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 97 /* read the word at location addr in the USER area. */ 98 case PTRACE_PEEKUSR: { 99 unsigned long tmp; 100 101 ret = -EIO; 102 if ((addr & 3) || addr < 0 || 103 addr > sizeof(struct user) - 3) 104 break; 105 106 if (addr < sizeof(struct pt_regs)) 107 tmp = get_stack_long(child, addr); 108 else if (addr >= (long) &dummy->fpu && 109 addr < (long) &dummy->u_fpvalid) { 110 if (!tsk_used_math(child)) { 111 if (addr == (long)&dummy->fpu.fpscr) 112 tmp = FPSCR_INIT; 113 else 114 tmp = 0; 115 } else 116 tmp = ((long *)&child->thread.fpu) 117 [(addr - (long)&dummy->fpu) >> 2]; 118 } else if (addr == (long) &dummy->u_fpvalid) 119 tmp = !!tsk_used_math(child); 120 else 121 tmp = 0; 122 ret = put_user(tmp, (unsigned long __user *)data); 123 break; 124 } 125 126 /* when I and D space are separate, this will have to be fixed. */ 127 case PTRACE_POKETEXT: /* write the word at location addr. */ 128 case PTRACE_POKEDATA: 129 ret = generic_ptrace_pokedata(child, addr, data); 130 break; 131 132 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ 133 ret = -EIO; 134 if ((addr & 3) || addr < 0 || 135 addr > sizeof(struct user) - 3) 136 break; 137 138 if (addr < sizeof(struct pt_regs)) 139 ret = put_stack_long(child, addr, data); 140 else if (addr >= (long) &dummy->fpu && 141 addr < (long) &dummy->u_fpvalid) { 142 set_stopped_child_used_math(child); 143 ((long *)&child->thread.fpu) 144 [(addr - (long)&dummy->fpu) >> 2] = data; 145 ret = 0; 146 } else if (addr == (long) &dummy->u_fpvalid) { 147 conditional_stopped_child_used_math(data, child); 148 ret = 0; 149 } 150 break; 151 152 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 153 case PTRACE_CONT: { /* restart after signal. */ 154 ret = -EIO; 155 if (!valid_signal(data)) 156 break; 157 if (request == PTRACE_SYSCALL) 158 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 159 else 160 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 161 162 ptrace_disable_singlestep(child); 163 164 child->exit_code = data; 165 wake_up_process(child); 166 ret = 0; 167 break; 168 } 169 170 /* 171 * make the child exit. Best I can do is send it a sigkill. 172 * perhaps it should be put in the status that it wants to 173 * exit. 174 */ 175 case PTRACE_KILL: { 176 ret = 0; 177 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 178 break; 179 ptrace_disable_singlestep(child); 180 child->exit_code = SIGKILL; 181 wake_up_process(child); 182 break; 183 } 184 185 case PTRACE_SINGLESTEP: { /* set the trap flag. */ 186 long pc; 187 struct pt_regs *regs = NULL; 188 189 ret = -EIO; 190 if (!valid_signal(data)) 191 break; 192 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 193 if ((child->ptrace & PT_DTRACE) == 0) { 194 /* Spurious delayed TF traps may occur */ 195 child->ptrace |= PT_DTRACE; 196 } 197 198 pc = get_stack_long(child, (long)®s->pc); 199 200 /* Next scheduling will set up UBC */ 201 if (child->thread.ubc_pc == 0) 202 ubc_usercnt += 1; 203 child->thread.ubc_pc = pc; 204 205 set_tsk_thread_flag(child, TIF_SINGLESTEP); 206 child->exit_code = data; 207 /* give it a chance to run. */ 208 wake_up_process(child); 209 ret = 0; 210 break; 211 } 212 213 case PTRACE_DETACH: /* detach a process that was attached. */ 214 ret = ptrace_detach(child, data); 215 break; 216 217 #ifdef CONFIG_SH_DSP 218 case PTRACE_GETDSPREGS: { 219 unsigned long dp; 220 221 ret = -EIO; 222 dp = ((unsigned long) child) + THREAD_SIZE - 223 sizeof(struct pt_dspregs); 224 if (*((int *) (dp - 4)) == SR_FD) { 225 copy_to_user(addr, (void *) dp, 226 sizeof(struct pt_dspregs)); 227 ret = 0; 228 } 229 break; 230 } 231 232 case PTRACE_SETDSPREGS: { 233 unsigned long dp; 234 235 ret = -EIO; 236 dp = ((unsigned long) child) + THREAD_SIZE - 237 sizeof(struct pt_dspregs); 238 if (*((int *) (dp - 4)) == SR_FD) { 239 copy_from_user((void *) dp, addr, 240 sizeof(struct pt_dspregs)); 241 ret = 0; 242 } 243 break; 244 } 245 #endif 246 default: 247 ret = ptrace_request(child, request, addr, data); 248 break; 249 } 250 251 return ret; 252 } 253 254 asmlinkage void do_syscall_trace(void) 255 { 256 struct task_struct *tsk = current; 257 258 if (!test_thread_flag(TIF_SYSCALL_TRACE) && 259 !test_thread_flag(TIF_SINGLESTEP)) 260 return; 261 if (!(tsk->ptrace & PT_PTRACED)) 262 return; 263 /* the 0x80 provides a way for the tracing parent to distinguish 264 between a syscall stop and SIGTRAP delivery */ 265 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) && 266 !test_thread_flag(TIF_SINGLESTEP) ? 0x80 : 0)); 267 268 /* 269 * this isn't the same as continuing with a signal, but it will do 270 * for normal use. strace only continues with a signal if the 271 * stopping signal is not SIGTRAP. -brl 272 */ 273 if (tsk->exit_code) { 274 send_sig(tsk->exit_code, tsk, 1); 275 tsk->exit_code = 0; 276 } 277 } 278