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      1 /* libunwind - a platform-independent unwind library
      2    Copyright (c) 2004 Hewlett-Packard Development Company, L.P.
      3 	Contributed by David Mosberger-Tang <davidm (at) hpl.hp.com>
      4 
      5 This file is part of libunwind.
      6 
      7 Permission is hereby granted, free of charge, to any person obtaining
      8 a copy of this software and associated documentation files (the
      9 "Software"), to deal in the Software without restriction, including
     10 without limitation the rights to use, copy, modify, merge, publish,
     11 distribute, sublicense, and/or sell copies of the Software, and to
     12 permit persons to whom the Software is furnished to do so, subject to
     13 the following conditions:
     14 
     15 The above copyright notice and this permission notice shall be
     16 included in all copies or substantial portions of the Software.
     17 
     18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     21 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     24 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
     25 
     26 #include <stdlib.h>
     27 
     28 #include "unwind_i.h"
     29 
     30 #ifndef UNW_REMOTE_ONLY
     31 
     32 #if defined(__linux)
     33 
     34 # include <sys/syscall.h>
     35 
     36 static NORETURN inline long
     37 my_rt_sigreturn (void *new_sp, int in_syscall)
     38 {
     39   register unsigned long r25 __asm__ ("r25") = (in_syscall != 0);
     40   register unsigned long r20 __asm__ ("r20") = SYS_rt_sigreturn;
     41 
     42   __asm__ __volatile__ ("copy %0, %%sp\n"
     43 			"be,l 0x100(%%sr2,%%r0),%%sr0,%%r31\n"
     44 			"nop"
     45 			:
     46 			: "r"(new_sp), "r"(r20), "r"(r25)
     47 			: "memory");
     48   abort ();
     49 }
     50 
     51 #endif /* __linux */
     52 
     53 HIDDEN inline int
     54 hppa_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
     55 {
     56 #if defined(__linux)
     57   struct cursor *c = (struct cursor *) cursor;
     58   ucontext_t *uc = c->dwarf.as_arg;
     59 
     60   /* Ensure c->pi is up-to-date.  On PA-RISC, it's relatively common to be
     61      missing DWARF unwind info.  We don't want to fail in that case,
     62      because the frame-chain still would let us do a backtrace at
     63      least.  */
     64   dwarf_make_proc_info (&c->dwarf);
     65 
     66   if (unlikely (c->sigcontext_format != HPPA_SCF_NONE))
     67     {
     68       struct sigcontext *sc = (struct sigcontext *) c->sigcontext_addr;
     69 
     70       Debug (8, "resuming at ip=%x via sigreturn(%p)\n", c->dwarf.ip, sc);
     71       my_rt_sigreturn (sc, (sc->sc_flags & PARISC_SC_FLAG_IN_SYSCALL) != 0);
     72     }
     73   else
     74     {
     75       Debug (8, "resuming at ip=%x via setcontext()\n", c->dwarf.ip);
     76       setcontext (uc);
     77     }
     78 #else
     79 # warning Implement me!
     80 #endif
     81   return -UNW_EINVAL;
     82 }
     83 
     84 #endif /* !UNW_REMOTE_ONLY */
     85 
     86 /* This routine is responsible for copying the register values in
     87    cursor C and establishing them as the current machine state. */
     88 
     89 static inline int
     90 establish_machine_state (struct cursor *c)
     91 {
     92   int (*access_reg) (unw_addr_space_t, unw_regnum_t, unw_word_t *,
     93 		     int write, void *);
     94   int (*access_fpreg) (unw_addr_space_t, unw_regnum_t, unw_fpreg_t *,
     95 		       int write, void *);
     96   unw_addr_space_t as = c->dwarf.as;
     97   void *arg = c->dwarf.as_arg;
     98   unw_fpreg_t fpval;
     99   unw_word_t val;
    100   int reg;
    101 
    102   access_reg = as->acc.access_reg;
    103   access_fpreg = as->acc.access_fpreg;
    104 
    105   Debug (8, "copying out cursor state\n");
    106 
    107   for (reg = 0; reg <= UNW_REG_LAST; ++reg)
    108     {
    109       Debug (16, "copying %s %d\n", unw_regname (reg), reg);
    110       if (unw_is_fpreg (reg))
    111 	{
    112 	  if (tdep_access_fpreg (c, reg, &fpval, 0) >= 0)
    113 	    (*access_fpreg) (as, reg, &fpval, 1, arg);
    114 	}
    115       else
    116 	{
    117 	  if (tdep_access_reg (c, reg, &val, 0) >= 0)
    118 	    (*access_reg) (as, reg, &val, 1, arg);
    119 	}
    120     }
    121   return 0;
    122 }
    123 
    124 PROTECTED int
    125 unw_resume (unw_cursor_t *cursor)
    126 {
    127   struct cursor *c = (struct cursor *) cursor;
    128   int ret;
    129 
    130   Debug (1, "(cursor=%p)\n", c);
    131 
    132   if (!c->dwarf.ip)
    133     {
    134       /* This can happen easily when the frame-chain gets truncated
    135          due to bad or missing unwind-info.  */
    136       Debug (1, "refusing to resume execution at address 0\n");
    137       return -UNW_EINVAL;
    138     }
    139 
    140   if ((ret = establish_machine_state (c)) < 0)
    141     return ret;
    142 
    143   return (*c->dwarf.as->acc.resume) (c->dwarf.as, (unw_cursor_t *) c,
    144 				     c->dwarf.as_arg);
    145 }
    146