1/* 2 * Kernel support for the ptrace() and syscall tracing interfaces. 3 * 4 * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc. 5 * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx> 6 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org> 7 */ 8 9#include <linux/kernel.h> 10#include <linux/sched.h> 11#include <linux/mm.h> 12#include <linux/smp.h> 13#include <linux/errno.h> 14#include <linux/ptrace.h> 15#include <linux/user.h> 16#include <linux/personality.h> 17#include <linux/security.h> 18#include <linux/compat.h> 19#include <linux/signal.h> 20 21#include <asm/uaccess.h> 22#include <asm/pgtable.h> 23#include <asm/system.h> 24#include <asm/processor.h> 25#include <asm/asm-offsets.h> 26 27/* PSW bits we allow the debugger to modify */ 28#define USER_PSW_BITS (PSW_N | PSW_V | PSW_CB) 29 30#undef DEBUG_PTRACE 31 32#ifdef DEBUG_PTRACE 33#define DBG(x...) printk(x) 34#else 35#define DBG(x...) 36#endif 37 38#ifdef CONFIG_64BIT 39 40/* This function is needed to translate 32 bit pt_regs offsets in to 41 * 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel 42 * will request offset 12 if it wants gr3, but the lower 32 bits of 43 * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4). 44 * This code relies on a 32 bit pt_regs being comprised of 32 bit values 45 * except for the fp registers which (a) are 64 bits, and (b) follow 46 * the gr registers at the start of pt_regs. The 32 bit pt_regs should 47 * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[] 48 * being 64 bit in both cases. 49 */ 50 51static long translate_usr_offset(long offset) 52{ 53 if (offset < 0) 54 return -1; 55 else if (offset <= 32*4) /* gr[0..31] */ 56 return offset * 2 + 4; 57 else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */ 58 return offset + 32*4; 59 else if (offset < sizeof(struct pt_regs)/2 + 32*4) 60 return offset * 2 + 4 - 32*8; 61 else 62 return -1; 63} 64#endif 65 66/* 67 * Called by kernel/ptrace.c when detaching.. 68 * 69 * Make sure single step bits etc are not set. 70 */ 71void ptrace_disable(struct task_struct *child) 72{ 73 /* make sure the trap bits are not set */ 74 pa_psw(child)->r = 0; 75 pa_psw(child)->t = 0; 76 pa_psw(child)->h = 0; 77 pa_psw(child)->l = 0; 78} 79 80long arch_ptrace(struct task_struct *child, long request, long addr, long data) 81{ 82 long ret; 83#ifdef DEBUG_PTRACE 84 long oaddr=addr, odata=data; 85#endif 86 87 switch (request) { 88 case PTRACE_PEEKTEXT: /* read word at location addr. */ 89 case PTRACE_PEEKDATA: { 90 int copied; 91 92#ifdef CONFIG_64BIT 93 if (__is_compat_task(child)) { 94 unsigned int tmp; 95 96 addr &= 0xffffffffL; 97 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 98 ret = -EIO; 99 if (copied != sizeof(tmp)) 100 goto out_tsk; 101 ret = put_user(tmp,(unsigned int *) data); 102 DBG("sys_ptrace(PEEK%s, %d, %lx, %lx) returning %ld, data %x\n", 103 request == PTRACE_PEEKTEXT ? "TEXT" : "DATA", 104 pid, oaddr, odata, ret, tmp); 105 } 106 else 107#endif 108 { 109 unsigned long tmp; 110 111 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 112 ret = -EIO; 113 if (copied != sizeof(tmp)) 114 goto out_tsk; 115 ret = put_user(tmp,(unsigned long *) data); 116 } 117 goto out_tsk; 118 } 119 120 /* when I and D space are separate, this will have to be fixed. */ 121 case PTRACE_POKETEXT: /* write the word at location addr. */ 122 case PTRACE_POKEDATA: 123 ret = 0; 124#ifdef CONFIG_64BIT 125 if (__is_compat_task(child)) { 126 unsigned int tmp = (unsigned int)data; 127 DBG("sys_ptrace(POKE%s, %d, %lx, %lx)\n", 128 request == PTRACE_POKETEXT ? "TEXT" : "DATA", 129 pid, oaddr, odata); 130 addr &= 0xffffffffL; 