| /* |
| * Copyright 2022 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * https://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| .macro adr_l, reg:req, sym:req |
| adrp \reg, \sym |
| add \reg, \reg, :lo12:\sym |
| .endm |
| |
| /** |
| * This is a generic entry point for an image. It carries out the operations |
| * required to prepare the loaded image to be run. Specifically, it zeroes the |
| * bss section using registers x25 and above, prepares the stack, enables |
| * floating point, and sets up the exception vector. |
| */ |
| .section .init.entry, "ax" |
| .global entry |
| entry: |
| /* Disable trapping floating point access in EL1. */ |
| mrs x30, cpacr_el1 |
| orr x30, x30, #(0x3 << 20) |
| msr cpacr_el1, x30 |
| isb |
| |
| /* Zero out the bss section. */ |
| adr_l x29, bss_begin |
| adr_l x30, bss_end |
| 0: cmp x29, x30 |
| b.hs 1f |
| stp xzr, xzr, [x29], #16 |
| b 0b |
| |
| 1: /* Prepare the stack. */ |
| adr x30, boot_stack_end |
| mov sp, x30 |
| |
| /* Call into Rust code. */ |
| bl main |
| |
| /* Loop forever waiting for interrupts. */ |
| 2: wfi |
| b 2b |