arch/um/sys-i386/ptrace.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/config.h>
   7 #include <linux/compiler.h>
   8 #include "linux/sched.h"
   9 #include "linux/mm.h"
  10 #include "asm/elf.h"
  11 #include "asm/ptrace.h"
  12 #include "asm/uaccess.h"
  13 #include "asm/unistd.h"
  14 #include "sysdep/ptrace.h"
  15 #include "sysdep/sigcontext.h"
  16 #include "sysdep/sc.h"
  17
  18 void arch_switch(void)
  19 {
  20         update_debugregs(current->thread.arch.debugregs_seq);
  21 }
  22
  23 int is_syscall(unsigned long addr)
  24 {
  25         unsigned short instr;
  26         int n;
  27
  28         n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
  29         if(n){
  30                 /* access_process_vm() grants access to vsyscall and stub,
  31                  * while copy_from_user doesn't. Maybe access_process_vm is
  32                  * slow, but that doesn't matter, since it will be called only
  33                  * in case of singlestepping, if copy_from_user failed.
  34                  */
  35                 n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
  36                 if(n != sizeof(instr)) {
  37                         printk("is_syscall : failed to read instruction from "
  38                                "0x%lx\n", addr);
  39                         return(1);
  40                 }
  41         }
  42         /* int 0x80 or sysenter */
  43         return((instr == 0x80cd) || (instr == 0x340f));
  44 }
  45
  46 /* determines which flags the user has access to. */
  47 /* 1 = access 0 = no access */
  48 #define FLAG_MASK 0x00044dd5
  49
  50 int putreg(struct task_struct *child, int regno, unsigned long value)
  51 {
  52         regno >>= 2;
  53         switch (regno) {
  54         case FS:
  55                 if (value && (value & 3) != 3)
  56                         return -EIO;
  57                 PT_REGS_FS(&child->thread.regs) = value;
  58                 return 0;
  59         case GS:
  60                 if (value && (value & 3) != 3)
  61                         return -EIO;
  62                 PT_REGS_GS(&child->thread.regs) = value;
  63                 return 0;
  64         case DS:
  65         case ES:
  66                 if (value && (value & 3) != 3)
  67                         return -EIO;
  68                 value &= 0xffff;
  69                 break;
  70         case SS:
  71         case CS:
  72                 if ((value & 3) != 3)
  73                         return -EIO;
  74                 value &= 0xffff;
  75                 break;
  76         case EFL:
  77                 value &= FLAG_MASK;
  78                 value |= PT_REGS_EFLAGS(&child->thread.regs);
  79                 break;
  80         }
  81         PT_REGS_SET(&child->thread.regs, regno, value);
  82         return 0;
  83 }
  84
  85 int poke_user(struct task_struct *child, long addr, long data)
  86 {
  87         if ((addr & 3) || addr < 0)
  88                 return -EIO;
  89
  90         if (addr < MAX_REG_OFFSET)
  91                 return putreg(child, addr, data);
  92
  93         else if((addr >= offsetof(struct user, u_debugreg[0])) &&
  94                 (addr <= offsetof(struct user, u_debugreg[7]))){
  95                 addr -= offsetof(struct user, u_debugreg[0]);
  96                 addr = addr >> 2;
  97                 if((addr == 4) || (addr == 5)) return -EIO;
  98                 child->thread.arch.debugregs[addr] = data;
  99                 return 0;
 100         }
 101         return -EIO;
 102 }
 103
 104 unsigned long getreg(struct task_struct *child, int regno)
 105 {
 106         unsigned long retval = ~0UL;
 107
 108         regno >>= 2;
 109         switch (regno) {
 110         case FS:
 111         case GS:
 112         case DS:
 113         case ES:
 114         case SS:
 115         case CS:
 116                 retval = 0xffff;
 117                 /* fall through */
 118         default:
 119                 retval &= PT_REG(&child->thread.regs, regno);
 120         }
 121         return retval;
 122 }
 123
 124 int peek_user(struct task_struct *child, long addr, long data)
 125 {
 126 /* read the word at location addr in the USER area. */
 127         unsigned long tmp;
 128
 129         if ((addr & 3) || addr < 0)
 130                 return -EIO;
 131
 132         tmp = 0;  /* Default return condition */
 133         if(addr < MAX_REG_OFFSET){
 134                 tmp = getreg(child, addr);
 135         }
 136         else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 137                 (addr <= offsetof(struct user, u_debugreg[7]))){
 138                 addr -= offsetof(struct user, u_debugreg[0]);
 139                 addr = addr >> 2;
 140                 tmp = child->thread.arch.debugregs[addr];
 141         }
 142         return put_user(tmp, (unsigned long *) data);
 143 }
 144
 145 struct i387_fxsave_struct {
 146         unsigned short  cwd;
 147         unsigned short  swd;
 148         unsigned short  twd;
 149         unsigned short  fop;
 150         long    fip;
 151         long    fcs;
 152         long    foo;
 153         long    fos;
 154         long    mxcsr;
 155         long    reserved;
 156         long    st_space[32];   /* 8*16 bytes for each FP-reg = 128 bytes */
 157         long    xmm_space[32];  /* 8*16 bytes for each XMM-reg = 128 bytes */
 158         long    padding[56];
 159 };
 160
 161 /*
 162  * FPU tag word conversions.
