1 /* Target-dependent code for OpenBSD/amd64.
3 Copyright (C) 2003-2014 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
22 #include "frame-unwind.h"
30 #include "trad-frame.h"
34 #include "obsd-tdep.h"
35 #include "amd64-tdep.h"
36 #include "i387-tdep.h"
37 #include "solib-svr4.h"
38 #include "bsd-uthread.h"
40 /* Support for core dumps. */
43 amd64obsd_supply_regset (const struct regset *regset,
44 struct regcache *regcache, int regnum,
45 const void *regs, size_t len)
47 struct gdbarch *gdbarch = get_regcache_arch (regcache);
48 const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
50 gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE);
52 i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
53 amd64_supply_fxsave (regcache, regnum,
54 ((const gdb_byte *)regs) + tdep->sizeof_gregset);
57 static const struct regset amd64obsd_combined_regset =
59 NULL, amd64obsd_supply_regset, NULL
62 static const struct regset *
63 amd64obsd_regset_from_core_section (struct gdbarch *gdbarch,
64 const char *sect_name, size_t sect_size)
66 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
68 /* OpenBSD core dumps don't use seperate register sets for the
69 general-purpose and floating-point registers. */
71 if (strcmp (sect_name, ".reg") == 0
72 && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE)
73 return &amd64obsd_combined_regset;
79 /* Support for signal handlers. */
81 /* Default page size. */
82 static const int amd64obsd_page_size = 4096;
84 /* Return whether THIS_FRAME corresponds to an OpenBSD sigtramp
88 amd64obsd_sigtramp_p (struct frame_info *this_frame)
90 CORE_ADDR pc = get_frame_pc (this_frame);
91 CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
92 const gdb_byte osigreturn[] =
95 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
96 0xcd, 0x80 /* int $0x80 */
98 const gdb_byte sigreturn[] =
101 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
102 0x0f, 0x05 /* syscall */
104 size_t buflen = (sizeof sigreturn) + 1;
108 /* If the function has a valid symbol name, it isn't a
110 find_pc_partial_function (pc, &name, NULL, NULL);
114 /* If the function lives in a valid section (even without a starting
115 point) it isn't a trampoline. */
116 if (find_pc_section (pc) != NULL)
119 /* If we can't read the instructions at START_PC, return zero. */
120 buf = alloca ((sizeof sigreturn) + 1);
121 if (!safe_frame_unwind_memory (this_frame, start_pc + 6, buf, buflen))
124 /* Check for sigreturn(2). Depending on how the assembler encoded
125 the `movq %rsp, %rdi' instruction, the code starts at offset 6 or
126 7. OpenBSD 5.0 and later use the `syscall' instruction. Older
127 versions use `int $0x80'. Check for both. */
128 if (memcmp (buf, sigreturn, sizeof sigreturn)
129 && memcmp (buf + 1, sigreturn, sizeof sigreturn)
130 && memcmp (buf, osigreturn, sizeof osigreturn)
131 && memcmp (buf + 1, osigreturn, sizeof osigreturn))
137 /* Assuming THIS_FRAME is for a BSD sigtramp routine, return the
138 address of the associated sigcontext structure. */
141 amd64obsd_sigcontext_addr (struct frame_info *this_frame)
143 CORE_ADDR pc = get_frame_pc (this_frame);
144 ULONGEST offset = (pc & (amd64obsd_page_size - 1));
146 /* The %rsp register points at `struct sigcontext' upon entry of a
147 signal trampoline. The relevant part of the trampoline is
152 movq $SYS_sigreturn,%rax
155 (see /usr/src/sys/arch/amd64/amd64/locore.S). The `pushq'
156 instruction clobbers %rsp, but its value is saved in `%rdi'. */
159 return get_frame_register_unsigned (this_frame, AMD64_RDI_REGNUM);
161 return get_frame_register_unsigned (this_frame, AMD64_RSP_REGNUM);
164 /* OpenBSD 3.5 or later. */
166 /* Mapping between the general-purpose registers in `struct reg'
167 format and GDB's register cache layout. */
169 /* From <machine/reg.h>. */
170 int amd64obsd_r_reg_offset[] =
187 11 * 8, /* ... %r15 */
189 17 * 8, /* %eflags */
198 /* From <machine/signal.h>. */
