1 /* 2 * linux/arch/sh/kernel/ptrace.c 3 * 4 * Original x86 implementation: 5 * By Ross Biro 1/23/92 6 * edited by Linus Torvalds 7 * 8 * SuperH version: Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka 9 * 10 */ 11 #include <linux/kernel.h> 12 #include <linux/sched.h> 13 #include <linux/mm.h> 14 #include <linux/smp.h> 15 #include <linux/smp_lock.h> 16 #include <linux/errno.h> 17 #include <linux/ptrace.h> 18 #include <linux/user.h> 19 #include <linux/slab.h> 20 #include <linux/security.h> 21 #include <linux/signal.h> 22 #include <linux/io.h> 23 #include <asm/uaccess.h> 24 #include <asm/pgtable.h> 25 #include <asm/system.h> 26 #include <asm/processor.h> 27 #include <asm/mmu_context.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 /* 35 * This routine will get a word off of the process kernel stack. 36 */ 37 static inline int get_stack_long(struct task_struct *task, int offset) 38 { 39 unsigned char *stack; 40 41 stack = (unsigned char *)task_pt_regs(task); 42 stack += offset; 43 return (*((int *)stack)); 44 } 45 46 /* 47 * This routine will put a word on the process kernel stack. 48 */ 49 static inline int put_stack_long(struct task_struct *task, int offset, 50 unsigned long data) 51 { 52 unsigned char *stack; 53 54 stack = (unsigned char *)task_pt_regs(task); 55 stack += offset; 56 *(unsigned long *) stack = data; 57 return 0; 58 } 59 60 static void ptrace_disable_singlestep(struct task_struct *child) 61 { 62 clear_tsk_thread_flag(child, TIF_SINGLESTEP); 63 64 /* 65 * Ensure the UBC is not programmed at the next context switch. 66 * 67 * Normally this is not needed but there are sequences such as 68 * singlestep, signal delivery, and continue that leave the 69 * ubc_pc non-zero leading to spurious SIGTRAPs. 70 */ 71 if (child->thread.ubc_pc != 0) { 72 ubc_usercnt -= 1; 73 child->thread.ubc_pc = 0; 74 } 75 } 76 77 /* 78 * Called by kernel/ptrace.c when detaching.. 79 * 80 * Make sure single step bits etc are not set. 81 */ 82 void ptrace_disable(struct task_struct *child) 83 { 84 ptrace_disable_singlestep(child); 85 } 86 87 long arch_ptrace(struct task_struct *child, long request, long addr, long data) 88 { 89 struct user * dummy = NULL; 90 int ret; 91 92 switch (request) { 93 /* when I and D space are separate, these will need to be fixed. */ 94 case PTRACE_PEEKTEXT: /* read word at location addr. */ 95 case PTRACE_PEEKDATA: { 96 unsigned long tmp; 97 int copied; 98 99 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 100 ret = -EIO; 101 if (copied != sizeof(tmp)) 102 break; 103 ret = put_user(tmp,(unsigned long *) data); 104 break; 105 } 106 107 /* read the word at location addr in the USER area. */ 108 case PTRACE_PEEKUSR: { 109 unsigned long tmp; 110 111 ret = -EIO; 112 if ((addr & 3) || addr < 0 || 113 addr > sizeof(struct user) - 3) 114 break; 115 116 if (addr < sizeof(struct pt_regs)) 117 tmp = get_stack_long(child, addr); 118 else if (addr >= (long) &dummy->fpu && 119 addr < (long) &dummy->u_fpvalid) { 120 if (!tsk_used_math(child)) { 121 if (addr == (long)&dummy->fpu.fpscr) 122 tmp = FPSCR_INIT; 123 else 124 tmp = 0; 125 } else 126 tmp = ((long *)&child->thread.fpu) 127 [(addr - (long)&dummy->fpu) >> 2]; 128 } else if (addr == (long) &dummy->u_fpvalid) 129 tmp = !!tsk_used_math(child); 130 else 131 tmp = 0; 132 ret = put_user(tmp, (unsigned long *)data); 133 break; 134 } 135 136 /* when I and D space are separate, this will have to be fixed. */ 137 case PTRACE_POKETEXT: /* write the word at location addr. */ 138 case PTRACE_POKEDATA: 139 ret = 0; 140 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) 141 break; 142 ret = -EIO; 143 break; 144 145 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ 146 ret = -EIO; 147 