 163  */
 164
 165 static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
 166 {
 167         unsigned int tmp; /* to avoid 16 bit prefixes in the code */
 168
 169         /* Transform each pair of bits into 01 (valid) or 00 (empty) */
 170         tmp = ~twd;
 171         tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
 172         /* and move the valid bits to the lower byte. */
 173         tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
 174         tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
 175         tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
 176         return tmp;
 177 }
 178
 179 static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave )
 180 {
 181         struct _fpxreg *st = NULL;
 182         unsigned long twd = (unsigned long) fxsave->twd;
 183         unsigned long tag;
 184         unsigned long ret = 0xffff0000;
 185         int i;
 186
 187 #define FPREG_ADDR(f, n)        ((char *)&(f)->st_space + (n) * 16);
 188
 189         for ( i = 0 ; i < 8 ; i++ ) {
 190                 if ( twd & 0x1 ) {
 191                         st = (struct _fpxreg *) FPREG_ADDR( fxsave, i );
 192
 193                         switch ( st->exponent & 0x7fff ) {
 194                         case 0x7fff:
 195                                 tag = 2;                /* Special */
 196                                 break;
 197                         case 0x0000:
 198                                 if ( !st->significand[0] &&
 199                                      !st->significand[1] &&
 200                                      !st->significand[2] &&
 201                                      !st->significand[3] ) {
 202                                         tag = 1;        /* Zero */
 203                                 } else {
 204                                         tag = 2;        /* Special */
 205                                 }
 206                                 break;
 207                         default:
 208                                 if ( st->significand[3] & 0x8000 ) {
 209                                         tag = 0;        /* Valid */
 210                                 } else {
 211                                         tag = 2;        /* Special */
 212                                 }
 213                                 break;
 214                         }
 215                 } else {
 216                         tag = 3;                        /* Empty */
 217                 }
 218                 ret |= (tag << (2 * i));
 219                 twd = twd >> 1;
 220         }
 221         return ret;
 222 }
 223
 224 /*
 225  * FXSR floating point environment conversions.
 226  */
 227
 228 #ifdef CONFIG_MODE_TT
 229 static inline int convert_fxsr_to_user_tt(struct _fpstate __user *buf,
 230                                           struct pt_regs *regs)
 231 {
 232         struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
 233         unsigned long env[7];
 234         struct _fpreg __user *to;
 235         struct _fpxreg *from;
 236         int i;
 237
 238         env[0] = (unsigned long)fxsave->cwd | 0xffff0000;
 239         env[1] = (unsigned long)fxsave->swd | 0xffff0000;
 240         env[2] = twd_fxsr_to_i387(fxsave);
 241         env[3] = fxsave->fip;
 242         env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
 243         env[5] = fxsave->foo;
 244         env[6] = fxsave->fos;
 245
 246         if ( __copy_to_user( buf, env, 7 * sizeof(unsigned long) ) )
 247                 return 1;
 248
 249         to = &buf->_st[0];
 250         from = (struct _fpxreg *) &fxsave->st_space[0];
 251         for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
 252                 if ( __copy_to_user( to, from, sizeof(*to) ) )
 253                         return 1;
 254         }
 255         return 0;
 256 }
 257 #endif
 258
 259 static inline int convert_fxsr_to_user(struct _fpstate __user *buf,
 260                                        struct pt_regs *regs)
 261 {
 262         return(CHOOSE_MODE(convert_fxsr_to_user_tt(buf, regs), 0));
 263 }
 264
 265 #ifdef CONFIG_MODE_TT
 266 static inline int convert_fxsr_from_user_tt(struct pt_regs *regs,
 267                                             struct _fpstate __user *buf)
 268 {
 269         struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
 270         unsigned long env[7];
 271         struct _fpxreg *to;
 272         struct _fpreg __user *from;
 273         int i;
 274
 275         if ( __copy_from_user( env, buf, 7 * sizeof(long) ) )
 276                 return 1;
 277
 278         fxsave->cwd = (unsigned short)(env[0] & 0xffff);
 279         fxsave->swd = (unsigned short)(env[1] & 0xffff);
 280         fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
 281         fxsave->fip = env[3];
