gdb: PowerPC fix gdb.base/break-interp.exp

This patch fixes eight test failures on PowerPC for the test
gdb.base/break-interp.exp. The patch adds a funtion and registers it to
setup the displaced stepping for ppc-linux platform.  The patch moves the
struct ppc_inferior_data to the ppc-tdep.h include file to make it visible
to the ppc-linux-tdep.c and rs6000-tdep.c files.  Additionally the function
get_ppc_per_inferior is made external in ppc-tdep.h to make it visible in
both files.

Tested on Power 10 ppc64le-linux with no regressions.

3 files changed, 33 insertions, 9 deletions

diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index 6df2411..9e89542 100644
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -2014,6 +2014,23 @@ ppc64_linux_gcc_target_options (struct gdbarch *gdbarch)
   return "";
 }
 
+static displaced_step_prepare_status
+ppc_linux_displaced_step_prepare  (gdbarch *arch, thread_info *thread,
+				   CORE_ADDR &displaced_pc)
+{
+  ppc_inferior_data *per_inferior = get_ppc_per_inferior (thread->inf);
+  if (!per_inferior->disp_step_buf.has_value ())
+    {
+      /* Figure out where the displaced step buffer is.  */
+      CORE_ADDR disp_step_buf_addr
+	= linux_displaced_step_location (thread->inf->gdbarch);
+
+      per_inferior->disp_step_buf.emplace (disp_step_buf_addr);
+    }
+
+  return per_inferior->disp_step_buf->prepare (thread, displaced_pc);
+}
+
 static void
 ppc_linux_init_abi (struct gdbarch_info info,
 		    struct gdbarch *gdbarch)
@@ -2190,6 +2207,11 @@ ppc_linux_init_abi (struct gdbarch_info info,
 
   ppc_init_linux_record_tdep (&ppc_linux_record_tdep, 4);
   ppc_init_linux_record_tdep (&ppc64_linux_record_tdep, 8);
+
+  /* Setup displaced stepping.  */
+  set_gdbarch_displaced_step_prepare (gdbarch,
+				      ppc_linux_displaced_step_prepare);
+
 }
 
 void _initialize_ppc_linux_tdep ();
diff --git a/gdb/ppc-tdep.h b/gdb/ppc-tdep.h
index 6b305c4..cfd0aac 100644
--- a/gdb/ppc-tdep.h
+++ b/gdb/ppc-tdep.h
@@ -438,4 +438,14 @@ extern int ppc_process_record (struct gdbarch *gdbarch,
 /* Estimate for the maximum number of instructions in a function epilogue.  */
 #define PPC_MAX_EPILOGUE_INSTRUCTIONS  52
 
+struct ppc_inferior_data
+{
+  /* This is an optional in case we add more fields to ppc_inferior_data, we
+     don't want it instantiated as soon as we get the ppc_inferior_data for an
+     inferior.  */
+  gdb::optional<displaced_step_buffers> disp_step_buf;
+};
+
+extern ppc_inferior_data * get_ppc_per_inferior (inferior *inf);
+
 #endif /* ppc-tdep.h */
diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
index 0d61894..87a494e 100644
--- a/gdb/rs6000-tdep.c
+++ b/gdb/rs6000-tdep.c
@@ -155,19 +155,11 @@ static const char *powerpc_vector_abi_string = "auto";
 
 /* PowerPC-related per-inferior data.  */
 
-struct ppc_inferior_data
-{
-  /* This is an optional in case we add more fields to ppc_inferior_data, we
-     don't want it instantiated as soon as we get the ppc_inferior_data for an
-     inferior.  */
-  gdb::optional<displaced_step_buffers> disp_step_buf;
-};
-
 static inferior_key<ppc_inferior_data> ppc_inferior_data_key;
 
 /* Get the per-inferior PowerPC data for INF.  */
 
-static ppc_inferior_data *
+ppc_inferior_data *
 get_ppc_per_inferior (inferior *inf)
 {
   ppc_inferior_data *per_inf = ppc_inferior_data_key.get (inf);