1 /* 2 * linux/arch/m68k/kernel/ptrace.c 3 * 4 * Copyright (C) 1994 by Hamish Macdonald 5 * Taken from linux/kernel/ptrace.c and modified for M680x0. 6 * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds 7 * 8 * This file is subject to the terms and conditions of the GNU General 9 * Public License. See the file COPYING in the main directory of 10 * this archive for more details. 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/sched.h> 15 #include <linux/mm.h> 16 #include <linux/smp.h> 17 #include <linux/smp_lock.h> 18 #include <linux/errno.h> 19 #include <linux/ptrace.h> 20 #include <linux/user.h> 21 #include <linux/config.h> 22 23 #include <asm/uaccess.h> 24 #include <asm/page.h> 25 #include <asm/pgtable.h> 26 #include <asm/system.h> 27 #include <asm/processor.h> 28 29 /* 30 * does not yet catch signals sent when the child dies. 31 * in exit.c or in signal.c. 32 */ 33 34 /* determines which bits in the SR the user has access to. */ 35 /* 1 = access 0 = no access */ 36 #define SR_MASK 0x001f 37 38 /* sets the trace bits. */ 39 #define TRACE_BITS 0x8000 40 41 /* Find the stack offset for a register, relative to thread.esp0. */ 42 #define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg) 43 #define SW_REG(reg) ((long)&((struct switch_stack *)0)->reg \ 44 - sizeof(struct switch_stack)) 45 /* Mapping from PT_xxx to the stack offset at which the register is 46 saved. Notice that usp has no stack-slot and needs to be treated 47 specially (see get_reg/put_reg below). */ 48 static int regoff[] = { 49 [0] = PT_REG(d1), 50 [1] = PT_REG(d2), 51 [2] = PT_REG(d3), 52 [3] = PT_REG(d4), 53 [4] = PT_REG(d5), 54 [5] = SW_REG(d6), 55 [6] = SW_REG(d7), 56 [7] = PT_REG(a0), 57 [8] = PT_REG(a1), 58 [9] = PT_REG(a2), 59 [10] = SW_REG(a3), 60 [11] = SW_REG(a4), 61 [12] = SW_REG(a5), 62 [13] = SW_REG(a6), 63 [14] = PT_REG(d0), 64 [15] = -1, 65 [16] = PT_REG(orig_d0), 66 [17] = PT_REG(sr), 67 [18] = PT_REG(pc), 68 }; 69 70 /* 71 * Get contents of register REGNO in task TASK. 72 */ 73 static inline long get_reg(struct task_struct *task, int regno) 74 { 75 unsigned long *addr; 76 77 if (regno == PT_USP) 78 addr = &task->thread.usp; 79 else if (regno < sizeof(regoff)/sizeof(regoff[0])) 80 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]); 81 else 82 return 0; 83 return *addr; 84 } 85 86 /* 87 * Write contents of register REGNO in task TASK. 88 */ 89 static inline int put_reg(struct task_struct *task, int regno, 90 unsigned long data) 91 { 92 unsigned long *addr; 93 94 if (regno == PT_USP) 95 addr = &task->thread.usp; 96 else if (regno < sizeof(regoff)/sizeof(regoff[0])) 97 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]); 98 else 99 return -1; 100 *addr = data; 101 return 0; 102 } 103 104 /* 105 * Called by kernel/ptrace.c when detaching.. 106 * 107 * Make sure the single step bit is not set. 108 */ 109 void ptrace_disable(struct task_struct *child) 110 { 111 unsigned long tmp; 112 /* make sure the single step bit is not set. */ 113 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16); 114 put_reg(child, PT_SR, tmp); 115 child->thread.work.delayed_trace = 0; 116 child->thread.work.syscall_trace = 0; 117 } 118 119 asmlinkage int sys_ptrace(long request, long pid, long addr, long data) 120 { 121 struct task_struct *child; 122 int ret; 123 124 lock_kernel(); 125 ret = -EPERM; 126 if (request == PTRACE_TRACEME) { 127 /* are we already being traced? */ 128 if (current->ptrace & PT_PTRACED) 129 goto out; 130 /* set the ptrace bit in the process flags. */ 131 current->ptrace |= PT_PTRACED; 132 ret = 0; 133 goto out; 134 } 135 ret = -ESRCH; 136 read_lock(&tasklist_lock); 137 child = find_task_by_pid(pid); 138 if (child) 139 get_task_struct(child); 140 read_unlock(&tasklist_lock); 141 if (!child) 142 goto out; 143 144 ret = -EPERM; 145 if (pid == 1) /* you may not mess with init */ 146 goto out_tsk; 147 148 if (request == PTRACE_ATTACH) { 149 ret = ptrace_attach(child); 150 goto out_tsk; 151 } 152 153 ret = ptrace_check_attach(child, request == PTRACE_KILL); 154 if (ret < 0) 155 goto out_tsk; 156 157 switch (request) { 158 /* when I and D space are separate, these will need to be fixed. */ 159 case PTRACE_PEEKTEXT: /* read word at location addr. */ 160 case PTRACE_PEEKDATA: { 161 unsigned long tmp; 162 int copied; 163 164 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 165 ret = -EIO; 166 if (copied != sizeof(tmp)) 167 break; 168 ret = put_user(tmp,(unsigned long *) data); 169 break; 170 } 171 172 /* read the word at location addr in the USER area. */ 173 case PTRACE_PEEKUSR: { 174 unsigned long tmp; 175 176 ret = -EIO; 177 if ((addr & 3) || addr < 0 || 178 addr > sizeof(struct user) - 3) 179 break; 180 181 tmp = 0; /* Default return condition */ 182 addr = addr >> 2; /* temporary hack. */ 183 ret = -EIO; 184 if (addr < 19) { 185 tmp = get_reg(child, addr); 186 if (addr == PT_SR) 187 tmp >>= 16; 188 } else if (addr >= 21 && addr < 49) { 189 tmp = child->thread.fp[addr - 21]; 190 #ifdef CONFIG_M68KFPU_EMU 191 /* Convert internal fpu reg representation 192 * into long double format 193 */ 194 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) 195 tmp = ((tmp & 0xffff0000) << 15) | 196 ((tmp & 0x0000ffff) << 16); 197 #endif 198 } else 199 break; 200 ret = put_user(tmp,(unsigned long *) data); 201 break; 202 } 203 204 /* when I and D space are separate, this will have to be fixed. */ 205 case PTRACE_POKETEXT: /* write the word at location addr. */ 206 case PTRACE_POKEDATA: 207 ret = 0; 208 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) 209 break; 210 ret = -EIO; 211 break; 212 213 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ 214 ret = -EIO; 215 if ((addr & 3) || addr < 0 || 216 addr > sizeof(struct user) - 3) 217 break; 218 219 addr = addr >> 2; /* temporary hack. */ 220 221 if (addr == PT_SR) { 222 data &= SR_MASK; 223 data <<= 16; 224 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16); 225 } 226 if (addr < 19) { 227 if (put_reg(child, addr, data)) 228 break; 229 ret = 0; 230 break; 231 } 232 if (addr >= 21 && addr < 48) 233 { 234 #ifdef CONFIG_M68KFPU_EMU 235 /* Convert long double format 236 * into internal fpu reg representation 237 */ 238 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) { 239 data = (unsigned long)data << 15; 240 data = (data & 0xffff0000) | 241 ((data & 0x0000ffff) >> 1); 242 } 243 #endif 244 child->thread.fp[addr - 21] = data; 245 ret = 0; 246 } 247 break; 248 249 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 250 case PTRACE_CONT: { /* restart after signal. */ 251 long tmp; 252 253 ret = -EIO; 254 if ((unsigned long) data > _NSIG) 255 break; 256 if (request == PTRACE_SYSCALL) { 257 child->thread.work.syscall_trace = ~0; 258 } else { 259 child->thread.work.syscall_trace = 0; 260 } 261 child->exit_code = data; 262 /* make sure the single step bit is not set. */ 263 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16); 264 put_reg(child, PT_SR, tmp); 265 child->thread.work.delayed_trace = 0; 266 wake_up_process(child); 267 ret = 0; 268 break; 269 } 270 271 /* 272 * make the child exit. Best I can do is send it a sigkill. 