gdb/patches/gdb-bz592031-siginfo-lost-5of5.patch

   1 http://sourceware.org/ml/gdb-patches/2010-09/msg00361.html
   2 Subject: [patch 4/4]#3 Remove redundant lp->siginfo
   3
   4 Hi,
   5
   6 this is a simplification which should not affect GDB behavior.  As linux-nat
   7 now stops on each received signal without any reordering of them then
   8 PTRACE_GETSIGINFO is enough to access siginfo, without any need to copy it in
   9 advance.
  10
  11
  12 Thanks,
  13 Jan
  14
  15
  16 gdb/
  17 2010-09-20  Jan Kratochvil  <jan.kratochvil@redhat.com>
  18
  19         * linux-nat.c (resume_callback) <lp->stopped && lp->status == 0>
  20         (linux_nat_resume): Remove LP->SIGINFO clearing.
  21         (save_siginfo): Remove.
  22         (stop_wait_callback) <WSTOPSIG (status) != SIGSTOP>
  23         (linux_nat_filter_event) <linux_nat_status_is_event (status)>: Remove
  24         the save_siginfo call.
  25         (resume_stopped_resumed_lwps): Remove LP->SIGINFO clearing.
  26         (linux_nat_set_siginfo_fixup): Use PTRACE_GETSIGINFO.
  27         * linux-nat.h (struct lwp_info) <siginfo>: Remove.
  28
  29 Index: gdb-7.2.50.20101116/gdb/linux-nat.c
  30 ===================================================================
  31 --- gdb-7.2.50.20101116.orig/gdb/linux-nat.c    2010-11-16 09:12:26.000000000 +0100
  32 +++ gdb-7.2.50.20101116/gdb/linux-nat.c 2010-11-16 09:13:21.000000000 +0100
  33 @@ -1850,7 +1850,6 @@ resume_callback (struct lwp_info *lp, vo
  34                             target_pid_to_str (lp->ptid));
  35        lp->stopped = 0;
  36        lp->step = 0;
  37 -      memset (&lp->siginfo, 0, sizeof (lp->siginfo));
  38        lp->stopped_by_watchpoint = 0;
  39      }
  40    else if (lp->stopped && debug_linux_nat)
  41 @@ -1993,7 +1992,6 @@ linux_nat_resume (struct target_ops *ops
  42    ptid = pid_to_ptid (GET_LWP (lp->ptid));
  43
  44    linux_ops->to_resume (linux_ops, ptid, step, signo);
  45 -  memset (&lp->siginfo, 0, sizeof (lp->siginfo));
  46    lp->stopped_by_watchpoint = 0;
  47
  48    if (debug_linux_nat)
  49 @@ -2503,22 +2501,6 @@ wait_lwp (struct lwp_info *lp)
  50    return status;
  51  }
  52
  53 -/* Save the most recent siginfo for LP.  This is currently only called
  54 -   for SIGTRAP; some ports use the si_addr field for
  55 -   target_stopped_data_address.  In the future, it may also be used to
  56 -   restore the siginfo of requeued signals.  */
  57 -
  58 -static void
  59 -save_siginfo (struct lwp_info *lp)
  60 -{
  61 -  errno = 0;
  62 -  ptrace (PTRACE_GETSIGINFO, GET_LWP (lp->ptid),
  63 -         (PTRACE_TYPE_ARG3) 0, &lp->siginfo);
  64 -
  65 -  if (errno != 0)
  66 -    memset (&lp->siginfo, 0, sizeof (lp->siginfo));
  67 -}
  68 -
  69  /* Send a SIGSTOP to LP.  */
  70
  71  static int
  72 @@ -2787,9 +2769,6 @@ stop_wait_callback (struct lwp_info *lp,
  73         {
  74           /* The thread was stopped with a signal other than SIGSTOP.  */
  75
  76 -         /* Save the trap's siginfo in case we need it later.  */
  77 -         save_siginfo (lp);
  78 -
  79           save_sigtrap (lp);
  80
  81           if (debug_linux_nat)
  82 @@ -3155,12 +3134,7 @@ linux_nat_filter_event (int lwpid, int s
  83      }
  84
  85    if (linux_nat_status_is_event (status))
  86 -    {
  87 -      /* Save the trap's siginfo in case we need it later.  */
  88 -      save_siginfo (lp);
  89 -
  90 -      save_sigtrap (lp);
  91 -    }
  92 +    save_sigtrap (lp);
  93
  94    /* Check if the thread has exited.  */
  95    if ((WIFEXITED (status) || WIFSIGNALED (status))
  96 @@ -3763,7 +3737,6 @@ resume_stopped_resumed_lwps (struct lwp_
  97        linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
  98                             lp->step, TARGET_SIGNAL_0);
  99        lp->stopped = 0;
 100 -      memset (&lp->siginfo, 0, sizeof (lp->siginfo));
 101        lp->stopped_by_watchpoint = 0;
 102      }
 103
 104 @@ -5932,11 +5905,19 @@ linux_nat_set_siginfo_fixup (struct targ
 105  struct siginfo *
 106  linux_nat_get_siginfo (ptid_t ptid)
 107  {
 108 -  struct lwp_info *lp = find_lwp_pid (ptid);
 109 +  static struct siginfo siginfo;
 110 +  int pid;
 111
 112 -  gdb_assert (lp != NULL);
 113 +  pid = GET_LWP (ptid);
 114 +  if (pid == 0)
 115 +    pid = GET_PID (ptid);
 116 +
 117 +  errno = 0;
 118 +  ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
 119 +  if (errno != 0)
 120 +    memset (&siginfo, 0, sizeof (siginfo));
 121
 122 -  return &lp->siginfo;
 123 +  return &siginfo;
 124  }
 125
 126  /* Provide a prototype to silence -Wmissing-prototypes.  */
 127 Index: gdb-7.2.50.20101116/gdb/linux-nat.h
 128 ===================================================================
 129 --- gdb-7.2.50.20101116.orig/gdb/linux-nat.h    2010-11-16 07:54:36.000000000 +0100
 130 +++ gdb-7.2.50.20101116/gdb/linux-nat.h 2010-11-16 09:12:44.000000000 +0100
 131 @@ -58,10 +58,6 @@ struct lwp_info
 132    /* The kind of stepping of this LWP.  */
 133    enum resume_step step;
 134
 135 -  /* Non-zero si_signo if this LWP stopped with a trap.  si_addr may
 136 -     be the address of a hardware watchpoint.  */
 137 -  struct siginfo siginfo;
 138 -
 139    /* STOPPED_BY_WATCHPOINT is non-zero if this LWP stopped with a data
 140       watchpoint trap.  */
 141    int stopped_by_watchpoint;