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649f1fb344
bad/missing unwind information, which could result in libunwind dereferencing bad pointers. This mechanism is based on msync(2) system call and significantly reduces the chances of a bad pointer dereference in libunwind. The original idea was to turn this mechanism on only when necessary i.e. libunwind didn't find proper unwind information for a IP. There are a couple of problems in the current implementation. * The flag is global and is modified without locking * The flag isn't reset when starting a new unwind The attached patch makes ->validate a per-thread setting by moving it into struct cursor from unw_local_addr_space and resets it to false when starting a new unwind. As a result, cursor->as_arg points to the cursor itself instead of the ucontext (for the local case). This was found to reduce the number of msync() system calls from an application using libunwind significantly. Signed-off-by: Paul Pluzhnikov <ppluzhnikov@google.com> Signed-off-by: Arun Sharma <arun.sharma@google.com>
198 lines
6.4 KiB
C
198 lines
6.4 KiB
C
/* libunwind - a platform-independent unwind library
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Copyright (C) 2002-2005 Hewlett-Packard Co
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Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
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Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
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This file is part of libunwind.
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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#ifndef X86_64_LIBUNWIND_I_H
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#define X86_64_LIBUNWIND_I_H
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/* Target-dependent definitions that are internal to libunwind but need
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to be shared with target-independent code. */
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#include <stdlib.h>
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#include <libunwind.h>
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#include "elf64.h"
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#include "mempool.h"
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#include "dwarf.h"
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struct unw_addr_space
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{
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struct unw_accessors acc;
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unw_caching_policy_t caching_policy;
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#ifdef HAVE_ATOMIC_OPS_H
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AO_t cache_generation;
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#else
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uint32_t cache_generation;
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#endif
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unw_word_t dyn_generation; /* see dyn-common.h */
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unw_word_t dyn_info_list_addr; /* (cached) dyn_info_list_addr */
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struct dwarf_rs_cache global_cache;
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struct unw_debug_frame_list *debug_frames;
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};
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struct cursor
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{
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struct dwarf_cursor dwarf; /* must be first */
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/* Format of sigcontext structure and address at which it is
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stored: */
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enum
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{
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X86_64_SCF_NONE, /* no signal frame encountered */
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X86_64_SCF_LINUX_RT_SIGFRAME /* POSIX ucontext_t */
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}
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sigcontext_format;
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unw_word_t sigcontext_addr;
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int validate;
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ucontext_t *uc;
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};
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static inline ucontext_t *
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dwarf_get_uc(const struct dwarf_cursor *cursor)
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{
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const struct cursor *c = (struct cursor *) cursor->as_arg;
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return c->uc;
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}
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#define DWARF_GET_LOC(l) ((l).val)
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#ifdef UNW_LOCAL_ONLY
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# define DWARF_NULL_LOC DWARF_LOC (0, 0)
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# define DWARF_IS_NULL_LOC(l) (DWARF_GET_LOC (l) == 0)
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# define DWARF_LOC(r, t) ((dwarf_loc_t) { .val = (r) })
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# define DWARF_IS_REG_LOC(l) 0
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# define DWARF_REG_LOC(c,r) (DWARF_LOC((unw_word_t) \
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tdep_uc_addr(dwarf_get_uc(c), (r)), 0))
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# define DWARF_MEM_LOC(c,m) DWARF_LOC ((m), 0)
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# define DWARF_FPREG_LOC(c,r) (DWARF_LOC((unw_word_t) \
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tdep_uc_addr(dwarf_get_uc(c), (r)), 0))
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#else /* !UNW_LOCAL_ONLY */
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# define DWARF_LOC_TYPE_FP (1 << 0)
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# define DWARF_LOC_TYPE_REG (1 << 1)
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# define DWARF_NULL_LOC DWARF_LOC (0, 0)
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# define DWARF_IS_NULL_LOC(l) \
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({ dwarf_loc_t _l = (l); _l.val == 0 && _l.type == 0; })
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# define DWARF_LOC(r, t) ((dwarf_loc_t) { .val = (r), .type = (t) })
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# define DWARF_IS_REG_LOC(l) (((l).type & DWARF_LOC_TYPE_REG) != 0)
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# define DWARF_IS_FP_LOC(l) (((l).type & DWARF_LOC_TYPE_FP) != 0)
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# define DWARF_REG_LOC(c,r) DWARF_LOC((r), DWARF_LOC_TYPE_REG)
