dtrace: ensure SDT probe processing can handle symbols with same names

The process used to determine SDT probe information on arm64 broke due
to multiple occurences of the same symbol (global and local, or multiple
local symbols).  The logic to determine a correct matching of symbols
between the linked kernel image (.tmp_vmlinux1) and the kernel object
(vmlinux.o) has been updated to account for this possibility.

Orabug: 29134607
Signed-off-by: Kris Van Hees <[email protected]>
Reviewed-by: Nick Alcock <[email protected]>

Author: kvanhees

scripts/dtrace_sdt_arm64.sh

@@ -54,12 +54,12 @@ fi
 #	<section> <address> B <name>
 #	    Named identifier at a specific address (global variable).
 #
-# We also process any function symbols, and build a lookup map with varying
-# levels of detail to assist in symbol lookup later on (each map entry stores
-# the symbol offset relative to its section):
-#	section, name, and offset
+# We also process any function symbols, and build a lookup map for section-name
+# pairs and just name.  Due to the possibility of having symbols with identical
+# names (in the same section, e.g. global and/or one or more local), we append
+# -<n> to every 2nd and later copy of the same symbol name in the current
+# section.
 #	section and name
-#	name and offset
 #	name
 # (If multiple symbols map to any of the above combinations, that specific
 #  combination is omitted from the mapping.)
@@ -68,7 +68,7 @@ fi
 # is not located in a section that starts with .exit.text, .init.text, or
 # .meminit.text) we determine its in-section offset and output a record:
 #
-#	<section> <offset> F <name> <address>
+#	<section> <offset> F <name> <address> <section-base-address>
 #	    Named function at a specific address.
 #
 # Finally, each relocation record from a non-init or exit section that relates
@@ -103,7 +103,7 @@ fi
 		     if (v0h >= v1h) {
 			 d = sprintf("%08x%08x", v0h - v1h, v0l - v1l);
 		     } else {
-			 printf "ERROR: Invalid addresses: %s vs %s\n", v0, v1;
+			 printf "ERROR: [1.a] Invalid: %s - %s\n", v0, v1;
 			 d = 0;
 			 errc++;
 		     }
@@ -113,7 +113,7 @@ fi
 			 v0l += 4294967296;
 			 d = sprintf("%08x%08x", v0h - v1h, v0l - v1l);
 		     } else {
-			 printf "ERROR: Invalid addresses: %s vs %s\n", v0, v1;
+			 printf "ERROR: [1.b] Invalid: %s - %s\n", v0, v1;
 			 d = 0;
 			 errc++;
 		     }
@@ -134,6 +134,7 @@ fi
 
 	 /^SYMBOL / {
 	     phase++;
+	     delete scnt;
 	     next;
 	 }
 
@@ -157,28 +158,22 @@ fi
 		 next;
 
 	     off = subl($1, secs[$4]);
-	     id = $4 " " $6 " " off;
-	     if (id in smap) {
-		 if (smap[id] != $1)
-		     smap[id] = 0;
-	     } else
-		 smap[id] = $1;
 
-	     id = $4 " " $6;
-	     if (id in smap) {
-		 if (smap[id] != $1)
-		     smap[id] = 0;
-	     } else
-		 smap[id] = $1;
+	     sym = $NF;
+	     scnt[sym]++;
+	     if (scnt[sym] > 1)
+		 sym = sym"-"(scnt[sym] - 1);
 
-	     id = $6 " " off;
+	     # section and name
+	     id = $4 " " sym;
 	     if (id in smap) {
 		 if (smap[id] != $1)
 		     smap[id] = 0;
 	     } else
 		 smap[id] = $1;
 
-	     id = $6;
+	     # name
+	     id = sym;
 	     if (id in smap) {
 		 if (smap[id] != $1)
 		     smap[id] = 0;
@@ -192,19 +187,22 @@ fi
 	     if ($4 ~ /^\.(exit|init|meminit)\.text/)
 		 next;
 
-	     id = $4 " " $6 " " $1;
-	     if (!(id in smap))
-		 id = $4 " " $6;
-	     if (!(id in smap))
-		 id = $6 " " $1;
+	     sym = $NF;
+	     scnt[sym]++;
+	     if (scnt[sym] > 1)
+		 sym = sym"-"(scnt[sym] - 1);
+
+	     # section and name
+	     id = $4 " " sym;
 	     if (!(id in smap))
-		 id = $6;
+		 id = sym;
+	     # name
 	     if (id in smap) {
 		 addr = smap[id];
 		 if (!addr)
-		     print "ERROR: Non-unique symbol: " $4 " " $6 " " $1;
+		     print "ERROR: Not unique: " $4 " " $6 " " $1 " ["sym"]";
 	     } else {
-		 print "ERROR: Could not find " $4 " " $6 " " $1;
+		 print "ERROR: Not found " $4 " " $6 " " $1 " ["sym"]";
 		 addr = 0;
 	     }
 
@@ -256,7 +254,7 @@ fi
 		 if (length(d) <= 8) {
 		     d = sprintf("%08x%08x", v0h, v0l);
 		 } else {
-		     printf "#error Invalid addresses: %s + %s\n", v0, v1 \
+		     printf "#error [2.a] Invalid: %s + %s\n", v0, v1 \
 			    >"/dev/stderr";
 		     errc++;
 		 }
@@ -284,7 +282,7 @@ fi
 		     if (v0h >= v1h) {
 			 d = sprintf("%08x%08x", v0h - v1h, v0l - v1l);
 		     } else {
-			 printf "#error Invalid addresses: %s - %s\n", v0, v1 \
+			 printf "#error [2.b] Invalid: %s - %s\n", v0, v1 \
 				>"/dev/stderr";
 			 errc++;
 		     }
@@ -294,7 +292,7 @@ fi
 			 v0l += 4294967296;
 			 d = sprintf("%08x%08x", v0h - v1h, v0l - v1l);
 		     } else {
-			 printf "#error Invalid addresses: %s - %s\n", v0, v1 \
+			 printf "#error [2.c] Invalid: %s - %s\n", v0, v1 \
 				>"/dev/stderr";
 			 errc++;
 		     }