gdb/sparc-nat.c

   1 /* Native-dependent code for SPARC.
   2
   3    Copyright (C) 2003-2020 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 "gdbsupport/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 regcache *regcache, int regnum)
 138 {
 139   struct gdbarch *gdbarch = regcache->arch ();
 140   pid_t pid;
 141
 142   /* NOTE: cagney/2002-12-03: This code assumes that the currently
 143      selected light weight processes' registers can be written
 144      directly into the selected thread's register cache.  This works
 145      fine when given an 1:1 LWP:thread model (such as found on
 146      GNU/Linux) but will, likely, have problems when used on an N:1
 147      (userland threads) or N:M (userland multiple LWP) model.  In the
 148      case of the latter two, the LWP's registers do not necessarily
 149      belong to the selected thread (the LWP could be in the middle of
 150      executing the thread switch code).
 151
 152      These functions should instead be parameterized with an explicit
 153      object (struct regcache, struct thread_info?) into which the LWPs
 154      registers can be written.  */
 155   pid = get_ptrace_pid (regcache->ptid ());
 156
 157   if (regnum == SPARC_G0_REGNUM)
 158     {
 159       gdb_byte zero[8] = { 0 };
 160
 161       regcache->raw_supply (SPARC_G0_REGNUM, &zero);
 162       return;
 163     }
 164
 165   if (regnum == -1 || sparc_gregset_supplies_p (gdbarch, regnum))
 166     {
 167       gregset_t regs;
 168
 169       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 170         perror_with_name (_("Couldn't get registers"));
 171
 172       sparc_supply_gregset (sparc_gregmap, regcache, -1, &regs);
 173       if (regnum != -1)
 174         return;
 175     }
 176
 177   if (regnum == -1 || sparc_fpregset_supplies_p (gdbarch, regnum))
 178     {
 179       fpregset_t fpregs;
 180
 181       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 182         perror_with_name (_("Couldn't get floating point status"));
 183
 184       sparc_supply_fpregset (sparc_fpregmap, regcache, -1, &fpregs);
 185     }
 186 }
 187
 188 void
 189 sparc_store_inferior_registers (struct regcache *regcache, int regnum)
 190 {
 191   struct gdbarch *gdbarch = regcache->arch ();
 192   pid_t pid;
 193
 194   /* NOTE: cagney/2002-12-02: See comment in fetch_inferior_registers
 195      about threaded assumptions.  */
 196   pid = get_ptrace_pid (regcache->ptid ());
 197
 198   if (regnum == -1 || sparc_gregset_supplies_p (gdbarch, regnum))
 199     {
 200       gregset_t regs;
 201
 202       if (ptrace (PTRACE_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 203         perror_with_name (_("Couldn't get registers"));
 204
 205       sparc_collect_gregset (sparc_gregmap, regcache, regnum, &regs);
 206
 207       if (ptrace (PTRACE_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 208         perror_with_name (_("Couldn't write registers"));
 209
 210       /* Deal with the stack regs.  */
 211       if (regnum == -1 || regnum == SPARC_SP_REGNUM
 212           || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
 213         {
 214           ULONGEST sp;
 215
 216           regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);
 217           sparc_collect_rwindow (regcache, sp, regnum);
 218         }
 219
 220       if (regnum != -1)
 221         return;
 222     }
 223
 224   if (regnum == -1 || sparc_fpregset_supplies_p (gdbarch, regnum))
 225     {
 226       fpregset_t fpregs, saved_fpregs;
 227
 228       if (ptrace (PTRACE_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 229         perror_with_name (_("Couldn't get floating-point registers"));
 230
 231       memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
 232       sparc_collect_fpregset (sparc_fpregmap, regcache, regnum, &fpregs);
