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237 lines
7.4 KiB
237 lines
7.4 KiB
/* |
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* Copyright (c) 2008 Mans Rullgard <mans@mansr.com> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "config.h" |
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#ifdef __ELF__ |
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# define ELF |
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#else |
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# define ELF # |
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#endif |
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#if HAVE_AS_FUNC |
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# define FUNC |
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#else |
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# define FUNC # |
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#endif |
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#ifndef __has_feature |
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# define __has_feature(x) 0 |
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#endif |
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/* Support macros for |
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* - Armv8.3-A Pointer Authentication and |
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* - Armv8.5-A Branch Target Identification |
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* features which require emitting a .note.gnu.property section with the |
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* appropriate architecture-dependent feature bits set. |
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* |
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* |AARCH64_SIGN_LINK_REGISTER| and |AARCH64_VALIDATE_LINK_REGISTER| expand to |
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* PACIxSP and AUTIxSP, respectively. |AARCH64_SIGN_LINK_REGISTER| should be |
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* used immediately before saving the LR register (x30) to the stack. |
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* |AARCH64_VALIDATE_LINK_REGISTER| should be used immediately after restoring |
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* it. Note |AARCH64_SIGN_LINK_REGISTER|'s modifications to LR must be undone |
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* with |AARCH64_VALIDATE_LINK_REGISTER| before RET. The SP register must also |
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* have the same value at the two points. For example: |
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* |
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* .global f |
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* f: |
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* AARCH64_SIGN_LINK_REGISTER |
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* stp x29, x30, [sp, #-96]! |
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* mov x29, sp |
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* ... |
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* ldp x29, x30, [sp], #96 |
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* AARCH64_VALIDATE_LINK_REGISTER |
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* ret |
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* |
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* |AARCH64_VALID_CALL_TARGET| expands to BTI 'c'. Either it, or |
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* |AARCH64_SIGN_LINK_REGISTER|, must be used at every point that may be an |
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* indirect call target. In particular, all symbols exported from a file must |
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* begin with one of these macros. For example, a leaf function that does not |
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* save LR can instead use |AARCH64_VALID_CALL_TARGET|: |
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* |
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* .globl return_zero |
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* return_zero: |
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* AARCH64_VALID_CALL_TARGET |
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* mov x0, #0 |
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* ret |
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* |
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* A non-leaf function which does not immediately save LR may need both macros |
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* because |AARCH64_SIGN_LINK_REGISTER| appears late. For example, the function |
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* may jump to an alternate implementation before setting up the stack: |
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* |
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* .globl with_early_jump |
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* with_early_jump: |
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* AARCH64_VALID_CALL_TARGET |
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* cmp x0, #128 |
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* b.lt .Lwith_early_jump_128 |
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* AARCH64_SIGN_LINK_REGISTER |
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* stp x29, x30, [sp, #-96]! |
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* mov x29, sp |
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* ... |
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* ldp x29, x30, [sp], #96 |
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* AARCH64_VALIDATE_LINK_REGISTER |
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* ret |
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* |
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* .Lwith_early_jump_128: |
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* ... |
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* ret |
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* |
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* These annotations are only required with indirect calls. Private symbols that |
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* are only the target of direct calls do not require annotations. Also note |
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* that |AARCH64_VALID_CALL_TARGET| is only valid for indirect calls (BLR), not |
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* indirect jumps (BR). Indirect jumps in assembly are supported through |
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* |AARCH64_VALID_JUMP_TARGET|. Landing Pads which shall serve for jumps and |
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* calls can be created using |AARCH64_VALID_JUMP_CALL_TARGET|. |
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* |
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* Although not necessary, it is safe to use these macros in 32-bit ARM |
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* assembly. This may be used to simplify dual 32-bit and 64-bit files. |
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* |
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* References: |
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* - "ELF for the Arm® 64-bit Architecture" |
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* https: *github.com/ARM-software/abi-aa/blob/master/aaelf64/aaelf64.rst |
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* - "Providing protection for complex software" |
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* https://developer.arm.com/architectures/learn-the-architecture/providing-protection-for-complex-software |
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*/ |
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#if defined(__ARM_FEATURE_BTI_DEFAULT) && (__ARM_FEATURE_BTI_DEFAULT == 1) |
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# define GNU_PROPERTY_AARCH64_BTI (1 << 0) // Has BTI |
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# define AARCH64_VALID_CALL_TARGET hint #34 // BTI 'c' |
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# define AARCH64_VALID_JUMP_TARGET hint #38 // BTI 'j' |
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#else |
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# define GNU_PROPERTY_AARCH64_BTI 0 // No BTI |
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# define AARCH64_VALID_CALL_TARGET |
