truss: Decode correctly 64bits arguments on 32bits arm.

When decoding 32bits arm syscall, make sure we account for the padding when
decoding 64bits args. Do it too when using a 64bits truss on a 32bits binary.

MFC After:	1 week
PR:		256199

usr.bin/truss/syscalls.c

@@ -792,11 +792,14 @@ print_mask_arg32(bool (*decoder)(FILE *, uint32_t, uint32_t *), FILE *fp,
  * decoding arguments.
  */
 static void
-quad_fixup(struct syscall_decode *sc)
+quad_fixup(struct procabi *abi, struct syscall_decode *sc)
 {
 	int offset, prev;
 	u_int i;
 
+#ifndef __aarch64__
+	(void)abi;
+#endif
 	offset = 0;
 	prev = -1;
 	for (i = 0; i < sc->nargs; i++) {
@@ -810,17 +813,20 @@ quad_fixup(struct syscall_decode *sc)
 		switch (sc->args[i].type & ARG_MASK) {
 		case Quad:
 		case QuadHex:
-#ifdef __powerpc__
+#if defined(__powerpc__) || defined(__arm__) || defined(__aarch64__)
 			/*
-			 * 64-bit arguments on 32-bit powerpc must be
+			 * 64-bit arguments on 32-bit powerpc and arm must be
 			 * 64-bit aligned.  If the current offset is
 			 * not aligned, the calling convention inserts
 			 * a 32-bit pad argument that should be skipped.
 			 */
-			if (sc->args[i].offset % 2 == 1) {
-				sc->args[i].offset++;
-				offset++;
-			}
+#ifdef __aarch64__
+			if (abi->pointer_size == sizeof(uint32_t))
+#endif
+				if (sc->args[i].offset % 2 == 1) {
+					sc->args[i].offset++;
+					offset++;
+				}
 #endif
 			offset++;
 		default:
@@ -854,7 +860,7 @@ add_syscall(struct procabi *abi, u_int number, struct syscall *sc)
 	 *  procabi instead.
 	 */
 	if (abi->pointer_size == 4)
-		quad_fixup(&sc->decode);
+		quad_fixup(abi, &sc->decode);
 
 	if (number < nitems(abi->syscalls)) {
 		assert(abi->syscalls[number] == NULL);