gdb/sparc-nat.c

   1 /* Native-dependent code for SPARC.
   2
   3    Copyright (C) 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "defs.h"
  23 #include "inferior.h"
  24 #include "regcache.h"
  25 #include "target.h"
  26
  27 #include "gdb_assert.h"
  28 #include <signal.h>
  29 #include "gdb_string.h"
  30 #include <sys/ptrace.h>
  31 #include "gdb_wait.h"
  32 #ifdef HAVE_MACHINE_REG_H
  33 #include <machine/reg.h>
  34 #endif
  35
  36 #include "sparc-tdep.h"
  37 #include "sparc-nat.h"
  38 #include "inf-ptrace.h"
  39
  40 /* With some trickery we can use the code in this file for most (if
  41    not all) ptrace(2) based SPARC systems, which includes SunOS 4,
  42    GNU/Linux and the various SPARC BSD's.
  43
  44    First, we need a data structure for use with ptrace(2).  SunOS has
  45    `struct regs' and `struct fp_status' in <machine/reg.h>.  BSD's
  46    have `struct reg' and `struct fpreg' in <machine/reg.h>.  GNU/Linux
  47    has the same structures as SunOS 4, but they're in <asm/reg.h>,
  48    which is a kernel header.  As a general rule we avoid including
  49    GNU/Linux kernel headers.  Fortunately GNU/Linux has a `gregset_t'
  50    and a `fpregset_t' that are equivalent to `struct regs' and `struct
  51    fp_status' in <sys/ucontext.h>, which is automatically included by
  52    <signal.h>.  Settling on using the `gregset_t' and `fpregset_t'
  53    typedefs, providing them for the other systems, therefore solves
  54    the puzzle.  */
  55
  56 #ifdef HAVE_MACHINE_REG_H
  57 #ifdef HAVE_STRUCT_REG
  58 typedef struct reg gregset_t;
  59 typedef struct fpreg fpregset_t;
  60 #else
  61 typedef struct regs gregset_t;
  62 typedef struct fp_status fpregset_t;
  63 #endif
  64 #endif
  65
  66 /* Second, we need to remap the BSD ptrace(2) requests to their SunOS
  67    equivalents.  GNU/Linux already follows SunOS here.  */
  68
  69 #ifndef PTRACE_GETREGS
  70 #define PTRACE_GETREGS PT_GETREGS
  71 #endif
  72
  73 #ifndef PTRACE_SETREGS
  74 #define PTRACE_SETREGS PT_SETREGS
  75 #endif
  76
  77 #ifndef PTRACE_GETFPREGS
  78 #define PTRACE_GETFPREGS PT_GETFPREGS
  79 #endif
  80
  81 #ifndef PTRACE_SETFPREGS
  82 #define PTRACE_SETFPREGS PT_SETFPREGS
  83 #endif
  84
  85 /* Register set description.  */
  86 const struct sparc_gregset *sparc_gregset;
  87 void (*sparc_supply_gregset) (const struct sparc_gregset *,
  88                               struct regcache *, int , const void *);
  89 void (*sparc_collect_gregset) (const struct sparc_gregset *,
  90                                const struct regcache *, int, void *);
  91 void (*sparc_supply_fpregset) (struct regcache *, int , const void *);
  92 void (*sparc_collect_fpregset) (const struct regcache *, int , void *);
  93 int (*sparc_gregset_supplies_p) (int);
  94 int (*sparc_fpregset_supplies_p) (int);
  95
  96 /* Determine whether `gregset_t' contains register REGNUM.  */
  97
  98 int
  99 sparc32_gregset_supplies_p (int regnum)
 100 {
 101   /* Integer registers.  */
 102   if ((regnum >= SPARC_G1_REGNUM && regnum <= SPARC_G7_REGNUM)
 103       || (regnum >= SPARC_O0_REGNUM && regnum <= SPARC_O7_REGNUM)
 104       || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_L7_REGNUM)
 105       || (regnum >= SPARC_I0_REGNUM && regnum <= SPARC_I7_REGNUM))
 106     return 1;
 107
 108   /* Control registers.  */
 109   if (regnum == SPARC32_PC_REGNUM
 110       || regnum == SPARC32_NPC_REGNUM
 111       || regnum == SPARC32_PSR_REGNUM
 112       || regnum == SPARC32_Y_REGNUM)
 113     return 1;
 114
 115   return 0;
 116 }
 117
