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 break; 88 case ORIG_EAX: 89 /* Update the syscall number. */ 90 UPT_SYSCALL_NR(&child->thread.regs.regs) = value; 91 break; 92 case FS: 93 if (value && (value & 3) != 3) 94 return -EIO; 95 break; 96 case GS: 97 if (value && (value & 3) != 3) 98 return -EIO; 99 break; 100 case DS: 101 case ES: 102 if (value && (value & 3) != 3) 103 return -EIO; 104 value &= 0xffff; 105 break; 106 case SS: 107 case CS: 108 if ((value & 3) != 3) 109 return -EIO; 110 value &= 0xffff; 111 break; 112 case EFL: 113 value &= FLAG_MASK; 114 child->thread.regs.regs.gp[HOST_EFLAGS] |= value; 115 return 0; 116 default : 117 panic("Bad register in putreg() : %d\n", regno); 118 } 119 child->thread.regs.regs.gp[reg_offsets[regno]] = value; 120 return 0; 121 } 122 123 int poke_user(struct task_struct *child, long addr, long data) 124 { 125 if ((addr & 3) || addr < 0) 126 return -EIO; 127 128 if (addr < MAX_REG_OFFSET) 129 return putreg(child, addr, data); 130 else if ((addr >= offsetof(struct user, u_debugreg[0])) && 131 (addr <= offsetof(struct user, u_debugreg[7]))) { 132 addr -= offsetof(struct user, u_debugreg[0]); 133 addr = addr >> 2; 134 if ((addr == 4) || (addr == 5)) 135 return -EIO; 136 child->thread.arch.debugregs[addr] = data; 137 return 0; 138 } 139 return -EIO; 140 } 141 142 unsigned long getreg(struct task_struct *child, int regno) 143 { 144 unsigned long mask = ~0UL; 145 146 regno >>= 2; 147 switch (regno) { 148 case FS: 149 case GS: 150 case DS: 151 case ES: 152 case SS: 153 case CS: 154 mask = 0xffff; 155 break; 156 case EIP: 157 case UESP: 158 case EAX: 159 case EBX: 160 case ECX: 161 case EDX: 162 case ESI: 163 case EDI: 164 case EBP: 165 case EFL: 166 case ORIG_EAX: 167 break; 168 default: 169 panic("Bad register in getreg() : %d\n", regno); 170 } 171 return mask & child->thread.regs.regs.gp[reg_offsets[regno]]; 172 } 173 174 /* read the word at location addr in the USER area. */ 175 int peek_user(struct task_struct *child, long addr, long data) 176 { 177 unsigned long tmp; 178 179 if ((addr & 3) || addr < 0) 180 return -EIO; 181 182 tmp = 0; /* Default return condition */ 183 if (addr < MAX_REG_OFFSET) { 184 tmp = getreg(child, addr); 185 } 186 else if ((addr >= offsetof(struct user, u_debugreg[0])) && 187 (addr <= offsetof(struct user, u_debugreg[7]))) { 188 addr -= offsetof(struct user, u_debugreg[0]); 189 addr = addr >> 2; 190 tmp = child->thread.arch.debugregs[addr]; 191 } 192 return put_user(tmp, (unsigned long __user *) data); 193 } 194 195 static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child) 196 { 197 int err, n, cpu = task_cpu(child); 198 struct user_i387_struct fpregs; 199 200 err = save_i387_registers(userspace_pid[cpu], 201 (unsigned long *) &fpregs); 202 if (err) 203 return err; 204 205 n = copy_to_user(buf, &fpregs, sizeof(fpregs)); 206 if(n > 0) 207 return -EFAULT; 208 209 return n; 210 } 211 212 static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child) 213 { 214 int n, cpu = task_cpu(child); 215 struct user_i387_struct fpregs; 216 217 n = copy_from_user(&fpregs, buf, sizeof(fpregs)); 218 if (n > 0) 219 return -EFAULT; 220 221 return restore_i387_registers(userspace_pid[cpu], 222 (unsigned long *) &fpregs); 223 } 224 225 static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child) 226 { 227 int err, n, cpu = task_cpu(child); 228 struct user_fxsr_struct fpregs; 229 230 err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs); 231 if (err) 232 return err; 233 234 n = copy_to_user(buf, &fpregs, sizeof(fpregs)); 235 if(n > 0) 236 return -EFAULT; 237 238 return n; 239 } 240 241 static int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child) 242 { 243 int n, cpu = task_cpu(child); 244 struct user_fxsr_struct fpregs; 245 246 n = copy_from_user(&fpregs, buf, sizeof(fpregs)); 247 if (n > 0) 248 return -EFAULT; 249 250 return restore_fpx_registers(userspace_pid[cpu], 251 (unsigned long *) &fpregs); 252 } 253 254 long subarch_ptrace(struct task_struct *child, long request, 255 unsigned long addr, unsigned long data) 256 { 257 int ret = -EIO; 258 void __user *datap = (void __user *) data; 259 switch (request) { 260 case PTRACE_GETFPREGS: /* Get the child FPU state. */ 261 ret = get_fpregs(datap, child); 262 break; 263 case PTRACE_SETFPREGS: /* Set the child FPU state. */ 264 ret = set_fpregs(datap, child); 265 break; 266 case PTRACE_GETFPXREGS: /* Get the child FPU state. */ 267 ret = get_fpxregs(datap, child); 268 break; 269 case PTRACE_SETFPXREGS: /* Set the child FPU state. */ 270 ret = set_fpxregs(datap, child); 271 break; 272 default: 273 ret = -EIO; 274 } 275 return ret; 276 } 277