[PATCH 2/2] gdb/s390: Fill guess_tracepoint_registers hook.

["Marcin Kościelnicki" <koriakin@0x04.net>]

gdb/ChangeLog:

	* s390-linux-tdep.c (s390_guess_tracepoint_registers): New function.
	(s390_gdbarch_init): Fill guess_tracepoint_registers hook.
---
 gdb/ChangeLog         |  5 +++++
 gdb/s390-linux-tdep.c | 24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 95afe29..2823f70 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2016-02-18  Marcin Kościelnicki  <koriakin@0x04.net>
 
+	* s390-linux-tdep.c (s390_guess_tracepoint_registers): New function.
+	(s390_gdbarch_init): Fill guess_tracepoint_registers hook.
+
+2016-02-18  Marcin Kościelnicki  <koriakin@0x04.net>
+
 	* gdbarch.c: Regenerate.
 	* gdbarch.h: Regenerate.
 	* gdbarch.sh: Add guess_tracepoint_registers hook, struct tracepoint
diff --git a/gdb/s390-linux-tdep.c b/gdb/s390-linux-tdep.c
index e827684..82902e4 100644
--- a/gdb/s390-linux-tdep.c
+++ b/gdb/s390-linux-tdep.c
@@ -167,6 +167,29 @@ s390_write_pc (struct regcache *regcache, CORE_ADDR pc)
     regcache_cooked_write_unsigned (regcache, S390_SYSTEM_CALL_REGNUM, 0);
 }
 
+/* The "guess_tracepoint_registers" gdbarch method.  For s390, we have
+   to supply the PSWA register.  For 64-bit inferior, PC maps straight
+   to PSWA.  For 31-bit, we additionally set the high bit to 1, since we
+   have to supply the whole register, and it's very unlikely the program
+   is in 24-bit addressing mode.  */
+
+static void
+s390_guess_tracepoint_registers (struct gdbarch *gdbarch,
+				 struct regcache *regcache,
+				 CORE_ADDR addr)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  int sz = register_size (gdbarch, S390_PSWA_REGNUM);
+  gdb_byte *reg = (gdb_byte *) alloca (sz);
+
+  /* 31-bit PSWA needs high bit set.  */
+  if (tdep->abi == ABI_LINUX_S390)
+    addr |= 0x80000000;
+
+  store_unsigned_integer (reg, sz, gdbarch_byte_order (gdbarch), addr);
+  regcache_raw_supply (regcache, S390_PSWA_REGNUM, reg);
+}
+
 
 /* DWARF Register Mapping.  */
 
@@ -7857,6 +7880,7 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 					    s390_iterate_over_regset_sections);
   set_gdbarch_cannot_store_register (gdbarch, s390_cannot_store_register);
   set_gdbarch_write_pc (gdbarch, s390_write_pc);
+  set_gdbarch_guess_tracepoint_registers (gdbarch, s390_guess_tracepoint_registers);
   set_gdbarch_pseudo_register_read (gdbarch, s390_pseudo_register_read);
   set_gdbarch_pseudo_register_write (gdbarch, s390_pseudo_register_write);
   set_tdesc_pseudo_register_name (gdbarch, s390_pseudo_register_name);
-- 
2.7.0