cc: introduce helpers to access pt_regs in an arch-independent manner

Convert some of the examples and tools to use the new helpers.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
diff --git a/tools/trace.py b/tools/trace.py
index 62d3143..9840233 100755
--- a/tools/trace.py
+++ b/tools/trace.py
@@ -202,13 +202,13 @@
                                 self.values.append(part)
 
         aliases = {
-                "retval": "ctx->ax",
-                "arg1": "ctx->di",
-                "arg2": "ctx->si",
-                "arg3": "ctx->dx",
-                "arg4": "ctx->cx",
-                "arg5": "ctx->r8",
-                "arg6": "ctx->r9",
+                "retval": "PT_REGS_RC(ctx)",
+                "arg1": "PT_REGS_PARM1(ctx)",
+                "arg2": "PT_REGS_PARM2(ctx)",
+                "arg3": "PT_REGS_PARM3(ctx)",
+                "arg4": "PT_REGS_PARM4(ctx)",
+                "arg5": "PT_REGS_PARM5(ctx)",
+                "arg6": "PT_REGS_PARM6(ctx)",
                 "$uid": "(unsigned)(bpf_get_current_uid_gid() & 0xffffffff)",
                 "$gid": "(unsigned)(bpf_get_current_uid_gid() >> 32)",
                 "$pid": "(unsigned)(bpf_get_current_pid_tgid() & 0xffffffff)",