From 20b100acd702e64ac1d2db9ddcd10c25aafa51a2 Mon Sep 17 00:00:00 2001
From: AceVest <zhaoyanbai@126.com>
Date: Fri, 2 May 2014 10:56:10 +0800
Subject: [PATCH] cancel to paging virtual address below 0xC0000000

---
 boot/multiboot.S | 2 ++
 include/system.h | 2 ++
 kernel/init.c    | 9 +++++----
 mm/mm.c          | 1 +
 setup/system.c   | 2 +-
 5 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/boot/multiboot.S b/boot/multiboot.S
index 95546dc..4db6d52 100644
--- a/boot/multiboot.S
+++ b/boot/multiboot.S
@@ -23,6 +23,7 @@
 .extern init_pgd
 .extern init_pgt
 .extern kernel_virtual_addr_start
+.extern kernel_init_stack
 
 .section .multiboot_header
 .align 32
@@ -121,6 +122,7 @@ kernel_entry:
 Label:
     call    CheckKernel
     addl    $8,%esp
+    movl    $kernel_init_stack + KRNL_INIT_STACK_SIZE, %esp
     call    KernelEntry
 
 Die:
diff --git a/include/system.h b/include/system.h
index 15ca050..4cd0b33 100644
--- a/include/system.h
+++ b/include/system.h
@@ -227,4 +227,6 @@ extern    System system;
 
 #define ROOT_DEV    system.root_dev
 
+#define KRNL_INIT_STACK_SIZE    4096
+
 #endif //_SYSTEM_H
diff --git a/kernel/init.c b/kernel/init.c
index f452e81..d6a36e6 100644
--- a/kernel/init.c
+++ b/kernel/init.c
@@ -11,7 +11,6 @@
 #include <stat.h>
 #include <init.h>
 
-#define KRNL_STACK_SIZE    4096
 
 void    root_task_entry();
 void    setup_kernel();
@@ -19,14 +18,15 @@ void    setup_kernel();
 TSS    tss;
 System    system;
 
-static char __initdata kernel_stack[KRNL_STACK_SIZE] __attribute__ ((__aligned__(PAGE_SIZE)));
+char __initdata kernel_init_stack[KRNL_INIT_STACK_SIZE] __attribute__ ((__aligned__(PAGE_SIZE)));
 
 int KernelEntry()
 {
+    /*
     asm("movl $kernel_stack,%%esp;"
         "addl %%eax,%%esp;"
         ::"a"(KRNL_STACK_SIZE));
-
+*/
     setup_kernel();
 
     char *root_task_user_space_stack = (char *) alloc_pages(0, 0);
@@ -43,7 +43,8 @@ int KernelEntry()
         leal    root_task_entry,%%eax;    \
         pushl   %%eax;              \
         iret;"::"b"(root_task_user_space_stack+PAGE_SIZE));
-    return 0;
+
+    return 0; /* never come to here */
 }
 
 #if 0
diff --git a/mm/mm.c b/mm/mm.c
index 8521bb8..0525017 100644
--- a/mm/mm.c
+++ b/mm/mm.c
@@ -337,6 +337,7 @@ void init_paging()
     for(i=delta; i<PDECNT_PER_PAGE; ++i)
     {
         init_pgd[i] = init_pgd[i-delta];
+        init_pgd[i-delta] = 0;
     }
 
     // paging for user space
diff --git a/setup/system.c b/setup/system.c
index 62ebba0..f42501b 100644
--- a/setup/system.c
+++ b/setup/system.c
@@ -29,7 +29,7 @@ void    setup_gdt()
     pDesc    pdesc;
     //change to new gdt.
     sgdt();
-    memcpy(gdt, (void *)*((unsigned long*)(gdtr+2)),
+    memcpy(gdt, (void *)pa2va(*((unsigned long*)(gdtr+2))),
                 *((unsigned short *)gdtr));
     *((unsigned short *)gdtr)    = NGDT*sizeof(Desc);
     *((unsigned long  *)(gdtr+2))    = (unsigned long)gdt;
-- 
2.44.0