gdb/s390-nat.c

   1 /* S390 native-dependent code for GDB, the GNU debugger.
   2    Copyright (C) 2001, 2003, 2004, 2005, 2006
   3    Free Software Foundation, Inc
   4
   5    Contributed by D.J. Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
   6    for IBM Deutschland Entwicklung GmbH, IBM Corporation.
   7
   8    This file is part of GDB.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  23    Boston, MA 02110-1301, USA.  */
  24
  25 #include "defs.h"
  26 #include "regcache.h"
  27 #include "inferior.h"
  28 #include "target.h"
  29 #include "linux-nat.h"
  30
  31 #include "s390-tdep.h"
  32
  33 #include <asm/ptrace.h>
  34 #include <sys/ptrace.h>
  35 #include <asm/types.h>
  36 #include <sys/procfs.h>
  37 #include <sys/ucontext.h>
  38
  39
  40 /* Map registers to gregset/ptrace offsets.
  41    These arrays are defined in s390-tdep.c.  */
  42
  43 #ifdef __s390x__
  44 #define regmap_gregset s390x_regmap_gregset
  45 #else
  46 #define regmap_gregset s390_regmap_gregset
  47 #endif
  48
  49 #define regmap_fpregset s390_regmap_fpregset
  50
  51 /* When debugging a 32-bit executable running under a 64-bit kernel,
  52    we have to fix up the 64-bit registers we get from the kernel
  53    to make them look like 32-bit registers.  */
  54 #ifdef __s390x__
  55 #define SUBOFF(i) \
  56         ((gdbarch_ptr_bit (current_gdbarch) == 32 \
  57           && ((i) == S390_PSWA_REGNUM \
  58               || ((i) >= S390_R0_REGNUM && (i) <= S390_R15_REGNUM)))? 4 : 0)
  59 #else
  60 #define SUBOFF(i) 0
  61 #endif
  62
  63
  64 /* Fill GDB's register array with the general-purpose register values
  65    in *REGP.  */
  66 void
  67 supply_gregset (struct regcache *regcache, const gregset_t *regp)
  68 {
  69   int i;
  70   for (i = 0; i < S390_NUM_REGS; i++)
  71     if (regmap_gregset[i] != -1)
  72       regcache_raw_supply (regcache, i,
  73                            (const char *)regp + regmap_gregset[i] + SUBOFF (i));
  74 }
  75
  76 /* Fill register REGNO (if it is a general-purpose register) in
  77    *REGP with the value in GDB's register array.  If REGNO is -1,
  78    do this for all registers.  */
  79 void
  80 fill_gregset (const struct regcache *regcache, gregset_t *regp, int regno)
  81 {
  82   int i;
  83   for (i = 0; i < S390_NUM_REGS; i++)
  84     if (regmap_gregset[i] != -1)
  85       if (regno == -1 || regno == i)
  86         regcache_raw_collect (regcache, i,
  87                               (char *)regp + regmap_gregset[i] + SUBOFF (i));
  88 }
  89
  90 /* Fill GDB's register array with the floating-point register values
  91    in *REGP.  */
  92 void
  93 supply_fpregset (struct regcache *regcache, const fpregset_t *regp)
  94 {
  95   int i;
  96   for (i = 0; i < S390_NUM_REGS; i++)
  97     if (regmap_fpregset[i] != -1)
  98       regcache_raw_supply (regcache, i,
  99                            (const char *)regp + regmap_fpregset[i]);
 100 }
 101
 102 /* Fill register REGNO (if it is a general-purpose register) in
 103    *REGP with the value in GDB's register array.  If REGNO is -1,
 104    do this for all registers.  */
 105 void
 106 fill_fpregset (const struct regcache *regcache, fpregset_t *regp, int regno)
 107 {
 108   int i;
 109   for (i = 0; i < S390_NUM_REGS; i++)
 110     if (regmap_fpregset[i] != -1)
 111       if (regno == -1 || regno == i)
 112         regcache_raw_collect (regcache, i,
 113                               (char *)regp + regmap_fpregset[i]);
 114 }
 115
 116 /* Find the TID for the current inferior thread to use with ptrace.  */
 117 static int
 118 s390_inferior_tid (void)
 119 {
 120   /* GNU/Linux LWP ID's are process ID's.  */
 121   int tid = TIDGET (inferior_ptid);
 122   if (tid == 0)
 123     tid = PIDGET (inferior_ptid); /* Not a threaded program.  */
 124
 125   return tid;
 126 }
 127
 128 /* Fetch all general-purpose registers from process/thread TID and
 129    store their values in GDB's register cache.  */