 118 /* Determine whether `fpregset_t' contains register REGNUM.  */
 119
 120 int
 121 sparc32_fpregset_supplies_p (int regnum)
 122 {
 123   /* Floating-point registers.  */
 124   if (regnum >= SPARC_F0_REGNUM && regnum <= SPARC_F31_REGNUM)
 125     return 1;
 126
 127   /* Control registers.  */
 128   if (regnum == SPARC32_FSR_REGNUM)
 129     return 1;
 130
 131   return 0;
 132 }
 133
 134 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
 135    for all registers (including the floating-point registers).  */
 136
 137 void
 138 sparc_fetch_inferior_registers (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 regcache *regcache, int regnum)
 190 {
 191   int pid;
 192
 193   /* NOTE: cagney/2002-12-02: See comment in fetch_inferior_registers
 194      about threaded assumptions.  */
 195   pid = TIDGET (inferior_ptid);
 196   if (pid == 0)
 197     pid = PIDGET (inferior_ptid);
 198
 199   if (regnum == -1 || sparc_gregset_supplies_p (regnum))
 200     {
 201       gregset_t regs;
 202
 203       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 204         perror_with_name (_("Couldn't get registers"));
 205
 206       sparc_collect_gregset (sparc_gregset, regcache, regnum, &regs);
 207
 208       if (ptrace (PTRACE_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 209         perror_with_name (_("Couldn't write registers"));
 210
 211       /* Deal with the stack regs.  */
 212       if (regnum == -1 || regnum == SPARC_SP_REGNUM
 213           || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
 214         {
 215           ULONGEST sp;
 216
 217           regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);
 218           sparc_collect_rwindow (regcache, sp, regnum);
 219         }
 220
 221       if (regnum != -1)
 222         return;
 223     }
 224
 225   if (regnum == -1 || sparc_fpregset_supplies_p (regnum))
 226     {
 227       fpregset_t fpregs, saved_fpregs;
 228
 229       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 230         perror_with_name (_("Couldn't get floating-point registers"));
 231
 232       memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
 233       sparc_collect_fpregset (regcache, regnum, &fpregs);
 234
 235       /* Writing the floating-point registers will fail on NetBSD with
 236          EINVAL if the inferior process doesn't have an FPU state
 237          (i.e. if it didn't use the FPU yet).  Therefore we don't try
 238          to write the registers if nothing changed.  */
 239       if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
 240         {
 241           if (ptrace (PTRACE_SETFPREGS, pid,
 242                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 243             perror_with_name (_("Couldn't write floating-point registers"));
 244         }
 245
 246       if (regnum != -1)
 247         return;
 248     }
 249 }
 250
 251 \f
 252 /* Fetch StackGhost Per-Process XOR cookie.  */
 253
 254 LONGEST
 255 sparc_xfer_wcookie (struct target_ops *ops, enum target_object object,
 256                     const char *annex, gdb_byte *readbuf,
 257                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
 258 {
 259   unsigned long wcookie = 0;
 260   char *buf = (char *)&wcookie;
 261
 262   gdb_assert (object == TARGET_OBJECT_WCOOKIE);
 263   gdb_assert (readbuf && writebuf == NULL);
 264
 265   if (offset == sizeof (unsigned long))
 266     return 0;                   /* Signal EOF.  */
 267   if (offset > sizeof (unsigned long))
 268     return -1;
 269
 270 #ifdef PT_WCOOKIE
 271   /* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
