gdb/sparc-nat.c

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