gdb/sparc-nat.c

   1 /* Native-dependent code for SPARC.
   2
   3    Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
   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) (struct gdbarch *, int);
  93 int (*sparc_fpregset_supplies_p) (struct gdbarch *, int);
  94
  95 /* Determine whether `gregset_t' contains register REGNUM.  */
  96
  97 int
  98 sparc32_gregset_supplies_p (struct gdbarch *gdbarch, 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 (struct gdbarch *gdbarch, 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   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 141   int pid;
 142
 143   /* NOTE: cagney/2002-12-03: This code assumes that the currently
 144      selected light weight processes' registers can be written
 145      directly into the selected thread's register cache.  This works
 146      fine when given an 1:1 LWP:thread model (such as found on
 147      GNU/Linux) but will, likely, have problems when used on an N:1
 148      (userland threads) or N:M (userland multiple LWP) model.  In the
 149      case of the latter two, the LWP's registers do not necessarily
 150      belong to the selected thread (the LWP could be in the middle of
 151      executing the thread switch code).
 152
 153      These functions should instead be paramaterized with an explicit
 154      object (struct regcache, struct thread_info?) into which the LWPs
 155      registers can be written.  */
 156   pid = TIDGET (inferior_ptid);
 157   if (pid == 0)
 158     pid = PIDGET (inferior_ptid);
 159
 160   if (regnum == SPARC_G0_REGNUM)
 161     {
 162       gdb_byte zero[8] = { 0 };
 163
 164       regcache_raw_supply (regcache, SPARC_G0_REGNUM, &zero);
 165       return;
 166     }
 167
 168   if (regnum == -1 || sparc_gregset_supplies_p (gdbarch, regnum))
 169     {
 170       gregset_t regs;
 171
 172       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 173         perror_with_name (_("Couldn't get registers"));
 174
 175       sparc_supply_gregset (sparc_gregset, regcache, -1, &regs);
 176       if (regnum != -1)
 177         return;
 178     }
 179
 180   if (regnum == -1 || sparc_fpregset_supplies_p (gdbarch, regnum))
 181     {
 182       fpregset_t fpregs;
 183
 184       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 185         perror_with_name (_("Couldn't get floating point status"));
 186
 187       sparc_supply_fpregset (regcache, -1, &fpregs);
 188     }
 189 }
 190
 191 void
 192 sparc_store_inferior_registers (struct target_ops *ops,
 193                                 struct regcache *regcache, int regnum)
 194 {
 195   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 196   int pid;
 197
 198   /* NOTE: cagney/2002-12-02: See comment in fetch_inferior_registers
 199      about threaded assumptions.  */
 200   pid = TIDGET (inferior_ptid);
 201   if (pid == 0)
 202     pid = PIDGET (inferior_ptid);
 203
 204   if (regnum == -1 || sparc_gregset_supplies_p (gdbarch, regnum))
 205     {
 206       gregset_t regs;
 207
 208       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 209         perror_with_name (_("Couldn't get registers"));
 210
 211       sparc_collect_gregset (sparc_gregset, regcache, regnum, &regs);
 212
 213       if (ptrace (PTRACE_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 214         perror_with_name (_("Couldn't write registers"));
 215
 216       /* Deal with the stack regs.  */
 217       if (regnum == -1 || regnum == SPARC_SP_REGNUM
 218           || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
 219         {
 220           ULONGEST sp;
 221
 222           regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);
 223           sparc_collect_rwindow (regcache, sp, regnum);
 224         }
 225
 226       if (regnum != -1)
 227         return;
 228     }
 229
 230   if (regnum == -1 || sparc_fpregset_supplies_p (gdbarch, regnum))
 231     {
 232       fpregset_t fpregs, saved_fpregs;
 233
 234       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 235         perror_with_name (_("Couldn't get floating-point registers"));
 236
 237       memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
 238       sparc_collect_fpregset (regcache, regnum, &fpregs);
 239
 240       /* Writing the floating-point registers will fail on NetBSD with
 241          EINVAL if the inferior process doesn't have an FPU state
 242          (i.e. if it didn't use the FPU yet).  Therefore we don't try
 243          to write the registers if nothing changed.  */
 244       if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
 245         {
