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 #include <linux/signal.h> 23 24 #include <asm/uaccess.h> 25 #include <asm/page.h> 26 #include <asm/pgtable.h> 27 #include <asm/system.h> 28 #include <asm/processor.h> 29 30 /* 31 * does not yet catch signals sent when the child dies. 32 * in exit.c or in signal.c. 33 */ 34 35 /* determines which bits in the SR the user has access to. */ 36 /* 1 = access 0 = no access */ 37 #define SR_MASK 0x001f 38 39 /* sets the trace bits. */ 40 #define TRACE_BITS 0x8000 41 42 /* Find the stack offset for a register, relative to thread.esp0. */ 43 #define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg) 44 #define SW_REG(reg) ((long)&((struct switch_stack *)0)->reg \ 45 - sizeof(struct switch_stack)) 46 /* Mapping from PT_xxx to the stack offset at which the register is 47 saved. Notice that usp has no stack-slot and needs to be treated 48 specially (see get_reg/put_reg below). */ 49 static int regoff[] = { 50 [0] = PT_REG(d1), 51 [1] = PT_REG(d2), 52 [2] = PT_REG(d3), 53 [3] = PT_REG(d4), 54 [4] = PT_REG(d5), 55 [5] = SW_REG(d6), 56 [6] = SW_REG(d7), 57 [7] = PT_REG(a0), 58 [8] = PT_REG(a1), 59 [9] = PT_REG(a2), 60 [10] = SW_REG(a3), 61 [11] = SW_REG(a4), 62 [12] = SW_REG(a5), 63 [13] = SW_REG(a6), 64 [14] = PT_REG(d0), 65 [15] = -1, 66 [16] = PT_REG(orig_d0), 67 [17] = PT_REG(sr), 68 [18] = PT_REG(pc), 69 }; 70 71 /* 72 * Get contents of register REGNO in task TASK. 73 */ 74 static inline long get_reg(struct task_struct *task, int regno) 75 { 76 unsigned long *addr; 77 78 if (regno == PT_USP) 79 addr = &task->thread.usp; 80 else if (regno < sizeof(regoff)/sizeof(regoff[0])) 81 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]); 82 else 83 return 0; 84 return *addr; 85 } 86 87 /* 88 * Write contents of register REGNO in task TASK. 89 */ 90 static inline int put_reg(struct task_struct *task, int regno, 91 unsigned long data) 92 { 93 unsigned long *addr; 94 95 if (regno == PT_USP) 96 addr = &task->thread.usp; 97 else if (regno < sizeof(regoff)/sizeof(regoff[0])) 98 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]); 99 else 100 return -1; 101 *addr = data; 102 return 0; 103 } 104 105 /* 106 * Called by kernel/ptrace.c when detaching.. 107 * 108 * Make sure the single step bit is not set. 109 */ 110 void ptrace_disable(struct task_struct *child) 111 { 112 unsigned long tmp; 113 /* make sure the single step bit is not set. */ 114 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16); 115 put_reg(child, PT_SR, tmp); 116 child->thread.work.delayed_trace = 0; 117 child->thread.work.syscall_trace = 0; 118 } 119 120 asmlinkage int sys_ptrace(long request, long pid, long addr, long data) 121 { 122 struct task_struct *child; 123 int ret; 124 125 lock_kernel(); 126 ret = -EPERM; 127 if (request == PTRACE_TRACEME) { 128 /* are we already being traced? */ 129 if (current->ptrace & PT_PTRACED) 130 goto out; 131 /* set the ptrace bit in the process flags. */ 132 current->ptrace |= PT_PTRACED; 133 ret = 0; 134 goto out; 135 } 136 ret = -ESRCH; 137 read_lock(&tasklist_lock); 138 child = find_task_by_pid(pid); 139 if (child) 140 get_task_struct(child); 141 read_unlock(&tasklist_lock); 142 if (!child) 143 goto out; 144 145 ret = -EPERM; 146 if (pid == 1) /* you may not mess with init */ 147 goto out_tsk; 148 149 if (request == PTRACE_ATTACH) { 150 ret = ptrace_attach(child); 151 goto out_tsk; 152 } 153 154 ret = ptrace_check_attach(child, request == PTRACE_KILL); 155 if (ret < 0) 156 goto out_tsk; 157 158 switch (request) { 159 /* when I and D space are separate, these will need to be fixed. */ 160 case PTRACE_PEEKTEXT: /* read word at location addr. */ 161 case PTRACE_PEEKDATA: { 162 unsigned long tmp; 163 int copied; 164 165 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 166 ret = -EIO; 167 if (copied != sizeof(tmp)) 168 break; 169 ret = put_user(tmp,(unsigned long *) data); 170 break; 171 } 172 173 /* read the word at location addr in the USER area. */ 174 case PTRACE_PEEKUSR: { 175 unsigned long tmp; 176 177 ret = -EIO; 178 if ((addr & 3) || addr < 0 || 179 addr > sizeof(struct user) - 3) 180 break; 181 182 tmp = 0; /* Default return condition */ 183 addr = addr >> 2; /* temporary hack. */ 184 ret = -EIO; 185 if (addr < 19) { 186 tmp = get_reg(child, addr); 187 if (addr == PT_SR) 188 tmp >>= 16; 189 } else if (addr >= 21 && addr < 49) { 190 tmp = child->thread.fp[addr - 21]; 191 #ifdef CONFIG_M68KFPU_EMU 192 /* Convert internal fpu reg representation 193 * into long double format 194 */ 195 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) 196 tmp = ((tmp & 0xffff0000) << 15) | 197 ((tmp & 0x0000ffff) << 16); 198 #endif 199 } else 200 break; 201 ret = put_user(tmp,(unsigned long *) data); 202 break; 