gdb/sparc-nat.c

   1 /* Native-dependent code for SPARC.
   2
   3    Copyright 2003, 2004 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., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, 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 fetch_inferior_registers (int regnum)
 139 {
 140   struct regcache *regcache = current_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 (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 (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 store_inferior_registers (int regnum)
 191 {
 192   struct regcache *regcache = current_regcache;
 193   int pid;
 194
 195   /* NOTE: cagney/2002-12-02: See comment in fetch_inferior_registers
 196      about threaded assumptions.  */
 197   pid = TIDGET (inferior_ptid);
 198   if (pid == 0)
 199     pid = PIDGET (inferior_ptid);
 200
 201   if (regnum == -1 || sparc_gregset_supplies_p (regnum))
 202     {
 203       gregset_t regs;
 204
 205       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 206         perror_with_name ("Couldn't get registers");
 207
 208       sparc_collect_gregset (sparc_gregset, regcache, regnum, &regs);
 209
 210       if (ptrace (PTRACE_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 211         perror_with_name ("Couldn't write registers");
 212
 213       /* Deal with the stack regs.  */
 214       if (regnum == -1 || regnum == SPARC_SP_REGNUM
 215           || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
 216         {
 217           ULONGEST sp;
 218
 219           regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);
 220           sparc_collect_rwindow (regcache, sp, regnum);
 221         }
 222
 223       if (regnum != -1)
 224         return;
 225     }
 226
 227   if (regnum == -1 || sparc_fpregset_supplies_p (regnum))
 228     {
 229       fpregset_t fpregs, saved_fpregs;
 230
 231       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 232         perror_with_name ("Couldn't get floating-point registers");
 233
 234       memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
 235       sparc_collect_fpregset (regcache, regnum, &fpregs);
 236
 237       /* Writing the floating-point registers will fail on NetBSD with
 238          EINVAL if the inferior process doesn't have an FPU state
 239          (i.e. if it didn't use the FPU yet).  Therefore we don't try
 240          to write the registers if nothing changed.  */
 241       if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
 242         {
 243           if (ptrace (PTRACE_SETFPREGS, pid,
 244                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 245             perror_with_name ("Couldn't write floating-point registers");
 246         }
 247
 248       if (regnum != -1)
 249         return;
 250     }
 251 }
 252
 253 \f
 254 /* Fetch StackGhost Per-Process XOR cookie.  */
 255
 256 LONGEST
 257 sparc_xfer_wcookie (struct target_ops *ops, enum target_object object,
 258                     const char *annex, void *readbuf, const void *writebuf,
 259                     ULONGEST offset, LONGEST len)
 260 {
 261   unsigned long wcookie = 0;
 262   char *buf = (char *)&wcookie;
 263
 264   gdb_assert (object == TARGET_OBJECT_WCOOKIE);
 265   gdb_assert (readbuf && writebuf == NULL);
 266
 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).  As of release 3.4, OpenBSD doesn't use a randomized
 274      cookie yet, but a future release probably will.  */
 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 \f
 309 /* Create a prototype generic SPARC target.  The client can override
 310    it with local methods.  */
 311
 312 struct target_ops *
 313 sparc_target (void)
 314 {
 315   struct target_ops *t;
 316
 317   t = inf_ptrace_target ();
 318   t->to_fetch_registers = fetch_inferior_registers;
 319   t->to_store_registers = store_inferior_registers;
 320   return t;
 321 }
 322
 323 \f
 324 /* Provide a prototype to silence -Wmissing-prototypes.  */
 325 void _initialize_sparc_nat (void);
 326
 327 void
 328 _initialize_sparc_nat (void)
 329 {
 330   /* Deafult to using SunOS 4 register sets.  */
 331   if (sparc_gregset == NULL)
 332     sparc_gregset = &sparc32_sunos4_gregset;
 333   if (sparc_supply_gregset == NULL)
 334     sparc_supply_gregset = sparc32_supply_gregset;
 335   if (sparc_collect_gregset == NULL)
 336     sparc_collect_gregset = sparc32_collect_gregset;
 337   if (sparc_supply_fpregset == NULL)
 338     sparc_supply_fpregset = sparc32_supply_fpregset;
 339   if (sparc_collect_fpregset == NULL)
 340     sparc_collect_fpregset = sparc32_collect_fpregset;
 341   if (sparc_gregset_supplies_p == NULL)
 342     sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
 343   if (sparc_fpregset_supplies_p == NULL)
 344     sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
 345 }