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# define DWARF_MEM_LOC(c,m) DWARF_LOC ((m), 0)
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# define DWARF_FPREG_LOC(c,r) DWARF_LOC((r), (DWARF_LOC_TYPE_REG \
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| DWARF_LOC_TYPE_FP))
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#endif /* !UNW_LOCAL_ONLY */
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static inline int
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dwarf_getfp (struct dwarf_cursor *c, dwarf_loc_t loc, unw_fpreg_t *val)
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{
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if (DWARF_IS_NULL_LOC (loc))
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return -UNW_EBADREG;
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abort ();
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}
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static inline int
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dwarf_putfp (struct dwarf_cursor *c, dwarf_loc_t loc, unw_fpreg_t val)
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{
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if (DWARF_IS_NULL_LOC (loc))
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return -UNW_EBADREG;
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abort ();
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}
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static inline int
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dwarf_get (struct dwarf_cursor *c, dwarf_loc_t loc, unw_word_t *val)
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{
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if (DWARF_IS_NULL_LOC (loc))
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return -UNW_EBADREG;
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if (DWARF_IS_REG_LOC (loc))
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return (*c->as->acc.access_reg) (c->as, DWARF_GET_LOC (loc), val,
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0, c->as_arg);
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else
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return (*c->as->acc.access_mem) (c->as, DWARF_GET_LOC (loc), val,
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0, c->as_arg);
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}
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static inline int
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dwarf_put (struct dwarf_cursor *c, dwarf_loc_t loc, unw_word_t val)
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{
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if (DWARF_IS_NULL_LOC (loc))
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return -UNW_EBADREG;
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if (DWARF_IS_REG_LOC (loc))
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return (*c->as->acc.access_reg) (c->as, DWARF_GET_LOC (loc), &val,
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1, c->as_arg);
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else
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return (*c->as->acc.access_mem) (c->as, DWARF_GET_LOC (loc), &val,
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1, c->as_arg);
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}
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#define tdep_needs_initialization UNW_OBJ(needs_initialization)
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#define tdep_init UNW_OBJ(init)
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/* Platforms that support UNW_INFO_FORMAT_TABLE need to define
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tdep_search_unwind_table. */
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#define tdep_search_unwind_table dwarf_search_unwind_table
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#define tdep_uc_addr UNW_ARCH_OBJ(uc_addr)
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#define tdep_get_elf_image UNW_ARCH_OBJ(get_elf_image)
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#define tdep_access_reg UNW_OBJ(access_reg)
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#define tdep_access_fpreg UNW_OBJ(access_fpreg)
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#ifdef UNW_LOCAL_ONLY
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# define tdep_find_proc_info(c,ip,n) \
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dwarf_find_proc_info((c)->as, (ip), &(c)->pi, (n), \
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(c)->as_arg)
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# define tdep_put_unwind_info(as,pi,arg) \
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dwarf_put_unwind_info((as), (pi), (arg))
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#else
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# define tdep_find_proc_info(c,ip,n) \
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(*(c)->as->acc.find_proc_info)((c)->as, (ip), &(c)->pi, (n), \
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(c)->as_arg)
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# define tdep_put_unwind_info(as,pi,arg) \
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(*(as)->acc.put_unwind_info)((as), (pi), (arg))
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#endif
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#define tdep_get_as(c) ((c)->dwarf.as)
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#define tdep_get_as_arg(c) ((c)->dwarf.as_arg)
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#define tdep_get_ip(c) ((c)->dwarf.ip)
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#define tdep_big_endian(as) 0
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extern int tdep_needs_initialization;
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extern void tdep_init (void);
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extern int tdep_search_unwind_table (unw_addr_space_t as, unw_word_t ip,
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unw_dyn_info_t *di, unw_proc_info_t *pi,
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int need_unwind_info, void *arg);
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extern void *tdep_uc_addr (ucontext_t *uc, int reg);
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extern int tdep_get_elf_image (struct elf_image *ei, pid_t pid, unw_word_t ip,
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unsigned long *segbase, unsigned long *mapoff);
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extern int tdep_access_reg (struct cursor *c, unw_regnum_t reg,
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unw_word_t *valp, int write);
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extern int tdep_access_fpreg (struct cursor *c, unw_regnum_t reg,
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unw_fpreg_t *valp, int write);
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#endif /* X86_64_LIBUNWIND_I_H */
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