gdb/sparc-nat.c

   1 /* Native-dependent code for SPARC.
   2
   3    Copyright (C) 2003-2015 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 <signal.h>
  26 #include <sys/ptrace.h>
  27 #include "gdb_wait.h"
  28 #ifdef HAVE_MACHINE_REG_H
  29 #include <machine/reg.h>
  30 #endif
  31
  32 #include "sparc-tdep.h"
  33 #include "sparc-nat.h"
  34 #include "inf-ptrace.h"
  35
  36 /* With some trickery we can use the code in this file for most (if
  37    not all) ptrace(2) based SPARC systems, which includes SunOS 4,
  38    GNU/Linux and the various SPARC BSD's.
  39
  40    First, we need a data structure for use with ptrace(2).  SunOS has
  41    `struct regs' and `struct fp_status' in <machine/reg.h>.  BSD's
  42    have `struct reg' and `struct fpreg' in <machine/reg.h>.  GNU/Linux
  43    has the same structures as SunOS 4, but they're in <asm/reg.h>,
  44    which is a kernel header.  As a general rule we avoid including
  45    GNU/Linux kernel headers.  Fortunately GNU/Linux has a `gregset_t'
  46    and a `fpregset_t' that are equivalent to `struct regs' and `struct
  47    fp_status' in <sys/ucontext.h>, which is automatically included by
  48    <signal.h>.  Settling on using the `gregset_t' and `fpregset_t'
  49    typedefs, providing them for the other systems, therefore solves
  50    the puzzle.  */
  51
  52 #ifdef HAVE_MACHINE_REG_H
  53 #ifdef HAVE_STRUCT_REG
  54 typedef struct reg gregset_t;
  55 typedef struct fpreg fpregset_t;
  56 #else
  57 typedef struct regs gregset_t;
  58 typedef struct fp_status fpregset_t;
  59 #endif
  60 #endif
  61
  62 /* Second, we need to remap the BSD ptrace(2) requests to their SunOS
  63    equivalents.  GNU/Linux already follows SunOS here.  */
  64
  65 #ifndef PTRACE_GETREGS
  66 #define PTRACE_GETREGS PT_GETREGS
  67 #endif
  68
  69 #ifndef PTRACE_SETREGS
  70 #define PTRACE_SETREGS PT_SETREGS
  71 #endif
  72
  73 #ifndef PTRACE_GETFPREGS
  74 #define PTRACE_GETFPREGS PT_GETFPREGS
  75 #endif
  76
  77 #ifndef PTRACE_SETFPREGS
  78 #define PTRACE_SETFPREGS PT_SETFPREGS
  79 #endif
  80
  81 /* Register set description.  */
  82 const struct sparc_gregmap *sparc_gregmap;
  83 const struct sparc_fpregmap *sparc_fpregmap;
  84 void (*sparc_supply_gregset) (const struct sparc_gregmap *,
  85                               struct regcache *, int , const void *);
  86 void (*sparc_collect_gregset) (const struct sparc_gregmap *,
  87                                const struct regcache *, int, void *);
  88 void (*sparc_supply_fpregset) (const struct sparc_fpregmap *,
  89                                struct regcache *, int , const void *);
  90 void (*sparc_collect_fpregset) (const struct sparc_fpregmap *,
  91                                 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 = ptid_get_lwp (inferior_ptid);
 157   if (pid == 0)
 158     pid = ptid_get_pid (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_gregmap, 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 (sparc_fpregmap, 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 = ptid_get_lwp (inferior_ptid);
 201   if (pid == 0)
 202     pid = ptid_get_pid (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_gregmap, 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 (sparc_fpregmap, 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 /* Implement the to_xfer_partial target_ops method for
 258    TARGET_OBJECT_WCOOKIE.  Fetch StackGhost Per-Process XOR cookie.  */
 259
 260 static enum target_xfer_status
 261 sparc_xfer_wcookie (struct target_ops *ops, enum target_object object,
 262                     const char *annex, gdb_byte *readbuf,
 263                     const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
 264                     ULONGEST *xfered_len)
 265 {
 266   unsigned long wcookie = 0;
 267   char *buf = (char *)&wcookie;
 268
 269   gdb_assert (object == TARGET_OBJECT_WCOOKIE);
 270   gdb_assert (readbuf && writebuf == NULL);
 271
 272   if (offset == sizeof (unsigned long))
 273     return TARGET_XFER_EOF;                     /* Signal EOF.  */
 274   if (offset > sizeof (unsigned long))
 275     return TARGET_XFER_E_IO;
 276
 277 #ifdef PT_WCOOKIE
 278   /* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
 279      running on an OpenBSD release that uses StackGhost (3.1 or
 280      later).  Since release 3.6, OpenBSD uses a fully randomized
 281      cookie.  */
 282   {
 283     int pid = ptid_get_pid (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   *xfered_len = (ULONGEST) len;
 310   return TARGET_XFER_OK;
 311 }
 312
 313 target_xfer_partial_ftype *inf_ptrace_xfer_partial;
 314
 315 static enum target_xfer_status
 316 sparc_xfer_partial (struct target_ops *ops, enum target_object object,
 317                     const char *annex, gdb_byte *readbuf,
 318                     const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
 319                     ULONGEST *xfered_len)
 320 {
 321   if (object == TARGET_OBJECT_WCOOKIE)
 322     return sparc_xfer_wcookie (ops, object, annex, readbuf, writebuf,
 323                                offset, len, xfered_len);
 324
 325   return inf_ptrace_xfer_partial (ops, object, annex, readbuf, writebuf,
 326                                   offset, len, xfered_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_gregmap == NULL)
 354     sparc_gregmap = &sparc32_sunos4_gregmap;
 355   if (sparc_fpregmap == NULL)
 356     sparc_fpregmap = &sparc32_sunos4_fpregmap;
 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 }