Changeset b112055 in mainline

Timestamp:

2011-08-17T19:10:44Z (14 years ago)

Author:

Martin Sucha <sucha14@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

f4fa6d9

Parents:

16dc887

Message:

Boot ia32 without Page Size Extensions

File:

• kernel/arch/ia32/src/boot/boot.S (modified) (4 diffs)

kernel/arch/ia32/src/boot/boot.S

@@ -140 +140 @@
                 jmp hlt0
 
+/** Calculate unmapped address of the end of the kernel. */
+calc_end_of_kernel:
+        movl $hardcoded_load_address, %edi
+        andl $0x7fffffff, %edi
+        movl (%edi), %esi
+        andl $0x7fffffff, %esi
+        
+        movl $hardcoded_ktext_size, %edi
+        andl $0x7fffffff, %edi
+        addl (%edi), %esi
+        andl $0x7fffffff, %esi
+        
+        movl $hardcoded_kdata_size, %edi
+        andl $0x7fffffff, %edi
+        addl (%edi), %esi
+        andl $0x7fffffff, %esi
+        movl %esi, end_of_kernel
+        ret
+
+/** Find free 2M (+4k for alignment) region where to store page tables */
+find_mem_for_pt:
+        /* Check if multiboot info is present */
+        cmpl $0x2BADB002, grub_eax
+        je check_multiboot_map
+        ret
+check_multiboot_map:
+        /* Copy address of the multiboot info to ebx */
+        movl grub_ebx, %ebx
+        /* Check if memory map flag is present */
+        movl (%ebx), %edx
+        andl $(1 << 6), %edx
+        jnz use_multiboot_map
+        ret
+use_multiboot_map:
+        /* Copy address of the memory map to edx */
+        movl 48(%ebx), %edx
+        movl %edx, %ecx
+        addl 44(%ebx), %ecx
+        /* Find a free region at least 2M in size */
+        check_memmap_loop:
+                /* Is this a free region? */
+                cmp $1, 20(%edx)
+                jnz next_region
+                /* Check size */
+                cmp $0, 16(%edx)
+                jnz next_region
+                cmpl $(2 * 1024 * 1024 + 4 * 1024), 12(%edx)
+                jbe next_region
+                cmp $0, 8(%edx)
+                jz found_region
+        next_region:
+                cmp %ecx, %edx
+                jbe next_region_do
+                ret
+        next_region_do:
+                addl (%edx), %edx
+                addl $4, %edx
+                jmp check_memmap_loop
+        found_region:
+                /* Use end of the found region */
+                mov 4(%edx), %ecx
+                add 12(%edx), %ecx
+                sub $(2 * 1024 * 1024), %ecx
+                mov %ecx, free_area
+        ret
+                
+
 /** Setup mapping for the kernel.
  *
@@ -148 +215 @@
 .global map_kernel
 map_kernel:
+        /* Paging features */
         movl %cr4, %ecx
-        orl $(1 << 4), %ecx      /* PSE on */
         andl $(~(1 << 5)), %ecx  /* PAE off */
         movl %ecx, %cr4
         
+        call calc_end_of_kernel
+        call find_mem_for_pt
+        mov end_of_kernel, %esi
+        mov free_area, %ecx
+        cmpl %esi, %ecx
+        jbe use_end_of_kernel
+        mov %ecx, %esi
+        /* Align address down to 4k */
+        andl $(~4095), %esi
+use_end_of_kernel:
+        
+        /* Align address to 4k */
+        addl $4095, %esi
+        andl $(~4095), %esi
+        
+        /* Allocate space for page tables*/     
+        movl %esi, pt_loc
+        movl $ballocs, %edi
+        andl $0x7fffffff, %edi
+        movl %esi, (%edi)
+        addl $4, %edi
+        movl $(2*1024*1024), (%edi)
+        
+        /* Fill page tables */
+        xorl %ecx, %ecx
+        xorl %ebx, %ebx
+        
+        floop_pt:
+                movl $((1 << 1) | (1 << 0)), %eax
+                orl %ebx, %eax
+                movl %eax, (%esi, %ecx, 4)
+                addl $(4 * 1024), %ebx
+                
+                incl %ecx
+                cmpl $(512 * 1024), %ecx
+                jl floop_pt
+        
+        /* Fill page directory */
         movl $(page_directory + 0), %esi
         movl $(page_directory + 2048), %edi
         xorl %ecx, %ecx
-        xorl %ebx, %ebx
+        movl pt_loc, %ebx
         
         floop:
-                movl $((1 << 7) | (1 << 1) | (1 << 0)), %eax
+                movl $((1 << 1) | (1 << 0)), %eax
                 orl %ebx, %eax
                 /* Mapping 0x00000000 + %ecx * 4M => 0x00000000 + %ecx * 4M */
@@ -165 +270 @@
                 /* Mapping 0x80000000 + %ecx * 4M => 0x00000000 + %ecx * 4M */
                 movl %eax, (%edi, %ecx, 4)
-                addl $(4 * 1024 * 1024), %ebx
+                addl $(4 * 1024), %ebx
                 
                 incl %ecx
@@ -523 +628 @@
 
 grub_ebx:
+        .long 0
+
+pt_loc:
+        .long 0
+end_of_kernel:
+        .long 0
+free_area:
         .long 0