| // Copyright 2018 The Fuchsia Authors |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #include <asm.h> |
| #include <arch/asm_macros.h> |
| #include <zircon/boot/image.h> |
| |
| #define SCTLR_I (1 << 12) // Instruction cache enable |
| #define SCTLR_C (1 << 2) // Cache enable |
| #define SCTLR_M (1 << 0) // MMU enable |
| |
| // scratch register, not saved across function calls |
| tmp .req x16 |
| |
| #define STACK_SIZE 4096 |
| |
| .section .text.boot0,"ax" |
| FUNCTION(_start) |
| // magic instruction that gives us UEFI "MZ" signature |
| add x13, x18, #0x16 |
| b header_end |
| |
| .quad 0 // image offset from start of ram (unused) |
| .quad 0 // image size (unused) |
| .quad 0 |
| .quad 0 |
| .quad 0 |
| .quad 0 |
| |
| // arm64 magic number |
| .byte 'A' |
| .byte 'R' |
| .byte 'M' |
| .byte 0x64 |
| .align 3 |
| |
| header_end: |
| // x0 typically points to device tree at entry |
| |
| // what EL are we running at? |
| mrs tmp, CurrentEL |
| cmp tmp, #(1 << 2) |
| beq cache_disable_el1 |
| |
| // Disable caches and MMU (EL2 version) |
| mrs tmp, sctlr_el2 |
| bic tmp, tmp, #SCTLR_I |
| bic tmp, tmp, #SCTLR_C |
| bic tmp, tmp, #SCTLR_M |
| msr sctlr_el2, tmp |
| b cache_disable_done |
| |
| cache_disable_el1: |
| // Disable caches and MMU (EL1 version) |
| mrs tmp, sctlr_el1 |
| bic tmp, tmp, #SCTLR_I |
| bic tmp, tmp, #SCTLR_C |
| bic tmp, tmp, #SCTLR_M |
| msr sctlr_el1, tmp |
| |
| cache_disable_done: |
| dsb sy |
| isb |
| |
| // setup stack |
| adr tmp, stack_end |
| mov sp, tmp |
| |
| // x0: pointer to device tree |
| bl boot_shim |
| |
| // x0: bootdata_t* to pass to kernel |
| // x1: kernel entry point |
| br x1 |
| END_FUNCTION(_start) |
| |
| .bss |
| .balign 16 |
| LOCAL_DATA(stack) |
| .skip STACK_SIZE |
| LOCAL_DATA(stack_end) |
| END_DATA(stack) |