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# define AARCH64_VALID_JUMP_TARGET |
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#endif |
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#if defined(__ARM_FEATURE_PAC_DEFAULT) |
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# if ((__ARM_FEATURE_PAC_DEFAULT & (1 << 0)) != 0) // authentication using key A |
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# define AARCH64_SIGN_LINK_REGISTER paciasp |
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# define AARCH64_VALIDATE_LINK_REGISTER autiasp |
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# elif ((__ARM_FEATURE_PAC_DEFAULT & (1 << 1)) != 0) // authentication using key B |
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# define AARCH64_SIGN_LINK_REGISTER pacibsp |
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# define AARCH64_VALIDATE_LINK_REGISTER autibsp |
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# else |
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# error Pointer authentication defines no valid key! |
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# endif |
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# if ((__ARM_FEATURE_PAC_DEFAULT & (1 << 2)) != 0) |
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# error Authentication of leaf functions is enabled but not supported in FFmpeg! |
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# endif |
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# define GNU_PROPERTY_AARCH64_PAC (1 << 1) |
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#else |
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# define GNU_PROPERTY_AARCH64_PAC 0 |
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# define AARCH64_SIGN_LINK_REGISTER |
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# define AARCH64_VALIDATE_LINK_REGISTER |
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#endif |
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#if (GNU_PROPERTY_AARCH64_BTI != 0 || GNU_PROPERTY_AARCH64_PAC != 0) && defined(__ELF__) |
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.pushsection .note.gnu.property, "a" |
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.balign 8 |
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.long 4 |
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.long 0x10 |
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.long 0x5 |
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.asciz "GNU" |
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.long 0xc0000000 /* GNU_PROPERTY_AARCH64_FEATURE_1_AND */ |
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.long 4 |
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.long (GNU_PROPERTY_AARCH64_BTI | GNU_PROPERTY_AARCH64_PAC) |
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.long 0 |
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.popsection |
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#endif |
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.macro function name, export=0, align=2 |
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.macro endfunc |
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ELF .size \name, . - \name |
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FUNC .endfunc |
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.purgem endfunc |
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.endm |
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.text |
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.align \align |
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.if \export |
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.global EXTERN_ASM\name |
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ELF .type EXTERN_ASM\name, %function |
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FUNC .func EXTERN_ASM\name |
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EXTERN_ASM\name: |
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AARCH64_VALID_CALL_TARGET |
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.else |
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ELF .type \name, %function |
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FUNC .func \name |
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\name: |
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.endif |
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.endm |
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.macro const name, align=2, relocate=0 |
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.macro endconst |
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ELF .size \name, . - \name |
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.purgem endconst |
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.endm |
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#if HAVE_SECTION_DATA_REL_RO |
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.if \relocate |
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.section .data.rel.ro |
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.else |
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.section .rodata |
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.endif |
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#elif defined(_WIN32) |
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.section .rdata |
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#elif !defined(__MACH__) |
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.section .rodata |
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#else |
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.const_data |
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#endif |
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.align \align |
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\name: |
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.endm |
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.macro movrel rd, val, offset=0 |
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#if CONFIG_PIC && defined(__APPLE__) |
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.if \offset < 0 |
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adrp \rd, \val@PAGE |
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add \rd, \rd, \val@PAGEOFF |
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sub \rd, \rd, -(\offset) |
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.else |
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adrp \rd, \val+(\offset)@PAGE |
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add \rd, \rd, \val+(\offset)@PAGEOFF |
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.endif |
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#elif CONFIG_PIC && defined(_WIN32) |
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.if \offset < 0 |
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adrp \rd, \val |
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add \rd, \rd, :lo12:\val |
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sub \rd, \rd, -(\offset) |
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.else |
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adrp \rd, \val+(\offset) |
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add \rd, \rd, :lo12:\val+(\offset) |
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.endif |
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#elif CONFIG_PIC |
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# if __has_feature(hwaddress_sanitizer) |
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adrp \rd, :pg_hi21_nc:\val+(\offset) |
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# else |
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adrp \rd, \val+(\offset) |
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# endif |
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add \rd, \rd, :lo12:\val+(\offset) |
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#else |
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ldr \rd, =\val+\offset |
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#endif |
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.endm |
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#define GLUE(a, b) a ## b |
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#define JOIN(a, b) GLUE(a, b) |
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#define X(s) JOIN(EXTERN_ASM, s) |
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#define x18 do_not_use_x18 |
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#define w18 do_not_use_w18
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