xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/s390-linux-nat.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /* S390 native-dependent code for GDB, the GNU debugger.
2    Copyright (C) 2001-2016 Free Software Foundation, Inc.
3 
4    Contributed by D.J. Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
5    for IBM Deutschland Entwicklung GmbH, IBM Corporation.
6 
7    This file is part of GDB.
8 
9    This program is free software; you can redistribute it and/or modify
10    it under the terms of the GNU General Public License as published by
11    the Free Software Foundation; either version 3 of the License, or
12    (at your option) any later version.
13 
14    This program is distributed in the hope that it will be useful,
15    but WITHOUT ANY WARRANTY; without even the implied warranty of
16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17    GNU General Public License for more details.
18 
19    You should have received a copy of the GNU General Public License
20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
21 
22 #include "defs.h"
23 #include "regcache.h"
24 #include "inferior.h"
25 #include "target.h"
26 #include "linux-nat.h"
27 #include "auxv.h"
28 #include "gregset.h"
29 #include "regset.h"
30 #include "nat/linux-ptrace.h"
31 
32 #include "s390-linux-tdep.h"
33 #include "elf/common.h"
34 
35 #include <asm/ptrace.h>
36 #include "nat/gdb_ptrace.h"
37 #include <asm/types.h>
38 #include <sys/procfs.h>
39 #include <sys/ucontext.h>
40 #include <elf.h>
41 
42 /* Per-thread arch-specific data.  */
43 
44 struct arch_lwp_info
45 {
46   /* Non-zero if the thread's PER info must be re-written.  */
47   int per_info_changed;
48 };
49 
50 static int have_regset_last_break = 0;
51 static int have_regset_system_call = 0;
52 static int have_regset_tdb = 0;
53 static int have_regset_vxrs = 0;
54 
55 /* Register map for 32-bit executables running under a 64-bit
56    kernel.  */
57 
58 #ifdef __s390x__
59 static const struct regcache_map_entry s390_64_regmap_gregset[] =
60   {
61     /* Skip PSWM and PSWA, since they must be handled specially.  */
62     { 2, REGCACHE_MAP_SKIP, 8 },
63     { 1, S390_R0_UPPER_REGNUM, 4 }, { 1, S390_R0_REGNUM, 4 },
64     { 1, S390_R1_UPPER_REGNUM, 4 }, { 1, S390_R1_REGNUM, 4 },
65     { 1, S390_R2_UPPER_REGNUM, 4 }, { 1, S390_R2_REGNUM, 4 },
66     { 1, S390_R3_UPPER_REGNUM, 4 }, { 1, S390_R3_REGNUM, 4 },
67     { 1, S390_R4_UPPER_REGNUM, 4 }, { 1, S390_R4_REGNUM, 4 },
68     { 1, S390_R5_UPPER_REGNUM, 4 }, { 1, S390_R5_REGNUM, 4 },
69     { 1, S390_R6_UPPER_REGNUM, 4 }, { 1, S390_R6_REGNUM, 4 },
70     { 1, S390_R7_UPPER_REGNUM, 4 }, { 1, S390_R7_REGNUM, 4 },
71     { 1, S390_R8_UPPER_REGNUM, 4 }, { 1, S390_R8_REGNUM, 4 },
72     { 1, S390_R9_UPPER_REGNUM, 4 }, { 1, S390_R9_REGNUM, 4 },
73     { 1, S390_R10_UPPER_REGNUM, 4 }, { 1, S390_R10_REGNUM, 4 },
74     { 1, S390_R11_UPPER_REGNUM, 4 }, { 1, S390_R11_REGNUM, 4 },
75     { 1, S390_R12_UPPER_REGNUM, 4 }, { 1, S390_R12_REGNUM, 4 },
76     { 1, S390_R13_UPPER_REGNUM, 4 }, { 1, S390_R13_REGNUM, 4 },
77     { 1, S390_R14_UPPER_REGNUM, 4 }, { 1, S390_R14_REGNUM, 4 },
78     { 1, S390_R15_UPPER_REGNUM, 4 }, { 1, S390_R15_REGNUM, 4 },
79     { 16, S390_A0_REGNUM, 4 },
80     { 1, REGCACHE_MAP_SKIP, 4 }, { 1, S390_ORIG_R2_REGNUM, 4 },
81     { 0 }
82   };
83 
84 static const struct regset s390_64_gregset =
85   {
86     s390_64_regmap_gregset,
87     regcache_supply_regset,
88     regcache_collect_regset
89   };
90 
91 #define S390_PSWM_OFFSET 0
92 #define S390_PSWA_OFFSET 8
93 #endif
94 
95 /* Fill GDB's register array with the general-purpose register values
96    in *REGP.
