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Kernel: Unmap first MB after jumping above 3GB

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etaIneLp 2020-05-25 17:58:49 -04:00 • committed by Andreas Kling
parent 826dc94187
commit 82d0352a67
1 changed files with 10 additions and 1 deletions
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11
Kernel/Arch/i386/Boot/boot.S
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@ -151,7 +151,6 @@ start:
/* identity map the 0 to 2MB range */ /* identity map the 0 to 2MB range */
movl $512, %ecx movl $512, %ecx
movl $(boot_pd0_pt0 - 0xc0000000), %edi movl $(boot_pd0_pt0 - 0xc0000000), %edi
/*movl $0x100000, %eax*/
xorl %eax, %eax xorl %eax, %eax
1: 1:
@ -203,6 +202,16 @@ start:
movl %cr3, %eax movl %cr3, %eax
movl %eax, %cr3 movl %eax, %cr3
/* unmap the 0-1MB range, which isn't used after jmp-ing up here */
movl $256, %ecx
movl $(boot_pd0_pt0 - 0xc0000000), %edi
xorl %eax, %eax
1:
movl %eax, 0(%edi)
addl $8, %edi
loop 1b
/* set up initial stack and jump into C++ land */ /* set up initial stack and jump into C++ land */
mov $stack_top, %esp mov $stack_top, %esp
and $-16, %esp and $-16, %esp