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