diff options
Diffstat (limited to 'Kernel/Arch')
| -rw-r--r-- | Kernel/Arch/i386/Boot/boot.S | 100 |
1 files changed, 69 insertions, 31 deletions
diff --git a/Kernel/Arch/i386/Boot/boot.S b/Kernel/Arch/i386/Boot/boot.S index 7646585453..9289cb5a5f 100644 --- a/Kernel/Arch/i386/Boot/boot.S +++ b/Kernel/Arch/i386/Boot/boot.S @@ -42,8 +42,14 @@ boot_pd0: .global boot_pd3 boot_pd3: .skip 4096 -.global boot_pd3_pde1023_pt -boot_pd3_pde1023_pt: +.global boot_pd0_pt0 +boot_pd0_pt0: +.skip 4096 * 4 +.global boot_pd3_pts +boot_pd3_pts: +.skip 4096 * 4 +.global boot_pd3_pt1023 +boot_pd3_pt1023: .skip 4096 .section .text @@ -69,18 +75,18 @@ pdpt boot_pd0 : 512 pde's - 0: (0-2MB) (id 2MB page) - 1: (2-4MB) (id 2MB page) - 2: (4-6MB) (id 2MB page) - 3: (6-8MB) (id 2MB page) + 0: boot_pd0_pt0 (0-2MB) (id 512 4KB pages) boot_pd3 : 512 pde's - 0: boot_pd3_pde0 (3072-3074MB) (pseudo) - 1: boot_pd3_pde1 (3074-3076MB) (pseudo) - 2: boot_pd3_pde2 (3076-3078MB) (pseudo) - 3: boot_pd3_pde3 (3078-3080MB) (pseudo) - 4: boot_pd3_pde1023_pt (4094-4096MB) (for page table mappings) + 0: boot_pd3_pts[0] (3072-3074MB) (pseudo 512 4KB pages) + 1: boot_pd3_pts[1] (3074-3076MB) (pseudo 512 4KB pages) + 2: boot_pd3_pts[2] (3076-3078MB) (pseudo 512 4KB pages) + 3: boot_pd3_pts[3] (3078-3080MB) (pseudo 512 4KB pages) + 4: boot_pd3_pt1023 (4094-4096MB) (for page table mappings) + +the 9 page tables each contain 512 pte's that map individual 4KB pages + */ start: @@ -104,41 +110,74 @@ start: xorl %eax, %eax rep stosl - /* identity map bottom 8MB using 2MB pages (only PDE, no PTE) */ - movl $4, %ecx + /* clear pd3 */ + movl $(boot_pd3 - 0xc0000000), %edi + movl $1024, %ecx + xorl %eax, %eax + rep stosl + + /* clear pd0's pt's */ + movl $(boot_pd0_pt0 - 0xc0000000), %edi + movl $(1024 * 4), %ecx xorl %eax, %eax + rep stosl + + /* clear pd3's pt's */ + movl $(boot_pd3_pts - 0xc0000000), %edi + movl $(1024 * 5), %ecx + xorl %eax, %eax + rep stosl + + /* add boot_pd0_pt0 to boot_pd0 */ movl $(boot_pd0 - 0xc0000000), %edi -1: + movl $(boot_pd0_pt0 - 0xc0000000), %eax movl %eax, 0(%edi) - /* PS(2MB) + R/W + Present */ - orl $0x83, 0(%edi) + /* R/W + Present */ + orl $0x3, 0(%edi) + + /* add boot_pd3_pts to boot_pd3 */ + movl $4, %ecx + movl $(boot_pd3 - 0xc0000000), %edi + movl $(boot_pd3_pts - 0xc0000000), %eax +1: + movl %eax, 0(%edi) + /* R/W + Present */ + orl $0x3, 0(%edi) addl $8, %edi - addl $(1048576 * 2), %eax + addl $4096, %eax loop 1b - /* clear pd3 */ - movl $(boot_pd3 - 0xc0000000), %edi - movl $1024, %ecx + /* identity map the 0 to 2MB range */ + movl $512, %ecx + movl $(boot_pd0_pt0 - 0xc0000000), %edi + /*movl $0x100000, %eax*/ xorl %eax, %eax - rep stosl - /* pseudo-identity map first 8MB above 3GB mark using 2MB pages again */ - movl $4, %ecx - xorl %eax, %eax - movl $(boot_pd3 - 0xc0000000), %edi 1: movl %eax, 0(%edi) - /* PS(2MB) + R/W + Present */ - orl $0x83, 0(%edi) + /* R/W + Present */ + orl $0x3, 0(%edi) + addl $8, %edi + addl $4096, %eax + loop 1b + + /* pseudo identity map the 3072-3080MB range */ + movl $(512 * 4), %ecx + movl $(boot_pd3_pts - 0xc0000000), %edi + xorl %eax, %eax +1: + movl %eax, 0(%edi) + /* R/W + Present */ + orl $0x3, 0(%edi) addl $8, %edi - addl $(1048576 * 2), %eax + addl $4096, %eax loop 1b /* create an empty page table for the top 2MB at the 4GB mark */ movl $(boot_pd3 - 0xc0000000), %edi - movl $(boot_pd3_pde1023_pt - 0xc0000000), 4088(%edi) + movl $(boot_pd3_pt1023 - 0xc0000000), 4088(%edi) orl $0x3, 4088(%edi) movl $0, 4092(%edi) @@ -158,10 +197,9 @@ start: /* jmp to an address above the 3GB mark */ push %cs - push $1f + push $1f retf 1: - movl %cr3, %eax movl %eax, %cr3 |