1 /* 2 * linux/arch/m68k/kernel/ptrace.c 3 * 4 * Copyright (C) 1994 by Hamish Macdonald 5 * Taken from linux/kernel/ptrace.c and modified for M680x0. 6 * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds 7 * 8 * This file is subject to the terms and conditions of the GNU General 9 * Public License. See the file COPYING in the main directory of 10 * this archive for more details. 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/sched.h> 15 #include <linux/mm.h> 16 #include <linux/smp.h> 17 #include <linux/errno.h> 18 #include <linux/ptrace.h> 19 #include <linux/user.h> 20 #include <linux/signal.h> 21 22 #include <asm/uaccess.h> 23 #include <asm/page.h> 24 #include <asm/pgtable.h> 25 #include <asm/system.h> 26 #include <asm/processor.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 /* determines which bits in the SR the user has access to. */ 34 /* 1 = access 0 = no access */ 35 #define SR_MASK 0x001f 36 37 /* sets the trace bits. */ 38 #define TRACE_BITS 0xC000 39 #define T1_BIT 0x8000 40 #define T0_BIT 0x4000 41 42 /* Find the stack offset for a register, relative to thread.esp0. */ 43 #define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg) 44 #define SW_REG(reg) ((long)&((struct switch_stack *)0)->reg \ 45 - sizeof(struct switch_stack)) 46 /* Mapping from PT_xxx to the stack offset at which the register is 47 saved. Notice that usp has no stack-slot and needs to be treated 48 specially (see get_reg/put_reg below). */ 49 static const int regoff[] = { 50 [0] = PT_REG(d1), 51 [1] = PT_REG(d2), 52 [2] = PT_REG(d3), 53 [3] = PT_REG(d4), 54 [4] = PT_REG(d5), 55 [5] = SW_REG(d6), 56 [6] = SW_REG(d7), 57 [7] = PT_REG(a0), 58 [8] = PT_REG(a1), 59 [9] = PT_REG(a2), 60 [10] = SW_REG(a3), 61 [11] = SW_REG(a4), 62 [12] = SW_REG(a5), 63 [13] = SW_REG(a6), 64 [14] = PT_REG(d0), 65 [15] = -1, 66 [16] = PT_REG(orig_d0), 67 [17] = PT_REG(sr), 68 [18] = PT_REG(pc), 69 }; 70 71 /* 72 * Get contents of register REGNO in task TASK. 73 */ 74 static inline long get_reg(struct task_struct *task, int regno) 75 { 76 unsigned long *addr; 77 78 if (regno == PT_USP) 79 addr = &task->thread.usp; 80 else if (regno < ARRAY_SIZE(regoff)) 81 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]); 82 else 83 return 0; 84 /* Need to take stkadj into account. */ 85 if (regno == PT_SR || regno == PT_PC) { 86 long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj)); 87 addr = (unsigned long *) ((unsigned long)addr + stkadj); 88 /* The sr is actually a 16 bit register. */ 89 if (regno == PT_SR) 90 return *(unsigned short *)addr; 91 } 92 return *addr; 93 } 94 95 /* 96 * Write contents of register REGNO in task TASK. 97 */ 98 static inline int put_reg(struct task_struct *task, int regno, 99 unsigned long data) 100 { 101 unsigned long *addr; 102 103 if (regno == PT_USP) 104 addr = &task->thread.usp; 105 else if (regno < ARRAY_SIZE(regoff)) 106 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]); 107 else 108 return -1; 109 /* Need to take stkadj into account. */ 110 if (regno == PT_SR || regno == PT_PC) { 111 long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj)); 112 addr = (unsigned long *) ((unsigned long)addr + stkadj); 113 /* The sr is actually a 16 bit register. */ 114 if (regno == PT_SR) { 115 *(unsigned short *)addr = data; 116 return 0; 117 } 118 } 119 *addr = data; 120 return 0; 121 } 122 123 /* 124 * Make sure the single step bit is not set. 125 */ 126 static inline void singlestep_disable(struct task_struct *child) 127 { 128 unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS; 129 put_reg(child, PT_SR, tmp); 130 clear_tsk_thread_flag(child, TIF_DELAYED_TRACE); 131 } 132 133 /* 134 * Called by kernel/ptrace.c when detaching.. 