1 /* 2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 3 * Licensed under the GPL 4 */ 5 6 #include <linux/mm.h> 7 #include <linux/sched.h> 8 #include <asm/uaccess.h> 9 #include <asm/ptrace-abi.h> 10 #include <skas.h> 11 12 extern int arch_switch_tls(struct task_struct *to); 13 14 void arch_switch_to(struct task_struct *to) 15 { 16 int err = arch_switch_tls(to); 17 if (!err) 18 return; 19 20 if (err != -EINVAL) 21 printk(KERN_WARNING "arch_switch_tls failed, errno %d, " 22 "not EINVAL\n", -err); 23 else 24 printk(KERN_WARNING "arch_switch_tls failed, errno = EINVAL\n"); 25 } 26 27 int is_syscall(unsigned long addr) 28 { 29 unsigned short instr; 30 int n; 31 32 n = copy_from_user(&instr, (void __user *) addr, sizeof(instr)); 33 if (n) { 34 /* access_process_vm() grants access to vsyscall and stub, 35 * while copy_from_user doesn't. Maybe access_process_vm is 36 * slow, but that doesn't matter, since it will be called only 37 * in case of singlestepping, if copy_from_user failed. 38 */ 39 n = access_process_vm(current, addr, &instr, sizeof(instr), 0); 40 if (n != sizeof(instr)) { 41 printk(KERN_ERR "is_syscall : failed to read " 42 "instruction from 0x%lx\n", addr); 43 return 1; 44 } 45 } 46 /* int 0x80 or sysenter */ 47 return (instr == 0x80cd) || (instr == 0x340f); 48 } 49 50 /* determines which flags the user has access to. */ 51 /* 1 = access 0 = no access */ 52 #define FLAG_MASK 0x00044dd5 53 54 static const int reg_offsets[] = { 55 [EBX] = HOST_BX, 56 [ECX] = HOST_CX, 57 [EDX] = HOST_DX, 58 [ESI] = HOST_SI, 59 [EDI] = HOST_DI, 60 [EBP] = HOST_BP, 61 [EAX] = HOST_AX, 62 [DS] = HOST_DS, 63 [ES] = HOST_ES, 64 [FS] = HOST_FS, 65 [GS] = HOST_GS, 66 [EIP] = HOST_IP, 67 [CS] = HOST_CS, 68 [EFL] = HOST_EFLAGS, 69 [UESP] = HOST_SP, 70 [SS] = HOST_SS, 71 [ORIG_EAX] = HOST_ORIG_AX, 72 }; 73 74 int putreg(struct task_struct *child, int regno, unsigned long value) 75 { 76 regno >>= 2; 77 switch (regno) { 78 case EBX: 79 case ECX: 80 case EDX: 81 case ESI: 82 case EDI: 83 case EBP: 84 case EAX: 85 case EIP: 86 case UESP: 87 case ORIG_EAX: 88 break; 89 case FS: 90 if (value && (value & 3) != 3) 91 return -EIO; 92 break; 93 case GS: 94 if (value && (value & 3) != 3) 95 return -EIO; 96 break; 97 case DS: 98 case ES: 99 if (value && (value & 3) != 3) 100 return -EIO; 101 value &= 0xffff; 102 break; 103 case SS: 104 case CS: 105 if ((value & 3) != 3) 106 return -EIO; 107 value &= 0xffff; 108 break; 109 case EFL: 110 value &= FLAG_MASK; 111 child->thread.regs.regs.gp[HOST_EFLAGS] |= value; 112 return 0; 113 default : 114 panic("Bad register in putreg() : %d\n", regno); 115 } 116 child->thread.regs.regs.gp[reg_offsets[regno]] = value; 117 return 0; 118 } 119 120 int poke_user(struct task_struct *child, long addr, long data) 121 { 122 if ((addr & 3) || addr < 0) 123 return -EIO; 124 125 if (addr < MAX_REG_OFFSET) 126 return putreg(child, addr, data); 127 else if ((addr >= offsetof(struct user, u_debugreg[0])) && 128 (addr <= offsetof(struct user, u_debugreg[7]))) { 129 addr -= offsetof(struct user, u_debugreg[0]); 130 addr = addr >> 2; 131 if ((addr == 4) || (addr == 5)) 132 return -EIO; 133 child->thread.arch.debugregs[addr] = data; 134 return 0; 135 } 136 return -EIO; 137 } 138 139 unsigned long getreg(struct task_struct *child, int regno) 140 { 141 unsigned long mask = ~0UL; 