gdb/sparc-nat.c

   1 /* Native-dependent code for SPARC.
   2
   3    Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "inferior.h"
  23 #include "regcache.h"
  24 #include "target.h"
  25
  26 #include "gdb_assert.h"
  27 #include <signal.h>
  28 #include "gdb_string.h"
  29 #include <sys/ptrace.h>
  30 #include "gdb_wait.h"
  31 #ifdef HAVE_MACHINE_REG_H
  32 #include <machine/reg.h>
  33 #endif
  34
  35 #include "sparc-tdep.h"
  36 #include "sparc-nat.h"
  37 #include "inf-ptrace.h"
  38
  39 /* With some trickery we can use the code in this file for most (if
  40    not all) ptrace(2) based SPARC systems, which includes SunOS 4,
  41    GNU/Linux and the various SPARC BSD's.
  42
  43    First, we need a data structure for use with ptrace(2).  SunOS has
  44    `struct regs' and `struct fp_status' in <machine/reg.h>.  BSD's
  45    have `struct reg' and `struct fpreg' in <machine/reg.h>.  GNU/Linux
  46    has the same structures as SunOS 4, but they're in <asm/reg.h>,
  47    which is a kernel header.  As a general rule we avoid including
  48    GNU/Linux kernel headers.  Fortunately GNU/Linux has a `gregset_t'
  49    and a `fpregset_t' that are equivalent to `struct regs' and `struct
  50    fp_status' in <sys/ucontext.h>, which is automatically included by
  51    <signal.h>.  Settling on using the `gregset_t' and `fpregset_t'
  52    typedefs, providing them for the other systems, therefore solves
  53    the puzzle.  */
  54
  55 #ifdef HAVE_MACHINE_REG_H
  56 #ifdef HAVE_STRUCT_REG
  57 typedef struct reg gregset_t;
  58 typedef struct fpreg fpregset_t;
  59 #else
  60 typedef struct regs gregset_t;
  61 typedef struct fp_status fpregset_t;
  62 #endif
  63 #endif
  64
  65 /* Second, we need to remap the BSD ptrace(2) requests to their SunOS
  66    equivalents.  GNU/Linux already follows SunOS here.  */
  67
  68 #ifndef PTRACE_GETREGS
  69 #define PTRACE_GETREGS PT_GETREGS
  70 #endif
  71
  72 #ifndef PTRACE_SETREGS
  73 #define PTRACE_SETREGS PT_SETREGS
  74 #endif
  75
  76 #ifndef PTRACE_GETFPREGS
  77 #define PTRACE_GETFPREGS PT_GETFPREGS
  78 #endif
  79
  80 #ifndef PTRACE_SETFPREGS
  81 #define PTRACE_SETFPREGS PT_SETFPREGS
  82 #endif
  83
  84 /* Register set description.  */
  85 const struct sparc_gregset *sparc_gregset;
  86 void (*sparc_supply_gregset) (const struct sparc_gregset *,
  87                               struct regcache *, int , const void *);
  88 void (*sparc_collect_gregset) (const struct sparc_gregset *,
  89                                const struct regcache *, int, void *);
  90 void (*sparc_supply_fpregset) (struct regcache *, int , const void *);
  91 void (*sparc_collect_fpregset) (const struct regcache *, int , void *);
  92 int (*sparc_gregset_supplies_p) (int);
  93 int (*sparc_fpregset_supplies_p) (int);
  94
  95 /* Determine whether `gregset_t' contains register REGNUM.  */
  96
  97 int
  98 sparc32_gregset_supplies_p (int regnum)
  99 {
 100   /* Integer registers.  */
 101   if ((regnum >= SPARC_G1_REGNUM && regnum <= SPARC_G7_REGNUM)
 102       || (regnum >= SPARC_O0_REGNUM && regnum <= SPARC_O7_REGNUM)
 103       || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_L7_REGNUM)
 104       || (regnum >= SPARC_I0_REGNUM && regnum <= SPARC_I7_REGNUM))
 105     return 1;
 106
 107   /* Control registers.  */
 108   if (regnum == SPARC32_PC_REGNUM
 109       || regnum == SPARC32_NPC_REGNUM
 110       || regnum == SPARC32_PSR_REGNUM
 111       || regnum == SPARC32_Y_REGNUM)
 112     return 1;
 113
 114   return 0;
 115 }
 116
 117 /* Determine whether `fpregset_t' contains register REGNUM.  */
 118
 119 int
 120 sparc32_fpregset_supplies_p (int regnum)
 121 {
 122   /* Floating-point registers.  */
 123   if (regnum >= SPARC_F0_REGNUM && regnum <= SPARC_F31_REGNUM)
 124     return 1;
 125
 126   /* Control registers.  */
 127   if (regnum == SPARC32_FSR_REGNUM)
 128     return 1;
 129
 130   return 0;
 131 }
 132
 133 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
 134    for all registers (including the floating-point registers).  */
 135
 136 void
 137 sparc_fetch_inferior_registers (struct target_ops *ops,
 138                                 struct regcache *regcache, int regnum)
 139 {
 140   int pid;
 141
 142   /* NOTE: cagney/2002-12-03: This code assumes that the currently
 143      selected light weight processes' registers can be written
 144      directly into the selected thread's register cache.  This works
 145      fine when given an 1:1 LWP:thread model (such as found on
 146      GNU/Linux) but will, likely, have problems when used on an N:1
 147      (userland threads) or N:M (userland multiple LWP) model.  In the
 148      case of the latter two, the LWP's registers do not necessarily
 149      belong to the selected thread (the LWP could be in the middle of
 150      executing the thread switch code).