 130 static void
 131 fetch_regs (struct regcache *regcache, int tid)
 132 {
 133   gregset_t regs;
 134   ptrace_area parea;
 135
 136   parea.len = sizeof (regs);
 137   parea.process_addr = (addr_t) &regs;
 138   parea.kernel_addr = offsetof (struct user_regs_struct, psw);
 139   if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea) < 0)
 140     perror_with_name (_("Couldn't get registers"));
 141
 142   supply_gregset (regcache, (const gregset_t *) &regs);
 143 }
 144
 145 /* Store all valid general-purpose registers in GDB's register cache
 146    into the process/thread specified by TID.  */
 147 static void
 148 store_regs (const struct regcache *regcache, int tid, int regnum)
 149 {
 150   gregset_t regs;
 151   ptrace_area parea;
 152
 153   parea.len = sizeof (regs);
 154   parea.process_addr = (addr_t) &regs;
 155   parea.kernel_addr = offsetof (struct user_regs_struct, psw);
 156   if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea) < 0)
 157     perror_with_name (_("Couldn't get registers"));
 158
 159   fill_gregset (regcache, &regs, regnum);
 160
 161   if (ptrace (PTRACE_POKEUSR_AREA, tid, (long) &parea) < 0)
 162     perror_with_name (_("Couldn't write registers"));
 163 }
 164
 165 /* Fetch all floating-point registers from process/thread TID and store
 166    their values in GDB's register cache.  */
 167 static void
 168 fetch_fpregs (struct regcache *regcache, int tid)
 169 {
 170   fpregset_t fpregs;
 171   ptrace_area parea;
 172
 173   parea.len = sizeof (fpregs);
 174   parea.process_addr = (addr_t) &fpregs;
 175   parea.kernel_addr = offsetof (struct user_regs_struct, fp_regs);
 176   if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea) < 0)
 177     perror_with_name (_("Couldn't get floating point status"));
 178
 179   supply_fpregset (regcache, (const fpregset_t *) &fpregs);
 180 }
 181
 182 /* Store all valid floating-point registers in GDB's register cache
 183    into the process/thread specified by TID.  */
 184 static void
 185 store_fpregs (const struct regcache *regcache, int tid, int regnum)
 186 {
 187   fpregset_t fpregs;
 188   ptrace_area parea;
 189
 190   parea.len = sizeof (fpregs);
 191   parea.process_addr = (addr_t) &fpregs;
 192   parea.kernel_addr = offsetof (struct user_regs_struct, fp_regs);
 193   if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea) < 0)
 194     perror_with_name (_("Couldn't get floating point status"));
 195
 196   fill_fpregset (regcache, &fpregs, regnum);
 197
 198   if (ptrace (PTRACE_POKEUSR_AREA, tid, (long) &parea) < 0)
 199     perror_with_name (_("Couldn't write floating point status"));
 200 }
 201
 202 /* Fetch register REGNUM from the child process.  If REGNUM is -1, do
 203    this for all registers.  */
 204 static void
 205 s390_linux_fetch_inferior_registers (struct regcache *regcache, int regnum)
 206 {
 207   int tid = s390_inferior_tid ();
 208
 209   if (regnum == -1
 210       || (regnum < S390_NUM_REGS && regmap_gregset[regnum] != -1))
 211     fetch_regs (regcache, tid);
 212
 213   if (regnum == -1
 214       || (regnum < S390_NUM_REGS && regmap_fpregset[regnum] != -1))
 215     fetch_fpregs (regcache, tid);
 216 }
 217
 218 /* Store register REGNUM back into the child process.  If REGNUM is
 219    -1, do this for all registers.  */
 220 static void
 221 s390_linux_store_inferior_registers (struct regcache *regcache, int regnum)
 222 {
 223   int tid = s390_inferior_tid ();
 224
 225   if (regnum == -1
 226       || (regnum < S390_NUM_REGS && regmap_gregset[regnum] != -1))
 227     store_regs (regcache, tid, regnum);
 228
 229   if (regnum == -1
 230       || (regnum < S390_NUM_REGS && regmap_fpregset[regnum] != -1))
 231     store_fpregs (regcache, tid, regnum);
 232 }
 233
 234
 235 /* Hardware-assisted watchpoint handling.  */
 236
 237 /* We maintain a list of all currently active watchpoints in order
 238    to properly handle watchpoint removal.