199 static int amd64obsd_sc_reg_offset[] =
216 11 * 8, /* ... %r15 */
218 23 * 8, /* %eflags */
227 /* From /usr/src/lib/libpthread/arch/amd64/uthread_machdep.c. */
228 static int amd64obsd_uthread_reg_offset[] =
238 12 * 8, /* %r8 ... */
245 5 * 8, /* ... %r15 */
256 /* Offset within the thread structure where we can find the saved
257 stack pointer (%esp). */
258 #define AMD64OBSD_UTHREAD_RSP_OFFSET 400
261 amd64obsd_supply_uthread (struct regcache *regcache,
262 int regnum, CORE_ADDR addr)
264 struct gdbarch *gdbarch = get_regcache_arch (regcache);
265 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
266 CORE_ADDR sp_addr = addr + AMD64OBSD_UTHREAD_RSP_OFFSET;
271 gdb_assert (regnum >= -1);
273 if (regnum == -1 || regnum == AMD64_RSP_REGNUM)
277 /* Fetch stack pointer from thread structure. */
278 sp = read_memory_unsigned_integer (sp_addr, 8, byte_order);
280 /* Adjust the stack pointer such that it looks as if we just
281 returned from _thread_machdep_switch. */
282 offset = amd64obsd_uthread_reg_offset[AMD64_RIP_REGNUM] + 8;
283 store_unsigned_integer (buf, 8, byte_order, sp + offset);
284 regcache_raw_supply (regcache, AMD64_RSP_REGNUM, buf);
287 for (i = 0; i < ARRAY_SIZE (amd64obsd_uthread_reg_offset); i++)
289 if (amd64obsd_uthread_reg_offset[i] != -1
290 && (regnum == -1 || regnum == i))
292 /* Fetch stack pointer from thread structure (if we didn't
295 sp = read_memory_unsigned_integer (sp_addr, 8, byte_order);
297 /* Read the saved register from the stack frame. */
298 read_memory (sp + amd64obsd_uthread_reg_offset[i], buf, 8);
299 regcache_raw_supply (regcache, i, buf);
305 amd64obsd_collect_uthread (const struct regcache *regcache,
306 int regnum, CORE_ADDR addr)
308 struct gdbarch *gdbarch = get_regcache_arch (regcache);
309 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
310 CORE_ADDR sp_addr = addr + AMD64OBSD_UTHREAD_RSP_OFFSET;
315 gdb_assert (regnum >= -1);
317 if (regnum == -1 || regnum == AMD64_RSP_REGNUM)
321 /* Calculate the stack pointer (frame pointer) that will be
322 stored into the thread structure. */
323 offset = amd64obsd_uthread_reg_offset[AMD64_RIP_REGNUM] + 8;
324 regcache_raw_collect (regcache, AMD64_RSP_REGNUM, buf);
325 sp = extract_unsigned_integer (buf, 8, byte_order) - offset;
327 /* Store the stack pointer. */
328 write_memory_unsigned_integer (sp_addr, 8, byte_order, sp);
330 /* The stack pointer was (potentially) modified. Make sure we
331 build a proper stack frame. */
335 for (i = 0; i < ARRAY_SIZE (amd64obsd_uthread_reg_offset); i++)
337 if (amd64obsd_uthread_reg_offset[i] != -1
338 && (regnum == -1 || regnum == i))
340 /* Fetch stack pointer from thread structure (if we didn't
341 calculate it already). */
343 sp = read_memory_unsigned_integer (sp_addr, 8, byte_order);
345 /* Write the register into the stack frame. */
346 regcache_raw_collect (regcache, i, buf);
347 write_memory (sp + amd64obsd_uthread_reg_offset[i], buf, 8);
351 /* Kernel debugging support. */
353 /* From <machine/frame.h>. Easy since `struct trapframe' matches
354 `struct sigcontext'. */
355 #define amd64obsd_tf_reg_offset amd64obsd_sc_reg_offset
357 static struct trad_frame_cache *
358 amd64obsd_trapframe_cache (struct frame_info *this_frame, void **this_cache)
360 struct gdbarch *gdbarch = get_frame_arch (this_frame);
361 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
362 struct trad_frame_cache *cache;
363 CORE_ADDR func, sp, addr;
371 cache = trad_frame_cache_zalloc (this_frame);
374 func = get_frame_func (this_frame);
375 sp = get_frame_register_unsigned (this_frame, AMD64_RSP_REGNUM);
377 find_pc_partial_function (func, &name, NULL, NULL);
378 if (name && strncmp (name, "Xintr", 5) == 0)
379 addr = sp + 8; /* It's an interrupt frame. */
383 for (i = 0; i < ARRAY_SIZE (amd64obsd_tf_reg_offset); i++)
384 if (amd64obsd_tf_reg_offset[i] != -1)
385 trad_frame_set_reg_addr (cache, i, addr + amd64obsd_tf_reg_offset[i]);
