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"
32 #include "gdb_assert.h"
35 #include "obsd-tdep.h"
36 #include "amd64-tdep.h"
37 #include "i387-tdep.h"
38 #include "solib-svr4.h"
39 #include "bsd-uthread.h"
41 /* Support for core dumps. */
44 amd64obsd_supply_regset (const struct regset
*regset
,
45 struct regcache
*regcache
, int regnum
,
46 const void *regs
, size_t len
)
48 const struct gdbarch_tdep
*tdep
= gdbarch_tdep (regset
->arch
);
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
*
58 amd64obsd_regset_from_core_section (struct gdbarch
*gdbarch
,
59 const char *sect_name
, size_t sect_size
)
61 struct gdbarch_tdep
*tdep
= gdbarch_tdep (gdbarch
);
63 /* OpenBSD core dumps don't use seperate register sets for the
64 general-purpose and floating-point registers. */
66 if (strcmp (sect_name
, ".reg") == 0
67 && sect_size
>= tdep
->sizeof_gregset
+ I387_SIZEOF_FXSAVE
)
69 if (tdep
->gregset
== NULL
)
70 tdep
->gregset
= regset_alloc (gdbarch
, amd64obsd_supply_regset
, NULL
);
78 /* Support for signal handlers. */
80 /* Default page size. */
81 static const int amd64obsd_page_size
= 4096;
83 /* Return whether THIS_FRAME corresponds to an OpenBSD sigtramp
87 amd64obsd_sigtramp_p (struct frame_info
*this_frame
)
89 CORE_ADDR pc
= get_frame_pc (this_frame
);
90 CORE_ADDR start_pc
= (pc
& ~(amd64obsd_page_size
- 1));
91 const gdb_byte osigreturn
[] =
94 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
95 0xcd, 0x80 /* int $0x80 */
97 const gdb_byte sigreturn
[] =
100 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
101 0x0f, 0x05 /* syscall */
103 size_t buflen
= (sizeof sigreturn
) + 1;
107 /* If the function has a valid symbol name, it isn't a
109 find_pc_partial_function (pc
, &name
, NULL
, NULL
);
113 /* If the function lives in a valid section (even without a starting
114 point) it isn't a trampoline. */
115 if (find_pc_section (pc
) != NULL
)
118 /* If we can't read the instructions at START_PC, return zero. */
119 buf
= alloca ((sizeof sigreturn
) + 1);
120 if (!safe_frame_unwind_memory (this_frame
, start_pc
+ 6, buf
, buflen
))
123 /* Check for sigreturn(2). Depending on how the assembler encoded
124 the `movq %rsp, %rdi' instruction, the code starts at offset 6 or
125 7. OpenBSD 5.0 and later use the `syscall' instruction. Older
126 versions use `int $0x80'. Check for both. */
127 if (memcmp (buf
, sigreturn
, sizeof sigreturn
)
128 && memcmp (buf
+ 1, sigreturn
, sizeof sigreturn
)
129 && memcmp (buf
, osigreturn
, sizeof osigreturn
)
130 && memcmp (buf
+ 1, osigreturn
, sizeof osigreturn
))
136 /* Assuming THIS_FRAME is for a BSD sigtramp routine, return the
137 address of the associated sigcontext structure. */
140 amd64obsd_sigcontext_addr (struct frame_info
*this_frame
)
142 CORE_ADDR pc
= get_frame_pc (this_frame
);
143 ULONGEST offset
= (pc
& (amd64obsd_page_size
- 1));
145 /* The %rsp register points at `struct sigcontext' upon entry of a
146 signal trampoline. The relevant part of the trampoline is
151 movq $SYS_sigreturn,%rax
154 (see /usr/src/sys/arch/amd64/amd64/locore.S). The `pushq'
155 instruction clobbers %rsp, but its value is saved in `%rdi'. */
158 return get_frame_register_unsigned (this_frame
, AMD64_RDI_REGNUM
);
160 return get_frame_register_unsigned (this_frame
, AMD64_RSP_REGNUM
);
163 /* OpenBSD 3.5 or later. */
165 /* Mapping between the general-purpose registers in `struct reg'
166 format and GDB's register cache layout. */
168 /* From <machine/reg.h>. */
169 int amd64obsd_r_reg_offset
[] =
186 11 * 8, /* ... %r15 */
188 17 * 8, /* %eflags */
197 /* From <machine/signal.h>. */
198 static int amd64obsd_sc_reg_offset
[] =
215 11 * 8, /* ... %r15 */
217 23 * 8, /* %eflags */
226 /* From /usr/src/lib/libpthread/arch/amd64/uthread_machdep.c. */
227 static int amd64obsd_uthread_reg_offset
[] =
237 12 * 8, /* %r8 ... */
244 5 * 8, /* ... %r15 */
