1 // Copyright (c) 2012, Google Inc. 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 // A minimalistic implementation of getcontext() to be used by 31 // Google Breakpad on Android. 32 33 #include "common/android/ucontext_constants.h" 34 35 /* int getcontext (ucontext_t *ucp) */ 36 37 #if defined(__arm__) 38 39 .text 40 .global breakpad_getcontext 41 .hidden breakpad_getcontext 42 .type breakpad_getcontext, #function 43 .align 0 44 .fnstart 45 breakpad_getcontext: 46 47 /* First, save r4-r11 */ 48 add r1, r0, #(MCONTEXT_GREGS_OFFSET + 4*4) 49 stm r1, {r4-r11} 50 51 /* r12 is a scratch register, don't save it */ 52 53 /* Save sp and lr explicitly. */ 54 /* - sp can't be stored with stmia in Thumb-2 */ 55 /* - STM instructions that store sp and pc are deprecated in ARM */ 56 str sp, [r0, #(MCONTEXT_GREGS_OFFSET + 13*4)] 57 str lr, [r0, #(MCONTEXT_GREGS_OFFSET + 14*4)] 58 59 /* Save the caller's address in 'pc' */ 60 str lr, [r0, #(MCONTEXT_GREGS_OFFSET + 15*4)] 61 62 /* Save ucontext_t* pointer across next call */ 63 mov r4, r0 64 65 /* Call sigprocmask(SIG_BLOCK, NULL, &(ucontext->uc_sigmask)) */ 66 mov r0, #0 /* SIG_BLOCK */ 67 mov r1, #0 /* NULL */ 68 add r2, r4, #UCONTEXT_SIGMASK_OFFSET 69 bl sigprocmask(PLT) 70 71 /* Intentionally do not save the FPU state here. This is because on 72 * Linux/ARM, one should instead use ptrace(PTRACE_GETFPREGS) or 73 * ptrace(PTRACE_GETVFPREGS) to get it. 74 * 75 * Note that a real implementation of getcontext() would need to save 76 * this here to allow setcontext()/swapcontext() to work correctly. 77 */ 78 79 /* Restore the values of r4 and lr */ 80 mov r0, r4 81 ldr lr, [r0, #(MCONTEXT_GREGS_OFFSET + 14*4)] 82 ldr r4, [r0, #(MCONTEXT_GREGS_OFFSET + 4*4)] 83 84 /* Return 0 */ 85 mov r0, #0 86 bx lr 87 88 .fnend 89 .size breakpad_getcontext, . - breakpad_getcontext 90 91 #elif defined(__aarch64__) 92 93 #define _NSIG 64 94 #define __NR_rt_sigprocmask 135 95 96 .text 97 .global breakpad_getcontext 98 .hidden breakpad_getcontext 99 .type breakpad_getcontext, #function 100 .align 4 101 .cfi_startproc 102 breakpad_getcontext: 103 104 /* The saved context will return to the getcontext() call point 105 with a return value of 0 */ 106 str xzr, [x0, MCONTEXT_GREGS_OFFSET + 0 * REGISTER_SIZE] 107 108 stp x18, x19, [x0, MCONTEXT_GREGS_OFFSET + 18 * REGISTER_SIZE] 109 stp x20, x21, [x0, MCONTEXT_GREGS_OFFSET + 20 * REGISTER_SIZE] 110 stp x22, x23, [x0, MCONTEXT_GREGS_OFFSET + 22 * REGISTER_SIZE] 111 stp x24, x25, [x0, MCONTEXT_GREGS_OFFSET + 24 * REGISTER_SIZE] 112 stp x26, x27, [x0, MCONTEXT_GREGS_OFFSET + 26 * REGISTER_SIZE] 113 stp x28, x29, [x0, MCONTEXT_GREGS_OFFSET + 28 * REGISTER_SIZE] 114 str x30, [x0, MCONTEXT_GREGS_OFFSET + 30 * REGISTER_SIZE] 115 116 /* Place LR into the saved PC, this will ensure that when 117 switching to this saved context with setcontext() control 118 will pass back to the caller of getcontext(), we have 119 already arranged to return the appropriate return value in x0 120 