97 
98    When debugging a 32-bit executable running under a 64-bit kernel,
99    we have to fix up the 64-bit registers we get from the kernel to
100    make them look like 32-bit registers.  */
101 
102 void
103 supply_gregset (struct regcache *regcache, const gregset_t *regp)
104 {
105 #ifdef __s390x__
106   struct gdbarch *gdbarch = get_regcache_arch (regcache);
107   if (gdbarch_ptr_bit (gdbarch) == 32)
108     {
109       enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
110       ULONGEST pswm, pswa;
111       gdb_byte buf[4];
112 
113       regcache_supply_regset (&s390_64_gregset, regcache, -1,
114 			      regp, sizeof (gregset_t));
115       pswm = extract_unsigned_integer ((const gdb_byte *) regp
116 				       + S390_PSWM_OFFSET, 8, byte_order);
117       pswa = extract_unsigned_integer ((const gdb_byte *) regp
118 				       + S390_PSWA_OFFSET, 8, byte_order);
119       store_unsigned_integer (buf, 4, byte_order, (pswm >> 32) | 0x80000);
120       regcache_raw_supply (regcache, S390_PSWM_REGNUM, buf);
121       store_unsigned_integer (buf, 4, byte_order,
122 			      (pswa & 0x7fffffff) | (pswm & 0x80000000));
123       regcache_raw_supply (regcache, S390_PSWA_REGNUM, buf);
124       return;
125     }
126 #endif
127 
128   regcache_supply_regset (&s390_gregset, regcache, -1, regp,
129 			  sizeof (gregset_t));
130 }
131 
132 /* Fill register REGNO (if it is a general-purpose register) in
133    *REGP with the value in GDB's register array.  If REGNO is -1,
134    do this for all registers.  */
135 
136 void
137 fill_gregset (const struct regcache *regcache, gregset_t *regp, int regno)
138 {
139 #ifdef __s390x__
140   struct gdbarch *gdbarch = get_regcache_arch (regcache);
141   if (gdbarch_ptr_bit (gdbarch) == 32)
142     {
143       regcache_collect_regset (&s390_64_gregset, regcache, regno,
144 			       regp, sizeof (gregset_t));
145 
146       if (regno == -1
147 	  || regno == S390_PSWM_REGNUM || regno == S390_PSWA_REGNUM)
148 	{
149 	  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
150 	  ULONGEST pswa, pswm;
151 	  gdb_byte buf[4];
152 	  gdb_byte *pswm_p = (gdb_byte *) regp + S390_PSWM_OFFSET;
153 	  gdb_byte *pswa_p = (gdb_byte *) regp + S390_PSWA_OFFSET;
154 
155 	  pswm = extract_unsigned_integer (pswm_p, 8, byte_order);
156 
157 	  if (regno == -1 || regno == S390_PSWM_REGNUM)
158 	    {
159 	      pswm &= 0x80000000;
160 	      regcache_raw_collect (regcache, S390_PSWM_REGNUM, buf);
161 	      pswm |= (extract_unsigned_integer (buf, 4, byte_order)
162 		       & 0xfff7ffff) << 32;
163 	    }
164 
165 	  if (regno == -1 || regno == S390_PSWA_REGNUM)
166 	    {
167 	      regcache_raw_collect (regcache, S390_PSWA_REGNUM, buf);
168 	      pswa = extract_unsigned_integer (buf, 4, byte_order);
169 	      pswm ^= (pswm ^ pswa) & 0x80000000;
170 	      pswa &= 0x7fffffff;
171 	      store_unsigned_integer (pswa_p, 8, byte_order, pswa);
172 	    }
173 
174 	  store_unsigned_integer (pswm_p, 8, byte_order, pswm);
175 	}
176       return;
177     }
178 #endif
179 
180   regcache_collect_regset (&s390_gregset, regcache, regno, regp,
181 			   sizeof (gregset_t));
182 }
183 
184 /* Fill GDB's register array with the floating-point register values
185    in *REGP.  */
186 void
187 supply_fpregset (struct regcache *regcache, const fpregset_t *regp)
188 {
189   regcache_supply_regset (&s390_fpregset, regcache, -1, regp,
190 			  sizeof (fpregset_t));
191 }
192 
193 /* Fill register REGNO (if it is a general-purpose register) in
194    *REGP with the value in GDB's register array.  If REGNO is -1,
195    do this for all registers.  */
196 void