if ((addr & 3) || addr < 0 || 148 addr > sizeof(struct user) - 3) 149 break; 150 151 if (addr < sizeof(struct pt_regs)) 152 ret = put_stack_long(child, addr, data); 153 else if (addr >= (long) &dummy->fpu && 154 addr < (long) &dummy->u_fpvalid) { 155 set_stopped_child_used_math(child); 156 ((long *)&child->thread.fpu) 157 [(addr - (long)&dummy->fpu) >> 2] = data; 158 ret = 0; 159 } else if (addr == (long) &dummy->u_fpvalid) { 160 conditional_stopped_child_used_math(data, child); 161 ret = 0; 162 } 163 break; 164 165 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 166 case PTRACE_CONT: { /* restart after signal. */ 167 ret = -EIO; 168 if (!valid_signal(data)) 169 break; 170 if (request == PTRACE_SYSCALL) 171 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 172 else 173 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 174 175 ptrace_disable_singlestep(child); 176 177 child->exit_code = data; 178 wake_up_process(child); 179 ret = 0; 180 break; 181 } 182 183 /* 184 * make the child exit. Best I can do is send it a sigkill. 185 * perhaps it should be put in the status that it wants to 186 * exit. 187 */ 188 case PTRACE_KILL: { 189 ret = 0; 190 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 191 break; 192 ptrace_disable_singlestep(child); 193 child->exit_code = SIGKILL; 194 wake_up_process(child); 195 break; 196 } 197 198 case PTRACE_SINGLESTEP: { /* set the trap flag. */ 199 long pc; 200 struct pt_regs *dummy = NULL; 201 202 ret = -EIO; 203 if (!valid_signal(data)) 204 break; 205 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 206 if ((child->ptrace & PT_DTRACE) == 0) { 207 /* Spurious delayed TF traps may occur */ 208 child->ptrace |= PT_DTRACE; 209 } 210 211 pc = get_stack_long(child, (long)&dummy->pc); 212 213 /* Next scheduling will set up UBC */ 214 if (child->thread.ubc_pc == 0) 215 ubc_usercnt += 1; 216 child->thread.ubc_pc = pc; 217 218 set_tsk_thread_flag(child, TIF_SINGLESTEP); 219 child->exit_code = data; 220 /* give it a chance to run. */ 221 wake_up_process(child); 222 ret = 0; 223 break; 224 } 225 226 case PTRACE_DETACH: /* detach a process that was attached. */ 227 ret = ptrace_detach(child, data); 228 break; 229 230 #ifdef CONFIG_SH_DSP 231 case PTRACE_GETDSPREGS: { 232 unsigned long dp; 233 234 ret = -EIO; 235 dp = ((unsigned long) child) + THREAD_SIZE - 236 sizeof(struct pt_dspregs); 237 if (*((int *) (dp - 4)) == SR_FD) { 238 copy_to_user(addr, (void *) dp, 239 sizeof(struct pt_dspregs)); 240 ret = 0; 241 } 242 break; 243 } 244 245 case PTRACE_SETDSPREGS: { 246 unsigned long dp; 247 248 ret = -EIO; 249 dp = ((unsigned long) child) + THREAD_SIZE - 250 sizeof(struct pt_dspregs); 251 if (*((int *) (dp - 4)) == SR_FD) { 252 copy_from_user((void *) dp, addr, 253 sizeof(struct pt_dspregs)); 254 ret = 0; 255 } 256 break; 257 } 258 #endif 259 default: 260 ret = ptrace_request(child, request, addr, data); 261 break; 262 } 263 264 return ret; 265 } 266 267 asmlinkage void do_syscall_trace(void) 268 { 269 struct task_struct *tsk = current; 270 271 if (!test_thread_flag(TIF_SYSCALL_TRACE) && 272 !test_thread_flag(TIF_SINGLESTEP)) 273 return; 274 if (!(tsk->ptrace & PT_PTRACED)) 275 return; 276 /* the 0x80 provides a way for the tracing parent to distinguish 277 between a syscall stop and SIGTRAP delivery */ 278 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) && 279 !test_thread_flag(TIF_SINGLESTEP) ? 0x80 : 0)); 280 281 /* 282 * this isn't the same as continuing with a signal, but it will do 283 * for normal use. strace only continues with a signal if the 284 * stopping signal is not SIGTRAP. -brl 285 */ 286 if (tsk->exit_code) { 287 send_sig(tsk->exit_code, tsk, 1); 288 tsk->exit_code = 0; 289 } 290 } 291