| 1 | /* |
| 2 | * Copyright (c) 2007, 2011 Apple Inc. All rights reserved. |
| 3 | * |
| 4 | * @APPLE_LICENSE_HEADER_START@ |
| 5 | * |
| 6 | * This file contains Original Code and/or Modifications of Original Code |
| 7 | * as defined in and that are subject to the Apple Public Source License |
| 8 | * Version 2.0 (the 'License'). You may not use this file except in |
| 9 | * compliance with the License. Please obtain a copy of the License at |
| 10 | * http://www.opensource.apple.com/apsl/ and read it before using this |
| 11 | * file. |
| 12 | * |
| 13 | * The Original Code and all software distributed under the License are |
| 14 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
| 15 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
| 16 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
| 17 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
| 18 | * Please see the License for the specific language governing rights and |
| 19 | * limitations under the License. |
| 20 | * |
| 21 | * @APPLE_LICENSE_HEADER_END@ |
| 22 | */ |
| 23 | |
| 24 | #include <sys/syscall.h> |
| 25 | |
| 26 | #define UC_TRAD 1 |
| 27 | #define UC_FLAVOR 30 |
| 28 | |
| 29 | /* Structure fields for ucontext and mcontext. */ |
| 30 | #define UCONTEXT_UC_MCONTEXT 48 |
| 31 | |
| 32 | #define MCONTEXT_ES_EXCEPTION 0 |
| 33 | #define MCONTEXT_SS_RAX 16 |
| 34 | #define MCONTEXT_SS_RBX 24 |
| 35 | #define MCONTEXT_SS_RCX 32 |
| 36 | #define MCONTEXT_SS_RDX 40 |
| 37 | #define MCONTEXT_SS_RDI 48 |
| 38 | #define MCONTEXT_SS_RSI 56 |
| 39 | #define MCONTEXT_SS_RBP 64 |
| 40 | #define MCONTEXT_SS_RSP 72 |
| 41 | #define MCONTEXT_SS_R8 80 |
| 42 | #define MCONTEXT_SS_RIP 144 |
| 43 | |
| 44 | /* register use: |
| 45 | %rbx uctx |
| 46 | %r12 token |
| 47 | |
| 48 | void |
| 49 | _sigtramp( |
| 50 | union __sigaction_u __sigaction_u, %rdi |
| 51 | int sigstyle, %rsi |
| 52 | int sig, %rdx |
| 53 | siginfo_t *sinfo, %rcx |
| 54 | ucontext_t *uctx %r8 |
| 55 | uintptr_t token %r8 |
| 56 | ) |
| 57 | */ |
| 58 | |
| 59 | #if RDAR_35834092 |
| 60 | .private_extern __sigtramp |
| 61 | #endif |
| 62 | .globl __sigtramp |
| 63 | .text |
| 64 | .align 4,0x90 |
| 65 | __sigtramp: |
| 66 | Lstart: |
| 67 | /* Although this routine does not need any stack frame, various parts |
| 68 | of the OS can't analyse the stack without them. */ |
| 69 | pushq %rbp |
| 70 | movq %rsp, %rbp |
| 71 | |
| 72 | movq %rdi, %rax # set up address for call |
| 73 | |
| 74 | #if defined(__DYNAMIC__) |
| 75 | incl ___in_sigtramp(%rip) |
| 76 | #endif |
| 77 | /* Save uctx in %rbx. */ |
| 78 | movq %r8, %rbx |
| 79 | /* Save token in %r12. */ |
| 80 | movq %r9, %r12 |
| 81 | /* Call the signal handler. |
| 82 | Some variants are not supposed to get the last two parameters, |
| 83 | but the test to prevent this is more expensive than just passing |
| 84 | them. */ |
| 85 | movl %edx, %edi |
| 86 | movq %rcx, %rsi |
| 87 | movq %r8, %rdx |
| 88 | Lcall_start: |
| 89 | call *%rax |
| 90 | Lcall_end: |
| 91 | #if defined(__DYNAMIC__) |
| 92 | decl ___in_sigtramp(%rip) |
| 93 | #endif |
| 94 | movq %rbx, %rdi |
| 95 | movl $ UC_FLAVOR, %esi |
| 96 | movq %r12, %rdx |
| 97 | callq ___sigreturn |