255 /* Offset within the thread structure where we can find the saved
256 stack pointer (%esp). */
257 #define AMD64OBSD_UTHREAD_RSP_OFFSET 400
260 amd64obsd_supply_uthread (struct regcache
*regcache
,
261 int regnum
, CORE_ADDR addr
)
263 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
264 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
265 CORE_ADDR sp_addr
= addr
+ AMD64OBSD_UTHREAD_RSP_OFFSET
;
270 gdb_assert (regnum
>= -1);
272 if (regnum
== -1 || regnum
== AMD64_RSP_REGNUM
)
276 /* Fetch stack pointer from thread structure. */
277 sp
= read_memory_unsigned_integer (sp_addr
, 8, byte_order
);
279 /* Adjust the stack pointer such that it looks as if we just
280 returned from _thread_machdep_switch. */
281 offset
= amd64obsd_uthread_reg_offset
[AMD64_RIP_REGNUM
] + 8;
282 store_unsigned_integer (buf
, 8, byte_order
, sp
+ offset
);
283 regcache_raw_supply (regcache
, AMD64_RSP_REGNUM
, buf
);
286 for (i
= 0; i
< ARRAY_SIZE (amd64obsd_uthread_reg_offset
); i
++)
288 if (amd64obsd_uthread_reg_offset
[i
] != -1
289 && (regnum
== -1 || regnum
== i
))
291 /* Fetch stack pointer from thread structure (if we didn't
294 sp
= read_memory_unsigned_integer (sp_addr
, 8, byte_order
);
296 /* Read the saved register from the stack frame. */
297 read_memory (sp
+ amd64obsd_uthread_reg_offset
[i
], buf
, 8);
298 regcache_raw_supply (regcache
, i
, buf
);
304 amd64obsd_collect_uthread (const struct regcache
*regcache
,
305 int regnum
, CORE_ADDR addr
)
307 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
308 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
309 CORE_ADDR sp_addr
= addr
+ AMD64OBSD_UTHREAD_RSP_OFFSET
;
314 gdb_assert (regnum
>= -1);
316 if (regnum
== -1 || regnum
== AMD64_RSP_REGNUM
)
320 /* Calculate the stack pointer (frame pointer) that will be
321 stored into the thread structure. */
322 offset
= amd64obsd_uthread_reg_offset
[AMD64_RIP_REGNUM
] + 8;
323 regcache_raw_collect (regcache
, AMD64_RSP_REGNUM
, buf
);
324 sp
= extract_unsigned_integer (buf
, 8, byte_order
) - offset
;
326 /* Store the stack pointer. */
327 write_memory_unsigned_integer (sp_addr
, 8, byte_order
, sp
);
329 /* The stack pointer was (potentially) modified. Make sure we
330 build a proper stack frame. */
334 for (i
= 0; i
< ARRAY_SIZE (amd64obsd_uthread_reg_offset
); i
++)
336 if (amd64obsd_uthread_reg_offset
[i
] != -1
337 && (regnum
== -1 || regnum
== i
))
339 /* Fetch stack pointer from thread structure (if we didn't
340 calculate it already). */
342 sp
= read_memory_unsigned_integer (sp_addr
, 8, byte_order
);
344 /* Write the register into the stack frame. */
345 regcache_raw_collect (regcache
, i
, buf
);
346 write_memory (sp
+ amd64obsd_uthread_reg_offset
[i
], buf
, 8);
350 /* Kernel debugging support. */
352 /* From <machine/frame.h>. Easy since `struct trapframe' matches
353 `struct sigcontext'. */
354 #define amd64obsd_tf_reg_offset amd64obsd_sc_reg_offset
356 static struct trad_frame_cache
*
357 amd64obsd_trapframe_cache (struct frame_info
*this_frame
, void **this_cache
)
359 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
360 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
361 struct trad_frame_cache
*cache
;
362 CORE_ADDR func
, sp
, addr
;
370 cache
= trad_frame_cache_zalloc (this_frame
);
373 func
= get_frame_func (this_frame
);
374 sp
= get_frame_register_unsigned (this_frame
, AMD64_RSP_REGNUM
);
376 find_pc_partial_function (func
, &name
, NULL
, NULL
);
377 if (name
&& strncmp (name
, "Xintr", 5) == 0)
378 addr
= sp
+ 8; /* It's an interrupt frame. */
382 for (i
= 0; i
< ARRAY_SIZE (amd64obsd_tf_reg_offset
); i
++)
383 if (amd64obsd_tf_reg_offset
[i
] != -1)
384 trad_frame_set_reg_addr (cache
, i
, addr
+ amd64obsd_tf_reg_offset
[i
]);
386 /* Read %cs from trap frame. */
387 addr
+= amd64obsd_tf_reg_offset
[AMD64_CS_REGNUM
];
388 cs
= read_memory_unsigned_integer (addr
