mirror of
https://github.com/Zeal-Operating-System/ZealOS.git
synced 2024-12-25 23:10:32 +00:00
8297c769e6
Previously the zealbooter memmap e820 assignment loop used the entry count value passed via limine, without checking if it was over MEM_E820_ENTRIES_NUM, the #define constant value limit of entries that are stored in the kernel header's e820 region. This commit bumps up the constant entry count to 64 from 48, and also adds a small check in zealbooter to ensure that the entry count value used in the memmap loop caps off at the constant value.
51 lines
824 B
ArmAsm
51 lines
824 B
ArmAsm
.section .text
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.global trampoline
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trampoline:
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// Set new stack
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mov %rdx, %rsp
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// Load GDTR
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lgdt (%rcx)
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// Far jump to 32-bit compatibility mode
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// AKA (set CS to CGDT.cs32)
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pushq $0x30
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addq $(1f - trampoline), %rax
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pushq %rax
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lretq
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.code32
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1:
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// Set all data segments to CGDT.ds
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mov $0x10, %eax
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mov %eax, %ds
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mov %eax, %es
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mov %eax, %fs
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mov %eax, %gs
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mov %eax, %ss
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// Disable paging
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mov %cr0, %eax
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btr $31, %eax
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mov %eax, %cr0
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// Disable LME and friends
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mov $0xc0000080, %ecx
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xor %eax, %eax
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xor %edx, %edx
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wrmsr
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// Set CR0 to (PE | NE) AKA SYS_START_CR0
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mov $0x11, %eax
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mov %eax, %cr0
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// Set flags to 0x02
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pushl $0x02
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popfl
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jmp *%ebx
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.global trampoline_end
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trampoline_end:
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