135 */ 136 void ptrace_disable(struct task_struct *child) 137 { 138 singlestep_disable(child); 139 } 140 141 void user_enable_single_step(struct task_struct *child) 142 { 143 unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS; 144 put_reg(child, PT_SR, tmp | T1_BIT); 145 set_tsk_thread_flag(child, TIF_DELAYED_TRACE); 146 } 147 148 void user_enable_block_step(struct task_struct *child) 149 { 150 unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS; 151 put_reg(child, PT_SR, tmp | T0_BIT); 152 } 153 154 void user_disable_single_step(struct task_struct *child) 155 { 156 singlestep_disable(child); 157 } 158 159 long arch_ptrace(struct task_struct *child, long request, 160 unsigned long addr, unsigned long data) 161 { 162 unsigned long tmp; 163 int i, ret = 0; 164 int regno = addr >> 2; /* temporary hack. */ 165 unsigned long __user *datap = (unsigned long __user *) data; 166 167 switch (request) { 168 /* read the word at location addr in the USER area. */ 169 case PTRACE_PEEKUSR: 170 if (addr & 3) 171 goto out_eio; 172 173 if (regno >= 0 && regno < 19) { 174 tmp = get_reg(child, regno); 175 } else if (regno >= 21 && regno < 49) { 176 tmp = child->thread.fp[regno - 21]; 177 /* Convert internal fpu reg representation 178 * into long double format 179 */ 180 if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) 181 tmp = ((tmp & 0xffff0000) << 15) | 182 ((tmp & 0x0000ffff) << 16); 183 } else 184 goto out_eio; 185 ret = put_user(tmp, datap); 186 break; 187 188 case PTRACE_POKEUSR: 189 /* write the word at location addr in the USER area */ 190 if (addr & 3) 191 goto out_eio; 192 193 if (regno == PT_SR) { 194 data &= SR_MASK; 195 data |= get_reg(child, PT_SR) & ~SR_MASK; 196 } 197 if (regno >= 0 && regno < 19) { 198 if (put_reg(child, regno, data)) 199 goto out_eio; 200 } else if (regno >= 21 && regno < 48) { 201 /* Convert long double format 202 * into internal fpu reg representation 203 */ 204 if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) { 205 data <<= 15; 206 data = (data & 0xffff0000) | 207 ((data & 0x0000ffff) >> 1); 208 } 209 child->thread.fp[regno - 21] = data; 210 } else 211 goto out_eio; 212 break; 213 214 case PTRACE_GETREGS: /* Get all gp regs from the child. */ 215 for (i = 0; i < 19; i++) { 216 tmp = get_reg(child, i); 217 ret = put_user(tmp, datap); 218 if (ret) 219 break; 220 datap++; 221 } 222 break; 223 224 case PTRACE_SETREGS: /* Set all gp regs in the child. */ 225 for (i = 0; i < 19; i++) { 226 ret = get_user(tmp, datap); 227 if (ret) 228 break; 229 if (i == PT_SR) { 230 tmp &= SR_MASK; 231 tmp |= get_reg(child, PT_SR) & ~SR_MASK; 232 } 233 put_reg(child, i, tmp); 234 datap++; 235 } 236 break; 237 238 case PTRACE_GETFPREGS: /* Get the child FPU state. */ 239 if (copy_to_user(datap, &child->thread.fp, 240 sizeof(struct user_m68kfp_struct))) 241 ret = -EFAULT; 242 break; 243 244 case PTRACE_SETFPREGS: /* Set the child FPU state. */ 245 if (copy_from_user(&child->thread.fp, datap, 246 sizeof(struct user_m68kfp_struct))) 247 ret = -EFAULT; 248 break; 249 250 case PTRACE_GET_THREAD_AREA: 251 ret = put_user(task_thread_info(child)->tp_value, datap); 252 break; 253 254 default: 255 ret = ptrace_request(child, request, addr, data); 256 break; 257 } 258 259 return ret; 260 out_eio: 261 return -EIO; 262 } 263 264 asmlinkage void syscall_trace(void) 265 { 266 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 267 ? 0x80 : 0)); 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 (current->exit_code) { 274 send_sig(current->exit_code, current, 1); 275 current->exit_code = 0; 276 } 277 } 278