 246           if (ptrace (PTRACE_SETFPREGS, pid,
 247                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 248             perror_with_name (_("Couldn't write floating-point registers"));
 249         }
 250
 251       if (regnum != -1)
 252         return;
 253     }
 254 }
 255
 256 \f
 257 /* Fetch StackGhost Per-Process XOR cookie.  */
 258
 259 LONGEST
 260 sparc_xfer_wcookie (struct target_ops *ops, enum target_object object,
 261                     const char *annex, gdb_byte *readbuf,
 262                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
 263 {
 264   unsigned long wcookie = 0;
 265   char *buf = (char *)&wcookie;
 266
 267   gdb_assert (object == TARGET_OBJECT_WCOOKIE);
 268   gdb_assert (readbuf && writebuf == NULL);
 269
 270   if (offset == sizeof (unsigned long))
 271     return 0;                   /* Signal EOF.  */
 272   if (offset > sizeof (unsigned long))
 273     return -1;
 274
 275 #ifdef PT_WCOOKIE
 276   /* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
 277      running on an OpenBSD release that uses StackGhost (3.1 or
 278      later).  Since release 3.6, OpenBSD uses a fully randomized
 279      cookie.  */
 280   {
 281     int pid;
 282
 283     pid = TIDGET (inferior_ptid);
 284     if (pid == 0)
 285       pid = PIDGET (inferior_ptid);
 286
 287     /* Sanity check.  The proper type for a cookie is register_t, but
 288        we can't assume that this type exists on all systems supported
 289        by the code in this file.  */
 290     gdb_assert (sizeof (wcookie) == sizeof (register_t));
 291
 292     /* Fetch the cookie.  */
 293     if (ptrace (PT_WCOOKIE, pid, (PTRACE_TYPE_ARG3) &wcookie, 0) == -1)
 294       {
 295         if (errno != EINVAL)
 296           perror_with_name (_("Couldn't get StackGhost cookie"));
 297
 298         /* Although PT_WCOOKIE is defined on OpenBSD 3.1 and later,
 299            the request wasn't implemented until after OpenBSD 3.4.  If
 300            the kernel doesn't support the PT_WCOOKIE request, assume
 301            we're running on a kernel that uses non-randomized cookies.  */
 302         wcookie = 0x3;
 303       }
 304   }
 305 #endif /* PT_WCOOKIE */
 306
 307   if (len > sizeof (unsigned long) - offset)
 308     len = sizeof (unsigned long) - offset;
 309
 310   memcpy (readbuf, buf + offset, len);
 311   return len;
 312 }
 313
 314 LONGEST (*inf_ptrace_xfer_partial) (struct target_ops *, enum target_object,
 315                                     const char *, gdb_byte *, const gdb_byte *,
 316                                     ULONGEST, LONGEST);
 317
 318 static LONGEST
 319 sparc_xfer_partial (struct target_ops *ops, enum target_object object,
 320                     const char *annex, gdb_byte *readbuf,
 321                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
 322 {
 323   if (object == TARGET_OBJECT_WCOOKIE)
 324     return sparc_xfer_wcookie (ops, object, annex, readbuf, writebuf,
 325                                offset, len);
 326
 327   return inf_ptrace_xfer_partial (ops, object, annex, readbuf, writebuf,
 328                                   offset, len);
 329 }
 330 \f
 331 /* Create a prototype generic SPARC target.  The client can override
 332    it with local methods.  */
 333
 334 struct target_ops *
 335 sparc_target (void)
 336 {
 337   struct target_ops *t;
 338
 339   t = inf_ptrace_target ();
 340   t->to_fetch_registers = sparc_fetch_inferior_registers;
 341   t->to_store_registers = sparc_store_inferior_registers;
 342   inf_ptrace_xfer_partial = t->to_xfer_partial;
 343   t->to_xfer_partial = sparc_xfer_partial;
 344   return t;
 345 }
 346
 347 \f
 348 /* Provide a prototype to silence -Wmissing-prototypes.  */
 349 void _initialize_sparc_nat (void);
 350
 351 void
 352 _initialize_sparc_nat (void)
 353 {
 354   /* Deafult to using SunOS 4 register sets.  */
 355   if (sparc_gregset == NULL)
 356     sparc_gregset = &sparc32_sunos4_gregset;
 357   if (sparc_supply_gregset == NULL)
 358     sparc_supply_gregset = sparc32_supply_gregset;
 359   if (sparc_collect_gregset == NULL)
 360     sparc_collect_gregset = sparc32_collect_gregset;
 361   if (sparc_supply_fpregset == NULL)
 362     sparc_supply_fpregset = sparc32_supply_fpregset;
 363   if (sparc_collect_fpregset == NULL)
 364     sparc_collect_fpregset = sparc32_collect_fpregset;
 365   if (sparc_gregset_supplies_p == NULL)
 366     sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
 367   if (sparc_fpregset_supplies_p == NULL)
 368     sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
 369 }