197 fill_fpregset (const struct regcache *regcache, fpregset_t *regp, int regno)
198 {
199   regcache_collect_regset (&s390_fpregset, regcache, regno, regp,
200 			   sizeof (fpregset_t));
201 }
202 
203 /* Find the TID for the current inferior thread to use with ptrace.  */
204 static int
205 s390_inferior_tid (void)
206 {
207   /* GNU/Linux LWP ID's are process ID's.  */
208   int tid = ptid_get_lwp (inferior_ptid);
209   if (tid == 0)
210     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
211 
212   return tid;
213 }
214 
215 /* Fetch all general-purpose registers from process/thread TID and
216    store their values in GDB's register cache.  */
217 static void
218 fetch_regs (struct regcache *regcache, int tid)
219 {
220   gregset_t regs;
221   ptrace_area parea;
222 
223   parea.len = sizeof (regs);
224   parea.process_addr = (addr_t) &regs;
225   parea.kernel_addr = offsetof (struct user_regs_struct, psw);
226   if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea, 0) < 0)
227     perror_with_name (_("Couldn't get registers"));
228 
229   supply_gregset (regcache, (const gregset_t *) &regs);
230 }
231 
232 /* Store all valid general-purpose registers in GDB's register cache
233    into the process/thread specified by TID.  */
234 static void
235 store_regs (const struct regcache *regcache, int tid, int regnum)
236 {
237   gregset_t regs;
238   ptrace_area parea;
239 
240   parea.len = sizeof (regs);
241   parea.process_addr = (addr_t) &regs;
242   parea.kernel_addr = offsetof (struct user_regs_struct, psw);
243   if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea, 0) < 0)
244     perror_with_name (_("Couldn't get registers"));
245 
246   fill_gregset (regcache, &regs, regnum);
247 
248   if (ptrace (PTRACE_POKEUSR_AREA, tid, (long) &parea, 0) < 0)
249     perror_with_name (_("Couldn't write registers"));
250 }
251 
252 /* Fetch all floating-point registers from process/thread TID and store
253    their values in GDB's register cache.  */
254 static void
255 fetch_fpregs (struct regcache *regcache, int tid)
256 {
257   fpregset_t fpregs;
258   ptrace_area parea;
259 
260   parea.len = sizeof (fpregs);
261   parea.process_addr = (addr_t) &fpregs;
262   parea.kernel_addr = offsetof (struct user_regs_struct, fp_regs);
263   if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea, 0) < 0)
264     perror_with_name (_("Couldn't get floating point status"));
265 
266   supply_fpregset (regcache, (const fpregset_t *) &fpregs);
267 }
268 
269 /* Store all valid floating-point registers in GDB's register cache
270    into the process/thread specified by TID.  */
271 static void
272 store_fpregs (const struct regcache *regcache, int tid, int regnum)
273 {
274   fpregset_t fpregs;
275   ptrace_area parea;
276 
277   parea.len = sizeof (fpregs);
278   parea.process_addr = (addr_t) &fpregs;
279   parea.kernel_addr = offsetof (struct user_regs_struct, fp_regs);
280   if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea, 0) < 0)
281     perror_with_name (_("Couldn't get floating point status"));
282 
283   fill_fpregset (regcache, &fpregs, regnum);
284 
285   if (ptrace (PTRACE_POKEUSR_AREA, tid, (long) &parea, 0) < 0)
286     perror_with_name (_("Couldn't write floating point status"));
287 }
288 
289 /* Fetch all registers in the kernel's register set whose number is
290    REGSET_ID, whose size is REGSIZE, and whose layout is described by
291    REGSET, from process/thread TID and store their values in GDB's
292    register cache.  */
293 static void
294 fetch_regset (struct regcache *regcache, int tid,
295 	      int regset_id, int regsize, const struct regset *regset)
296 {
297   void *buf = alloca (regsize);
