@@ -1,3 +1,19 @@
+2018-02-28 John Baldwin <jhb@FreeBSD.org>
+
+ * fbsd-nat.c: Include "inf-ptrace.h".
+ (USE_SIGTRAP_SIGINFO): Conditionally define.
+ [USE_SIGTRAP_SIGINFO] (fbsd_handle_debug_trap): New function.
+ (fbsd_wait) [USE_SIGTRAP_SIGINFO]: Call "fbsd_handle_debug_trap".
+ [USE_SIGTRAP_SIGINFO] (fbsd_stopped_by_sw_breakpoint): New
+ function.
+ [USE_SIGTRAP_SIGINFO] (fbsd_supports_stopped_by_sw_breakpoint):
+ Likewise.
+ [USE_SIGTRAP_SIGINFO] (fbsd_supports_stopped_by_hw_breakpoint):
+ Likewise.
+ (fbsd_nat_add_target) [USE_SIGTRAP_SIGINFO]: Set
+ "stopped_by_sw_breakpoint", "supports_stopped_by_sw_breakpoint",
+ "supports_stopped_by_hw_breakpoint" target methods.
+
2018-02-28 John Baldwin <jhb@FreeBSD.org>
* NEWS (Changes since GDB 8.1): Add "set/show debug fbsd-nat".
@@ -26,6 +26,7 @@
#include "gdbcmd.h"
#include "gdbthread.h"
#include "gdb_wait.h"
+#include "inf-ptrace.h"
#include <sys/types.h>
#include <sys/procfs.h>
#include <sys/ptrace.h>
@@ -45,6 +46,16 @@
#include <list>
+#ifdef TRAP_BRKPT
+/*
+ * MIPS does not set si_code for SIGTRAP. sparc64 reports
+ * non-standard values in si_code for SIGTRAP.
+ */
+#if !defined(__mips__) && !defined(__sparc64__)
+#define USE_SIGTRAP_SIGINFO
+#endif
+#endif
+
/* Return the name of a file that can be opened to get the symbols for
the child process identified by PID. */
@@ -1187,6 +1198,56 @@ fbsd_resume (struct target_ops *ops,
super_resume (ops, ptid, step, signo);
}
+#ifdef USE_SIGTRAP_SIGINFO
+/* Handle breakpoint and trace traps reported via SIGTRAP. If the
+ trap was a breakpoint or trace trap that should be reported to the
+ core, return true. */
+
+static bool
+fbsd_handle_debug_trap (struct target_ops *ops, ptid_t ptid,
+ const struct ptrace_lwpinfo &pl)
+{
+
+ /* Ignore traps without valid siginfo or for signals other than
+ SIGTRAP. */
+ if (! (pl.pl_flags & PL_FLAG_SI) || pl.pl_siginfo.si_signo != SIGTRAP)
+ return false;
+
+ /* Trace traps are either a single step or a hardware watchpoint or
+ breakpoint. */
+ if (pl.pl_siginfo.si_code == TRAP_TRACE)
+ {
+ if (debug_fbsd_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "FNAT: trace trap for LWP %ld\n", ptid.lwp ());
+ return true;
+ }
+
+ if (pl.pl_siginfo.si_code == TRAP_BRKPT)
+ {
+ /* Fixup PC for the software breakpoint. */
+ struct regcache *regcache = get_thread_regcache (ptid);
+ struct gdbarch *gdbarch = regcache->arch ();
+ int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
+
+ if (debug_fbsd_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "FNAT: sw breakpoint trap for LWP %ld\n",
+ ptid.lwp ());
+ if (decr_pc != 0)
+ {
+ CORE_ADDR pc;
+
+ pc = regcache_read_pc (regcache);
+ regcache_write_pc (regcache, pc - decr_pc);
+ }
+ return true;
+ }
+
+ return false;
+}
+#endif
+
/* Wait for the child specified by PTID to do something. Return the
process ID of the child, or MINUS_ONE_PTID in case of error; store
the status in *OURSTATUS. */
@@ -1372,6 +1433,13 @@ fbsd_wait (struct target_ops *ops,
}
#endif
+#ifdef USE_SIGTRAP_SIGINFO
+ if (fbsd_handle_debug_trap (ops, wptid, pl))
+ {
+ return wptid;
+ }
+#endif
+
/* Note that PL_FLAG_SCE is set for any event reported while
a thread is executing a system call in the kernel. In
particular, signals that interrupt a sleep in a system
@@ -1410,6 +1478,41 @@ fbsd_wait (struct target_ops *ops,
}
}
+#ifdef USE_SIGTRAP_SIGINFO
+/* Implement the "to_stopped_by_sw_breakpoint" target_ops method. */
+
+static int
+fbsd_stopped_by_sw_breakpoint (struct target_ops *ops)
+{
+ struct ptrace_lwpinfo pl;
+
+ if (ptrace (PT_LWPINFO, get_ptrace_pid (inferior_ptid), (caddr_t) &pl,
+ sizeof pl) == -1)
+ return 0;
+
+ return (pl.pl_flags & PL_FLAG_SI) && pl.pl_siginfo.si_signo == SIGTRAP
+ && pl.pl_siginfo.si_code == TRAP_BRKPT;
+}
+
+/* Implement the "to_supports_stopped_by_sw_breakpoint" target_ops
+ method. */
+
+static int
+fbsd_supports_stopped_by_sw_breakpoint (struct target_ops *ops)
+{
+ return 1;
+}
+
+/* Implement the "to_supports_stopped_by_hw_breakpoint" target_ops
+ method. */
+
+static int
+fbsd_supports_stopped_by_hw_breakpoint (struct target_ops *ops)
+{
+ return ops->to_stopped_by_hw_breakpoint != NULL;
+}
+#endif
+
#ifdef TDP_RFPPWAIT
/* Target hook for follow_fork. On entry and at return inferior_ptid is
the ptid of the followed inferior. */
@@ -1560,6 +1663,13 @@ fbsd_nat_add_target (struct target_ops *t)
t->to_wait = fbsd_wait;
t->to_post_startup_inferior = fbsd_post_startup_inferior;
t->to_post_attach = fbsd_post_attach;
+#ifdef USE_SIGTRAP_SIGINFO
+ t->to_stopped_by_sw_breakpoint = fbsd_stopped_by_sw_breakpoint;
+ t->to_supports_stopped_by_sw_breakpoint =
+ fbsd_supports_stopped_by_sw_breakpoint;
+ t->to_supports_stopped_by_hw_breakpoint =
+ fbsd_supports_stopped_by_hw_breakpoint;
+#endif
#ifdef TDP_RFPPWAIT
t->to_follow_fork = fbsd_follow_fork;
t->to_insert_fork_catchpoint = fbsd_insert_fork_catchpoint;