aarch64 multi-arch support (part 2): siginfo fixup

This patch is to fixup the siginfo_t when aarch64 gdb or gdbserver
read from or write to the arm inferior.  It is to convert the
"struct siginfo_t" between aarch64 and arm, which is quite mechanical.

gdb/gdbserver:

2015-09-15  Yao Qi  <yao.qi@linaro.org>

	* linux-aarch64-low.c (aarch64_linux_siginfo_fixup): New
	function.
	(struct linux_target_ops the_low_target): Install
	aarch64_linux_siginfo_fixup.

gdb:

2015-09-15  Yao Qi  <yao.qi@linaro.org>

	* aarch64-linux-nat.c (aarch64_linux_siginfo_fixup): New function.
	(_initialize_aarch64_linux_nat): Call linux_nat_set_siginfo_fixup.
	* nat/aarch64-linux.c (aarch64_compat_siginfo_from_siginfo):
	New function.
	(aarch64_siginfo_from_compat_siginfo): New function.
	* nat/aarch64-linux.h: Include signal.h.
	(compat_int_t, compat_uptr_t, compat_time_t): Typedef.
	(compat_timer_t, compat_clock_t): Likewise.
	(struct compat_timeval): New.
	(union compat_sigval): New.
	(struct compat_siginfo): New.
	(cpt_si_pid, cpt_si_uid, cpt_si_timerid): New macros.
	(cpt_si_overrun, cpt_si_status, cpt_si_utime): Likewise.
	(cpt_si_stime, cpt_si_ptr, cpt_si_addr): Likewise.
	(cpt_si_band, cpt_si_fd): Likewise.

1 files changed, 31 insertions, 0 deletions

diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
index f2ef41bb7a..ddb2788ba8 100644
--- a/gdb/aarch64-linux-nat.c
+++ b/gdb/aarch64-linux-nat.c
@@ -543,6 +543,34 @@ aarch64_linux_read_description (struct target_ops *ops)
   return tdesc_aarch64;
 }
 
+/* Convert a native/host siginfo object, into/from the siginfo in the
+   layout of the inferiors' architecture.  Returns true if any
+   conversion was done; false otherwise.  If DIRECTION is 1, then copy
+   from INF to NATIVE.  If DIRECTION is 0, copy from NATIVE to
+   INF.  */
+
+static int
+aarch64_linux_siginfo_fixup (siginfo_t *native, gdb_byte *inf, int direction)
+{
+  struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
+
+  /* Is the inferior 32-bit?  If so, then do fixup the siginfo
+     object.  */
+  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+    {
+      if (direction == 0)
+	aarch64_compat_siginfo_from_siginfo ((struct compat_siginfo *) inf,
+					     native);
+      else
+	aarch64_siginfo_from_compat_siginfo (native,
+					     (struct compat_siginfo *) inf);
+
+      return 1;
+    }
+
+  return 0;
+}
+
 /* Returns the number of hardware watchpoints of type TYPE that we can
    set.  Value is positive if we can set CNT watchpoints, zero if
    setting watchpoints of type TYPE is not supported, and negative if
@@ -841,4 +869,7 @@ _initialize_aarch64_linux_nat (void)
   linux_nat_set_new_fork (t, aarch64_linux_new_fork);
   linux_nat_set_forget_process (t, aarch64_forget_process);
   linux_nat_set_prepare_to_resume (t, aarch64_linux_prepare_to_resume);
+
+  /* Add our siginfo layout converter.  */
+  linux_nat_set_siginfo_fixup (t, aarch64_linux_siginfo_fixup);
 }