131 if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1) == sizeof(tmp)) 132 goto out_tsk; 133 } 134 else 135#endif 136 { 137 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) 138 goto out_tsk; 139 } 140 ret = -EIO; 141 goto out_tsk; 142 143 /* Read the word at location addr in the USER area. For ptraced 144 processes, the kernel saves all regs on a syscall. */ 145 case PTRACE_PEEKUSR: { 146 ret = -EIO; 147#ifdef CONFIG_64BIT 148 if (__is_compat_task(child)) { 149 unsigned int tmp; 150 151 if (addr & (sizeof(int)-1)) 152 goto out_tsk; 153 if ((addr = translate_usr_offset(addr)) < 0) 154 goto out_tsk; 155 156 tmp = *(unsigned int *) ((char *) task_regs(child) + addr); 157 ret = put_user(tmp, (unsigned int *) data); 158 DBG("sys_ptrace(PEEKUSR, %d, %lx, %lx) returning %ld, addr %lx, data %x\n", 159 pid, oaddr, odata, ret, addr, tmp); 160 } 161 else 162#endif 163 { 164 unsigned long tmp; 165 166 if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs)) 167 goto out_tsk; 168 tmp = *(unsigned long *) ((char *) task_regs(child) + addr); 169 ret = put_user(tmp, (unsigned long *) data); 170 } 171 goto out_tsk; 172 } 173 174 case PTRACE_POKEUSR: 175 ret = -EIO; 176 /* Some register values written here may be ignored in 177 * entry.S:syscall_restore_rfi; e.g. iaoq is written with 178 * r31/r31+4, and not with the values in pt_regs. 179 */ 180 /* PT_PSW=0, so this is valid for 32 bit processes under 64 181 * bit kernels. 182 */ 183 if (addr == PT_PSW) { 184 /* PT_PSW=0, so this is valid for 32 bit processes 185 * under 64 bit kernels. 186 * 187 * Allow writing to Nullify, Divide-step-correction, 188 * and carry/borrow bits. 189 * BEWARE, if you set N, and then single step, it won't 190 * stop on the nullified instruction. 191 */ 192 DBG("sys_ptrace(POKEUSR, %d, %lx, %lx)\n", 193 pid, oaddr, odata); 194 data &= USER_PSW_BITS; 195 task_regs(child)->gr[0] &= ~USER_PSW_BITS; 196 task_regs(child)->gr[0] |= data; 197 ret = 0; 198 goto out_tsk; 199 } 200#ifdef CONFIG_64BIT 201 if (__is_compat_task(child)) { 202 if (addr & (sizeof(int)-1)) 203 goto out_tsk; 204 if ((addr = translate_usr_offset(addr)) < 0) 205 goto out_tsk; 206 DBG("sys_ptrace(POKEUSR, %d, %lx, %lx) addr %lx\n", 207 pid, oaddr, odata, addr); 208 if (addr >= PT_FR0 && addr <= PT_FR31 + 4) { 209 /* Special case, fp regs are 64 bits anyway */ 210 *(unsigned int *) ((char *) task_regs(child) + addr) = data; 211 ret = 0; 212 } 213 else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) || 214 addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 || 215 addr == PT_SAR+4) { 216 /* Zero the top 32 bits */ 217 *(unsigned int *) ((char *) task_regs(child) + addr - 4) = 0; 218 *(unsigned int *) ((char *) task_regs(child) + addr) = data; 219 ret = 0; 220 } 221 goto out_tsk; 222 } 223 else 224#endif 225 { 226 if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs)) 227 goto out_tsk; 228 if ((addr >= PT_GR1 && addr <= PT_GR31) || 229 addr == PT_IAOQ0 || addr == PT_IAOQ1 || 230 (addr >= PT_FR0 && addr <= PT_FR31 + 4) || 231 addr == PT_SAR) { 232 *(unsigned long *) ((char *) task_regs(child) + addr) = data; 233 ret = 0; 234 } 235 goto out_tsk; 236 } 237 238 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 239 case PTRACE_CONT: 240 ret = -EIO; 241 DBG("sys_ptrace(%s)\n", 242 request == PTRACE_SYSCALL ? "SYSCALL" : "CONT"); 243 if (!valid_signal(data)) 244 goto out_tsk; 245 child->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP); 246 if (request == PTRACE_SYSCALL) { 247 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 248 } else { 249 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 