 151
 152      These functions should instead be paramaterized with an explicit
 153      object (struct regcache, struct thread_info?) into which the LWPs
 154      registers can be written.  */
 155   pid = TIDGET (inferior_ptid);
 156   if (pid == 0)
 157     pid = PIDGET (inferior_ptid);
 158
 159   if (regnum == SPARC_G0_REGNUM)
 160     {
 161       regcache_raw_supply (regcache, SPARC_G0_REGNUM, NULL);
 162       return;
 163     }
 164
 165   if (regnum == -1 || sparc_gregset_supplies_p (regnum))
 166     {
 167       gregset_t regs;
 168
 169       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 170         perror_with_name (_("Couldn't get registers"));
 171
 172       sparc_supply_gregset (sparc_gregset, regcache, -1, &regs);
 173       if (regnum != -1)
 174         return;
 175     }
 176
 177   if (regnum == -1 || sparc_fpregset_supplies_p (regnum))
 178     {
 179       fpregset_t fpregs;
 180
 181       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 182         perror_with_name (_("Couldn't get floating point status"));
 183
 184       sparc_supply_fpregset (regcache, -1, &fpregs);
 185     }
 186 }
 187
 188 void
 189 sparc_store_inferior_registers (struct target_ops *ops,
 190                                 struct regcache *regcache, int regnum)
 191 {
 192   int pid;
 193
 194   /* NOTE: cagney/2002-12-02: See comment in fetch_inferior_registers
 195      about threaded assumptions.  */
 196   pid = TIDGET (inferior_ptid);
 197   if (pid == 0)
 198     pid = PIDGET (inferior_ptid);
 199
 200   if (regnum == -1 || sparc_gregset_supplies_p (regnum))
 201     {
 202       gregset_t regs;
 203
 204       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 205         perror_with_name (_("Couldn't get registers"));
 206
 207       sparc_collect_gregset (sparc_gregset, regcache, regnum, &regs);
 208
 209       if (ptrace (PTRACE_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 210         perror_with_name (_("Couldn't write registers"));
 211
 212       /* Deal with the stack regs.  */
 213       if (regnum == -1 || regnum == SPARC_SP_REGNUM
 214           || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
 215         {
 216           ULONGEST sp;
 217
 218           regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);
 219           sparc_collect_rwindow (regcache, sp, regnum);
 220         }
 221
 222       if (regnum != -1)
 223         return;
 224     }
 225
 226   if (regnum == -1 || sparc_fpregset_supplies_p (regnum))
 227     {
 228       fpregset_t fpregs, saved_fpregs;
 229
 230       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 231         perror_with_name (_("Couldn't get floating-point registers"));
 232
 233       memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
 234       sparc_collect_fpregset (regcache, regnum, &fpregs);
 235
 236       /* Writing the floating-point registers will fail on NetBSD with
 237          EINVAL if the inferior process doesn't have an FPU state
 238          (i.e. if it didn't use the FPU yet).  Therefore we don't try
 239          to write the registers if nothing changed.  */
 240       if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
 241         {
 242           if (ptrace (PTRACE_SETFPREGS, pid,
 243                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 244             perror_with_name (_("Couldn't write floating-point registers"));
 245         }
 246
 247       if (regnum != -1)
 248         return;
 249     }
 250 }
 251
 252 \f
 253 /* Fetch StackGhost Per-Process XOR cookie.  */
 254
 255 LONGEST
 256 sparc_xfer_wcookie (struct target_ops *ops, enum target_object object,
 257                     const char *annex, gdb_byte *readbuf,
 258                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
 259 {
 260   unsigned long wcookie = 0;
 261   char *buf = (char *)&wcookie;
 262
