gdb/sparc-nat.c

   1 /* Native-dependent code for SPARC.
   2
   3    Copyright (C) 2003-2021 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 static PTRACE_TYPE_RET
  82 gdb_ptrace (PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr)
  83 {
  84 #ifdef __NetBSD__
  85   /* Support for NetBSD threads: unlike other ptrace implementations in this
  86      file, NetBSD requires that we pass both the pid and lwp.  */
  87   return ptrace (request, ptid.pid (), addr, ptid.lwp ());
  88 #else
  89   pid_t pid = get_ptrace_pid (ptid);
  90   return ptrace (request, pid, addr, 0);
  91 #endif
  92 }
  93
  94 /* Register set description.  */
  95 const struct sparc_gregmap *sparc_gregmap;
  96 const struct sparc_fpregmap *sparc_fpregmap;
  97 void (*sparc_supply_gregset) (const struct sparc_gregmap *,
  98                               struct regcache *, int , const void *);
  99 void (*sparc_collect_gregset) (const struct sparc_gregmap *,
 100                                const struct regcache *, int, void *);
 101 void (*sparc_supply_fpregset) (const struct sparc_fpregmap *,
 102                                struct regcache *, int , const void *);
 103 void (*sparc_collect_fpregset) (const struct sparc_fpregmap *,
 104                                 const struct regcache *, int , void *);
 105 int (*sparc_gregset_supplies_p) (struct gdbarch *, int);
 106 int (*sparc_fpregset_supplies_p) (struct gdbarch *, int);
 107
 108 /* Determine whether `gregset_t' contains register REGNUM.  */
 109
 110 int
 111 sparc32_gregset_supplies_p (struct gdbarch *gdbarch, int regnum)
 112 {
 113   /* Integer registers.  */
 114   if ((regnum >= SPARC_G1_REGNUM && regnum <= SPARC_G7_REGNUM)
 115       || (regnum >= SPARC_O0_REGNUM && regnum <= SPARC_O7_REGNUM)
 116       || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_L7_REGNUM)
 117       || (regnum >= SPARC_I0_REGNUM && regnum <= SPARC_I7_REGNUM))
 118     return 1;
 119
 120   /* Control registers.  */
 121   if (regnum == SPARC32_PC_REGNUM
 122       || regnum == SPARC32_NPC_REGNUM
 123       || regnum == SPARC32_PSR_REGNUM
 124       || regnum == SPARC32_Y_REGNUM)
 125     return 1;
 126
 127   return 0;
 128 }
 129
 130 /* Determine whether `fpregset_t' contains register REGNUM.  */
 131
 132 int
 133 sparc32_fpregset_supplies_p (struct gdbarch *gdbarch, int regnum)
 134 {
 135   /* Floating-point registers.  */
 136   if (regnum >= SPARC_F0_REGNUM && regnum <= SPARC_F31_REGNUM)
 137     return 1;
 138
 139   /* Control registers.  */
 140   if (regnum == SPARC32_FSR_REGNUM)
 141     return 1;
 142
 143   return 0;
 144 }
 145
 146 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
 147    for all registers (including the floating-point registers).  */
 148
 149 void
 150 sparc_fetch_inferior_registers (process_stratum_target *proc_target,
 151                                 regcache *regcache, int regnum)
 152 {
 153   struct gdbarch *gdbarch = regcache->arch ();
 154   ptid_t ptid = regcache->ptid ();
 155
 156   if (regnum == SPARC_G0_REGNUM)
 157     {
 158       gdb_byte zero[8] = { 0 };
 159
 160       regcache->raw_supply (SPARC_G0_REGNUM, &zero);
 161       return;
 162     }
 163
 164   if (regnum == -1 || sparc_gregset_supplies_p (gdbarch, regnum))
 165     {
 166       gregset_t regs;
 167
 168       if (gdb_ptrace (PTRACE_GETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
 169         perror_with_name (_("Couldn't get registers"));
 170
 171       /* Deep down, sparc_supply_rwindow reads memory, so needs the global
 172          thread context to be set.  */
 173       scoped_restore restore_inferior_ptid
 174         = make_scoped_restore (&inferior_ptid, ptid);
 175
 176       sparc_supply_gregset (sparc_gregmap, regcache, -1, &regs);
 177       if (regnum != -1)
 178         return;
 179     }
 180
 181   if (regnum == -1 || sparc_fpregset_supplies_p (gdbarch, regnum))
 182     {
 183       fpregset_t fpregs;
 184
 185       if (gdb_ptrace (PTRACE_GETFPREGS, ptid, (PTRACE_TYPE_ARG3) &fpregs) == -1)
 186         perror_with_name (_("Couldn't get floating point status"));
 187
 188       sparc_supply_fpregset (sparc_fpregmap, regcache, -1, &fpregs);
 189     }
 190 }
 191
 192 void
 193 sparc_store_inferior_registers (process_stratum_target *proc_target,
 194                                 regcache *regcache, int regnum)
 195 {
 196   struct gdbarch *gdbarch = regcache->arch ();
 197   ptid_t ptid = regcache->ptid ();
 198
 199   if (regnum == -1 || sparc_gregset_supplies_p (gdbarch, regnum))
 200     {
 201       gregset_t regs;
 202
 203       if (gdb_ptrace (PTRACE_GETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
 204         perror_with_name (_("Couldn't get registers"));
 205
 206       sparc_collect_gregset (sparc_gregmap, regcache, regnum, &regs);
 207
 208       if (gdb_ptrace (PTRACE_SETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
 209         perror_with_name (_("Couldn't write registers"));