387 /* Read %cs from trap frame. */
388 addr += amd64obsd_tf_reg_offset[AMD64_CS_REGNUM];
389 cs = read_memory_unsigned_integer (addr, 8, byte_order);
390 if ((cs & I386_SEL_RPL) == I386_SEL_UPL)
392 /* Trap from user space; terminate backtrace. */
393 trad_frame_set_id (cache, outer_frame_id);
397 /* Construct the frame ID using the function start. */
398 trad_frame_set_id (cache, frame_id_build (sp + 16, func));
405 amd64obsd_trapframe_this_id (struct frame_info *this_frame,
406 void **this_cache, struct frame_id *this_id)
408 struct trad_frame_cache *cache =
409 amd64obsd_trapframe_cache (this_frame, this_cache);
411 trad_frame_get_id (cache, this_id);
414 static struct value *
415 amd64obsd_trapframe_prev_register (struct frame_info *this_frame,
416 void **this_cache, int regnum)
418 struct trad_frame_cache *cache =
419 amd64obsd_trapframe_cache (this_frame, this_cache);
421 return trad_frame_get_register (cache, this_frame, regnum);
425 amd64obsd_trapframe_sniffer (const struct frame_unwind *self,
426 struct frame_info *this_frame,
427 void **this_prologue_cache)
432 /* Check Current Privilege Level and bail out if we're not executing
434 cs = get_frame_register_unsigned (this_frame, AMD64_CS_REGNUM);
435 if ((cs & I386_SEL_RPL) == I386_SEL_UPL)
438 find_pc_partial_function (get_frame_pc (this_frame), &name, NULL, NULL);
439 return (name && ((strcmp (name, "calltrap") == 0)
440 || (strcmp (name, "osyscall1") == 0)
441 || (strcmp (name, "Xsyscall") == 0)
442 || (strncmp (name, "Xintr", 5) == 0)));
445 static const struct frame_unwind amd64obsd_trapframe_unwind = {
446 /* FIXME: kettenis/20051219: This really is more like an interrupt
447 frame, but SIGTRAMP_FRAME would print <signal handler called>,
448 which really is not what we want here. */
450 default_frame_unwind_stop_reason,
451 amd64obsd_trapframe_this_id,
452 amd64obsd_trapframe_prev_register,
454 amd64obsd_trapframe_sniffer
459 amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
461 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
463 amd64_init_abi (info, gdbarch);
464 obsd_init_abi (info, gdbarch);
466 /* Initialize general-purpose register set details. */
467 tdep->gregset_reg_offset = amd64obsd_r_reg_offset;
468 tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_r_reg_offset);
469 tdep->sizeof_gregset = 24 * 8;
471 tdep->jb_pc_offset = 7 * 8;
473 tdep->sigtramp_p = amd64obsd_sigtramp_p;
474 tdep->sigcontext_addr = amd64obsd_sigcontext_addr;
475 tdep->sc_reg_offset = amd64obsd_sc_reg_offset;
476 tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset);
478 /* OpenBSD provides a user-level threads implementation. */
479 bsd_uthread_set_supply_uthread (gdbarch, amd64obsd_supply_uthread);
480 bsd_uthread_set_collect_uthread (gdbarch, amd64obsd_collect_uthread);
482 /* OpenBSD uses SVR4-style shared libraries. */
483 set_solib_svr4_fetch_link_map_offsets
484 (gdbarch, svr4_lp64_fetch_link_map_offsets);
486 /* Unwind kernel trap frames correctly. */
487 frame_unwind_prepend_unwinder (gdbarch, &amd64obsd_trapframe_unwind);
490 /* Traditional (a.out) NetBSD-style core dumps. */
493 amd64obsd_core_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
495 amd64obsd_init_abi (info, gdbarch);
497 set_gdbarch_regset_from_core_section
498 (gdbarch, amd64obsd_regset_from_core_section);
502 /* Provide a prototype to silence -Wmissing-prototypes. */
503 void _initialize_amd64obsd_tdep (void);
506 _initialize_amd64obsd_tdep (void)
508 /* The OpenBSD/amd64 native dependent code makes this assumption. */
509 gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == AMD64_NUM_GREGS);
511 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
512 GDB_OSABI_OPENBSD_ELF, amd64obsd_init_abi);
514 /* OpenBSD uses traditional (a.out) NetBSD-style core dumps. */
515 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
516 GDB_OSABI_NETBSD_AOUT, amd64obsd_core_init_abi);