| Imre Kis | 2cfb2b4 | 2021-12-15 19:15:42 +0100 | [diff] [blame] | 1 | /* SPDX-License-Identifier: BSD-3-Clause */ |
| 2 | /* |
| Imre Kis | eefeac3 | 2022-10-27 15:26:50 +0200 | [diff] [blame] | 3 | * Copyright (c) 2021-2023, Arm Limited and Contributors. All rights reserved. |
| Imre Kis | 2cfb2b4 | 2021-12-15 19:15:42 +0100 | [diff] [blame] | 4 | */ |
| 5 | |
| 6 | #include <asm.S> |
| 7 | |
| 8 | #define R_AARCH64_RELATIVE 1027 |
| 9 | |
| 10 | /** |
| 11 | * The following code is responsible for setting the initial value of the stack |
| 12 | * pointer and doing relocation on SP boot. |
| 13 | */ |
| 14 | FUNC __sp_entry, : |
| 15 | /* Use __stack_end linker symbol to set the load relative stack address. */ |
| 16 | adrp x4, __stack_end |
| 17 | add x4, x4, :lo12:__stack_end |
| 18 | mov sp, x4 |
| 19 | |
| 20 | /* |
| 21 | * X4 = load address |
| 22 | * X5 = relocation table start |
| 23 | * X6 = relocation table end |
| 24 | */ |
| 25 | adr x4, __sp_entry |
| 26 | adrp x5, __rela_start |
| 27 | add x5, x5, :lo12:__rela_start |
| 28 | adrp x6, __rela_end |
| 29 | add x6, x6, :lo12:__rela_end |
| 30 | |
| 31 | /* Iterating through relocation entries */ |
| 32 | cmp x5, x6 |
| 33 | beq 2f |
| 34 | |
| 35 | /* |
| 36 | * Loading relocation entry |
| 37 | * X7 = r_offset |
| 38 | * X8 = r_info |
| 39 | * X9 = r_addend |
| 40 | */ |
| 41 | 1: ldp x7, x8, [x5], #16 |
| 42 | ldr x9, [x5], #8 |
| 43 | |
| 44 | /* Only R_AARCH64_RELATIVE type is supported */ |
| 45 | cmp w8, #R_AARCH64_RELATIVE |
| Imre Kis | eefeac3 | 2022-10-27 15:26:50 +0200 | [diff] [blame] | 46 | bne relocation_error |
| Imre Kis | 2cfb2b4 | 2021-12-15 19:15:42 +0100 | [diff] [blame] | 47 | |
| 48 | /* |
| 49 | * Apply relative adjustment on address |
| 50 | * *(load_address + r_offset) = load_address + r_addend |
| 51 | */ |
| 52 | add x9, x9, x4 |
| 53 | str x9, [x7, x4] |
| 54 | |
| 55 | cmp x5, x6 |
| 56 | bne 1b |
| 57 | |
| 58 | 2: |
| Imre Kis | eefeac3 | 2022-10-27 15:26:50 +0200 | [diff] [blame] | 59 | /* Clear BSS */ |
| 60 | adrp x4, __bss_start |
| 61 | add x4, x4, :lo12:__bss_start |
| 62 | adrp x5, __bss_end |
| 63 | add x5, x5, :lo12:__bss_end |
| 64 | |
| 65 | cmp x4, x5 |
| 66 | b.eq clear_bss_end |
| 67 | |
| 68 | clear_bss: |
| 69 | str xzr, [x4], #8 |
| 70 | cmp x4, x5 |
| 71 | b.lt clear_bss |
| 72 | |
| 73 | clear_bss_end: |
| Imre Kis | 2cfb2b4 | 2021-12-15 19:15:42 +0100 | [diff] [blame] | 74 | b _sp_entry |
| 75 | |
| Imre Kis | eefeac3 | 2022-10-27 15:26:50 +0200 | [diff] [blame] | 76 | relocation_error: |
| Imre Kis | 2cfb2b4 | 2021-12-15 19:15:42 +0100 | [diff] [blame] | 77 | adr X0, error_invalid_relocation |
| 78 | bl trace_puts |
| 79 | b . |
| 80 | |
| 81 | .align 8 |
| 82 | error_invalid_relocation: |
| 83 | .asciz "Only R_AARCH64_RELATIVE type relocation is supported" |
| 84 | .align 8 |
| 85 | END_FUNC __sp_entry |
| Gabor Toth | c9d54f6 | 2024-06-06 14:09:14 +0200 | [diff] [blame] | 86 | |
| 87 | BTI(emit_aarch64_feature_1_and GNU_PROPERTY_AARCH64_FEATURE_1_BTI) |