fixes and refinements

[lunaix-os.git] / lunaix-os / arch / x86 / boot.S

diff --git a/lunaix-os/arch/x86/boot.S b/lunaix-os/arch/x86/boot.S
index b41d24bba5cd81b887032dbfc4272ea201223ae1..5f832aa34038364f2f202e084b379d779a8c1116 100644 (file)
--- a/lunaix-os/arch/x86/boot.S
+++ b/lunaix-os/arch/x86/boot.S
@@ -1,62 +1,86 @@
-#include "multiboot.h"
+#define __ASM__ 1
+#include <arch/x86/boot/multiboot.h>
+
+#define MB_FLAGS    MULTIBOOT_MEMORY_INFO | MULTIBOOT_PAGE_ALIGN
+#define KPG_SIZE    24*1024
 
 .section .multiboot
-    .long MB_MAGIC
-    .long MB_ALIGNED_4K_MEM_MAP
-    .long CHECKSUM(MB_ALIGNED_4K_MEM_MAP)
+    .long MULTIBOOT_MAGIC
+    .long MB_FLAGS
+    .long CHECKSUM(MB_FLAGS)
 
 .section .bss
-    /* According to System V ABI, the stack must be aligned at 16 bytes boundary */
+    .global mb_info
     .align 16
+    /* 为Multiboot info struct 预留空间 */
+    mb_info:
+        .skip 4096
+    /* 根据System V ABI，栈地址必须16字节对齐 */
+    /* 这里只是一个临时栈，在_hhk_init里面我们会初始化内核专用栈 */
     stack_bottom:
         .skip 16318, 0
     stack_top:
 
-.section .text
+
+/* 
+    1 page directory, 
+    5 page tables:
+        1. Mapping reserved area and hhk_init
+        2-5. Remapping the kernels
+*/
+
+.section .kpg
+    .global _k_ptd
+    _k_ptd:
+        .skip KPG_SIZE, 0
+
+
+.section .hhk_init
     .global start_
     .type start_, @function     /* Optional, this just give the 
                                  * linker more knowledge about the label 
                                  */
-    start_:
+    start_: 
         movl $stack_top, %esp
+
+        subl $16, %esp
+
         /* 
-            TODO: kernel init
-                1. Load GDT
-                2. Load IDT
-                3. Enable paging
+            将咱们的 multiboot_info 挪个地儿，就是上述预留的空间里
+            而后在_hhk_init里，我们会对所有的高半核初始化代码（arch/x86下的所有）进行Identity map
+            这样，我们能够保证当分页与虚拟地址开启后，我们的内核能够访问到multiboot info table
+         */
+
+        movl $mb_info, 4(%esp)
+        movl %ebx, (%esp)
+        call _save_multiboot_info
+
+        /*
+            _hhk_init用来初始化我们高半核：
+                1. 初始化最简单的PD与PT（重新映射我们的内核至3GiB处，以及对相应的地方进行Identity Map）
+        */
+
+        movl $(KPG_SIZE), 4(%esp)
+        movl $(_k_ptd - 0xC0000000), (%esp)    /* PTD物理地址 */
+        call _hhk_init
+
+        /*
+            基本的映射定义好了，我们可以放心的打开分页了
+            我们只需要把PTD的基地址加载进CR3就好了。
         */
-        call _kernel_init
-        
-        subl $0x6, %esp
-
-        movl $_gdt, 2(%esp)
-        movw _gdt_limit, %ax
-        movw %ax, (%esp)
-        lgdt (%esp)
-
-        movl $_idt, 2(%esp)
-        movw _idt_limit, %ax
-        movw %ax, (%esp)
-        lidt (%esp)
-
-        addl $0x6, %esp
-
-        movw $0x10, %cx
-        movw %cx, %es
-        movw %cx, %ds
-        movw %cx, %fs
-        movw %cx, %gs
-        movw %cx, %ss
-
-        pushw $0x08
-        pushl $_after_gdt
-        retf
-
-    _after_gdt:
-        pushl %ebx
-        call _kernel_main
-
-        cli
-    j_:
-        hlt
-        jmp j_
\ No newline at end of file
+
+        /* 加载PTD基地址（物理地址） */
+        movl (%esp), %eax
+        andl $0xfffff000, %eax      # 有点多余，但写上还算明白一点
+        movl %eax, %cr3
+
+        /* 开启分页与地址转换 (CR0.PG=1) */
+        movl %cr0, %eax
+        orl $0x80000000, %eax
+        movl %eax, %cr0
+
+        addl $16, %esp
+
+        /* 进入高半核！ */
+        pushl $hhk_entry_
+        ret
\ No newline at end of file