194 lines
3.9 KiB
ArmAsm
194 lines
3.9 KiB
ArmAsm
# Declare constants for the multiboot header.
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.set ALIGN, 1<<0 # align loaded modules on page boundaries
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.set MEMINFO, 1<<1 # provide memory map
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.set FLAGS, ALIGN | MEMINFO # this is the Multiboot 'flag' field
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.set MAGIC, 0x1BADB002 # 'magic number' lets bootloader find the header
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.set CHECKSUM, -(MAGIC + FLAGS) # checksum of above, to prove we are multiboot
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# Declare a header as in the Multiboot Standard.
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.section .multiboot
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.align 4
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.long MAGIC
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.long FLAGS
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.long CHECKSUM
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# Reserve a stack for the initial thread.
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.section .bss
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.align 16
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stack_bottom:
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.skip 16384 # 16 KiB
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stack_top:
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# The kernel entry point.
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.section .text
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.global _start
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.type _start, @function
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_start:
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movl $stack_top, %esp
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# Call the global constructors.
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call _init
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# Call early kernel (init GDT, IDT and other)
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call kernel_early_main
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# Transfer control to the main kernel.
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call kernel_main
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# Hang if kernel_main unexpectedly returns.
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cli
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1: hlt
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jmp 1b
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.size _start, . - _start
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.global gdt_flush
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gdt_flush:
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mov 0x4(%esp),%eax
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lgdt (%eax)
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mov $0x10,%ax
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mov %ax,%ds
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mov %ax,%es
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mov %ax,%fs
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mov %ax,%gs
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mov %ax,%ss
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jmp $0x8,$.flush
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.flush:
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ret
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// IDT
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.global idt_flush
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idt_flush:
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mov 0x4(%esp),%eax
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lidt (%eax)
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ret
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// Interrupt Service Routine
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.macro ISR_NOERRCODE num
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.global isr\num
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isr\num:
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cli
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push $0x0
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push $0x\num
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jmp isr_common_stub
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.endm
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.macro ISR_ERRCODE num
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.global isr\num
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isr\num:
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cli
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push $0x\num
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jmp isr_common_stub
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.endm
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// This macro creates a stub for an IRQ - the first parameter is
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// the IRQ number, the second is the ISR number it is remapped to.
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.macro IRQ num to
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.global irq\num
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irq\num:
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cli
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push $0x0
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push $0x\to
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jmp irq_common_stub
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.endm
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ISR_NOERRCODE 0 // Divide by sero
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ISR_NOERRCODE 1 // Debug
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ISR_NOERRCODE 2 // Non-maskable Interrupt
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ISR_NOERRCODE 3 // Breakpoint
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ISR_NOERRCODE 4 // Overflow
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ISR_NOERRCODE 5 // Bound Range Exceeded
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ISR_NOERRCODE 6 // Invalid Opcode
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ISR_NOERRCODE 7 // Device Not Avalible
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ISR_ERRCODE 8 // Double Fault
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ISR_NOERRCODE 9 // Coprocessor Segment Overrun
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ISR_ERRCODE 10 // Invalid TSS
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ISR_ERRCODE 11
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ISR_ERRCODE 12
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ISR_ERRCODE 13
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ISR_ERRCODE 14
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ISR_NOERRCODE 15
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ISR_NOERRCODE 16
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ISR_ERRCODE 17
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ISR_NOERRCODE 18
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ISR_NOERRCODE 19
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ISR_NOERRCODE 20
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ISR_NOERRCODE 21
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ISR_NOERRCODE 22
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ISR_NOERRCODE 23
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ISR_NOERRCODE 24
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ISR_NOERRCODE 25
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ISR_NOERRCODE 26
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ISR_NOERRCODE 27
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ISR_NOERRCODE 28
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ISR_NOERRCODE 29
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ISR_ERRCODE 30
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ISR_NOERRCODE 31
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IRQ 0, 32
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IRQ 1, 33
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IRQ 2, 34
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IRQ 3, 35
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IRQ 4, 36
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IRQ 5, 37
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IRQ 6, 38
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IRQ 7, 39
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IRQ 8, 40
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IRQ 9, 41
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IRQ 10, 42
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IRQ 11, 43
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IRQ 12, 44
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IRQ 13, 45
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IRQ 14, 46
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IRQ 15, 47
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isr_common_stub:
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pusha
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mov %ds,%ax
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push %eax
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mov $0x10,%ax
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mov %ax,%ds
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mov %ax,%es
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mov %ax,%fs
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mov %ax,%gs
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call isr_handler
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pop %eax
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mov %ax,%ds
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mov %ax,%es
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mov %ax,%fs
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mov %ax,%gs
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popa
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add $0x8,%esp
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sti
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iret
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//This is our common IRQ stub. It saves the processor state, sets
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//up for kernel mode segments, calls the C-level fault handler,
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//and finally restores the stack frame.
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irq_common_stub:
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pusha //Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax
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mov %ds, %ax //Lower 16-bits of eax = ds.
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push %eax //save the data segment descriptor
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mov $0x10, %ax //load the kernel data segment descriptor
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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call irq_handler
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pop %ebx //reload the original data segment descriptor
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mov %bx, %ds
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mov %bx, %es
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mov %bx, %fs
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mov %bx, %gs
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popa //Pops edi,esi,ebp...
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add $0x8, %esp //Cleans up the pushed error code and pushed ISR number
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sti
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iret
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