 210
 211       /* Deal with the stack regs.  */
 212       if (regnum == -1 || regnum == SPARC_SP_REGNUM
 213           || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
 214         {
 215           ULONGEST sp;
 216
 217           regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);
 218
 219           /* Deep down, sparc_collect_rwindow writes memory, so needs the global
 220              thread context to be set.  */
 221           scoped_restore restore_inferior_ptid
 222             = make_scoped_restore (&inferior_ptid, ptid);
 223
 224           sparc_collect_rwindow (regcache, sp, regnum);
 225         }
 226
 227       if (regnum != -1)
 228         return;
 229     }
 230
 231   if (regnum == -1 || sparc_fpregset_supplies_p (gdbarch, regnum))
 232     {
 233       fpregset_t fpregs, saved_fpregs;
 234
 235       if (gdb_ptrace (PTRACE_GETFPREGS, ptid, (PTRACE_TYPE_ARG3) &fpregs) == -1)
 236         perror_with_name (_("Couldn't get floating-point registers"));
 237
 238       memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
 239       sparc_collect_fpregset (sparc_fpregmap, regcache, regnum, &fpregs);
 240
 241       /* Writing the floating-point registers will fail on NetBSD with
 242          EINVAL if the inferior process doesn't have an FPU state
 243          (i.e. if it didn't use the FPU yet).  Therefore we don't try
 244          to write the registers if nothing changed.  */
 245       if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
 246         {
 247           if (gdb_ptrace (PTRACE_SETFPREGS, ptid,
 248                           (PTRACE_TYPE_ARG3) &fpregs) == -1)
 249             perror_with_name (_("Couldn't write floating-point registers"));
 250         }
 251
 252       if (regnum != -1)
 253         return;
 254     }
 255 }
 256
 257 \f
 258 /* Implement the to_xfer_partial target_ops method for
 259    TARGET_OBJECT_WCOOKIE.  Fetch StackGhost Per-Process XOR cookie.  */
 260
 261 enum target_xfer_status
 262 sparc_xfer_wcookie (enum target_object object,
 263                     const char *annex, gdb_byte *readbuf,
 264                     const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
 265                     ULONGEST *xfered_len)
 266 {
 267   unsigned long wcookie = 0;
 268   char *buf = (char *)&wcookie;
 269
 270   gdb_assert (object == TARGET_OBJECT_WCOOKIE);
 271   gdb_assert (readbuf && writebuf == NULL);
 272
 273   if (offset == sizeof (unsigned long))
 274     return TARGET_XFER_EOF;                     /* Signal EOF.  */
 275   if (offset > sizeof (unsigned long))
 276     return TARGET_XFER_E_IO;
 277
 278 #ifdef PT_WCOOKIE
 279   /* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
 280      running on an OpenBSD release that uses StackGhost (3.1 or
 281      later).  Since release 3.6, OpenBSD uses a fully randomized
 282      cookie.  */
 283   {
 284     int pid = inferior_ptid.pid ();
 285
 286     /* Sanity check.  The proper type for a cookie is register_t, but
 287        we can't assume that this type exists on all systems supported
 288        by the code in this file.  */
 289     gdb_assert (sizeof (wcookie) == sizeof (register_t));
 290
 291     /* Fetch the cookie.  */
 292     if (ptrace (PT_WCOOKIE, pid, (PTRACE_TYPE_ARG3) &wcookie, 0) == -1)
 293       {
 294         if (errno != EINVAL)
 295           perror_with_name (_("Couldn't get StackGhost cookie"));
 296
 297         /* Although PT_WCOOKIE is defined on OpenBSD 3.1 and later,
 298            the request wasn't implemented until after OpenBSD 3.4.  If
 299            the kernel doesn't support the PT_WCOOKIE request, assume
 300            we're running on a kernel that uses non-randomized cookies.  */
 301         wcookie = 0x3;
 302       }
 303   }
 304 #endif /* PT_WCOOKIE */
 305
 306   if (len > sizeof (unsigned long) - offset)
 307     len = sizeof (unsigned long) - offset;
 308
 309   memcpy (readbuf, buf + offset, len);
 310   *xfered_len = (ULONGEST) len;
 311   return TARGET_XFER_OK;
 312 }
 313 \f
 314
 315 void _initialize_sparc_nat ();
 316 void
 317 _initialize_sparc_nat ()
 318 {
 319   /* Default to using SunOS 4 register sets.  */
 320   if (sparc_gregmap == NULL)
 321     sparc_gregmap = &sparc32_sunos4_gregmap;
 322   if (sparc_fpregmap == NULL)
 323     sparc_fpregmap = &sparc32_sunos4_fpregmap;
 324   if (sparc_supply_gregset == NULL)
 325     sparc_supply_gregset = sparc32_supply_gregset;
 326   if (sparc_collect_gregset == NULL)
 327     sparc_collect_gregset = sparc32_collect_gregset;
 328   if (sparc_supply_fpregset == NULL)
 329     sparc_supply_fpregset = sparc32_supply_fpregset;
 330   if (sparc_collect_fpregset == NULL)
 331     sparc_collect_fpregset = sparc32_collect_fpregset;
 332   if (sparc_gregset_supplies_p == NULL)
 333     sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
 334   if (sparc_fpregset_supplies_p == NULL)
 335     sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
 336 }