, 8, byte_order
);
389 if ((cs
& I386_SEL_RPL
) == I386_SEL_UPL
)
391 /* Trap from user space; terminate backtrace. */
392 trad_frame_set_id (cache
, outer_frame_id
);
396 /* Construct the frame ID using the function start. */
397 trad_frame_set_id (cache
, frame_id_build (sp
+ 16, func
));
404 amd64obsd_trapframe_this_id (struct frame_info
*this_frame
,
405 void **this_cache
, struct frame_id
*this_id
)
407 struct trad_frame_cache
*cache
=
408 amd64obsd_trapframe_cache (this_frame
, this_cache
);
410 trad_frame_get_id (cache
, this_id
);
413 static struct value
*
414 amd64obsd_trapframe_prev_register (struct frame_info
*this_frame
,
415 void **this_cache
, int regnum
)
417 struct trad_frame_cache
*cache
=
418 amd64obsd_trapframe_cache (this_frame
, this_cache
);
420 return trad_frame_get_register (cache
, this_frame
, regnum
);
424 amd64obsd_trapframe_sniffer (const struct frame_unwind
*self
,
425 struct frame_info
*this_frame
,
426 void **this_prologue_cache
)
431 /* Check Current Privilege Level and bail out if we're not executing
433 cs
= get_frame_register_unsigned (this_frame
, AMD64_CS_REGNUM
);
434 if ((cs
& I386_SEL_RPL
) == I386_SEL_UPL
)
437 find_pc_partial_function (get_frame_pc (this_frame
), &name
, NULL
, NULL
);
438 return (name
&& ((strcmp (name
, "calltrap") == 0)
439 || (strcmp (name
, "osyscall1") == 0)
440 || (strcmp (name
, "Xsyscall") == 0)
441 || (strncmp (name
, "Xintr", 5) == 0)));
444 static const struct frame_unwind amd64obsd_trapframe_unwind
= {
445 /* FIXME: kettenis/20051219: This really is more like an interrupt
446 frame, but SIGTRAMP_FRAME would print <signal handler called>,
447 which really is not what we want here. */
449 default_frame_unwind_stop_reason
,
450 amd64obsd_trapframe_this_id
,
451 amd64obsd_trapframe_prev_register
,
453 amd64obsd_trapframe_sniffer
458 amd64obsd_init_abi (struct gdbarch_info info
, struct gdbarch
*gdbarch
)
460 struct gdbarch_tdep
*tdep
= gdbarch_tdep (gdbarch
);
462 amd64_init_abi (info
, gdbarch
);
463 obsd_init_abi (info
, gdbarch
);
465 /* Initialize general-purpose register set details. */
466 tdep
->gregset_reg_offset
= amd64obsd_r_reg_offset
;
467 tdep
->gregset_num_regs
= ARRAY_SIZE (amd64obsd_r_reg_offset
);
468 tdep
->sizeof_gregset
= 24 * 8;
470 tdep
->jb_pc_offset
= 7 * 8;
472 tdep
->sigtramp_p
= amd64obsd_sigtramp_p
;
473 tdep
->sigcontext_addr
= amd64obsd_sigcontext_addr
;
474 tdep
->sc_reg_offset
= amd64obsd_sc_reg_offset
;
475 tdep
->sc_num_regs
= ARRAY_SIZE (amd64obsd_sc_reg_offset
);
477 /* OpenBSD provides a user-level threads implementation. */
478 bsd_uthread_set_supply_uthread (gdbarch
, amd64obsd_supply_uthread
);
479 bsd_uthread_set_collect_uthread (gdbarch
, amd64obsd_collect_uthread
);
481 /* OpenBSD uses SVR4-style shared libraries. */
482 set_solib_svr4_fetch_link_map_offsets
483 (gdbarch
, svr4_lp64_fetch_link_map_offsets
);
485 /* Unwind kernel trap frames correctly. */
486 frame_unwind_prepend_unwinder (gdbarch
, &amd64obsd_trapframe_unwind
);
489 /* Traditional (a.out) NetBSD-style core dumps. */
492 amd64obsd_core_init_abi (struct gdbarch_info info
, struct gdbarch
*gdbarch
)
494 amd64obsd_init_abi (info
, gdbarch
);
496 set_gdbarch_regset_from_core_section
497 (gdbarch
, amd64obsd_regset_from_core_section
);
501 /* Provide a prototype to silence -Wmissing-prototypes. */
502 void _initialize_amd64obsd_tdep (void);
505 _initialize_amd64obsd_tdep (void)
507 /* The OpenBSD/amd64 native dependent code makes this assumption. */
508 gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset
) == AMD64_NUM_GREGS
);
510 gdbarch_register_osabi (bfd_arch_i386
, bfd_mach_x86_64
,
511 GDB_OSABI_OPENBSD_ELF
, amd64obsd_init_abi
);
513 /* OpenBSD uses traditional (a.out) NetBSD-style core dumps. */
514 gdbarch_register_osabi (bfd_arch_i386
, bfd_mach_x86_64
,
515 GDB_OSABI_NETBSD_AOUT
, amd64obsd_core_init_abi
);