1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 1992 Ross Biro 7 * Copyright (C) Linus Torvalds 8 * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle 9 * Copyright (C) 1996 David S. Miller 10 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com 11 * Copyright (C) 1999 MIPS Technologies, Inc. 12 * Copyright (C) 2000 Ulf Carlsson 13 * 14 * At this time Linux/MIPS64 only supports syscall tracing, even for 32-bit 15 * binaries. 16 */ 17 #include <linux/config.h> 18 #include <linux/compiler.h> 19 #include <linux/kernel.h> 20 #include <linux/sched.h> 21 #include <linux/mm.h> 22 #include <linux/errno.h> 23 #include <linux/ptrace.h> 24 #include <linux/audit.h> 25 #include <linux/smp.h> 26 #include <linux/smp_lock.h> 27 #include <linux/user.h> 28 #include <linux/security.h> 29 #include <linux/signal.h> 30 31 #include <asm/cpu.h> 32 #include <asm/fpu.h> 33 #include <asm/mipsregs.h> 34 #include <asm/pgtable.h> 35 #include <asm/page.h> 36 #include <asm/system.h> 37 #include <asm/uaccess.h> 38 #include <asm/bootinfo.h> 39 40 /* 41 * Called by kernel/ptrace.c when detaching.. 42 * 43 * Make sure single step bits etc are not set. 44 */ 45 void ptrace_disable(struct task_struct *child) 46 { 47 /* Nothing to do.. */ 48 } 49 50 asmlinkage int sys_ptrace(long request, long pid, long addr, long data) 51 { 52 struct task_struct *child; 53 int ret; 54 55 #if 0 56 printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n", 57 (int) request, (int) pid, (unsigned long) addr, 58 (unsigned long) data); 59 #endif 60 lock_kernel(); 61 ret = -EPERM; 62 if (request == PTRACE_TRACEME) { 63 /* are we already being traced? */ 64 if (current->ptrace & PT_PTRACED) 65 goto out; 66 if ((ret = security_ptrace(current->parent, current))) 67 goto out; 68 /* set the ptrace bit in the process flags. */ 69 current->ptrace |= PT_PTRACED; 70 ret = 0; 71 goto out; 72 } 73 ret = -ESRCH; 74 read_lock(&tasklist_lock); 75 child = find_task_by_pid(pid); 76 if (child) 77 get_task_struct(child); 78 read_unlock(&tasklist_lock); 79 if (!child) 80 goto out; 81 82 ret = -EPERM; 83 if (pid == 1) /* you may not mess with init */ 84 goto out_tsk; 85 86 if (request == PTRACE_ATTACH) { 87 ret = ptrace_attach(child); 88 goto out_tsk; 89 } 90 91 ret = ptrace_check_attach(child, request == PTRACE_KILL); 92 if (ret < 0) 93 goto out_tsk; 94 95 switch (request) { 96 /* when I and D space are separate, these will need to be fixed. */ 97 case PTRACE_PEEKTEXT: /* read word at location addr. */ 98 case PTRACE_PEEKDATA: { 99 unsigned long tmp; 100 int copied; 101 102 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 103 ret = -EIO; 104 if (copied != sizeof(tmp)) 105 break; 106 ret = put_user(tmp,(unsigned long __user *) data); 107 break; 108 } 109 110 /* Read the word at location addr in the USER area. */ 111 case PTRACE_PEEKUSR: { 112 struct pt_regs *regs; 113 unsigned long tmp = 0; 114 115 regs = (struct pt_regs *) ((unsigned long) child->thread_info + 116 THREAD_SIZE - 32 - sizeof(struct pt_regs)); 117 ret = 0; /* Default return value. */ 118 119 switch (addr) { 120 case 0 ... 31: 121 tmp = regs->regs[addr]; 122 break; 123 case FPR_BASE ... FPR_BASE + 31: 124 if (tsk_used_math(child)) { 125 fpureg_t *fregs = get_fpu_regs(child); 126 127 #ifdef CONFIG_32BIT 128 /* 129 * The odd registers are actually the high 130 * order bits of the values stored in the even 131 * registers - unless we're using r2k_switch.S. 132 */ 133 if (addr & 1) 134 tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32); 135 else 136 tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff); 137 #endif 138 #ifdef CONFIG_64BIT 139 tmp = fregs[addr - FPR_BASE]; 140 #endif 141 } else { 142 tmp = -1; /* FP not yet used */ 143 } 144 break; 145 case PC: 146 tmp = regs->cp0_epc; 147 break; 148 case CAUSE: 149 tmp = regs->cp0_cause; 150 break; 151 case BADVADDR: 152 tmp = regs->cp0_badvaddr; 153 break; 154 case MMHI: 155 tmp = regs->hi; 156 break; 157 case MMLO: 158 tmp = regs->lo; 159 break; 160 case FPC_CSR: 161 if (cpu_has_fpu) 162 tmp = child->thread.fpu.hard.fcr31; 163 else 164 tmp = child->thread.fpu.soft.fcr31; 165 break; 166 case FPC_EIR: { /* implementation / version register */ 167 unsigned int flags; 168 169 if (!cpu_has_fpu) 170 break; 171 172 flags = read_c0_status(); 173 __enable_fpu(); 174 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp)); 175 write_c0_status(flags); 176 break; 177 } 178 default: 179 tmp = 0; 180 ret = -EIO; 181 goto out_tsk; 182 } 183 ret = put_user(tmp, (unsigned long __user *) data); 184 break; 185 } 186 187 /* when I and D space are separate, this will have to be fixed. */ 188 case PTRACE_POKETEXT: /* write the word at location addr. */ 189 case PTRACE_POKEDATA: 190 ret = 0; 191 if (access_process_vm(child, addr, &data, sizeof(data), 1) 192 == sizeof(data)) 193 break; 194 ret = -EIO; 195 break; 196 197 case PTRACE_POKEUSR: { 198 struct pt_regs *regs; 199 ret = 0; 200 regs = (struct pt_regs *) ((unsigned long) child->thread_info + 201 THREAD_SIZE - 32 - sizeof(struct pt_regs)); 202 203 switch (addr) { 204 case 0 ... 