142 143 regno >>= 2; 144 switch (regno) { 145 case FS: 146 case GS: 147 case DS: 148 case ES: 149 case SS: 150 case CS: 151 mask = 0xffff; 152 break; 153 case EIP: 154 case UESP: 155 case EAX: 156 case EBX: 157 case ECX: 158 case EDX: 159 case ESI: 160 case EDI: 161 case EBP: 162 case EFL: 163 case ORIG_EAX: 164 break; 165 default: 166 panic("Bad register in getreg() : %d\n", regno); 167 } 168 return mask & child->thread.regs.regs.gp[reg_offsets[regno]]; 169 } 170 171 /* read the word at location addr in the USER area. */ 172 int peek_user(struct task_struct *child, long addr, long data) 173 { 174 unsigned long tmp; 175 176 if ((addr & 3) || addr < 0) 177 return -EIO; 178 179 tmp = 0; /* Default return condition */ 180 if (addr < MAX_REG_OFFSET) { 181 tmp = getreg(child, addr); 182 } 183 else if ((addr >= offsetof(struct user, u_debugreg[0])) && 184 (addr <= offsetof(struct user, u_debugreg[7]))) { 185 addr -= offsetof(struct user, u_debugreg[0]); 186 addr = addr >> 2; 187 tmp = child->thread.arch.debugregs[addr]; 188 } 189 return put_user(tmp, (unsigned long __user *) data); 190 } 191 192 static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child) 193 { 194 int err, n, cpu = ((struct thread_info *) child->stack)->cpu; 195 struct user_i387_struct fpregs; 196 197 err = save_fp_registers(userspace_pid[cpu], (unsigned long *) &fpregs); 198 if (err) 199 return err; 200 201 n = copy_to_user(buf, &fpregs, sizeof(fpregs)); 202 if(n > 0) 203 return -EFAULT; 204 205 return n; 206 } 207 208 static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child) 209 { 210 int n, cpu = ((struct thread_info *) child->stack)->cpu; 211 struct user_i387_struct fpregs; 212 213 n = copy_from_user(&fpregs, buf, sizeof(fpregs)); 214 if (n > 0) 215 return -EFAULT; 216 217 return restore_fp_registers(userspace_pid[cpu], 218 (unsigned long *) &fpregs); 219 } 220 221 static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child) 222 { 223 int err, n, cpu = ((struct thread_info *) child->stack)->cpu; 224 struct user_fxsr_struct fpregs; 225 226 err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs); 227 if (err) 228 return err; 229 230 n = copy_to_user(buf, &fpregs, sizeof(fpregs)); 231 if(n > 0) 232 return -EFAULT; 233 234 return n; 235 } 236 237 static int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child) 238 { 239 int n, cpu = ((struct thread_info *) child->stack)->cpu; 240 struct user_fxsr_struct fpregs; 241 242 n = copy_from_user(&fpregs, buf, sizeof(fpregs)); 243 if (n > 0) 244 return -EFAULT; 245 246 return restore_fpx_registers(userspace_pid[cpu], 247 (unsigned long *) &fpregs); 248 } 249 250 long subarch_ptrace(struct task_struct *child, long request, 251 unsigned long addr, unsigned long data) 252 { 253 int ret = -EIO; 254 void __user *datap = (void __user *) data; 255 switch (request) { 256 case PTRACE_GETFPREGS: /* Get the child FPU state. */ 257 ret = get_fpregs(datap, child); 258 break; 259 case PTRACE_SETFPREGS: /* Set the child FPU state. */ 260 ret = set_fpregs(datap, child); 261 break; 262 case PTRACE_GETFPXREGS: /* Get the child FPU state. */ 263 ret = get_fpxregs(datap, child); 264 break; 265 case PTRACE_SETFPXREGS: /* Set the child FPU state. */ 266 ret = set_fpxregs(datap, child); 267 break; 268 default: 269 ret = -EIO; 270 } 271 return ret; 272 } 273