273 * perhaps it should be put in the status that it wants to 274 * exit. 275 */ 276 case PTRACE_KILL: { 277 long tmp; 278 279 ret = 0; 280 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 281 break; 282 child->exit_code = SIGKILL; 283 /* make sure the single step bit is not set. */ 284 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16); 285 put_reg(child, PT_SR, tmp); 286 child->thread.work.delayed_trace = 0; 287 wake_up_process(child); 288 break; 289 } 290 291 case PTRACE_SINGLESTEP: { /* set the trap flag. */ 292 long tmp; 293 294 ret = -EIO; 295 if ((unsigned long) data > _NSIG) 296 break; 297 child->thread.work.syscall_trace = 0; 298 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16); 299 put_reg(child, PT_SR, tmp); 300 child->thread.work.delayed_trace = 1; 301 302 child->exit_code = data; 303 /* give it a chance to run. */ 304 wake_up_process(child); 305 ret = 0; 306 break; 307 } 308 309 case PTRACE_DETACH: /* detach a process that was attached. */ 310 ret = ptrace_detach(child, data); 311 break; 312 313 case PTRACE_GETREGS: { /* Get all gp regs from the child. */ 314 int i; 315 unsigned long tmp; 316 for (i = 0; i < 19; i++) { 317 tmp = get_reg(child, i); 318 if (i == PT_SR) 319 tmp >>= 16; 320 if (put_user(tmp, (unsigned long *) data)) { 321 ret = -EFAULT; 322 break; 323 } 324 data += sizeof(long); 325 } 326 ret = 0; 327 break; 328 } 329 330 case PTRACE_SETREGS: { /* Set all gp regs in the child. */ 331 int i; 332 unsigned long tmp; 333 for (i = 0; i < 19; i++) { 334 if (get_user(tmp, (unsigned long *) data)) { 335 ret = -EFAULT; 336 break; 337 } 338 if (i == PT_SR) { 339 tmp &= SR_MASK; 340 tmp <<= 16; 341 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16); 342 } 343 put_reg(child, i, tmp); 344 data += sizeof(long); 345 } 346 ret = 0; 347 break; 348 } 349 350 case PTRACE_GETFPREGS: { /* Get the child FPU state. */ 351 ret = 0; 352 if (copy_to_user((void *)data, &child->thread.fp, 353 sizeof(struct user_m68kfp_struct))) 354 ret = -EFAULT; 355 break; 356 } 357 358 case PTRACE_SETFPREGS: { /* Set the child FPU state. */ 359 ret = 0; 360 if (copy_from_user(&child->thread.fp, (void *)data, 361 sizeof(struct user_m68kfp_struct))) 362 ret = -EFAULT; 363 break; 364 } 365 366 default: 367 ret = ptrace_request(child, request, addr, data); 368 break; 369 } 370 out_tsk: 371 put_task_struct(child); 372 out: 373 unlock_kernel(); 374 return ret; 375 } 376 377 asmlinkage void syscall_trace(void) 378 { 379 if (!current->thread.work.delayed_trace && 380 !current->thread.work.syscall_trace) 381 return; 382 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 383 ? 0x80 : 0)); 384 /* 385 * this isn't the same as continuing with a signal, but it will do 386 * for normal use. strace only continues with a signal if the 387 * stopping signal is not SIGTRAP. -brl 388 */ 389 if (current->exit_code) { 390 send_sig(current->exit_code, current, 1); 391 current->exit_code = 0; 392 } 393 } 394