 233
 234       /* Writing the floating-point registers will fail on NetBSD with
 235          EINVAL if the inferior process doesn't have an FPU state
 236          (i.e. if it didn't use the FPU yet).  Therefore we don't try
 237          to write the registers if nothing changed.  */
 238       if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
 239         {
 240           if (ptrace (PTRACE_SETFPREGS, pid,
 241                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 242             perror_with_name (_("Couldn't write floating-point registers"));
 243         }
 244
 245       if (regnum != -1)
 246         return;
 247     }
 248 }
 249
 250 \f
 251 /* Implement the to_xfer_partial target_ops method for
 252    TARGET_OBJECT_WCOOKIE.  Fetch StackGhost Per-Process XOR cookie.  */
 253
 254 enum target_xfer_status
 255 sparc_xfer_wcookie (enum target_object object,
 256                     const char *annex, gdb_byte *readbuf,
 257                     const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
 258                     ULONGEST *xfered_len)
 259 {
 260   unsigned long wcookie = 0;
 261   char *buf = (char *)&wcookie;
 262
 263   gdb_assert (object == TARGET_OBJECT_WCOOKIE);
 264   gdb_assert (readbuf && writebuf == NULL);
 265
 266   if (offset == sizeof (unsigned long))
 267     return TARGET_XFER_EOF;                     /* Signal EOF.  */
 268   if (offset > sizeof (unsigned long))
 269     return TARGET_XFER_E_IO;
 270
 271 #ifdef PT_WCOOKIE
 272   /* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
 273      running on an OpenBSD release that uses StackGhost (3.1 or
 274      later).  Since release 3.6, OpenBSD uses a fully randomized
 275      cookie.  */
 276   {
 277     int pid = inferior_ptid.pid ();
 278
 279     /* Sanity check.  The proper type for a cookie is register_t, but
 280        we can't assume that this type exists on all systems supported
 281        by the code in this file.  */
 282     gdb_assert (sizeof (wcookie) == sizeof (register_t));
 283
 284     /* Fetch the cookie.  */
 285     if (ptrace (PT_WCOOKIE, pid, (PTRACE_TYPE_ARG3) &wcookie, 0) == -1)
 286       {
 287         if (errno != EINVAL)
 288           perror_with_name (_("Couldn't get StackGhost cookie"));
 289
 290         /* Although PT_WCOOKIE is defined on OpenBSD 3.1 and later,
 291            the request wasn't implemented until after OpenBSD 3.4.  If
 292            the kernel doesn't support the PT_WCOOKIE request, assume
 293            we're running on a kernel that uses non-randomized cookies.  */
 294         wcookie = 0x3;
 295       }
 296   }
 297 #endif /* PT_WCOOKIE */
 298
 299   if (len > sizeof (unsigned long) - offset)
 300     len = sizeof (unsigned long) - offset;
 301
 302   memcpy (readbuf, buf + offset, len);
 303   *xfered_len = (ULONGEST) len;
 304   return TARGET_XFER_OK;
 305 }
 306 \f
 307
 308 void _initialize_sparc_nat ();
 309 void
 310 _initialize_sparc_nat ()
 311 {
 312   /* Default to using SunOS 4 register sets.  */
 313   if (sparc_gregmap == NULL)
 314     sparc_gregmap = &sparc32_sunos4_gregmap;
 315   if (sparc_fpregmap == NULL)
 316     sparc_fpregmap = &sparc32_sunos4_fpregmap;
 317   if (sparc_supply_gregset == NULL)
 318     sparc_supply_gregset = sparc32_supply_gregset;
 319   if (sparc_collect_gregset == NULL)
 320     sparc_collect_gregset = sparc32_collect_gregset;
 321   if (sparc_supply_fpregset == NULL)
 322     sparc_supply_fpregset = sparc32_supply_fpregset;
 323   if (sparc_collect_fpregset == NULL)
 324     sparc_collect_fpregset = sparc32_collect_fpregset;
 325   if (sparc_gregset_supplies_p == NULL)
 326     sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
 327   if (sparc_fpregset_supplies_p == NULL)
 328     sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
 329 }