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 * Make sure the single step bit is not set. 107 */ 108 static inline void singlestep_disable(struct task_struct *child) 109 { 110 unsigned long tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16); 111 put_reg(child, PT_SR, tmp); 112 child->thread.work.delayed_trace = 0; 113 } 114 115 /* 116 * Called by kernel/ptrace.c when detaching.. 117 */ 118 void ptrace_disable(struct task_struct *child) 119 { 120 singlestep_disable(child); 121 child->thread.work.syscall_trace = 0; 122 } 123 124 asmlinkage long sys_ptrace(long request, long pid, long addr, long data) 125 { 126 struct task_struct *child; 127 unsigned long tmp; 128 int i, ret = 0; 129 130 lock_kernel(); 131 if (request == PTRACE_TRACEME) { 132 /* are we already being traced? */ 133 if (current->ptrace & PT_PTRACED) { 134 ret = -EPERM; 135 goto out; 136 } 137 /* set the ptrace bit in the process flags. */ 138 current->ptrace |= PT_PTRACED; 139 goto out; 140 } 141 read_lock(&tasklist_lock); 142 child = find_task_by_pid(pid); 143 if (child) 144 get_task_struct(child); 145 read_unlock(&tasklist_lock); 146 if (unlikely(!child)) { 147 ret = -ESRCH; 148 goto out; 149 } 150 151 /* you may not mess with init */ 152 if (unlikely(pid == 1)) { 153 ret = -EPERM; 154 goto out_tsk; 155 } 156 157 if (request == PTRACE_ATTACH) { 158 ret = ptrace_attach(child); 159 goto out_tsk; 160 } 161 162 ret = ptrace_check_attach(child, request == PTRACE_KILL); 163 if (ret) 164 goto out_tsk; 165 166 switch (request) { 167 /* when I and D space are separate, these will need to be fixed. */ 168 case PTRACE_PEEKTEXT: /* read word at location addr. */ 169 case PTRACE_PEEKDATA: 170 i = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 171 if (i != sizeof(tmp)) 172 goto out_eio; 173 ret = put_user(tmp, (unsigned long *)data); 174 break; 175 176 /* read the word at location addr in the USER area. */ 177 case PTRACE_PEEKUSR: 178 if (addr & 3) 179 goto out_eio; 180 addr >>= 2; /* temporary hack. */ 181 182 if (addr >= 0 && addr < 19) { 183 tmp = get_reg(child, addr); 184 if (addr == PT_SR) 185 tmp >>= 16; 186 } else if (addr >= 21 && addr < 49) { 187 tmp = child->thread.fp[addr - 21]; 188 /* Convert internal fpu reg representation 189 * into long double format 190 */ 191 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) 192 tmp = ((tmp & 0xffff0000) << 15) | 193 ((tmp & 0x0000ffff) << 16); 194 } else 195 break; 196 ret = put_user(tmp, (unsigned long *)data); 197 break; 198 199 /* when I and D space are separate, this will have to be fixed. */ 200 case PTRACE_POKETEXT: /* write the word at location addr. */ 201 case PTRACE_POKEDATA: 202 if (access_process_vm(child, addr, &data, sizeof(data), 1) != sizeof(data)) 203 goto out_eio; 204 break; 205 206 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ 207 if (addr & 3) 208 goto out_eio; 209 addr >>= 2; /* temporary hack. */ 210 211 if (addr == PT_SR) { 212 data &= SR_MASK; 213 data <<= 16; 214 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16); 215 } else if (addr >= 0 && addr < 19) { 216 if (put_reg(child, addr, data)) 217 goto out_eio; 218 } else if (addr >= 21 && addr < 48) { 219 /* Convert long double format 220 * into internal fpu reg representation 221 */ 222 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) { 223 data = (unsigned long)data << 15; 224 data = (data & 0xffff0000) | 225 ((data & 0x0000ffff) >> 1); 226 } 227 child->thread.fp[addr - 21] = data; 228 } else 229 goto out_eio; 230 break; 231 232 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 233 case PTRACE_CONT: /* restart after signal. */ 234 if (!valid_signal(data)) 235 goto out_eio; 236 237 if (request == PTRACE_SYSCALL) 238 child->thread.work.syscall_trace = ~0; 239 else 240 child->thread.work.syscall_trace = 0; 241 child->exit_code = data; 242 singlestep_disable(child); 243 wake_up_process(child); 244 break; 245 246 /* 247 * make the child exit. Best I can do is send it a sigkill. 248 * perhaps it should be put in the status that it wants to 249 * exit. 250 */ 251 case PTRACE_KILL: 252 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 253 break; 254 child->exit_code = SIGKILL; 255 singlestep_disable(child); 256 wake_up_process(child); 257 break; 258 259 case PTRACE_SINGLESTEP: /* set the trap flag. */ 260 if (!valid_signal(data)) 261 goto out_eio; 262 263 child->thread.work.syscall_trace = 0; 264 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16); 265 put_reg(child, PT_SR, tmp); 266 child->thread.work.delayed_trace = 1; 267 268 child->exit_code = data; 269 /* give it a chance to run. */ 270 wake_up_process(child); 271 break; 272 273 case PTRACE_DETACH: /* detach a process that was attached. */ 274 ret = ptrace_detach(child, data); 275 break; 276 277 case PTRACE_GETREGS: /* Get all gp regs from the child. */ 278 for (i = 0; i < 19; i++) { 279 tmp = get_reg(child, i); 280 if (i == PT_SR) 281 tmp >>= 16; 282 ret = put_user(tmp, (unsigned long *)data); 283 if (ret) 284 break; 285 data += sizeof(long); 286 } 287 break; 288 289 case PTRACE_SETREGS: /* Set all gp regs in the child. */ 290 for (i = 0; i < 19; i++) { 291 ret = get_user(tmp, (unsigned long *)data); 292 if (ret) 293 break; 294 if (i == PT_SR) { 295 tmp &= SR_MASK; 296 tmp <<= 16; 297 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16); 298 } 299 put_reg(child, i, tmp); 300 data += sizeof(long); 301 } 302 break; 303 304 case PTRACE_GETFPREGS: /* Get the child FPU state. */ 305 if (copy_to_user((void *)data, &child->thread.fp, 306 sizeof(struct user_m68kfp_struct))) 307 ret = -EFAULT; 308 break; 309 310 case PTRACE_SETFPREGS: /* Set the child FPU state. */ 311 if (copy_from_user(&child->thread.fp, (void *)data, 312 sizeof(struct user_m68kfp_struct))) 313 ret = -EFAULT; 314 break; 315 316 default: 317 ret = ptrace_request(child, request, addr, data); 318 break; 319 } 320 out_tsk: 321 put_task_struct(child); 322 out: 323 unlock_kernel(); 324 return ret; 325 out_eio: 326 ret = -EIO; 327 goto out_tsk; 328 } 329 330 asmlinkage void syscall_trace(void) 331 { 332 if (!current->thread.work.delayed_trace && 333 !current->thread.work.syscall_trace) 334 return; 335 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 336 ? 0x80 : 0)); 337 /* 338 * this isn't the same as continuing with a signal, but it will do 339 * for normal use. strace only continues with a signal if the 340 * stopping signal is not SIGTRAP. -brl 341 */ 342 if (current->exit_code) { 343 send_sig(current->exit_code, current, 1); 344 current->exit_code = 0; 345 } 346 } 347