31: 205 regs->regs[addr] = data; 206 break; 207 case FPR_BASE ... FPR_BASE + 31: { 208 fpureg_t *fregs = get_fpu_regs(child); 209 210 if (!tsk_used_math(child)) { 211 /* FP not yet used */ 212 memset(&child->thread.fpu.hard, ~0, 213 sizeof(child->thread.fpu.hard)); 214 child->thread.fpu.hard.fcr31 = 0; 215 } 216 #ifdef CONFIG_32BIT 217 /* 218 * The odd registers are actually the high order bits 219 * of the values stored in the even registers - unless 220 * we're using r2k_switch.S. 221 */ 222 if (addr & 1) { 223 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff; 224 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32; 225 } else { 226 fregs[addr - FPR_BASE] &= ~0xffffffffLL; 227 fregs[addr - FPR_BASE] |= data; 228 } 229 #endif 230 #ifdef CONFIG_64BIT 231 fregs[addr - FPR_BASE] = data; 232 #endif 233 break; 234 } 235 case PC: 236 regs->cp0_epc = data; 237 break; 238 case MMHI: 239 regs->hi = data; 240 break; 241 case MMLO: 242 regs->lo = data; 243 break; 244 case FPC_CSR: 245 if (cpu_has_fpu) 246 child->thread.fpu.hard.fcr31 = data; 247 else 248 child->thread.fpu.soft.fcr31 = data; 249 break; 250 default: 251 /* The rest are not allowed. */ 252 ret = -EIO; 253 break; 254 } 255 break; 256 } 257 258 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 259 case PTRACE_CONT: { /* restart after signal. */ 260 ret = -EIO; 261 if (!valid_signal(data)) 262 break; 263 if (request == PTRACE_SYSCALL) { 264 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 265 } 266 else { 267 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 268 } 269 child->exit_code = data; 270 wake_up_process(child); 271 ret = 0; 272 break; 273 } 274 275 /* 276 * make the child exit. Best I can do is send it a sigkill. 277 * perhaps it should be put in the status that it wants to 278 * exit. 279 */ 280 case PTRACE_KILL: 281 ret = 0; 282 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 283 break; 284 child->exit_code = SIGKILL; 285 wake_up_process(child); 286 break; 287 288 case PTRACE_DETACH: /* detach a process that was attached. */ 289 ret = ptrace_detach(child, data); 290 break; 291 292 case PTRACE_GET_THREAD_AREA: 293 ret = put_user(child->thread_info->tp_value, 294 (unsigned long __user *) data); 295 break; 296 297 default: 298 ret = ptrace_request(child, request, addr, data); 299 break; 300 } 301 302 out_tsk: 303 put_task_struct(child); 304 out: 305 unlock_kernel(); 306 return ret; 307 } 308 309 static inline int audit_arch(void) 310 { 311 #ifdef CONFIG_CPU_LITTLE_ENDIAN 312 #ifdef CONFIG_64BIT 313 if (!(current->thread.mflags & MF_32BIT_REGS)) 314 return AUDIT_ARCH_MIPSEL64; 315 #endif /* MIPS64 */ 316 return AUDIT_ARCH_MIPSEL; 317 318 #else /* big endian... */ 319 #ifdef CONFIG_64BIT 320 if (!(current->thread.mflags & MF_32BIT_REGS)) 321 return AUDIT_ARCH_MIPS64; 322 #endif /* MIPS64 */ 323 return AUDIT_ARCH_MIPS; 324 325 #endif /* endian */ 326 } 327 328 /* 329 * Notification of system call entry/exit 330 * - triggered by current->work.syscall_trace 331 */ 332 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit) 333 { 334 if (unlikely(current->audit_context) && entryexit) 335 audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]), regs->regs[2]); 336 337 if (!test_thread_flag(TIF_SYSCALL_TRACE)) 338 goto out; 339 if (!(current->ptrace & PT_PTRACED)) 340 goto out; 341 342 /* The 0x80 provides a way for the tracing parent to distinguish 343 between a syscall stop and SIGTRAP delivery */ 344 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 345 0x80 : 0)); 346 347 /* 348 * this isn't the same as continuing with a signal, but it will do 349 * for normal use. strace only continues with a signal if the 350 * stopping signal is not SIGTRAP. -brl 351 */ 352 if (current->exit_code) { 353 send_sig(current->exit_code, current, 1); 354 current->exit_code = 0; 355 } 356 out: 357 if (unlikely(current->audit_context) && !entryexit) 358 audit_syscall_entry(current, audit_arch(), regs->regs[2], 359 regs->regs[4], regs->regs[5], 360 regs->regs[6], regs->regs[7]); 361 } 362