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 regcache *regcache, int regnum)
 138 {
 139   int pid;
 140
 141   /* NOTE: cagney/2002-12-03: This code assumes that the currently
 142      selected light weight processes' registers can be written
 143      directly into the selected thread's register cache.  This works
 144      fine when given an 1:1 LWP:thread model (such as found on
 145      GNU/Linux) but will, likely, have problems when used on an N:1
 146      (userland threads) or N:M (userland multiple LWP) model.  In the
 147      case of the latter two, the LWP's registers do not necessarily
 148      belong to the selected thread (the LWP could be in the middle of
 149      executing the thread switch code).
 150
 151      These functions should instead be paramaterized with an explicit
 152      object (struct regcache, struct thread_info?) into which the LWPs
 153      registers can be written.  */
 154   pid = TIDGET (inferior_ptid);
 155   if (pid == 0)
 156     pid = PIDGET (inferior_ptid);
 157
 158   if (regnum == SPARC_G0_REGNUM)
 159     {
 160       regcache_raw_supply (regcache, SPARC_G0_REGNUM, NULL);
 161       return;
 162     }
 163
 164   if (regnum == -1 || sparc_gregset_supplies_p (regnum))
 165     {
 166       gregset_t regs;
 167
 168       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 169         perror_with_name (_("Couldn't get registers"));
 170
 171       sparc_supply_gregset (sparc_gregset, regcache, -1, &regs);
 172       if (regnum != -1)
 173         return;
 174     }
 175
 176   if (regnum == -1 || sparc_fpregset_supplies_p (regnum))
 177     {
 178       fpregset_t fpregs;
 179
 180       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 181         perror_with_name (_("Couldn't get floating point status"));
 182
 183       sparc_supply_fpregset (regcache, -1, &fpregs);
 184     }
 185 }
 186
 187 void
 188 sparc_store_inferior_registers (struct regcache *regcache, int regnum)
 189 {
 190   int pid;
 191
 192   /* NOTE: cagney/2002-12-02: See comment in fetch_inferior_registers
 193      about threaded assumptions.  */
 194   pid = TIDGET (inferior_ptid);
 195   if (pid == 0)
 196     pid = PIDGET (inferior_ptid);
 197
 198   if (regnum == -1 || sparc_gregset_supplies_p (regnum))
 199     {
 200       gregset_t regs;
 201
 202       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 203         perror_with_name (_("Couldn't get registers"));
 204
 205       sparc_collect_gregset (sparc_gregset, regcache, regnum, &regs);
 206
 207       if (ptrace (PTRACE_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 208         perror_with_name (_("Couldn't write registers"));
 209
 210       /* Deal with the stack regs.  */
 211       if (regnum == -1 || regnum == SPARC_SP_REGNUM
 212           || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
 213         {
 214           ULONGEST sp;
 215
 216           regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);
 217           sparc_collect_rwindow (regcache, sp, regnum);
 218         }
 219
 220       if (regnum != -1)
 221         return;
 222     }
 223
 224   if (regnum == -1 || sparc_fpregset_supplies_p (regnum))
 225     {
 226       fpregset_t fpregs, saved_fpregs;
 227
 228       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 229         perror_with_name (_("Couldn't get floating-point registers"));
 230
 231       memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
 232       sparc_collect_fpregset (regcache, regnum, &fpregs);
 233
 234       /* Writing the floating-point registers will fail on NetBSD with
 235          EINVAL if the inferior process doesn't have an FPU state
 236          (i.e. if it didn't use the FPU yet).  Therefore we don't try
 237          to write the registers if nothing changed.  */
 238       if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
 239         {
 240           if (ptrace (PTRACE_SETFPREGS, pid,
 241                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 242             perror_with_name (_("Couldn't write floating-point registers"));
 243         }
 244
 245       if (regnum != -1)
 246         return;
 247     }
 248 }
 249
 250 \f
 251 /* Fetch StackGhost Per-Process XOR cookie.  */