 239
 240    The only thing we actually need is the total address space area
 241    spanned by the watchpoints.  */
 242
 243 struct watch_area
 244 {
 245   struct watch_area *next;
 246   CORE_ADDR lo_addr;
 247   CORE_ADDR hi_addr;
 248 };
 249
 250 static struct watch_area *watch_base = NULL;
 251
 252 static int
 253 s390_stopped_by_watchpoint (void)
 254 {
 255   per_lowcore_bits per_lowcore;
 256   ptrace_area parea;
 257
 258   /* Speed up common case.  */
 259   if (!watch_base)
 260     return 0;
 261
 262   parea.len = sizeof (per_lowcore);
 263   parea.process_addr = (addr_t) & per_lowcore;
 264   parea.kernel_addr = offsetof (struct user_regs_struct, per_info.lowcore);
 265   if (ptrace (PTRACE_PEEKUSR_AREA, s390_inferior_tid (), &parea) < 0)
 266     perror_with_name (_("Couldn't retrieve watchpoint status"));
 267
 268   return per_lowcore.perc_storage_alteration == 1
 269          && per_lowcore.perc_store_real_address == 0;
 270 }
 271
 272 static void
 273 s390_fix_watch_points (void)
 274 {
 275   int tid = s390_inferior_tid ();
 276
 277   per_struct per_info;
 278   ptrace_area parea;
 279
 280   CORE_ADDR watch_lo_addr = (CORE_ADDR)-1, watch_hi_addr = 0;
 281   struct watch_area *area;
 282
 283   for (area = watch_base; area; area = area->next)
 284     {
 285       watch_lo_addr = min (watch_lo_addr, area->lo_addr);
 286       watch_hi_addr = max (watch_hi_addr, area->hi_addr);
 287     }
 288
 289   parea.len = sizeof (per_info);
 290   parea.process_addr = (addr_t) & per_info;
 291   parea.kernel_addr = offsetof (struct user_regs_struct, per_info);
 292   if (ptrace (PTRACE_PEEKUSR_AREA, tid, &parea) < 0)
 293     perror_with_name (_("Couldn't retrieve watchpoint status"));
 294
 295   if (watch_base)
 296     {
 297       per_info.control_regs.bits.em_storage_alteration = 1;
 298       per_info.control_regs.bits.storage_alt_space_ctl = 1;
 299     }
 300   else
 301     {
 302       per_info.control_regs.bits.em_storage_alteration = 0;
 303       per_info.control_regs.bits.storage_alt_space_ctl = 0;
 304     }
 305   per_info.starting_addr = watch_lo_addr;
 306   per_info.ending_addr = watch_hi_addr;
 307
 308   if (ptrace (PTRACE_POKEUSR_AREA, tid, &parea) < 0)
 309     perror_with_name (_("Couldn't modify watchpoint status"));
 310 }
 311
 312 static int
 313 s390_insert_watchpoint (CORE_ADDR addr, int len, int type)
 314 {
 315   struct watch_area *area = xmalloc (sizeof (struct watch_area));
 316   if (!area)
 317     return -1;
 318
 319   area->lo_addr = addr;
 320   area->hi_addr = addr + len - 1;
 321
 322   area->next = watch_base;
 323   watch_base = area;
 324
 325   s390_fix_watch_points ();
 326   return 0;
 327 }
 328
 329 static int
 330 s390_remove_watchpoint (CORE_ADDR addr, int len, int type)
 331 {
 332   struct watch_area *area, **parea;
 333
 334   for (parea = &watch_base; *parea; parea = &(*parea)->next)
 335     if ((*parea)->lo_addr == addr
 336         && (*parea)->hi_addr == addr + len - 1)
 337       break;
 338
 339   if (!*parea)
 340     {
 341       fprintf_unfiltered (gdb_stderr,
 342                           "Attempt to remove nonexistent watchpoint.\n");
 343       return -1;
 344     }
 345
 346   area = *parea;
 347   *parea = area->next;
 348   xfree (area);
 349
 350   s390_fix_watch_points ();
 351   return 0;
 352 }
 353
 354 static int
 355 s390_can_use_hw_breakpoint (int type, int cnt, int othertype)
 356 {
 357   return 1;
 358 }
 359
 360 static int
 361 s390_region_ok_for_hw_watchpoint (CORE_ADDR addr, int cnt)
 362 {
 363   return 1;
 364 }
 365
 366
 367 void _initialize_s390_nat (void);
 368
 369 void
 370 _initialize_s390_nat (void)
 371 {
 372   struct target_ops *t;
 373
 374   /* Fill in the generic GNU/Linux methods.  */
 375   t = linux_target ();
 376
 377   /* Add our register access methods.  */
 378   t->to_fetch_registers = s390_linux_fetch_inferior_registers;
 379   t->to_store_registers = s390_linux_store_inferior_registers;
 380
 381   /* Add our watchpoint methods.  */
 382   t->to_can_use_hw_breakpoint = s390_can_use_hw_breakpoint;
 383   t->to_region_ok_for_hw_watchpoint = s390_region_ok_for_hw_watchpoint;
 384   t->to_have_continuable_watchpoint = 1;
 385   t->to_stopped_by_watchpoint = s390_stopped_by_watchpoint;
 386   t->to_insert_watchpoint = s390_insert_watchpoint;
 387   t->to_remove_watchpoint = s390_remove_watchpoint;
 388
 389   /* Register the target.  */
 390   linux_nat_add_target (t);
 391 }