| 98 | ud2 /* __sigreturn returning is a fatal error */ |
| 99 | ret |
| 100 | Lend: |
| 101 | |
| 102 | /* DWARF unwind table #defines. */ |
| 103 | #define DW_CFA_advance_loc_4 0x44 |
| 104 | #define DW_CFA_def_cfa 0x0c |
| 105 | #define DW_CFA_def_cfa_expression 0x0F |
| 106 | #define DW_CFA_expression 0x10 |
| 107 | #define DW_CFA_val_expression 0x16 |
| 108 | #define DW_CFA_offset(column) 0x80+(column) |
| 109 | |
| 110 | /* DWARF expression #defines. */ |
| 111 | #define DW_OP_deref 0x06 |
| 112 | #define DW_OP_const1u 0x08 |
| 113 | #define DW_OP_dup 0x12 |
| 114 | #define DW_OP_drop 0x13 |
| 115 | #define DW_OP_over 0x14 |
| 116 | #define DW_OP_pick 0x15 |
| 117 | #define DW_OP_swap 0x16 |
| 118 | #define DW_OP_rot 0x17 |
| 119 | #define DW_OP_abs 0x19 |
| 120 | #define DW_OP_and 0x1a |
| 121 | #define DW_OP_div 0x1b |
| 122 | #define DW_OP_minus 0x1c |
| 123 | #define DW_OP_mod 0x1d |
| 124 | #define DW_OP_mul 0x1e |
| 125 | #define DW_OP_neg 0x1f |
| 126 | #define DW_OP_not 0x20 |
| 127 | #define DW_OP_or 0x21 |
| 128 | #define DW_OP_plus 0x22 |
| 129 | #define DW_OP_plus_uconst 0x23 |
| 130 | #define DW_OP_shl 0x24 |
| 131 | #define DW_OP_shr 0x25 |
| 132 | #define DW_OP_shra 0x26 |
| 133 | #define DW_OP_xor 0x27 |
| 134 | #define DW_OP_skip 0x2f |
| 135 | #define DW_OP_bra 0x28 |
| 136 | #define DW_OP_eq 0x29 |
| 137 | #define DW_OP_ge 0x2A |
| 138 | #define DW_OP_gt 0x2B |
| 139 | #define DW_OP_le 0x2C |
| 140 | #define DW_OP_lt 0x2D |
| 141 | #define DW_OP_ne 0x2E |
| 142 | #define DW_OP_lit(n) 0x30+(n) |
| 143 | #define DW_OP_breg(n) 0x70+(n) |
| 144 | #define DW_OP_deref_size 0x94 |
| 145 | |
| 146 | /* The location expression we'll use. */ |
| 147 | |
| 148 | #define loc_expr_for_reg(regno, offs) \ |
| 149 | .byte DW_CFA_expression, regno, 5 /* block length */, \ |
| 150 | DW_OP_breg(3), UCONTEXT_UC_MCONTEXT, DW_OP_deref, \ |
| 151 | DW_OP_plus_uconst, offs |
| 152 | |
| 153 | /* For r8 through r13 */ |
| 154 | #define loc_expr_rN(regno) \ |
| 155 | loc_expr_for_reg(regno, MCONTEXT_SS_R8+(8*(regno-8))) |
| 156 | |
| 157 | /* For r14 through r15 */ |
| 158 | #define loc_expr_rN_long(regno) \ |
| 159 | .byte DW_CFA_expression, regno, 6 /* block length */, \ |
| 160 | DW_OP_breg(3), UCONTEXT_UC_MCONTEXT, DW_OP_deref, \ |
| 161 | DW_OP_plus_uconst, MCONTEXT_SS_R8+(8*(regno-8)), 1 |
| 162 | |
| 163 | /* Unwind tables. */ |
| 164 | .section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support |
| 165 | EH_frame1: |
| 166 | .set L$set$0,LECIE1-LSCIE1 |
| 167 | .long L$set$0 # Length of Common Information Entry |
| 168 | LSCIE1: |
| 169 | .long 0 # CIE Identifier Tag |
| 170 | .byte 0x1 # CIE Version |
| 171 | .ascii "zRS\0" # CIE Augmentation |
| 172 | .byte 0x1 # uleb128 0x1; CIE Code Alignment Factor |
| 173 | .byte 0x78 # sleb128 -8; CIE Data Alignment Factor |
| 174 | .byte 0x10 # CIE RA Column |
| 175 | .byte 0x1 # uleb128 0x1; Augmentation size |
| 176 | .byte 0x10 # FDE Encoding (pcrel) |
| 177 | .byte DW_CFA_def_cfa |
| 178 | .byte 0x7 # uleb128 0x5 |
| 179 | .byte 0x8 # uleb128 0x4 |
| 180 | .byte DW_CFA_offset(16) |
| 181 | .byte 0x1 # uleb128 0x1 |
| 182 | .byte DW_CFA_offset(16) // duplicate DW_CFA_offset (rip, -8) tells linker to not make compact unwind |