above. */ 121 str x30, [x0, MCONTEXT_PC_OFFSET] 122 123 /* Save the current SP */ 124 mov x2, sp 125 str x2, [x0, MCONTEXT_SP_OFFSET] 126 127 /* Initialize the pstate. */ 128 str xzr, [x0, MCONTEXT_PSTATE_OFFSET] 129 130 /* Figure out where to place the first context extension 131 block. */ 132 add x2, x0, #MCONTEXT_EXTENSION_OFFSET 133 134 /* Write the context extension fpsimd header. */ 135 mov w3, #(FPSIMD_MAGIC & 0xffff) 136 movk w3, #(FPSIMD_MAGIC >> 16), lsl #16 137 str w3, [x2, #FPSIMD_CONTEXT_MAGIC_OFFSET] 138 mov w3, #FPSIMD_CONTEXT_SIZE 139 str w3, [x2, #FPSIMD_CONTEXT_SIZE_OFFSET] 140 141 /* Fill in the FP SIMD context. */ 142 add x3, x2, #(FPSIMD_CONTEXT_VREGS_OFFSET + 8 * SIMD_REGISTER_SIZE) 143 stp d8, d9, [x3], #(2 * SIMD_REGISTER_SIZE) 144 stp d10, d11, [x3], #(2 * SIMD_REGISTER_SIZE) 145 stp d12, d13, [x3], #(2 * SIMD_REGISTER_SIZE) 146 stp d14, d15, [x3], #(2 * SIMD_REGISTER_SIZE) 147 148 add x3, x2, FPSIMD_CONTEXT_FPSR_OFFSET 149 150 mrs x4, fpsr 151 str w4, [x3] 152 153 mrs x4, fpcr 154 str w4, [x3, FPSIMD_CONTEXT_FPCR_OFFSET - FPSIMD_CONTEXT_FPSR_OFFSET] 155 156 /* Write the termination context extension header. */ 157 add x2, x2, #FPSIMD_CONTEXT_SIZE 158 159 str xzr, [x2, #FPSIMD_CONTEXT_MAGIC_OFFSET] 160 str xzr, [x2, #FPSIMD_CONTEXT_SIZE_OFFSET] 161 162 /* Grab the signal mask */ 163 /* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */ 164 add x2, x0, #UCONTEXT_SIGMASK_OFFSET 165 mov x0, #0 /* SIG_BLOCK */ 166 mov x1, #0 /* NULL */ 167 mov x3, #(_NSIG / 8) 168 mov x8, #__NR_rt_sigprocmask 169 svc 0 170 171 /* Return x0 for success */ 172 mov x0, 0 173 ret 174 175 .cfi_endproc 176 .size breakpad_getcontext, . - breakpad_getcontext 177 178 #elif defined(__i386__) 179 180 .text 181 .global breakpad_getcontext 182 .hidden breakpad_getcontext 183 .align 4 184 .type breakpad_getcontext, @function 185 186 breakpad_getcontext: 187 188 movl 4(%esp), %eax /* eax = uc */ 189 190 /* Save register values */ 191 movl %ecx, MCONTEXT_ECX_OFFSET(%eax) 192 movl %edx, MCONTEXT_EDX_OFFSET(%eax) 193 movl %ebx, MCONTEXT_EBX_OFFSET(%eax) 194 movl %edi, MCONTEXT_EDI_OFFSET(%eax) 195 movl %esi, MCONTEXT_ESI_OFFSET(%eax) 196 movl %ebp, MCONTEXT_EBP_OFFSET(%eax) 197 198 movl (%esp), %edx /* return address */ 199 lea 4(%esp), %ecx /* exclude return address from stack */ 200 mov %edx, MCONTEXT_EIP_OFFSET(%eax) 201 mov %ecx, MCONTEXT_ESP_OFFSET(%eax) 202 203 xorl %ecx, %ecx 204 movw %fs, %cx 205 mov %ecx, MCONTEXT_FS_OFFSET(%eax) 206 207 movl $0, MCONTEXT_EAX_OFFSET(%eax) 208 209 /* Save floating point state to fpregstate, then update 210 * the fpregs pointer to point to it */ 211 leal UCONTEXT_FPREGS_MEM_OFFSET(%eax), %ecx 212 fnstenv (%ecx) 213 fldenv (%ecx) 214 mov %ecx, UCONTEXT_FPREGS_OFFSET(%eax) 215 216 /* Save signal mask: sigprocmask(SIGBLOCK, NULL, &uc->uc_sigmask) */ 217 leal UCONTEXT_SIGMASK_OFFSET(%eax), %edx 218 xorl %ecx, %ecx 219 push %edx /* &uc->uc_sigmask */ 220 push %ecx /* NULL */ 221 push %ecx /* SIGBLOCK == 0 on i386 */ 222 call sigprocmask@PLT 223 addl $12, %esp 224 225 movl $0, %eax 226 ret 227 228 .size breakpad_getcontext, . - breakpad_getcontext 229 230 #elif defined(__mips__) 231 232 #if _MIPS_SIM != _ABIO32 233 #error "Unsupported mips ISA. Only mips o32 is supported." 