298   struct iovec iov;
299 
300   iov.iov_base = buf;
301   iov.iov_len = regsize;
302 
303   if (ptrace (PTRACE_GETREGSET, tid, (long) regset_id, (long) &iov) < 0)
304     {
305       if (errno == ENODATA)
306 	regcache_supply_regset (regset, regcache, -1, NULL, regsize);
307       else
308 	perror_with_name (_("Couldn't get register set"));
309     }
310   else
311     regcache_supply_regset (regset, regcache, -1, buf, regsize);
312 }
313 
314 /* Store all registers in the kernel's register set whose number is
315    REGSET_ID, whose size is REGSIZE, and whose layout is described by
316    REGSET, from GDB's register cache back to process/thread TID.  */
317 static void
318 store_regset (struct regcache *regcache, int tid,
319 	      int regset_id, int regsize, const struct regset *regset)
320 {
321   void *buf = alloca (regsize);
322   struct iovec iov;
323 
324   iov.iov_base = buf;
325   iov.iov_len = regsize;
326 
327   if (ptrace (PTRACE_GETREGSET, tid, (long) regset_id, (long) &iov) < 0)
328     perror_with_name (_("Couldn't get register set"));
329 
330   regcache_collect_regset (regset, regcache, -1, buf, regsize);
331 
332   if (ptrace (PTRACE_SETREGSET, tid, (long) regset_id, (long) &iov) < 0)
333     perror_with_name (_("Couldn't set register set"));
334 }
335 
336 /* Check whether the kernel provides a register set with number REGSET
337    of size REGSIZE for process/thread TID.  */
338 static int
339 check_regset (int tid, int regset, int regsize)
340 {
341   void *buf = alloca (regsize);
342   struct iovec iov;
343 
344   iov.iov_base = buf;
345   iov.iov_len = regsize;
346 
347   if (ptrace (PTRACE_GETREGSET, tid, (long) regset, (long) &iov) >= 0
348       || errno == ENODATA)
349     return 1;
350   return 0;
351 }
352 
353 /* Fetch register REGNUM from the child process.  If REGNUM is -1, do
354    this for all registers.  */
355 static void
356 s390_linux_fetch_inferior_registers (struct target_ops *ops,
357 				     struct regcache *regcache, int regnum)
358 {
359   int tid = s390_inferior_tid ();
360 
361   if (regnum == -1 || S390_IS_GREGSET_REGNUM (regnum))
362     fetch_regs (regcache, tid);
363 
364   if (regnum == -1 || S390_IS_FPREGSET_REGNUM (regnum))
365     fetch_fpregs (regcache, tid);
366 
367   if (have_regset_last_break)
368     if (regnum == -1 || regnum == S390_LAST_BREAK_REGNUM)
369       fetch_regset (regcache, tid, NT_S390_LAST_BREAK, 8,
370 		    (gdbarch_ptr_bit (get_regcache_arch (regcache)) == 32
371 		     ? &s390_last_break_regset : &s390x_last_break_regset));
372 
373   if (have_regset_system_call)
374     if (regnum == -1 || regnum == S390_SYSTEM_CALL_REGNUM)
375       fetch_regset (regcache, tid, NT_S390_SYSTEM_CALL, 4,
376 		    &s390_system_call_regset);
377 
378   if (have_regset_tdb)
379     if (regnum == -1 || S390_IS_TDBREGSET_REGNUM (regnum))
380       fetch_regset (regcache, tid, NT_S390_TDB, s390_sizeof_tdbregset,
381 		    &s390_tdb_regset);
382 
383   if (have_regset_vxrs)
384     {
385       if (regnum == -1 || (regnum >= S390_V0_LOWER_REGNUM
386 			   && regnum <= S390_V15_LOWER_REGNUM))
387 	fetch_regset (regcache, tid, NT_S390_VXRS_LOW, 16 * 8,
388 		      &s390_vxrs_low_regset);
389       if (regnum == -1 || (regnum >= S390_V16_REGNUM
390 			   && regnum <= S390_V31_REGNUM))
391 	fetch_regset (regcache, tid, NT_S390_VXRS_HIGH, 16 * 16,
392 		      &s390_vxrs_high_regset);
393     }
394 }
395 
396 /* Store register REGNUM back into the child process.  If REGNUM is
397    -1, do this for all registers.  */
398 static void
399 s390_linux_store_inferior_registers (struct target_ops *ops,
400 				     struct regcache *regcache, int regnum)
