -99,8 +105,9 @@ add_custom_command(OUTPUT extracted_kernel_main
     COMMAND ${CMAKE_AR} xf ${PROJECT_BINARY_DIR}/libkernel_main.a --output=${EXTRACT_DIR}
 )
 
-add_custom_command(OUTPUT user_space_programs
-    COMMAND make -C ${CMAKE_SOURCE_DIR}/user-space-program all
+add_custom_target(user_space_programs
+    COMMAND cp ${CMAKE_SOURCE_DIR}/user-space-program/Makefile.src ${CMAKE_SOURCE_DIR}/user-space-program/Makefile
+    COMMAND make -C ${CMAKE_SOURCE_DIR}/user-space-program CROSS_COMPILE=${TOOLCHAIN_PATH_AND_PREFIX} all
     COMMAND mkdir -p ${CMAKE_SOURCE_DIR}/user-space-program/build
     COMMAND rm -f ${CMAKE_SOURCE_DIR}/user-space-program/build/*
     COMMAND cp ${CMAKE_SOURCE_DIR}/user-space-program/*.res ${CMAKE_SOURCE_DIR}/user-space-program/build
@@ -110,15 +117,23 @@ add_custom_target(kernel.out
     DEPENDS extracted_bootloader
     DEPENDS extracted_kernel_main
     DEPENDS user_space_programs
-    DEPENDS ${CMAKE_SOURCE_DIR}/ldscript.ld
-    COMMAND ${CMAKE_LINKER} -T ${CMAKE_SOURCE_DIR}/ldscript.ld ${EXTRACT_DIR}/*.o ${CMAKE_SOURCE_DIR}/user-space-program/user.sym
+    DEPENDS ${CMAKE_SOURCE_DIR}/src/kernel.ld
+    COMMAND ${CMAKE_LINKER} -T ${CMAKE_SOURCE_DIR}/src/kernel.ld ${EXTRACT_DIR}/*.o ${CMAKE_SOURCE_DIR}/user-space-program/user.sym
     -melf_i386 -o ${CMAKE_BINARY_DIR}/kernel.out
 )
 
-add_custom_target(boot.img
+add_custom_target(mbr_hole.bin
     DEPENDS kernel.out
-    COMMAND ${CMAKE_OBJCOPY} --strip-debug -O binary
-    ${CMAKE_BINARY_DIR}/kernel.out boot.img)
+    COMMAND ${CMAKE_OBJCOPY} --strip-debug -O binary ${CMAKE_BINARY_DIR}/kernel.out mbr_hole.bin
+)
+
+add_custom_target(boot.img
+    DEPENDS mbr.bin
+    DEPENDS mbr_hole.bin
+    COMMAND dd if=mbr.bin of=boot.img
+    COMMAND dd if=mbr_hole.bin of=boot.img oflag=append conv=notrunc
+    COMMAND dd if=/dev/zero of=boot.img bs=32M count=0 seek=1
+)
 
 add_custom_command(OUTPUT run
     POST_BUILD

src/boot.s

@@ -1,59 +1,5 @@
-.section .text.bootsect
-.code16
-
-# mbr
-
-.globl _start
-
-_start:
-    jmp $0x07c0, $(real_start-_start)
-
-real_start:
-    movw %cs, %ax
-    movw %ax, %ds
-    movw %ax, %es
-    movw %ax, %ss
-
-# perform a temporary stack
-    movw $(stack_base-_start), %ax
-    movw %ax, %bp
-    movw %ax, %sp
-
-    call read_data
-
-    ljmp $0x07e0, $(loader_start-loader_start)
-
-die:
-    hlt
-    jmp die
-
-read_data:
-    movw $(read_data_pack-_start), %si
-    mov $0x42, %ah
-    mov $0x80, %dl
-    int $0x13
-    ret
-
-string_hello:
-.string "Hello World!"
-
-read_data_pack:
-    .byte 0x10, 0
-# TODO!!!
-# read more!
-    .word 128    # block count (read 64k)
-    .word 0x0000 # offset address
-    .word 0x07e0 # segment address
-    .long 1      # LBA to read
-
-stack_edge:
-.space 128
-stack_base:
-
 .section .text.loader
-
-# loader
-
+.code16
 loader_start:
 # set segment registers
     movw %cs, %ax
@@ -83,7 +29,7 @@ _get_memory_size:
     movw %dx, %bx
 
 _get_memory_size_use_ax:
-    movl $(asm_mem_size_info-loader_start), %edx
+    movl $asm_mem_size_info, %edx
     movw %ax, (%edx)
     addw $2, %dx
     movw %bx, (%edx)
@@ -101,7 +47,7 @@ _e820_mem_map_load:
     movw %cs, %ax
     movw %ax, %es
 
-    movl $(asm_e820_mem_map-loader_start), %edi
+    movl $asm_e820_mem_map, %edi
 
     # clear ebx
     xorl %ebx, %ebx
@@ -128,24 +74,24 @@ _e820_mem_map_load_loop:
 
 _e820_mem_map_load_fin:
     movl (%esp), %eax
-    movl $(asm_e820_mem_map_count-loader_start), %edi
+    movl $asm_e820_mem_map_count, %edi
     movl %eax, (%edi)
 
-    movl $(asm_e820_mem_map_entry_size-loader_start), %edi
+    movl $asm_e820_mem_map_entry_size, %edi
     movl %ecx, (%edi)
 
     jmp _load_gdt
 
 _load_gdt:
     cli
-    lgdt (asm_gdt_descriptor-loader_start)
+    lgdt asm_gdt_descriptor
 
