romlib: Allow patching of romlib functions

This change allows patching of functions in the
romlib. This can be done by adding "patch" at the
end of the jump table entry for the function that
needs to be patched in the file jmptbl.i.
Functions patched in the jump table list will be
built as part of the BL image and the romlib
version will not be used

Change-Id: Iefb200cb86e2a4b61ad3ee6180d3ecc39bad537f
Signed-off-by: Sathees Balya <sathees.balya@arm.com>

lib/romlib/genwrappers.sh

@@ -31,7 +31,7 @@ do
 done
 
 awk  '{sub(/[:blank:]*#.*/,"")}
-!/^$/ {print $1*4, $2, $3}' "$@" |
+!/^$/ && !/\\tpatch$/ {print $1*4, $2, $3}' "$@" |
 while read idx lib sym
 do
 	file=$build/${lib}_$sym

lib/romlib/jmptbl.i

@@ -3,6 +3,10 @@
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
+# Format:
+# index	lib	function	[patch]
+# Add "patch" at the end of the line to patch a function. For example:
+# 14	mbedtls	mbedtls_memory_buffer_alloc_init	patch
 
 0	rom	rom_lib_init
 1	fdt	fdt_getprop_namelen

make_helpers/build_macros.mk

@@ -338,7 +338,7 @@ LDPATHS = -L${LIB_DIR}
 LDLIBS += -l$(1)
 
 ifeq ($(USE_ROMLIB),1)
-LDLIBS := -lwrappers -lc
+LIBWRAPPER = -lwrappers
 endif
 
 all: ${LIB_DIR}/lib$(1).a
@@ -402,7 +402,7 @@ else
 endif
 	$$(Q)$$(LD) -o $$@ $$(TF_LDFLAGS) $$(LDFLAGS) -Map=$(MAPFILE) \
 		--script $(LINKERFILE) $(BUILD_DIR)/build_message.o \
-		$(OBJS) $(LDPATHS) $(LDLIBS) $(BL_LIBS)
+		$(OBJS) $(LDPATHS) $(LIBWRAPPER) $(LDLIBS) $(BL_LIBS)
 
 $(DUMP): $(ELF)
 	$${ECHO} "  OD      $$@"