401 {
402   int tid = s390_inferior_tid ();
403 
404   if (regnum == -1 || S390_IS_GREGSET_REGNUM (regnum))
405     store_regs (regcache, tid, regnum);
406 
407   if (regnum == -1 || S390_IS_FPREGSET_REGNUM (regnum))
408     store_fpregs (regcache, tid, regnum);
409 
410   /* S390_LAST_BREAK_REGNUM is read-only.  */
411 
412   if (have_regset_system_call)
413     if (regnum == -1 || regnum == S390_SYSTEM_CALL_REGNUM)
414       store_regset (regcache, tid, NT_S390_SYSTEM_CALL, 4,
415 		    &s390_system_call_regset);
416 
417   if (have_regset_vxrs)
418     {
419       if (regnum == -1 || (regnum >= S390_V0_LOWER_REGNUM
420 			   && regnum <= S390_V15_LOWER_REGNUM))
421 	store_regset (regcache, tid, NT_S390_VXRS_LOW, 16 * 8,
422 		      &s390_vxrs_low_regset);
423       if (regnum == -1 || (regnum >= S390_V16_REGNUM
424 			   && regnum <= S390_V31_REGNUM))
425 	store_regset (regcache, tid, NT_S390_VXRS_HIGH, 16 * 16,
426 		      &s390_vxrs_high_regset);
427     }
428 }
429 
430 
431 /* Hardware-assisted watchpoint handling.  */
432 
433 /* We maintain a list of all currently active watchpoints in order
434    to properly handle watchpoint removal.
435 
436    The only thing we actually need is the total address space area
437    spanned by the watchpoints.  */
438 
439 struct watch_area
440 {
441   struct watch_area *next;
442   CORE_ADDR lo_addr;
443   CORE_ADDR hi_addr;
444 };
445 
446 static struct watch_area *watch_base = NULL;
447 
448 static int
449 s390_stopped_by_watchpoint (struct target_ops *ops)
450 {
451   per_lowcore_bits per_lowcore;
452   ptrace_area parea;
453   int result;
454 
455   /* Speed up common case.  */
456   if (!watch_base)
457     return 0;
458 
459   parea.len = sizeof (per_lowcore);
460   parea.process_addr = (addr_t) & per_lowcore;
461   parea.kernel_addr = offsetof (struct user_regs_struct, per_info.lowcore);
462   if (ptrace (PTRACE_PEEKUSR_AREA, s390_inferior_tid (), &parea, 0) < 0)
463     perror_with_name (_("Couldn't retrieve watchpoint status"));
464 
465   result = (per_lowcore.perc_storage_alteration == 1
466 	    && per_lowcore.perc_store_real_address == 0);
467 
468   if (result)
469     {
470       /* Do not report this watchpoint again.  */
471       memset (&per_lowcore, 0, sizeof (per_lowcore));
472       if (ptrace (PTRACE_POKEUSR_AREA, s390_inferior_tid (), &parea, 0) < 0)
473 	perror_with_name (_("Couldn't clear watchpoint status"));
474     }
475 
476   return result;
477 }
478 
479 /* Each time before resuming a thread, update its PER info.  */
480 
481 static void
482 s390_prepare_to_resume (struct lwp_info *lp)
483 {
484   int tid;
485 
486   per_struct per_info;
487   ptrace_area parea;
488 
489   CORE_ADDR watch_lo_addr = (CORE_ADDR)-1, watch_hi_addr = 0;
490   struct watch_area *area;
491 
492   if (lp->arch_private == NULL
493       || !lp->arch_private->per_info_changed)
494     return;
495 
496   lp->arch_private->per_info_changed = 0;
497 
498   tid = ptid_get_lwp (lp->ptid);
499   if (tid == 0)
500     tid = ptid_get_pid (lp->ptid);
501 
502   for (area = watch_base; area; area = area->next)
503     {
504       watch_lo_addr = min (watch_lo_addr, area->lo_addr);
505       watch_hi_addr = max (watch_hi_addr, area->hi_addr);
506     }
507 
508   parea.len = sizeof (per_info);
509   parea.process_addr = (addr_t) & per_info;
510   parea.kernel_addr = offsetof (struct user_regs_struct, per_info);
511   if (ptrace (PTRACE_PEEKUSR_AREA, tid, &parea, 0) < 0)
512     perror_with_name (_("Couldn't retrieve watchpoint status"));
513 
514   if (watch_base)
515     {
516       per_info.control_regs.bits.em_storage_alteration = 1;