 272      running on an OpenBSD release that uses StackGhost (3.1 or
 273      later).  Since release 3.6, OpenBSD uses a fully randomized
 274      cookie.  */
 275   {
 276     int pid;
 277
 278     pid = TIDGET (inferior_ptid);
 279     if (pid == 0)
 280       pid = PIDGET (inferior_ptid);
 281
 282     /* Sanity check.  The proper type for a cookie is register_t, but
 283        we can't assume that this type exists on all systems supported
 284        by the code in this file.  */
 285     gdb_assert (sizeof (wcookie) == sizeof (register_t));
 286
 287     /* Fetch the cookie.  */
 288     if (ptrace (PT_WCOOKIE, pid, (PTRACE_TYPE_ARG3) &wcookie, 0) == -1)
 289       {
 290         if (errno != EINVAL)
 291           perror_with_name (_("Couldn't get StackGhost cookie"));
 292
 293         /* Although PT_WCOOKIE is defined on OpenBSD 3.1 and later,
 294            the request wasn't implemented until after OpenBSD 3.4.  If
 295            the kernel doesn't support the PT_WCOOKIE request, assume
 296            we're running on a kernel that uses non-randomized cookies.  */
 297         wcookie = 0x3;
 298       }
 299   }
 300 #endif /* PT_WCOOKIE */
 301
 302   if (len > sizeof (unsigned long) - offset)
 303     len = sizeof (unsigned long) - offset;
 304
 305   memcpy (readbuf, buf + offset, len);
 306   return len;
 307 }
 308
 309 LONGEST (*inf_ptrace_xfer_partial) (struct target_ops *, enum target_object,
 310                                     const char *, gdb_byte *, const gdb_byte *,
 311                                     ULONGEST, LONGEST);
 312
 313 static LONGEST
 314 sparc_xfer_partial (struct target_ops *ops, enum target_object object,
 315                     const char *annex, gdb_byte *readbuf,
 316                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
 317 {
 318   if (object == TARGET_OBJECT_WCOOKIE)
 319     return sparc_xfer_wcookie (ops, object, annex, readbuf, writebuf,
 320                                offset, len);
 321
 322   return inf_ptrace_xfer_partial (ops, object, annex, readbuf, writebuf,
 323                                   offset, len);
 324 }
 325 \f
 326 /* Create a prototype generic SPARC target.  The client can override
 327    it with local methods.  */
 328
 329 struct target_ops *
 330 sparc_target (void)
 331 {
 332   struct target_ops *t;
 333
 334   t = inf_ptrace_target ();
 335   t->to_fetch_registers = sparc_fetch_inferior_registers;
 336   t->to_store_registers = sparc_store_inferior_registers;
 337   inf_ptrace_xfer_partial = t->to_xfer_partial;
 338   t->to_xfer_partial = sparc_xfer_partial;
 339   return t;
 340 }
 341
 342 \f
 343 /* Provide a prototype to silence -Wmissing-prototypes.  */
 344 void _initialize_sparc_nat (void);
 345
 346 void
 347 _initialize_sparc_nat (void)
 348 {
 349   /* Deafult to using SunOS 4 register sets.  */
 350   if (sparc_gregset == NULL)
 351     sparc_gregset = &sparc32_sunos4_gregset;
 352   if (sparc_supply_gregset == NULL)
 353     sparc_supply_gregset = sparc32_supply_gregset;
 354   if (sparc_collect_gregset == NULL)
 355     sparc_collect_gregset = sparc32_collect_gregset;
 356   if (sparc_supply_fpregset == NULL)
 357     sparc_supply_fpregset = sparc32_supply_fpregset;
 358   if (sparc_collect_fpregset == NULL)
 359     sparc_collect_fpregset = sparc32_collect_fpregset;
 360   if (sparc_gregset_supplies_p == NULL)
 361     sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
 362   if (sparc_fpregset_supplies_p == NULL)
 363     sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
 364 }