0
我刚刚在qemu上完成高半程。但由于某种原因，给我错误虚拟盒和波奇：入口点不在一个段
entry point isnt in a segment.
please press any key to continue . . .
但在Qemu它的工作都很好。那么这里是我定义我的切入点，我的链接脚本：
/* The bootloader will look at this image and start execution at the symbol
designated as the entry point. */
ENTRY(loader)
SECTIONS {
/* The kernel will live at 3GB + 1MB in the virtual
address space, which will be mapped to 1MB in the
physical address space. */
. = 0xC0100000;
.text ALIGN (0x1000) : AT(ADDR(.text) - 0xC0000000) {
*(.multiboot)
*(.text)
*(.rodata*)
}
.data ALIGN (0x1000) : AT(ADDR(.data) - 0xC0000000) {
start_ctors = .;
KEEP(*(.init_array));
KEEP(*(SORT_BY_INIT_PRIORITY(.init_array.*)));
end_ctors = .;
*(.data)
}
.bss : AT(ADDR(.bss) - 0xC0000000) {
_sbss = .;
*(COMMON)
*(.bss)
_ebss = .;
}
}
和我boot.asm（GRUB）：
;Global MultiBoot Kernel Recongnzation
MAGIC equ 0x1badb002
FLAGS equ (1<<0 | 1<<1)
CHECKSUM equ -(MAGIC + FLAGS)
;Putting in object file
section .multiboot
dd MAGIC
dd FLAGS
dd CHECKSUM
section .data
KERNEL_VIRTUAL_BASE equ 0xC0000000 ; 3GB
KERNEL_PAGE_NUMBER equ (KERNEL_VIRTUAL_BASE >> 22) ; Page directory index of kernel's 4MB PTE.
align 0x1000
BootPageDirectory:
; This page directory entry identity-maps the first 4MB of the 32-bit physical address space.
; All bits are clear except the following:
; bit 7: PS The kernel page is 4MB.
; bit 1: RW The kernel page is read/write.
; bit 0: P The kernel page is present.
; This entry must be here -- otherwise the kernel will crash immediately after paging is
; enabled because it can't fetch the next instruction! It's ok to unmap this page later.
dd 0x00000083
times (KERNEL_PAGE_NUMBER - 1) dd 0 ; Pages before kernel space.
; This page directory entry defines a 4MB page containing the kernel.
dd 0x00000083
times (1024 - KERNEL_PAGE_NUMBER - 1) dd 0 ; Pages after the kernel image.
section .text
extern kernelMain
extern callConstructors
extern page_directory
extern pages_init
; reserve initial kernel stack space -- that's 16k.
STACKSIZE equ 0x4000
; setting up entry point for linker
loader equ (_loader - 0xC0000000)
global loader
_loader:
;Enable Paging START
; NOTE: Until paging is set up, the code must be position-independent and use physical
; addresses, not virtual ones!
mov ecx, (BootPageDirectory - KERNEL_VIRTUAL_BASE)
mov cr3, ecx ; Load Page Directory Base Register.
mov ecx, cr4
or ecx, 0x00000010 ; Set PSE bit in CR4 to enable 4MB pages.
mov cr4, ecx
mov ecx, cr0
or ecx, 0x80000000 ; Set PG bit in CR0 to enable paging.
mov cr0, ecx
lea ebx, [higherhalf]
jmp ebx
higherhalf:
; Unmap the identity-mapped first 4MB of physical address space. It should not be needed
; anymore.
mov dword [BootPageDirectory], 0
invlpg [0]
mov esp, stack ; set up the stack
call callConstructors
push eax
push ebx
call kernelMain
jmp _eof
_eof:
cli
hlt
jmp _eof
section .bss
align 32
stack:
resb STACKSIZE ; reserve 16k stack on a uint64_t boundary
这里是我的操作系统我的全部源代码：https://github.com/amanuel2/OS_MIRROR。帮助将不胜感激。
完全与您的问题无关。但我注意到你做了'mov esp，stack'。所以ESP将会从标签'堆栈'变小。但是你用'stack'定义'stack'： resb STACKSIZE'。问题在于堆栈会在标签堆栈之前进入内存。您应该在'resb STACKSIZE'之后放置一个标签，并将其用作堆栈的顶部。 –
@MichaelPetch所以mov esp，stack + STACKSIZE？ – amanuel2
在这种情况下就足够了。 –