 263   gdb_assert (object == TARGET_OBJECT_WCOOKIE);
 264   gdb_assert (readbuf && writebuf == NULL);
 265
 266   if (offset == sizeof (unsigned long))
 267     return 0;                   /* Signal EOF.  */
 268   if (offset > sizeof (unsigned long))
 269     return -1;
 270
 271 #ifdef PT_WCOOKIE
 272   /* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
 273      running on an OpenBSD release that uses StackGhost (3.1 or
 274      later).  Since release 3.6, OpenBSD uses a fully randomized
 275      cookie.  */
 276   {
 277     int pid;
 278
 279     pid = TIDGET (inferior_ptid);
 280     if (pid == 0)
 281       pid = PIDGET (inferior_ptid);
 282
 283     /* Sanity check.  The proper type for a cookie is register_t, but
 284        we can't assume that this type exists on all systems supported
 285        by the code in this file.  */
 286     gdb_assert (sizeof (wcookie) == sizeof (register_t));
 287
 288     /* Fetch the cookie.  */
 289     if (ptrace (PT_WCOOKIE, pid, (PTRACE_TYPE_ARG3) &wcookie, 0) == -1)
 290       {
 291         if (errno != EINVAL)
 292           perror_with_name (_("Couldn't get StackGhost cookie"));
 293
 294         /* Although PT_WCOOKIE is defined on OpenBSD 3.1 and later,
 295            the request wasn't implemented until after OpenBSD 3.4.  If
 296            the kernel doesn't support the PT_WCOOKIE request, assume
 297            we're running on a kernel that uses non-randomized cookies.  */
 298         wcookie = 0x3;
 299       }
 300   }
 301 #endif /* PT_WCOOKIE */
 302
 303   if (len > sizeof (unsigned long) - offset)
 304     len = sizeof (unsigned long) - offset;
 305
 306   memcpy (readbuf, buf + offset, len);
 307   return len;
 308 }
 309
 310 LONGEST (*inf_ptrace_xfer_partial) (struct target_ops *, enum target_object,
 311                                     const char *, gdb_byte *, const gdb_byte *,
 312                                     ULONGEST, LONGEST);
 313
 314 static LONGEST
 315 sparc_xfer_partial (struct target_ops *ops, enum target_object object,
 316                     const char *annex, gdb_byte *readbuf,
 317                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
 318 {
 319   if (object == TARGET_OBJECT_WCOOKIE)
 320     return sparc_xfer_wcookie (ops, object, annex, readbuf, writebuf,
 321                                offset, len);
 322
 323   return inf_ptrace_xfer_partial (ops, object, annex, readbuf, writebuf,
 324                                   offset, len);
 325 }
 326 \f
 327 /* Create a prototype generic SPARC target.  The client can override
 328    it with local methods.  */
 329
 330 struct target_ops *
 331 sparc_target (void)
 332 {
 333   struct target_ops *t;
 334
 335   t = inf_ptrace_target ();
 336   t->to_fetch_registers = sparc_fetch_inferior_registers;
 337   t->to_store_registers = sparc_store_inferior_registers;
 338   inf_ptrace_xfer_partial = t->to_xfer_partial;
 339   t->to_xfer_partial = sparc_xfer_partial;
 340   return t;
 341 }
 342
 343 \f
 344 /* Provide a prototype to silence -Wmissing-prototypes.  */
 345 void _initialize_sparc_nat (void);
 346
 347 void
 348 _initialize_sparc_nat (void)
 349 {
 350   /* Deafult to using SunOS 4 register sets.  */
 351   if (sparc_gregset == NULL)
 352     sparc_gregset = &sparc32_sunos4_gregset;
 353   if (sparc_supply_gregset == NULL)
 354     sparc_supply_gregset = sparc32_supply_gregset;
 355   if (sparc_collect_gregset == NULL)
 356     sparc_collect_gregset = sparc32_collect_gregset;
 357   if (sparc_supply_fpregset == NULL)
 358     sparc_supply_fpregset = sparc32_supply_fpregset;
 359   if (sparc_collect_fpregset == NULL)
 360     sparc_collect_fpregset = sparc32_collect_fpregset;
 361   if (sparc_gregset_supplies_p == NULL)
 362     sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
 363   if (sparc_fpregset_supplies_p == NULL)
 364     sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
 365 }