250 } 251 child->exit_code = data; 252 goto out_wake_notrap; 253 254 case PTRACE_KILL: 255 /* 256 * make the child exit. Best I can do is send it a 257 * sigkill. perhaps it should be put in the status 258 * that it wants to exit. 259 */ 260 ret = 0; 261 DBG("sys_ptrace(KILL)\n"); 262 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 263 goto out_tsk; 264 child->exit_code = SIGKILL; 265 goto out_wake_notrap; 266 267 case PTRACE_SINGLEBLOCK: 268 DBG("sys_ptrace(SINGLEBLOCK)\n"); 269 ret = -EIO; 270 if (!valid_signal(data)) 271 goto out_tsk; 272 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 273 child->ptrace &= ~PT_SINGLESTEP; 274 child->ptrace |= PT_BLOCKSTEP; 275 child->exit_code = data; 276 277 /* Enable taken branch trap. */ 278 pa_psw(child)->r = 0; 279 pa_psw(child)->t = 1; 280 pa_psw(child)->h = 0; 281 pa_psw(child)->l = 0; 282 goto out_wake; 283 284 case PTRACE_SINGLESTEP: 285 DBG("sys_ptrace(SINGLESTEP)\n"); 286 ret = -EIO; 287 if (!valid_signal(data)) 288 goto out_tsk; 289 290 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 291 child->ptrace &= ~PT_BLOCKSTEP; 292 child->ptrace |= PT_SINGLESTEP; 293 child->exit_code = data; 294 295 if (pa_psw(child)->n) { 296 struct siginfo si; 297 298 /* Nullified, just crank over the queue. */ 299 task_regs(child)->iaoq[0] = task_regs(child)->iaoq[1]; 300 task_regs(child)->iasq[0] = task_regs(child)->iasq[1]; 301 task_regs(child)->iaoq[1] = task_regs(child)->iaoq[0] + 4; 302 pa_psw(child)->n = 0; 303 pa_psw(child)->x = 0; 304 pa_psw(child)->y = 0; 305 pa_psw(child)->z = 0; 306 pa_psw(child)->b = 0; 307 ptrace_disable(child); 308 /* Don't wake up the child, but let the 309 parent know something happened. */ 310 si.si_code = TRAP_TRACE; 311 si.si_addr = (void __user *) (task_regs(child)->iaoq[0] & ~3); 312 si.si_signo = SIGTRAP; 313 si.si_errno = 0; 314 force_sig_info(SIGTRAP, &si, child); 315 //notify_parent(child, SIGCHLD); 316 //ret = 0; 317 goto out_wake; 318 } 319 320 /* Enable recovery counter traps. The recovery counter 321 * itself will be set to zero on a task switch. If the 322 * task is suspended on a syscall then the syscall return 323 * path will overwrite the recovery counter with a suitable 324 * value such that it traps once back in user space. We 325 * disable interrupts in the childs PSW here also, to avoid 326 * interrupts while the recovery counter is decrementing. 327 */ 328 pa_psw(child)->r = 1; 329 pa_psw(child)->t = 0; 330 pa_psw(child)->h = 0; 331 pa_psw(child)->l = 0; 332 /* give it a chance to run. */ 333 goto out_wake; 334 335 case PTRACE_DETACH: 336 ret = ptrace_detach(child, data); 337 goto out_tsk; 338 339 case PTRACE_GETEVENTMSG: 340 ret = put_user(child->ptrace_message, (unsigned int __user *) data); 341 goto out_tsk; 342 343 default: 344 ret = ptrace_request(child, request, addr, data); 345 goto out_tsk; 346 } 347 348out_wake_notrap: 349 ptrace_disable(child); 350out_wake: 351 wake_up_process(child); 352 ret = 0; 353out_tsk: 354 DBG("arch_ptrace(%ld, %d, %lx, %lx) returning %ld\n", 355 request, pid, oaddr, odata, ret); 356 return ret; 357} 358 359void syscall_trace(void) 360{ 361 if (!test_thread_flag(TIF_SYSCALL_TRACE)) 362 return; 363 if (!(current->ptrace & PT_PTRACED)) 364 return; 365 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 366 ? 0x80 : 0)); 367 /* 368 * this isn't the same as continuing with a signal, but it will do 369 * for normal use. strace only continues with a signal if the 370 * stopping signal is not SIGTRAP. -brl 371 */ 372 if (current->exit_code) { 373 send_sig(current->exit_code, current, 1); 374 current->exit_code = 0; 375 } 376} 377