234 #endif 235 236 // This implementation is inspired by implementation of getcontext in glibc. 237 #include <asm/asm.h> 238 #include <asm/regdef.h> 239 #include <asm/fpregdef.h> 240 #include <asm/unistd.h> // for __NR_rt_sigprocmask 241 242 #define _NSIG8 128 / 8 243 #define SIG_BLOCK 1 244 245 246 .text 247 LOCALS_NUM = 2 // save gp and ra on stack 248 FRAME_SIZE = ((LOCALS_NUM * SZREG) + ALSZ) & ALMASK 249 RA_FRAME_OFFSET = FRAME_SIZE - (1 * SZREG) 250 GP_FRAME_OFFSET = FRAME_SIZE - (2 * SZREG) 251 MCONTEXT_REG_SIZE = 8 252 253 NESTED (breakpad_getcontext, FRAME_SIZE, ra) 254 .mask 0x00000000, 0 255 .fmask 0x00000000, 0 256 257 .set noreorder 258 .cpload t9 259 .set reorder 260 261 move a2, sp 262 #define _SP a2 263 264 addiu sp, -FRAME_SIZE 265 sw ra, RA_FRAME_OFFSET(sp) 266 sw gp, GP_FRAME_OFFSET(sp) 267 268 sw s0, (16 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 269 sw s1, (17 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 270 sw s2, (18 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 271 sw s3, (19 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 272 sw s4, (20 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 273 sw s5, (21 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 274 sw s6, (22 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 275 sw s7, (23 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 276 sw _SP, (29 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 277 sw fp, (30 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 278 sw ra, (31 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) 279 sw ra, MCONTEXT_PC_OFFSET(a0) 280 281 #ifdef __mips_hard_float 282 s.d fs0, (20 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) 283 s.d fs1, (22 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) 284 s.d fs2, (24 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) 285 s.d fs3, (26 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) 286 s.d fs4, (28 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) 287 s.d fs5, (30 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) 288 289 cfc1 v1, fcr31 290 sw v1, MCONTEXT_FPC_CSR(a0) 291 #endif // __mips_hard_float 292 293 /* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */ 294 li a3, _NSIG8 295 addu a2, a0, UCONTEXT_SIGMASK_OFFSET 296 move a1, zero 297 li a0, SIG_BLOCK 298 li v0, __NR_rt_sigprocmask 299 syscall 300 301 lw ra, RA_FRAME_OFFSET(sp) 302 lw gp, GP_FRAME_OFFSET(sp) 303 addiu sp, FRAME_SIZE 304 jr ra 305 306 END (breakpad_getcontext) 307 308 #elif defined(__x86_64__) 309 /* The x64 implementation of breakpad_getcontext was derived in part 310 from the implementation of libunwind which requires the following 311 notice. */ 312 /* libunwind - a platform-independent unwind library 313 Copyright (C) 2008 Google, Inc 314 Contributed by Paul Pluzhnikov <ppluzhnikov (at) google.com> 315 Copyright (C) 2010 Konstantin Belousov <kib (at) freebsd.org> 316 317 This file is part of libunwind. 