1 // TODO some minor issues 2 /* 3 * This file is subject to the terms and conditions of the GNU General Public 4 * License. See the file "COPYING" in the main directory of this archive 5 * for more details. 6 * 7 * Copyright (C) 2001 - 2005 Tensilica Inc. 8 * 9 * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com> 10 * Chris Zankel <chris@zankel.net> 11 * Scott Foehner<sfoehner@yahoo.com>, 12 * Kevin Chea 13 * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca> 14 */ 15 16 #include <linux/config.h> 17 #include <linux/kernel.h> 18 #include <linux/sched.h> 19 #include <linux/mm.h> 20 #include <linux/errno.h> 21 #include <linux/ptrace.h> 22 #include <linux/smp.h> 23 #include <linux/smp_lock.h> 24 #include <linux/security.h> 25 #include <linux/signal.h> 26 27 #include <asm/pgtable.h> 28 #include <asm/page.h> 29 #include <asm/system.h> 30 #include <asm/uaccess.h> 31 #include <asm/ptrace.h> 32 #include <asm/elf.h> 33 34 #define TEST_KERNEL // verify kernel operations FIXME: remove 35 36 37 /* 38 * Called by kernel/ptrace.c when detaching.. 39 * 40 * Make sure single step bits etc are not set. 41 */ 42 43 void ptrace_disable(struct task_struct *child) 44 { 45 /* Nothing to do.. */ 46 } 47 48 long sys_ptrace(long request, long pid, long addr, long data) 49 { 50 struct task_struct *child; 51 int ret = -EPERM; 52 53 lock_kernel(); 54 55 #if 0 56 if ((int)request != 1) 57 printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n", 58 (int) request, (int) pid, (unsigned long) addr, 59 (unsigned long) data); 60 #endif 61 62 if (request == PTRACE_TRACEME) { 63 64 /* Are we already being traced? */ 65 66 if (current->ptrace & PT_PTRACED) 67 goto out; 68 69 if ((ret = security_ptrace(current->parent, current))) 70 goto out; 71 72 /* Set the ptrace bit in the process flags. */ 73 74 current->ptrace |= PT_PTRACED; 75 ret = 0; 76 goto out; 77 } 78 79 ret = -ESRCH; 80 read_lock(&tasklist_lock); 81 child = find_task_by_pid(pid); 82 if (child) 83 get_task_struct(child); 84 read_unlock(&tasklist_lock); 85 if (!child) 86 goto out; 87 88 ret = -EPERM; 89 if (pid == 1) /* you may not mess with init */ 90 goto out; 91 92 if (request == PTRACE_ATTACH) { 93 ret = ptrace_attach(child); 94 goto out_tsk; 95 } 96 97 if ((ret = ptrace_check_attach(child, request == PTRACE_KILL)) < 0) 98 goto out_tsk; 99 100 switch (request) { 101 case PTRACE_PEEKTEXT: /* read word at location addr. */ 102 case PTRACE_PEEKDATA: 103 { 104 unsigned long tmp; 105 int copied; 106 107 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 108 ret = -EIO; 109 if (copied != sizeof(tmp)) 110 break; 111 ret = put_user(tmp,(unsigned long *) data); 112 113 goto out; 114 } 115 116 /* Read the word at location addr in the USER area. */ 117 118 case PTRACE_PEEKUSR: 119 { 120 struct pt_regs *regs; 121 unsigned long tmp; 122 123 regs = xtensa_pt_regs(child); 124 tmp = 0; /* Default return value. */ 125 126 switch(addr) { 127 128 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1: 129 { 130 int ar = addr - REG_AR_BASE - regs->windowbase * 4; 131 ar &= (XCHAL_NUM_AREGS - 1); 132 if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0) 133 tmp = regs->areg[ar]; 134 else 135 ret = -EIO; 136 break; 137 } 138 case REG_A_BASE ... REG_A_BASE + 15: 139 tmp = regs->areg[addr - REG_A_BASE]; 140 break; 141 case REG_PC: 142 tmp = regs->pc; 143 break; 144 case REG_PS: 145 /* Note: PS.EXCM is not set while user task is running; 146 * its being set in regs is for exception handling 147 * convenience. */ 148 tmp = (regs->ps & ~XCHAL_PS_EXCM_MASK); 149 break; 150 case REG_WB: 151 tmp = regs->windowbase; 152 break; 153 case REG_WS: 154 tmp = regs->windowstart; 155 break; 156 case REG_LBEG: 157 tmp = regs->lbeg; 158 break; 159 case REG_LEND: 160 tmp = regs->lend; 161 break; 162 case REG_LCOUNT: 163 tmp = regs->lcount; 164 break; 165 case REG_SAR: 166 tmp = regs->sar; 167 break; 168 case REG_DEPC: 169 tmp = regs->depc; 170 break; 171 case REG_EXCCAUSE: 172 tmp = regs->exccause; 173 break; 174 case REG_EXCVADDR: 175 tmp = regs->excvaddr; 176 break; 177 case SYSCALL_NR: 178 tmp = regs->syscall; 179 break; 180 default: 181 tmp = 0; 182 ret = -EIO; 183 goto out; 184 } 185 ret = put_user(tmp, (unsigned long *) data); 186 goto out; 187 } 188 189 case PTRACE_POKETEXT: /* write the word at location addr. */ 190 case PTRACE_POKEDATA: 191 if (access_process_vm(child, addr, &data, sizeof(data), 1) 192 == sizeof(data)) 193 break; 194 ret = -EIO; 195 goto out; 196 197 case PTRACE_POKEUSR: 198 { 199 struct pt_regs *regs; 200 regs = xtensa_pt_regs(child); 201 202 switch (addr) { 203 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1: 204 { 205 int ar = addr - REG_AR_BASE - regs->windowbase * 4; 206 if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0) 207 regs->areg[ar & (XCHAL_NUM_AREGS - 1)] = data; 208 else 209 ret = -EIO; 210 break; 211 } 212 case REG_A_BASE ... REG_A_BASE + 15: 213 regs->areg[addr - REG_A_BASE] = data; 214 break; 215 case REG_PC: 216 regs->pc = data; 217 break; 218 case SYSCALL_NR: 219 regs->syscall = data; 220 break; 221 #ifdef TEST_KERNEL 222 case REG_WB: 223 regs->windowbase = data; 224 break; 225 case REG_WS: 226 regs->windowstart = data; 227 break; 228 #endif 229 230 default: 231 /* The rest are not allowed. */ 232 ret = -EIO; 233 break; 234 } 235 break; 236 } 237 238 /* continue and stop at next (return from) syscall */ 239 case PTRACE_SYSCALL: 240 case PTRACE_CONT: /* restart after signal. */ 241 { 242 ret = -EIO; 243 if (!valid_signal(data)) 244 break; 245 if (request == PTRACE_SYSCALL) 246 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 247 else 248 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 249 child->exit_code = data; 250 /* Make sure the single step bit is not set. */ 251 child->ptrace &= ~PT_SINGLESTEP; 252 wake_up_process(child); 253 ret = 0; 254 break; 255 } 256 257 /* 258 * make the child exit. Best I can do is send it a sigkill. 259 * perhaps it should be put in the status that it wants to 260 * exit. 261 */ 262 case PTRACE_KILL: 263 ret = 0; 264 if (child->state == EXIT_ZOMBIE) /* already dead */ 265 break; 266 child->exit_code = SIGKILL; 267 child->ptrace &= ~PT_SINGLESTEP; 268 wake_up_process(child); 269 break; 270 271 case PTRACE_SINGLESTEP: 272 ret = -EIO; 273 if (!valid_signal(data)) 274 break; 275 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 276 child->ptrace |= PT_SINGLESTEP; 277 child->exit_code = data; 278 wake_up_process(child); 279 ret = 0; 280 break; 281 282 case PTRACE_GETREGS: 283 { 284 /* 'data' points to user memory in which to write. 