203 } 204 205 /* when I and D space are separate, this will have to be fixed. */ 206 case PTRACE_POKETEXT: /* write the word at location addr. */ 207 case PTRACE_POKEDATA: 208 ret = 0; 209 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) 210 break; 211 ret = -EIO; 212 break; 213 214 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ 215 ret = -EIO; 216 if ((addr & 3) || addr < 0 || 217 addr > sizeof(struct user) - 3) 218 break; 219 220 addr = addr >> 2; /* temporary hack. */ 221 222 if (addr == PT_SR) { 223 data &= SR_MASK; 224 data <<= 16; 225 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16); 226 } 227 if (addr < 19) { 228 if (put_reg(child, addr, data)) 229 break; 230 ret = 0; 231 break; 232 } 233 if (addr >= 21 && addr < 48) 234 { 235 #ifdef CONFIG_M68KFPU_EMU 236 /* Convert long double format 237 * into internal fpu reg representation 238 */ 239 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) { 240 data = (unsigned long)data << 15; 241 data = (data & 0xffff0000) | 242 ((data & 0x0000ffff) >> 1); 243 } 244 #endif 245 child->thread.fp[addr - 21] = data; 246 ret = 0; 247 } 248 break; 249 250 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 251 case PTRACE_CONT: { /* restart after signal. */ 252 long tmp; 253 254 ret = -EIO; 255 if (!valid_signal(data)) 256 break; 257 if (request == PTRACE_SYSCALL) { 258 child->thread.work.syscall_trace = ~0; 259 } else { 260 child->thread.work.syscall_trace = 0; 261 } 262 child->exit_code = data; 263 /* make sure the single step bit is not set. */ 264 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16); 265 put_reg(child, PT_SR, tmp); 266 child->thread.work.delayed_trace = 0; 267 wake_up_process(child); 268 ret = 0; 269 break; 270 } 271 272 /* 273 * make the child exit. Best I can do is send it a sigkill. 274 * perhaps it should be put in the status that it wants to 275 * exit. 276 */ 277 case PTRACE_KILL: { 278 long tmp; 279 280 ret = 0; 281 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 282 break; 283 child->exit_code = SIGKILL; 284 /* make sure the single step bit is not set. */ 285 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16); 286 put_reg(child, PT_SR, tmp); 287 child->thread.work.delayed_trace = 0; 288 wake_up_process(child); 289 break; 290 } 291 292 case PTRACE_SINGLESTEP: { /* set the trap flag. */ 293 long tmp; 294 295 ret = -EIO; 296 if (!valid_signal(data)) 297 break; 298 child->thread.work.syscall_trace = 0; 299 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16); 300 put_reg(child, PT_SR, tmp); 301 child->thread.work.delayed_trace = 1; 302 303 child->exit_code = data; 304 /* give it a chance to run. */ 305 wake_up_process(child); 306 ret = 0; 307 break; 308 } 309 310 case PTRACE_DETACH: /* detach a process that was attached. */ 311 ret = ptrace_detach(child, data); 312 break; 313 314 case PTRACE_GETREGS: { /* Get all gp regs from the child. */ 315 int i; 316 unsigned long tmp; 317 for (i = 0; i < 19; i++) { 318 tmp = get_reg(child, i); 319 if (i == PT_SR) 320 tmp >>= 16; 321 if (put_user(tmp, (unsigned long *) data)) { 322 ret = -EFAULT; 323 break; 324 } 325 data += sizeof(long); 326 } 327 ret = 0; 328 break; 329 } 330 331 case PTRACE_SETREGS: { /* Set all gp regs in the child. */ 332 int i; 333 unsigned long tmp; 334 for (i = 0; i < 19; i++) { 335 if (get_user(tmp, (unsigned long *) data)) { 336 ret = -EFAULT; 337 break; 338 } 339 if (i == PT_SR) { 340 tmp &= SR_MASK; 341 tmp <<= 16; 342 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16); 343 } 344 put_reg(child, i, tmp); 345 data += sizeof(long); 346 } 347 ret = 0; 348 break; 349 } 350 351 case PTRACE_GETFPREGS: { /* Get the child FPU state. */ 352 ret = 0; 353 if (copy_to_user((void *)data, &child->thread.fp, 354 sizeof(struct user_m68kfp_struct))) 355 ret = -EFAULT; 356 break; 357 } 358 359 case PTRACE_SETFPREGS: { /* Set the child FPU state. */ 360 ret = 0; 361 if (copy_from_user(&child->thread.fp, (void *)data, 362 sizeof(struct user_m68kfp_struct))) 363 ret = -EFAULT; 364 break; 365 } 366 367 default: 368 ret = ptrace_request(child, request, addr, data); 369 break; 370 } 371 out_tsk: 372 put_task_struct(child); 373 out: 374 unlock_kernel(); 375 return ret; 376 } 377 378 asmlinkage void syscall_trace(void) 379 { 380 if (!current->thread.work.delayed_trace && 381 !current->thread.work.syscall_trace) 382 return; 383 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 384 ? 0x80 : 0)); 385 /* 386 * this isn't the same as continuing with a signal, but it will do 387 * for normal use. strace only continues with a signal if the 388 * stopping signal is not SIGTRAP. -brl 389 */ 390 if (current->exit_code) { 391 send_sig(current->exit_code, current, 1); 392 current->exit_code = 0; 393 } 394 } 395