517       per_info.control_regs.bits.storage_alt_space_ctl = 1;
518     }
519   else
520     {
521       per_info.control_regs.bits.em_storage_alteration = 0;
522       per_info.control_regs.bits.storage_alt_space_ctl = 0;
523     }
524   per_info.starting_addr = watch_lo_addr;
525   per_info.ending_addr = watch_hi_addr;
526 
527   if (ptrace (PTRACE_POKEUSR_AREA, tid, &parea, 0) < 0)
528     perror_with_name (_("Couldn't modify watchpoint status"));
529 }
530 
531 /* Make sure that LP is stopped and mark its PER info as changed, so
532    the next resume will update it.  */
533 
534 static void
535 s390_refresh_per_info (struct lwp_info *lp)
536 {
537   if (lp->arch_private == NULL)
538     lp->arch_private = XCNEW (struct arch_lwp_info);
539 
540   lp->arch_private->per_info_changed = 1;
541 
542   if (!lp->stopped)
543     linux_stop_lwp (lp);
544 }
545 
546 /* When attaching to a new thread, mark its PER info as changed.  */
547 
548 static void
549 s390_new_thread (struct lwp_info *lp)
550 {
551   lp->arch_private = XCNEW (struct arch_lwp_info);
552   lp->arch_private->per_info_changed = 1;
553 }
554 
555 static int
556 s390_insert_watchpoint (struct target_ops *self,
557 			CORE_ADDR addr, int len, enum target_hw_bp_type type,
558 			struct expression *cond)
559 {
560   struct lwp_info *lp;
561   struct watch_area *area = XNEW (struct watch_area);
562 
563   if (!area)
564     return -1;
565 
566   area->lo_addr = addr;
567   area->hi_addr = addr + len - 1;
568 
569   area->next = watch_base;
570   watch_base = area;
571 
572   ALL_LWPS (lp)
573     s390_refresh_per_info (lp);
574   return 0;
575 }
576 
577 static int
578 s390_remove_watchpoint (struct target_ops *self,
579 			CORE_ADDR addr, int len, enum target_hw_bp_type type,
580 			struct expression *cond)
581 {
582   struct lwp_info *lp;
583   struct watch_area *area, **parea;
584 
585   for (parea = &watch_base; *parea; parea = &(*parea)->next)
586     if ((*parea)->lo_addr == addr
587 	&& (*parea)->hi_addr == addr + len - 1)
588       break;
589 
590   if (!*parea)
591     {
592       fprintf_unfiltered (gdb_stderr,
593 			  "Attempt to remove nonexistent watchpoint.\n");
594       return -1;
595     }
596 
597   area = *parea;
598   *parea = area->next;
599   xfree (area);
600 
601   ALL_LWPS (lp)
602     s390_refresh_per_info (lp);
603   return 0;
604 }
605 
606 static int
607 s390_can_use_hw_breakpoint (struct target_ops *self,
608 			    enum bptype type, int cnt, int othertype)
609 {
610   return type == bp_hardware_watchpoint;
611 }
612 
613 static int
614 s390_region_ok_for_hw_watchpoint (struct target_ops *self,
615 				  CORE_ADDR addr, int cnt)
616 {
617   return 1;
618 }
619 
620 static int
621 s390_target_wordsize (void)
622 {
623   int wordsize = 4;
624 
625   /* Check for 64-bit inferior process.  This is the case when the host is
626      64-bit, and in addition bit 32 of the PSW mask is set.  */
627 #ifdef __s390x__
628   long pswm;
629 
630   errno = 0;
631   pswm = (long) ptrace (PTRACE_PEEKUSER, s390_inferior_tid (), PT_PSWMASK, 0);
632   if (errno == 0 && (pswm & 0x100000000ul) != 0)
633     wordsize = 8;
634 #endif
635 
636   return wordsize;
637 }
638 
639 static int
640 s390_auxv_parse (struct target_ops *ops, gdb_byte **readptr,
641 		 gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp)
642 {
643   int sizeof_auxv_field = s390_target_wordsize ();
644   enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
645   gdb_byte *ptr = *readptr;
646 
647   if (endptr == ptr)
648     return 0;
649 
650   if (endptr - ptr < sizeof_auxv_field * 2)
651     return -1;
652 
