1/* 2 Copyright Oliver Kowalke 2009. 3 Distributed under the Boost Software License, Version 1.0. 4 (See accompanying file LICENSE_1_0.txt or copy at 5 http://www.boost.org/LICENSE_1_0.txt) 6*/ 7 8/**************************************************************************************** 9 * * 10 * ---------------------------------------------------------------------------------- * 11 * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | * 12 * ---------------------------------------------------------------------------------- * 13 * | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | 0x18 | 0x1c | * 14 * ---------------------------------------------------------------------------------- * 15 * | fc_mxcsr|fc_x87_cw| guard | R12 | R13 | * 16 * ---------------------------------------------------------------------------------- * 17 * ---------------------------------------------------------------------------------- * 18 * | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | * 19 * ---------------------------------------------------------------------------------- * 20 * | 0x20 | 0x24 | 0x28 | 0x2c | 0x30 | 0x34 | 0x38 | 0x3c | * 21 * ---------------------------------------------------------------------------------- * 22 * | R14 | R15 | RBX | RBP | * 23 * ---------------------------------------------------------------------------------- * 24 * ---------------------------------------------------------------------------------- * 25 * | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | * 26 * ---------------------------------------------------------------------------------- * 27 * | 0x40 | 0x44 | | * 28 * ---------------------------------------------------------------------------------- * 29 * | RIP | | * 30 * ---------------------------------------------------------------------------------- * 31 * * 32 ****************************************************************************************/ 33 34# ifdef __i386__ 35# include "jump_i386_sysv_elf_gas.S" 36# else 37# if defined __CET__ 38# include <cet.h> 39# define SHSTK_ENABLED (__CET__ & 0x2) 40# define BOOST_CONTEXT_SHADOW_STACK (SHSTK_ENABLED && SHADOW_STACK_SYSCALL) 41# else 42# define _CET_ENDBR 43# endif 44.file "jump_x86_64_sysv_elf_gas.S" 45.text 46.globl jump_fcontext 47.type jump_fcontext,@function 48.align 16 49jump_fcontext: 50 _CET_ENDBR 51 leaq -0x40(%rsp), %rsp /* prepare stack */ 52 53#if !defined(BOOST_USE_TSX) 54 stmxcsr (%rsp) /* save MMX control- and status-word */ 55 fnstcw 0x4(%rsp) /* save x87 control-word */ 56#endif 57 58#if defined(BOOST_CONTEXT_TLS_STACK_PROTECTOR) 59 movq %fs:0x28, %rcx /* read stack guard from TLS record */ 60 movq %rcx, 0x8(%rsp) /* save stack guard */ 61#endif 62 63 movq %r12, 0x10(%rsp) /* save R12 */ 64 movq %r13, 0x18(%rsp) /* save R13 */ 65 movq %r14, 0x20(%rsp) /* save R14 */ 66 movq %r15, 0x28(%rsp) /* save R15 */ 67 movq %rbx, 0x30(%rsp) /* save RBX */ 68 movq %rbp, 0x38(%rsp) /* save RBP */ 69 70#if BOOST_CONTEXT_SHADOW_STACK 71 /* grow the stack to reserve space for shadow stack pointer(SSP) */ 72 leaq -0x8(%rsp), %rsp 73 /* read the current SSP and store it */ 74 rdsspq %rcx 75 movq %rcx, (%rsp) 76#endif 77 78#if BOOST_CONTEXT_SHADOW_STACK 79 /* grow the stack to reserve space for shadow stack pointer(SSP) */ 80 leaq -0x8(%rsp), %rsp 81 /* read the current SSP and store it */ 82 rdsspq %rcx 83 movq %rcx, (%rsp) 84# endif 85 86 /* store RSP (pointing to context-data) in RAX */ 87 movq %rsp, %rax 88 89 /* restore RSP (pointing to context-data) from RDI */ 90 movq %rdi, %rsp 91 92#if BOOST_CONTEXT_SHADOW_STACK 93 /* first 8 bytes are SSP */ 94 movq (%rsp), %rcx 95 leaq 0x8(%rsp), %rsp 96 97 /* Restore target(new) shadow stack */ 98 rstorssp -8(%rcx) 99 /* restore token for previous shadow stack is pushed */ 100 /* on previous shadow stack after saveprevssp */ 101 saveprevssp 102 103 /* when return, jump_fcontext jump to restored return address */ 104 /* (r8) instead of RET. This miss of RET implies us to unwind */ 105 /* shadow stack accordingly. Otherwise mismatch occur */ 106 movq $1, %rcx 107 incsspq %rcx 108#endif 109 110 movq 0x40(%rsp), %r8 /* restore return-address */ 111 112#if !defined(BOOST_USE_TSX) 113 ldmxcsr (%rsp) /* restore MMX control- and status-word */ 114 fldcw 0x4(%rsp) /* restore x87 control-word */ 115#endif 116 117#if defined(BOOST_CONTEXT_TLS_STACK_PROTECTOR) 118 movq 0x8(%rsp), %rdx /* load stack guard */ 119 movq %rdx, %fs:0x28 /* restore stack guard to TLS record */ 120#endif 121 122 movq 0x10(%rsp), %r12 /* restore R12 */ 123 movq 0x18(%rsp), %r13 /* restore R13 */ 124 movq 0x20(%rsp), %r14 /* restore R14 */ 125 movq 0x28(%rsp), %r15 /* restore R15 */ 126 movq 0x30(%rsp), %rbx /* restore RBX */ 127 movq 0x38(%rsp), %rbp /* restore RBP */ 128 129 leaq 0x48(%rsp), %rsp /* prepare stack */ 130 131 /* return transfer_t from jump */ 132#if !defined(_ILP32) 133 /* RAX == fctx, RDX == data */ 134 movq %rsi, %rdx 135#else 136 /* RAX == data:fctx */ 137 salq $32, %rsi 138 orq %rsi, %rax 139#endif 140 /* pass transfer_t as first arg in context function */ 141#if !defined(_ILP32) 142 /* RDI == fctx, RSI == data */ 143#else 144 /* RDI == data:fctx */ 145#endif 146 movq %rax, %rdi 147 148 /* indirect jump to context */ 149 jmp *%r8 150.size jump_fcontext,.-jump_fcontext 151 152/* Mark that we don't need executable stack. */ 153.section .note.GNU-stack,"",%progbits 154# endif 155