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/compiler.h>
   7 #include "linux/sched.h"
   8 #include "linux/mm.h"
   9 #include "asm/elf.h"
  10 #include "asm/ptrace.h"
  11 #include "asm/uaccess.h"
  12 #include "asm/unistd.h"
  13 #include "sysdep/ptrace.h"
  14 #include "sysdep/sigcontext.h"
  15 #include "sysdep/sc.h"
  16
  17 extern int arch_switch_tls(struct task_struct *from, struct task_struct *to);
  18
  19 void arch_switch_to(struct task_struct *from, struct task_struct *to)
  20 {
  21         int err = arch_switch_tls(from, to);
  22         if (!err)
  23                 return;
  24
  25         if (err != -EINVAL)
  26                 printk(KERN_WARNING "arch_switch_tls failed, errno %d, not EINVAL\n", -err);
  27         else
  28                 printk(KERN_WARNING "arch_switch_tls failed, errno = EINVAL\n");
  29 }
  30
  31 int is_syscall(unsigned long addr)
  32 {
  33         unsigned short instr;
  34         int n;
  35
  36         n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
  37         if(n){
  38                 /* access_process_vm() grants access to vsyscall and stub,
  39                  * while copy_from_user doesn't. Maybe access_process_vm is
  40                  * slow, but that doesn't matter, since it will be called only
  41                  * in case of singlestepping, if copy_from_user failed.
  42                  */
  43                 n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
  44                 if(n != sizeof(instr)) {
  45                         printk("is_syscall : failed to read instruction from "
  46                                "0x%lx\n", addr);
  47                         return(1);
  48                 }
  49         }
  50         /* int 0x80 or sysenter */
  51         return((instr == 0x80cd) || (instr == 0x340f));
  52 }
  53
  54 /* determines which flags the user has access to. */
  55 /* 1 = access 0 = no access */
  56 #define FLAG_MASK 0x00044dd5
  57
  58 int putreg(struct task_struct *child, int regno, unsigned long value)
  59 {
  60         regno >>= 2;
  61         switch (regno) {
  62         case FS:
  63                 if (value && (value & 3) != 3)
  64                         return -EIO;
  65                 PT_REGS_FS(&child->thread.regs) = value;
  66                 return 0;
  67         case GS:
  68                 if (value && (value & 3) != 3)
  69                         return -EIO;
  70                 PT_REGS_GS(&child->thread.regs) = value;
  71                 return 0;
  72         case DS:
  73         case ES:
  74                 if (value && (value & 3) != 3)
  75                         return -EIO;
  76                 value &= 0xffff;
  77                 break;
  78         case SS:
  79         case CS:
  80                 if ((value & 3) != 3)
  81                         return -EIO;
  82                 value &= 0xffff;
  83                 break;
  84         case EFL:
  85                 value &= FLAG_MASK;
  86                 value |= PT_REGS_EFLAGS(&child->thread.regs);
  87                 break;
  88         }
  89         PT_REGS_SET(&child->thread.regs, regno, value);
  90         return 0;
  91 }
  92
  93 int poke_user(struct task_struct *child, long addr, long data)
  94 {
  95         if ((addr & 3) || addr < 0)
  96                 return -EIO;
  97
  98         if (addr < MAX_REG_OFFSET)
  99                 return putreg(child, addr, data);
 100
 101         else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 102                 (addr <= offsetof(struct user, u_debugreg[7]))){
 103                 addr -= offsetof(struct user, u_debugreg[0]);
 104                 addr = addr >> 2;
 105                 if((addr == 4) || (addr == 5)) return -EIO;
 106                 child->thread.arch.debugregs[addr] = data;
 107                 return 0;
 108         }
 109         return -EIO;
 110 }
 111
 112 unsigned long getreg(struct task_struct *child, int regno)
 113 {
 114         unsigned long retval = ~0UL;
 115
 116         regno >>= 2;
 117         switch (regno) {
 118         case FS:
 119         case GS:
 120         case DS:
 121         case ES:
 122         case SS:
 123         case CS:
 124                 retval = 0xffff;
 125                 /* fall through */
 126         default:
 127                 retval &= PT_REG(&child->thread.regs, regno);
 128         }
 129         return retval;
 130 }
 131
 132 int peek_user(struct task_struct *child, long addr, long data)
 133 {
 134 /* read the word at location addr in the USER area. */
 135         unsigned long tmp;
 136
 137         if ((addr & 3) || addr < 0)
 138                 return -EIO;
 139
 140         tmp = 0;  /* Default return condition */
 141         if(addr < MAX_REG_OFFSET){
 142                 tmp = getreg(child, addr);
 143         }
 144         else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 145                 (addr <= offsetof(struct user, u_debugreg[7]))){
 146                 addr -= offsetof(struct user, u_debugreg[0]);
 147                 addr = addr >> 2;
 148                 tmp = child->thread.arch.debugregs[addr];
 149         }
 150         return put_user(tmp, (unsigned long __user *) data);
 151 }
 152
 153 struct i387_fxsave_struct {
 154         unsigned short  cwd;
 155         unsigned short  swd;
 156         unsigned short  twd;
 157         unsigned short  fop;
 158         long    fip;
 159         long    fcs;
 160         long    foo;
 161         long    fos;
 162         long    mxcsr;
 163         long    reserved;
 164         long    st_space[32];   /* 8*16 bytes for each FP-reg = 128 bytes */
 165         long    xmm_space[32];  /* 8*16 bytes for each XMM-reg = 128 bytes */
 166         long    padding[56];
 167 };
 168
 169 /*
 170  * FPU tag word conversions.