 282         fxsave->fop = (unsigned short)((env[4] & 0xffff0000) >> 16);
 283         fxsave->fcs = (env[4] & 0xffff);
 284         fxsave->foo = env[5];
 285         fxsave->fos = env[6];
 286
 287         to = (struct _fpxreg *) &fxsave->st_space[0];
 288         from = &buf->_st[0];
 289         for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
 290                 if ( __copy_from_user( to, from, sizeof(*from) ) )
 291                         return 1;
 292         }
 293         return 0;
 294 }
 295 #endif
 296
 297 static inline int convert_fxsr_from_user(struct pt_regs *regs,
 298                                          struct _fpstate __user *buf)
 299 {
 300         return(CHOOSE_MODE(convert_fxsr_from_user_tt(regs, buf), 0));
 301 }
 302
 303 int get_fpregs(unsigned long buf, struct task_struct *child)
 304 {
 305         int err;
 306
 307         err = convert_fxsr_to_user((struct _fpstate __user *) buf,
 308                                    &child->thread.regs);
 309         if(err) return(-EFAULT);
 310         else return(0);
 311 }
 312
 313 int set_fpregs(unsigned long buf, struct task_struct *child)
 314 {
 315         int err;
 316
 317         err = convert_fxsr_from_user(&child->thread.regs,
 318                                      (struct _fpstate __user *) buf);
 319         if(err) return(-EFAULT);
 320         else return(0);
 321 }
 322
 323 #ifdef CONFIG_MODE_TT
 324 int get_fpxregs_tt(unsigned long buf, struct task_struct *tsk)
 325 {
 326         struct pt_regs *regs = &tsk->thread.regs;
 327         struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
 328         int err;
 329
 330         err = __copy_to_user((void __user *) buf, fxsave,
 331                              sizeof(struct user_fxsr_struct));
 332         if(err) return -EFAULT;
 333         else return 0;
 334 }
 335 #endif
 336
 337 int get_fpxregs(unsigned long buf, struct task_struct *tsk)
 338 {
 339         return(CHOOSE_MODE(get_fpxregs_tt(buf, tsk), 0));
 340 }
 341
 342 #ifdef CONFIG_MODE_TT
 343 int set_fpxregs_tt(unsigned long buf, struct task_struct *tsk)
 344 {
 345         struct pt_regs *regs = &tsk->thread.regs;
 346         struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
 347         int err;
 348
 349         err = __copy_from_user(fxsave, (void __user *) buf,
 350                                sizeof(struct user_fxsr_struct) );
 351         if(err) return -EFAULT;
 352         else return 0;
 353 }
 354 #endif
 355
 356 int set_fpxregs(unsigned long buf, struct task_struct *tsk)
 357 {
 358         return(CHOOSE_MODE(set_fpxregs_tt(buf, tsk), 0));
 359 }
 360
 361 #ifdef notdef
 362 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 363 {
 364         fpu->cwd = (((SC_FP_CW(PT_REGS_SC(regs)) & 0xffff) << 16) |
 365                     (SC_FP_SW(PT_REGS_SC(regs)) & 0xffff));
 366         fpu->swd = SC_FP_CSSEL(PT_REGS_SC(regs)) & 0xffff;
 367         fpu->twd = SC_FP_IPOFF(PT_REGS_SC(regs));
 368         fpu->fip = SC_FP_CSSEL(PT_REGS_SC(regs)) & 0xffff;
 369         fpu->fcs = SC_FP_DATAOFF(PT_REGS_SC(regs));
 370         fpu->foo = SC_FP_DATASEL(PT_REGS_SC(regs));
 371         fpu->fos = 0;
 372         memcpy(fpu->st_space, (void *) SC_FP_ST(PT_REGS_SC(regs)),
 373                sizeof(fpu->st_space));
 374         return(1);
 375 }
 376 #endif
 377
 378 #ifdef CONFIG_MODE_TT
 379 static inline void copy_fpu_fxsave_tt(struct pt_regs *regs,
 380                                       struct user_i387_struct *buf)
 381 {
 382         struct i387_fxsave_struct *fpu = SC_FXSR_ENV(PT_REGS_SC(regs));
 383         unsigned short *to;
 384         unsigned short *from;
 385         int i;
 386
 387         memcpy( buf, fpu, 7 * sizeof(long) );
 388
 389         to = (unsigned short *) &buf->st_space[0];
 390         from = (unsigned short *) &fpu->st_space[0];
 391         for ( i = 0 ; i < 8 ; i++, to += 5, from += 8 ) {
 392                 memcpy( to, from, 5 * sizeof(unsigned short) );
 393         }
 394 }
 395 #endif
 396
 397 static inline void copy_fpu_fxsave(struct pt_regs *regs,
 398                                    struct user_i387_struct *buf)
 399 {
 400         (void) CHOOSE_MODE(copy_fpu_fxsave_tt(regs, buf), 0);
 401 }
 402
 403 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu )
 404 {
 405         copy_fpu_fxsave(regs, (struct user_i387_struct *) fpu);
 406         return(1);
 407 }
 408
 409 /*
 410  * Overrides for Emacs so that we follow Linus's tabbing style.
 411  * Emacs will notice this stuff at the end of the file and automatically
 412  * adjust the settings for this buffer only.  This must remain at the end
 413  * of the file.
 414  * ---------------------------------------------------------------------------
 415  * Local variables:
 416  * c-file-style: "linux"
 417  * End:
 418  */