653   *typep = extract_unsigned_integer (ptr, sizeof_auxv_field, byte_order);
654   ptr += sizeof_auxv_field;
655   *valp = extract_unsigned_integer (ptr, sizeof_auxv_field, byte_order);
656   ptr += sizeof_auxv_field;
657 
658   *readptr = ptr;
659   return 1;
660 }
661 
662 static const struct target_desc *
663 s390_read_description (struct target_ops *ops)
664 {
665   int tid = s390_inferior_tid ();
666 
667   have_regset_last_break
668     = check_regset (tid, NT_S390_LAST_BREAK, 8);
669   have_regset_system_call
670     = check_regset (tid, NT_S390_SYSTEM_CALL, 4);
671 
672   /* If GDB itself is compiled as 64-bit, we are running on a machine in
673      z/Architecture mode.  If the target is running in 64-bit addressing
674      mode, report s390x architecture.  If the target is running in 31-bit
675      addressing mode, but the kernel supports using 64-bit registers in
676      that mode, report s390 architecture with 64-bit GPRs.  */
677 #ifdef __s390x__
678   {
679     CORE_ADDR hwcap = 0;
680 
681     target_auxv_search (&current_target, AT_HWCAP, &hwcap);
682     have_regset_tdb = (hwcap & HWCAP_S390_TE)
683       && check_regset (tid, NT_S390_TDB, s390_sizeof_tdbregset);
684 
685     have_regset_vxrs = (hwcap & HWCAP_S390_VX)
686       && check_regset (tid, NT_S390_VXRS_LOW, 16 * 8)
687       && check_regset (tid, NT_S390_VXRS_HIGH, 16 * 16);
688 
689     if (s390_target_wordsize () == 8)
690       return (have_regset_vxrs ?
691 	      (have_regset_tdb ? tdesc_s390x_tevx_linux64 :
692 	       tdesc_s390x_vx_linux64) :
693 	      have_regset_tdb ? tdesc_s390x_te_linux64 :
694 	      have_regset_system_call ? tdesc_s390x_linux64v2 :
695 	      have_regset_last_break ? tdesc_s390x_linux64v1 :
696 	      tdesc_s390x_linux64);
697 
698     if (hwcap & HWCAP_S390_HIGH_GPRS)
699       return (have_regset_vxrs ?
700 	      (have_regset_tdb ? tdesc_s390_tevx_linux64 :
701 	       tdesc_s390_vx_linux64) :
702 	      have_regset_tdb ? tdesc_s390_te_linux64 :
703 	      have_regset_system_call ? tdesc_s390_linux64v2 :
704 	      have_regset_last_break ? tdesc_s390_linux64v1 :
705 	      tdesc_s390_linux64);
706   }
707 #endif
708 
709   /* If GDB itself is compiled as 31-bit, or if we're running a 31-bit inferior
710      on a 64-bit kernel that does not support using 64-bit registers in 31-bit
711      mode, report s390 architecture with 32-bit GPRs.  */
712   return (have_regset_system_call? tdesc_s390_linux32v2 :
713 	  have_regset_last_break? tdesc_s390_linux32v1 :
714 	  tdesc_s390_linux32);
715 }
716 
717 void _initialize_s390_nat (void);
718 
719 void
720 _initialize_s390_nat (void)
721 {
722   struct target_ops *t;
723 
724   /* Fill in the generic GNU/Linux methods.  */
725   t = linux_target ();
726 
727   /* Add our register access methods.  */
728   t->to_fetch_registers = s390_linux_fetch_inferior_registers;
729   t->to_store_registers = s390_linux_store_inferior_registers;
730 
731   /* Add our watchpoint methods.  */
732   t->to_can_use_hw_breakpoint = s390_can_use_hw_breakpoint;
733   t->to_region_ok_for_hw_watchpoint = s390_region_ok_for_hw_watchpoint;
734   t->to_have_continuable_watchpoint = 1;
735   t->to_stopped_by_watchpoint = s390_stopped_by_watchpoint;
736   t->to_insert_watchpoint = s390_insert_watchpoint;
737   t->to_remove_watchpoint = s390_remove_watchpoint;
738 
739   /* Detect target architecture.  */
740   t->to_read_description = s390_read_description;
741   t->to_auxv_parse = s390_auxv_parse;
742 
743   /* Register the target.  */
744   linux_nat_add_target (t);
745   linux_nat_set_new_thread (t, s390_new_thread);
746   linux_nat_set_prepare_to_resume (t, s390_prepare_to_resume);
747 }
748