 171  */
 172
 173 static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
 174 {
 175         unsigned int tmp; /* to avoid 16 bit prefixes in the code */
 176
 177         /* Transform each pair of bits into 01 (valid) or 00 (empty) */
 178         tmp = ~twd;
 179         tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
 180         /* and move the valid bits to the lower byte. */
 181         tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
 182         tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
 183         tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
 184         return tmp;
 185 }
 186
 187 static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave )
 188 {
 189         struct _fpxreg *st = NULL;
 190         unsigned long twd = (unsigned long) fxsave->twd;
 191         unsigned long tag;
 192         unsigned long ret = 0xffff0000;
 193         int i;
 194
 195 #define FPREG_ADDR(f, n)        ((char *)&(f)->st_space + (n) * 16);
 196
 197         for ( i = 0 ; i < 8 ; i++ ) {
 198                 if ( twd & 0x1 ) {
 199                         st = (struct _fpxreg *) FPREG_ADDR( fxsave, i );
 200
 201                         switch ( st->exponent & 0x7fff ) {
 202                         case 0x7fff:
 203                                 tag = 2;                /* Special */
 204                                 break;
 205                         case 0x0000:
 206                                 if ( !st->significand[0] &&
 207                                      !st->significand[1] &&
 208                                      !st->significand[2] &&
 209                                      !st->significand[3] ) {
 210                                         tag = 1;        /* Zero */
 211                                 } else {
 212                                         tag = 2;        /* Special */
 213                                 }
 214                                 break;
 215                         default:
 216                                 if ( st->significand[3] & 0x8000 ) {
 217                                         tag = 0;        /* Valid */
 218                                 } else {
 219                                         tag = 2;        /* Special */
 220                                 }
 221                                 break;
 222                         }
 223                 } else {
 224                         tag = 3;                        /* Empty */
 225                 }
 226                 ret |= (tag << (2 * i));
 227                 twd = twd >> 1;
 228         }
 229         return ret;
 230 }
 231
 232 static inline int convert_fxsr_to_user(struct _fpstate __user *buf,
 233                                        struct pt_regs *regs)
 234 {
 235         return 0;
 236 }
 237
 238 static inline int convert_fxsr_from_user(struct pt_regs *regs,
 239                                          struct _fpstate __user *buf)
 240 {
 241         return 0;
 242 }
 243
 244 int get_fpregs(unsigned long buf, struct task_struct *child)
 245 {
 246         int err;
 247
 248         err = convert_fxsr_to_user((struct _fpstate __user *) buf,
 249                                    &child->thread.regs);
 250         if(err) return(-EFAULT);
 251         else return(0);
 252 }
 253
 254 int set_fpregs(unsigned long buf, struct task_struct *child)
 255 {
 256         int err;
 257
 258         err = convert_fxsr_from_user(&child->thread.regs,
 259                                      (struct _fpstate __user *) buf);
 260         if(err) return(-EFAULT);
 261         else return(0);
 262 }
 263
 264 int get_fpxregs(unsigned long buf, struct task_struct *tsk)
 265 {
 266         return 0;
 267 }
 268
 269 int set_fpxregs(unsigned long buf, struct task_struct *tsk)
 270 {
 271         return 0;
 272 }
 273
 274 #ifdef notdef
 275 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 276 {
 277         fpu->cwd = (((SC_FP_CW(PT_REGS_SC(regs)) & 0xffff) << 16) |
 278                     (SC_FP_SW(PT_REGS_SC(regs)) & 0xffff));
 279         fpu->swd = SC_FP_CSSEL(PT_REGS_SC(regs)) & 0xffff;
 280         fpu->twd = SC_FP_IPOFF(PT_REGS_SC(regs));
 281         fpu->fip = SC_FP_CSSEL(PT_REGS_SC(regs)) & 0xffff;
 282         fpu->fcs = SC_FP_DATAOFF(PT_REGS_SC(regs));
 283         fpu->foo = SC_FP_DATASEL(PT_REGS_SC(regs));
 284         fpu->fos = 0;
 285         memcpy(fpu->st_space, (void *) SC_FP_ST(PT_REGS_SC(regs)),
 286                sizeof(fpu->st_space));
 287         return(1);
 288 }
 289 #endif
 290
 291 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu )
 292 {
 293         return 1;
 294 }
 295
 296 /*
 297  * Overrides for Emacs so that we follow Linus's tabbing style.
 298  * Emacs will notice this stuff at the end of the file and automatically
 299  * adjust the settings for this buffer only.  This must remain at the end
 300  * of the file.
 301  * ---------------------------------------------------------------------------
 302  * Local variables:
 303  * c-file-style: "linux"
 304  * End:
 305  */