gdb/sparc-nat.c

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