 252
 253 LONGEST
 254 sparc_xfer_wcookie (struct target_ops *ops, enum target_object object,
 255                     const char *annex, gdb_byte *readbuf,
 256                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
 257 {
 258   unsigned long wcookie = 0;
 259   char *buf = (char *)&wcookie;
 260
 261   gdb_assert (object == TARGET_OBJECT_WCOOKIE);
 262   gdb_assert (readbuf && writebuf == NULL);
 263
 264   if (offset == sizeof (unsigned long))
 265     return 0;                   /* Signal EOF.  */
 266   if (offset > sizeof (unsigned long))
 267     return -1;
 268
 269 #ifdef PT_WCOOKIE
 270   /* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
 271      running on an OpenBSD release that uses StackGhost (3.1 or
 272      later).  Since release 3.6, OpenBSD uses a fully randomized
 273      cookie.  */
 274   {
 275     int pid;
 276
 277     pid = TIDGET (inferior_ptid);
 278     if (pid == 0)
 279       pid = PIDGET (inferior_ptid);
 280
 281     /* Sanity check.  The proper type for a cookie is register_t, but
 282        we can't assume that this type exists on all systems supported
 283        by the code in this file.  */
 284     gdb_assert (sizeof (wcookie) == sizeof (register_t));
 285
 286     /* Fetch the cookie.  */
 287     if (ptrace (PT_WCOOKIE, pid, (PTRACE_TYPE_ARG3) &wcookie, 0) == -1)
 288       {
 289         if (errno != EINVAL)
 290           perror_with_name (_("Couldn't get StackGhost cookie"));
 291
 292         /* Although PT_WCOOKIE is defined on OpenBSD 3.1 and later,
 293            the request wasn't implemented until after OpenBSD 3.4.  If
 294            the kernel doesn't support the PT_WCOOKIE request, assume
 295            we're running on a kernel that uses non-randomized cookies.  */
 296         wcookie = 0x3;
 297       }
 298   }
 299 #endif /* PT_WCOOKIE */
 300
 301   if (len > sizeof (unsigned long) - offset)
 302     len = sizeof (unsigned long) - offset;
 303
 304   memcpy (readbuf, buf + offset, len);
 305   return len;
 306 }
 307
 308 LONGEST (*inf_ptrace_xfer_partial) (struct target_ops *, enum target_object,
 309                                     const char *, gdb_byte *, const gdb_byte *,
 310                                     ULONGEST, LONGEST);
 311
 312 static LONGEST
 313 sparc_xfer_partial (struct target_ops *ops, enum target_object object,
 314                     const char *annex, gdb_byte *readbuf,
 315                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
 316 {
 317   if (object == TARGET_OBJECT_WCOOKIE)
 318     return sparc_xfer_wcookie (ops, object, annex, readbuf, writebuf,
 319                                offset, len);
 320
 321   return inf_ptrace_xfer_partial (ops, object, annex, readbuf, writebuf,
 322                                   offset, len);
 323 }
 324 \f
 325 /* Create a prototype generic SPARC target.  The client can override
 326    it with local methods.  */
 327
 328 struct target_ops *
 329 sparc_target (void)
 330 {
 331   struct target_ops *t;
 332
 333   t = inf_ptrace_target ();
 334   t->to_fetch_registers = sparc_fetch_inferior_registers;
 335   t->to_store_registers = sparc_store_inferior_registers;
 336   inf_ptrace_xfer_partial = t->to_xfer_partial;
 337   t->to_xfer_partial = sparc_xfer_partial;
 338   return t;
 339 }
 340
 341 \f
 342 /* Provide a prototype to silence -Wmissing-prototypes.  */
 343 void _initialize_sparc_nat (void);
 344
 345 void
 346 _initialize_sparc_nat (void)
 347 {
 348   /* Deafult to using SunOS 4 register sets.  */
 349   if (sparc_gregset == NULL)
 350     sparc_gregset = &sparc32_sunos4_gregset;
 351   if (sparc_supply_gregset == NULL)
 352     sparc_supply_gregset = sparc32_supply_gregset;
 353   if (sparc_collect_gregset == NULL)
 354     sparc_collect_gregset = sparc32_collect_gregset;
 355   if (sparc_supply_fpregset == NULL)
 356     sparc_supply_fpregset = sparc32_supply_fpregset;
 357   if (sparc_collect_fpregset == NULL)
 358     sparc_collect_fpregset = sparc32_collect_fpregset;
 359   if (sparc_gregset_supplies_p == NULL)
 360     sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
 361   if (sparc_fpregset_supplies_p == NULL)
 362     sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
 363 }