285 * Mainly due to the non-live register values, we 286 * reformat the register values into something more 287 * standard. For convenience, we use the handy 288 * elf_gregset_t format. */ 289 290 xtensa_gregset_t format; 291 struct pt_regs *regs = xtensa_pt_regs(child); 292 293 do_copy_regs (&format, regs, child); 294 295 /* Now, copy to user space nice and easy... */ 296 ret = 0; 297 if (copy_to_user((void *)data, &format, sizeof(elf_gregset_t))) 298 ret = -EFAULT; 299 break; 300 } 301 302 case PTRACE_SETREGS: 303 { 304 /* 'data' points to user memory that contains the new 305 * values in the elf_gregset_t format. */ 306 307 xtensa_gregset_t format; 308 struct pt_regs *regs = xtensa_pt_regs(child); 309 310 if (copy_from_user(&format,(void *)data,sizeof(elf_gregset_t))){ 311 ret = -EFAULT; 312 break; 313 } 314 315 /* FIXME: Perhaps we want some sanity checks on 316 * these user-space values? See ARM version. Are 317 * debuggers a security concern? */ 318 319 do_restore_regs (&format, regs, child); 320 321 ret = 0; 322 break; 323 } 324 325 case PTRACE_GETFPREGS: 326 { 327 /* 'data' points to user memory in which to write. 328 * For convenience, we use the handy 329 * elf_fpregset_t format. */ 330 331 elf_fpregset_t fpregs; 332 struct pt_regs *regs = xtensa_pt_regs(child); 333 334 do_save_fpregs (&fpregs, regs, child); 335 336 /* Now, copy to user space nice and easy... */ 337 ret = 0; 338 if (copy_to_user((void *)data, &fpregs, sizeof(elf_fpregset_t))) 339 ret = -EFAULT; 340 341 break; 342 } 343 344 case PTRACE_SETFPREGS: 345 { 346 /* 'data' points to user memory that contains the new 347 * values in the elf_fpregset_t format. 348 */ 349 elf_fpregset_t fpregs; 350 struct pt_regs *regs = xtensa_pt_regs(child); 351 352 ret = 0; 353 if (copy_from_user(&fpregs, (void *)data, sizeof(elf_fpregset_t))) { 354 ret = -EFAULT; 355 break; 356 } 357 358 if (do_restore_fpregs (&fpregs, regs, child)) 359 ret = -EIO; 360 break; 361 } 362 363 case PTRACE_GETFPREGSIZE: 364 /* 'data' points to 'unsigned long' set to the size 365 * of elf_fpregset_t 366 */ 367 ret = put_user(sizeof(elf_fpregset_t), (unsigned long *) data); 368 break; 369 370 case PTRACE_DETACH: /* detach a process that was attached. */ 371 ret = ptrace_detach(child, data); 372 break; 373 374 default: 375 ret = ptrace_request(child, request, addr, data); 376 goto out; 377 } 378 out_tsk: 379 put_task_struct(child); 380 out: 381 unlock_kernel(); 382 return ret; 383 } 384 385 void do_syscall_trace(void) 386 { 387 if (!test_thread_flag(TIF_SYSCALL_TRACE)) 388 return; 389 390 if (!(current->ptrace & PT_PTRACED)) 391 return; 392 393 /* 394 * The 0x80 provides a way for the tracing parent to distinguish 395 * between a syscall stop and SIGTRAP delivery 396 */ 397 ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); 398 399 /* 400 * this isn't the same as continuing with a signal, but it will do 401 * for normal use. strace only continues with a signal if the 402 * stopping signal is not SIGTRAP. -brl 403 */ 404 if (current->exit_code) { 405 send_sig(current->exit_code, current, 1); 406 current->exit_code = 0; 407 } 408 } 409