318 319 Permission is hereby granted, free of charge, to any person obtaining 320 a copy of this software and associated documentation files (the 321 "Software"), to deal in the Software without restriction, including 322 without limitation the rights to use, copy, modify, merge, publish, 323 distribute, sublicense, and/or sell copies of the Software, and to 324 permit persons to whom the Software is furnished to do so, subject to 325 the following conditions: 326 327 The above copyright notice and this permission notice shall be 328 included in all copies or substantial portions of the Software. 329 330 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 331 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 332 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 333 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 334 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 335 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 336 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ 337 338 .text 339 .global breakpad_getcontext 340 .hidden breakpad_getcontext 341 .align 4 342 .type breakpad_getcontext, @function 343 344 breakpad_getcontext: 345 .cfi_startproc 346 347 /* Callee saved: RBX, RBP, R12-R15 */ 348 movq %r12, MCONTEXT_GREGS_R12(%rdi) 349 movq %r13, MCONTEXT_GREGS_R13(%rdi) 350 movq %r14, MCONTEXT_GREGS_R14(%rdi) 351 movq %r15, MCONTEXT_GREGS_R15(%rdi) 352 movq %rbp, MCONTEXT_GREGS_RBP(%rdi) 353 movq %rbx, MCONTEXT_GREGS_RBX(%rdi) 354 355 /* Save argument registers (not strictly needed, but setcontext 356 restores them, so don't restore garbage). */ 357 movq %r8, MCONTEXT_GREGS_R8(%rdi) 358 movq %r9, MCONTEXT_GREGS_R9(%rdi) 359 movq %rdi, MCONTEXT_GREGS_RDI(%rdi) 360 movq %rsi, MCONTEXT_GREGS_RSI(%rdi) 361 movq %rdx, MCONTEXT_GREGS_RDX(%rdi) 362 movq %rax, MCONTEXT_GREGS_RAX(%rdi) 363 movq %rcx, MCONTEXT_GREGS_RCX(%rdi) 364 365 /* Save fp state (not needed, except for setcontext not 366 restoring garbage). */ 367 leaq MCONTEXT_FPREGS_MEM(%rdi),%r8 368 movq %r8, MCONTEXT_FPREGS_PTR(%rdi) 369 fnstenv (%r8) 370 stmxcsr FPREGS_OFFSET_MXCSR(%r8) 371 372 leaq 8(%rsp), %rax /* exclude this call. */ 373 movq %rax, MCONTEXT_GREGS_RSP(%rdi) 374 375 movq 0(%rsp), %rax 376 movq %rax, MCONTEXT_GREGS_RIP(%rdi) 377 378 /* Save signal mask: sigprocmask(SIGBLOCK, NULL, &uc->uc_sigmask) */ 379 leaq UCONTEXT_SIGMASK_OFFSET(%rdi), %rdx // arg3 380 xorq %rsi, %rsi // arg2 NULL 381 xorq %rdi, %rdi // arg1 SIGBLOCK == 0 382 call sigprocmask@PLT 383 384 /* Always return 0 for success, even if sigprocmask failed. */ 385 xorl %eax, %eax 386 ret 387 .cfi_endproc 388 .size breakpad_getcontext, . - breakpad_getcontext 389 390 #else 391 #error "This file has not been ported for your CPU!" 392 #endif 393
