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// ============================================================================
// arch/aarch64/entry.S - Kernel entry point (AArch64)
//
// Called by the UEFI loader after ExitBootServices.
// - EL1, MMU on (identity map from UEFI)
// - X0 = pointer to BootInfo structure (AAPCS64 6.8.2 C.9 Pointer located in X[NGRN])
// - Interrupts masked (DAIF)
// ============================================================================
.section .text
.global _start
.extern kernel_main
_start:
// Mask all interrupts
msr daifset, #0xF
// Set up kernel stack pointer to Stack Pointer(SP)
adrp x1, _stack_top
add x1, x1, :lo12:_stack_top
mov sp, x1
// Clear frame pointer for clean stack traces
// x29 is Frame Pointer (FP), points to the prev stack frame. Make kerne_main is root of the call chain (remove UEFI calls)
// x30 is Link Register (LR), holds the return address from the last bl. Same logic.
mov x29, #0
mov x30, #0
// X0 already holds BootInfo*
bl kernel_main
// Should never return
.Lhalt:
wfi
b .Lhalt
// ============================================================================
// Kernel stack (16 KiB)
// Maybe in future i will increase this value, but i hope it's not necessary
// ============================================================================
.section .bss
.balign 4096
_stack_bottom:
.space CONFIG_KERNEL_STACK_SIZE
_stack_top:
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