darling-objc4/runtime/arm64-asm.h

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 * 
 * Copyright (c) 2018 Apple Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
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 * Version 2.0 (the 'License'). You may not use this file except in
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 * The Original Code and all software distributed under the License are
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 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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 */
/********************************************************************
 * 
 *  arm64-asm.h - asm tools for arm64/arm64_32 and ROP/JOP
 *
 ********************************************************************/

#if __arm64__

#include "objc-config.h"

#if __LP64__
// true arm64

#define SUPPORT_TAGGED_POINTERS 1
#define PTR .quad
#define PTRSIZE 8
#define PTRSHIFT 3  // 1<<PTRSHIFT == PTRSIZE
// "p" registers are pointer-sized
#define UXTP UXTX
#define p0  x0
#define p1  x1
#define p2  x2
#define p3  x3
#define p4  x4
#define p5  x5
#define p6  x6
#define p7  x7
#define p8  x8
#define p9  x9
#define p10 x10
#define p11 x11
#define p12 x12
#define p13 x13
#define p14 x14
#define p15 x15
#define p16 x16
#define p17 x17

// true arm64
#else
// arm64_32

#define SUPPORT_TAGGED_POINTERS 0
#define PTR .long
#define PTRSIZE 4
#define PTRSHIFT 2  // 1<<PTRSHIFT == PTRSIZE
// "p" registers are pointer-sized
#define UXTP UXTW
#define p0  w0
#define p1  w1
#define p2  w2
#define p3  w3
#define p4  w4
#define p5  w5
#define p6  w6
#define p7  w7
#define p8  w8
#define p9  w9
#define p10 w10
#define p11 w11
#define p12 w12
#define p13 w13
#define p14 w14
#define p15 w15
#define p16 w16
#define p17 w17

// arm64_32
#endif


#if __has_feature(ptrauth_returns)
// ROP
#   define SignLR pacibsp
#   define AuthenticateLR autibsp
#else
// not ROP
#   define SignLR
#   define AuthenticateLR
#endif

#if __has_feature(ptrauth_calls)
// JOP

.macro TailCallFunctionPointer
	// $0 = function pointer value
	braaz	$0
.endmacro

.macro TailCallCachedImp
	// $0 = cached imp, $1 = address of cached imp, $2 = SEL, $3 = isa
	eor	$1, $1, $2	// mix SEL into ptrauth modifier
	eor	$1, $1, $3  // mix isa into ptrauth modifier
	brab	$0, $1
.endmacro

.macro TailCallMethodListImp
	// $0 = method list imp, $1 = address of method list imp
	braa	$0, $1
.endmacro

.macro TailCallBlockInvoke
	// $0 = invoke function, $1 = address of invoke function
	braa	$0, $1
.endmacro

.macro AuthAndResignAsIMP
	// $0 = cached imp, $1 = address of cached imp, $2 = SEL, $3 = isa
	// note: assumes the imp is not nil
	eor	$1, $1, $2	// mix SEL into ptrauth modifier
	eor	$1, $1, $3  // mix isa into ptrauth modifier
	autib	$0, $1	// authenticate cached imp
	ldr	xzr, [$0]	// crash if authentication failed
	paciza	$0		// resign cached imp as IMP
.endmacro

.macro ExtractISA
	and	$0, $1, #ISA_MASK
#if ISA_SIGNING_AUTH_MODE == ISA_SIGNING_STRIP
	xpacd	$0
#elif ISA_SIGNING_AUTH_MODE == ISA_SIGNING_AUTH
	mov	x10, $2
	movk	x10, #ISA_SIGNING_DISCRIMINATOR, LSL #48
	autda	$0, x10
#endif
.endmacro

.macro AuthISASuper dst, addr_mutable, discriminator
#if ISA_SIGNING_AUTH_MODE == ISA_SIGNING_AUTH
	movk	\addr_mutable, #\discriminator, LSL #48
	autda	\dst, \addr_mutable
#elif ISA_SIGNING_AUTH_MODE == ISA_SIGNING_STRIP
	xpacd	\dst
#endif
.endmacro

.macro SignAsImp
	paciza	$0
.endmacro

// JOP
#else
// not JOP

.macro TailCallFunctionPointer
	// $0 = function pointer value
	br	$0
.endmacro

.macro TailCallCachedImp
	// $0 = cached imp, $1 = address of cached imp, $2 = SEL, $3 = isa
	eor	$0, $0, $3
	br	$0
.endmacro

.macro TailCallMethodListImp
	// $0 = method list imp, $1 = address of method list imp
	br	$0
.endmacro

.macro TailCallBlockInvoke
	// $0 = invoke function, $1 = address of invoke function
	br	$0
.endmacro

.macro AuthAndResignAsIMP
	// $0 = cached imp, $1 = address of cached imp, $2 = SEL
	eor	$0, $0, $3
.endmacro

.macro SignAsImp
.endmacro

.macro ExtractISA
	and    $0, $1, #ISA_MASK
.endmacro

// not JOP
#endif

#define TailCallBlockInvoke TailCallMethodListImp


// __arm64__
#endif