 # enable protection enable (PE) bit
     movl %cr0, %eax
     orl $1, %eax
     movl %eax, %cr0
 
-    ljmp $0x08, $0x7e00 + (start_32bit-loader_start)
+    ljmp $0x08, $start_32bit
 
 .code32
 
@@ -230,9 +176,8 @@ start_move_kernel:
     movl $__loader_end, %eax
     movl $__real_kernel_start, %ebx
 
-    movl $__kernel_text_and_data_size_offset, %ecx
+    movl $__p_kernel_text_and_data_size_addr, %ecx
     movl (%ecx), %ecx
-    addl $__loader_end, %ecx
     movl (%ecx), %ecx
 
 _move_kernel:
@@ -252,7 +197,7 @@ loader_halt:
 
 asm_gdt_descriptor:
     .word (5 * 8) - 1 # size
-    .long 0x7e00+(asm_gdt_table-loader_start)  # address
+    .long asm_gdt_table  # address
 
 .globl asm_gdt_descriptor
 .type asm_gdt_descriptor @object

ldscript.ld → src/kernel.ld

@@ -3,39 +3,25 @@ OUTPUT_ARCH(i386:i386)
 
 MEMORY
 {
-    WHOLE : org = 0x00000000, l = 4M
+    MEM : org = 0x00000000, l = 4096M
 }
 
 SECTIONS
 {
-    .text.bootsect : AT(0x00)
-    {
-        *(.text.bootsect)
-    } > WHOLE
-
-    .magicnumber : AT(0x1fe)
-    {
-        BYTE(0x55);
-        BYTE(0xaa);
-    } > WHOLE
-
-    .text.loader 0x7e00 : AT(0x200)
+    .text.loader 0x7e00 : AT(0x00000000)
     {
         *(.text.loader)
-        __kernel_text_and_data_size_offset = .;
-        LONG(LOADADDR(.data) - LOADADDR(.text));
+        __p_kernel_text_and_data_size_addr = .;
+        LONG(__loader_end + kernel_text_and_data_size - __real_kernel_start);
         __loader_end = .;
-    } > WHOLE
+    } > MEM
 
     .text 0x100000 : AT(LOADADDR(.text.loader) + SIZEOF(.text.loader))
     {
         __real_kernel_start = .;
         *(.text*)
         *(.rodata*)
-    } > WHOLE
 
-    .data : AT(LOADADDR(.text) + ADDR(.data) - ADDR(.text))
-    {
         kernel_text_and_data_size = .;
         LONG(__kernel_text_and_data_end - ADDR(.text));
         asm_kernel_size = .;
@@ -55,7 +41,7 @@ SECTIONS
         *(.data)
         *(.data*)
         __kernel_text_and_data_end = .;
-    } > WHOLE
+    } > MEM
 
     .bss ALIGN(0x1000) :
     {
@@ -63,12 +49,12 @@ SECTIONS
         *(.bss)
         *(.bss*)
         __bss_end = ALIGN(0x1000);
-    } > WHOLE
+    } > MEM
 
     .kernel_end :
     {
         __real_kernel_end = .;
-    } > WHOLE
+    } > MEM
 
     /* Stabs debugging sections.  */
     .stab          0 : { *(.stab) }
@@ -104,14 +90,11 @@ SECTIONS
     .debug_typenames 0 : { *(.debug_typenames) }
     .debug_varnames  0 : { *(.debug_varnames) }
 
-    .end : AT(0x0ffffff)
-    {
-        BYTE(0x00);
-    } > WHOLE
-
     /DISCARD/ :
     {
         *(.fini_array*)
         *(.eh_frame*)
+        *(.text.bootsect)
+        *(.note*)
     }
 }

src/mbr.S

@@ -0,0 +1,55 @@
+.section .text.bootsect
+.code16
+
+.globl mbr_start
+mbr_start:
+    movw %cs, %ax
+    movw %ax, %ds
+    movw %ax, %es
+    movw %ax, %ss
+
+# perform a temporary stack
+    movw $stack_base, %ax
+    movw %ax, %bp
+    movw %ax, %sp
+
+    call read_data
+
+# loader start
+    jmp 0x7e00
+
+read_data:
+    movw $read_data_pack, %si
+    mov $0x42, %ah
+    mov $0x80, %dl
+    int $0x13
+    jc read_data_error
+    ret
+
+read_data_error:
+    hlt
+    jmp read_data_error
+
+.align 4
+read_data_pack:
+    .byte 0x10, 0
+read_data_count:
+    .word 128    # sector count (read 64k)
+read_data_offset:
+    .word 0x0000 # offset address
+read_data_segment:
+    .word 0x07e0 # segment address
+read_data_lba:
+    .long 1      # lower 4 bytes of the LBA to read
+    .long 0      # higher 2 bytes of the LBA to read
+
+__mbr_code_border__:
+    .long 0xffffffff
+
+.align 16
+stack_edge:
+.space 128
+stack_base:
+
+. = 510
+.byte 0x55, 0xaa

src/mbr.ld

@@ -0,0 +1,15 @@
+OUTPUT_FORMAT(binary)
+OUTPUT_ARCH(i386:i386)
+
+SECTIONS
+{
+    .text 0x7c00 :
+    {
+        *(.text.bootsect)
+    }
+
+    /DISCARD/ :
+    {
+        *(.note*)
+    }
+}

user-space-program/Makefile.src

@@ -24,6 +24,7 @@ user.sym: $(OBJS) output_symbols.ld
 
 .PHONY: clean
 clean:
+	-rm -rf build
 	-rm $(OBJS)
 	-rm $(RES)
 	-rm user.sym