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/errno.h> 16 #include <linux/ptrace.h> 17 #include <linux/user.h> 18 #include <linux/slab.h> 19 #include <linux/security.h> 20 #include <linux/signal.h> 21 #include <linux/io.h> 22 #include <asm/uaccess.h> 23 #include <asm/pgtable.h> 24 #include <asm/system.h> 25 #include <asm/processor.h> 26 #include <asm/mmu_context.h> 27 28 /* 29 * does not yet catch signals sent when the child dies. 30 * in exit.c or in signal.c. 31 */ 32 33 /* 34 * This routine will get a word off of the process kernel stack. 35 */ 36 static inline int get_stack_long(struct task_struct *task, int offset) 37 { 38 unsigned char *stack; 39 40 stack = (unsigned char *)task_pt_regs(task); 41 stack += offset; 42 return (*((int *)stack)); 43 } 44 45 /* 46 * This routine will put a word on the process kernel stack. 47 */ 48 static inline int put_stack_long(struct task_struct *task, int offset, 49 unsigned long data) 50 { 51 unsigned char *stack; 52 53 stack = (unsigned char *)task_pt_regs(task); 54 stack += offset; 55 *(unsigned long *) stack = data; 56 return 0; 57 } 58 59 static void ptrace_disable_singlestep(struct task_struct *child) 60 { 61 clear_tsk_thread_flag(child, TIF_SINGLESTEP); 62 63 /* 64 * Ensure the UBC is not programmed at the next context switch. 65 * 66 * Normally this is not needed but there are sequences such as 67 * singlestep, signal delivery, and continue that leave the 68 * ubc_pc non-zero leading to spurious SIGTRAPs. 69 */ 70 if (child->thread.ubc_pc != 0) { 71 ubc_usercnt -= 1; 72 child->thread.ubc_pc = 0; 73 } 74 } 75 76 /* 77 * Called by kernel/ptrace.c when detaching.. 78 * 79 * Make sure single step bits etc are not set. 80 */ 81 void ptrace_disable(struct task_struct *child) 82 { 83 ptrace_disable_singlestep(child); 84 } 85 86 long arch_ptrace(struct task_struct *child, long request, long addr, long data) 87 { 88 struct user * dummy = NULL; 89 int ret; 90 91 switch (request) { 92 /* when I and D space are separate, these will need to be fixed. */ 93 case PTRACE_PEEKTEXT: /* read word at location addr. */ 94 case PTRACE_PEEKDATA: 95 ret = generic_ptrace_peekdata(child, addr, data); 96 break; 97 98 /* read the word at location addr in the USER area. */ 99 case PTRACE_PEEKUSR: { 100 unsigned long tmp; 101 102 ret = -EIO; 103 if ((addr & 3) || addr < 0 || 104 addr > sizeof(struct user) - 3) 105 break; 106 107 if (addr < sizeof(struct pt_regs)) 108 tmp = get_stack_long(child, addr); 109 else if (addr >= (long) &dummy->fpu && 110 addr < (long) &dummy->u_fpvalid) { 111 if (!tsk_used_math(child)) { 112 if (addr == (long)&dummy->fpu.fpscr) 113 tmp = FPSCR_INIT; 114 else 115 tmp = 0; 116 } else 117 tmp = ((long *)&child->thread.fpu) 118 [(addr - (long)&dummy->fpu) >> 2]; 119 } else if (addr == (long) &dummy->u_fpvalid) 120 tmp = !!tsk_used_math(child); 121 else 122 tmp = 0; 123 ret = put_user(tmp, (unsigned long __user *)data); 124 break; 125 } 126 127 /* when I and D space are separate, this will have to be fixed. */ 128 case PTRACE_POKETEXT: /* write the word at location addr. */ 129 case PTRACE_POKEDATA: 130 ret = generic_ptrace_pokedata(child, addr, data); 131 break; 132 133 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ 134 ret = -EIO; 135 if ((addr & 3) || addr < 0 || 136 addr > sizeof(struct user) - 3) 137 break; 138 139 if (addr < sizeof(struct pt_regs)) 140 ret = put_stack_long(child, addr, data); 141 else if (addr >= (long) &dummy->fpu && 142 addr < (long) &dummy->u_fpvalid) { 143 set_stopped_child_used_math(child); 144 ((long *)&child->thread.fpu) 145 [(addr - (long)&dummy->fpu) >> 2] = data; 146 ret = 0; 147 } else if (addr == (long) &dummy->u_fpvalid) { 148 conditional_stopped_child_used_math(data, child); 149 ret = 0; 150 } 151 break; 152 153 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 154 case PTRACE_CONT: { /* restart after signal. */ 155 ret = -EIO; 156 if (!valid_signal(data)) 157 break; 158 if (request == PTRACE_SYSCALL) 159 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 160 else 161 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 162 163 ptrace_disable_singlestep(child); 164 165 child->exit_code = data; 166 wake_up_process(child); 167 ret = 0; 168 break; 169 } 170 171 /* 172 * make the child exit. Best I can do is send it a sigkill. 173 * perhaps it should be put in the status that it wants to 174 * exit. 175 */ 176 case PTRACE_KILL: { 177 ret = 0; 178 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 179 break; 180 ptrace_disable_singlestep(child); 181 child->exit_code = SIGKILL; 182 wake_up_process(child); 183 break; 184 } 185 186 case PTRACE_SINGLESTEP: { /* set the trap flag. */ 187 long pc; 188 struct pt_regs *regs = NULL; 189 190 ret = -EIO; 191 if (!valid_signal(data)) 192 break; 193 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 194 if ((child->ptrace & PT_DTRACE) == 0) { 195 /* Spurious delayed TF traps may occur */ 196 child->ptrace |= PT_DTRACE; 197 } 198 199 pc = get_stack_long(child, (long)®s->pc); 200 201 /* Next scheduling will set up UBC */ 202 if (child->thread.ubc_pc == 0) 203 ubc_usercnt += 1; 204 child->thread.ubc_pc = pc; 205 206 set_tsk_thread_flag(child, TIF_SINGLESTEP); 207 child->exit_code = data; 208 /* give it a chance to run. */ 209 wake_up_process(child); 210 ret = 0; 211 break; 212 } 213 214 case PTRACE_DETACH: /* detach a process that was attached. */ 215 ret = ptrace_detach(child, data); 216 break; 217 218 #ifdef CONFIG_SH_DSP 219 case PTRACE_GETDSPREGS: { 220 unsigned long dp; 221 222 ret = -EIO; 223 dp = ((unsigned long) child) + THREAD_SIZE - 224 sizeof(struct pt_dspregs); 225 if (*((int *) (dp - 4)) == SR_FD) { 226 copy_to_user(addr, (void *) dp, 227 sizeof(struct pt_dspregs)); 228 ret = 0; 229 } 230 break; 231 } 232 233 case PTRACE_SETDSPREGS: { 234 unsigned long dp; 235 236 ret = -EIO; 237 dp = ((unsigned long) child) + THREAD_SIZE - 238 sizeof(struct pt_dspregs); 239 if (*((int *) (dp - 4)) == SR_FD) { 240 copy_from_user((void *) dp, addr, 241 sizeof(struct pt_dspregs)); 242 ret = 0; 243 } 244 break; 245 } 246 #endif 247 default: 248 ret = ptrace_request(child, request, addr, data); 249 break; 250 } 251 252 return ret; 253 } 254 255 asmlinkage void do_syscall_trace(void) 256 { 257 struct task_struct *tsk = current; 258 259 if (!test_thread_flag(TIF_SYSCALL_TRACE) && 260 !test_thread_flag(TIF_SINGLESTEP)) 261 return; 262 if (!(tsk->ptrace & PT_PTRACED)) 263 return; 264 /* the 0x80 provides a way for the tracing parent to distinguish 265 between a syscall stop and SIGTRAP delivery */ 266 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) && 267 !test_thread_flag(TIF_SINGLESTEP) ? 0x80 : 0)); 268 269 /* 270 * this isn't the same as continuing with a signal, but it will do 271 * for normal use. strace only continues with a signal if the 272 * stopping signal is not SIGTRAP. -brl 273 */ 274 if (tsk->exit_code) { 275 send_sig(tsk->exit_code, tsk, 1); 276 tsk->exit_code = 0; 277 } 278 } 279