| 183 | .byte 0x1 # uleb128 0x1 |
| 184 | .align 3 |
| 185 | LECIE1: |
| 186 | .globl _sigtramp.eh |
| 187 | _sigtramp.eh: |
| 188 | LSFDE1: |
| 189 | .set L$set$1,LEFDE1-LASFDE1 |
| 190 | .long L$set$1 # FDE Length |
| 191 | LASFDE1: |
| 192 | .long LASFDE1-EH_frame1 # FDE CIE offset |
| 193 | .quad Lstart-. # FDE initial location |
| 194 | .set L$set$2,Lend-Lstart |
| 195 | .quad L$set$2 # FDE address range |
| 196 | .byte 0x0 # uleb128 0x0; Augmentation size |
| 197 | |
| 198 | /* Now for the expressions, which all compute |
| 199 | uctx->uc_mcontext->register |
| 200 | for each register. |
| 201 | |
| 202 | Describe even the registers that are not call-saved because they |
| 203 | might be being used in the prologue to save other registers. |
| 204 | Only integer registers are described at present. */ |
| 205 | |
| 206 | loc_expr_for_reg (0, MCONTEXT_SS_RAX) |
| 207 | loc_expr_for_reg (1, MCONTEXT_SS_RDX) |
| 208 | loc_expr_for_reg (2, MCONTEXT_SS_RCX) |
| 209 | loc_expr_for_reg (3, MCONTEXT_SS_RBX) |
| 210 | loc_expr_for_reg (4, MCONTEXT_SS_RSI) |
| 211 | loc_expr_for_reg (5, MCONTEXT_SS_RDI) |
| 212 | loc_expr_for_reg (6, MCONTEXT_SS_RBP) |
| 213 | loc_expr_for_reg (7, MCONTEXT_SS_RSP) |
| 214 | loc_expr_rN (8) |
| 215 | loc_expr_rN (9) |
| 216 | loc_expr_rN (10) |
| 217 | loc_expr_rN (11) |
| 218 | loc_expr_rN (12) |
| 219 | loc_expr_rN (13) |
| 220 | loc_expr_rN_long (14) |
| 221 | loc_expr_rN_long (15) |
| 222 | |
| 223 | /* The Intel architecture classifies exceptions into three categories, |
| 224 | 'faults' which put the address of the faulting instruction |
| 225 | in EIP, 'traps' which put the following instruction in EIP, |
| 226 | and 'aborts' which don't typically report the instruction |
| 227 | causing the exception. |
| 228 | |
| 229 | The traps are #BP and #OF. */ |
| 230 | |
| 231 | .byte DW_CFA_val_expression, 16 |
| 232 | .set L$set$3,Lpc_end-Lpc_start |
| 233 | .byte L$set$3 |
| 234 | Lpc_start: |
| 235 | /* Push the mcontext address twice. */ |
| 236 | .byte DW_OP_breg(3), UCONTEXT_UC_MCONTEXT, DW_OP_deref, DW_OP_dup |
| 237 | /* Find the value of EIP. */ |
| 238 | .byte DW_OP_plus_uconst, MCONTEXT_SS_RIP, MCONTEXT_SS_RIP >> 7 |
| 239 | .byte DW_OP_deref, DW_OP_swap |
| 240 | /* Determine the exception type. */ |
| 241 | .byte DW_OP_plus_uconst, MCONTEXT_ES_EXCEPTION, DW_OP_deref_size, 4 |
| 242 | /* Check whether it is #BP (3) or #OF (4). */ |
| 243 | .byte DW_OP_dup, DW_OP_lit(3), DW_OP_ne |
| 244 | .byte DW_OP_swap, DW_OP_lit(4), DW_OP_ne, DW_OP_and |
| 245 | /* If it is not, then add 1 to the instruction address, so as to point |
| 246 | within or past the faulting instruction. */ |
| 247 | .byte DW_OP_plus |
| 248 | Lpc_end: |
| 249 | |
| 250 | /* The CFA will have been saved as the value of RSP (it is not |
| 251 | RSP+8). */ |
| 252 | .byte DW_CFA_def_cfa_expression |
| 253 | .set L$set$4,Lcfa_end-Lcfa_start |
| 254 | .byte L$set$4 |
| 255 | Lcfa_start: |
| 256 | .byte DW_OP_breg(3), UCONTEXT_UC_MCONTEXT, DW_OP_deref |
| 257 | .byte DW_OP_plus_uconst, MCONTEXT_SS_RSP, DW_OP_deref |
| 258 | Lcfa_end: |
| 259 | |
| 260 | .align 3 |
| 261 | LEFDE1: |
| 262 | |
| 263 | .subsections_via_symbols |