alif: Link with libnosys.

This allows the correct start up functions to be called by the stdlib.

Signed-off-by: iabdalkader <i.abdalkader@gmail.com>

ports/alif/alif.mk

@@ -68,9 +68,9 @@ CFLAGS += $(INC) \
           -mtune=cortex-m55 \
           $(CFLAGS_FPU) \
           -march=armv8.1-m.main+fp+mve.fp \
-          -nostdlib \
           -fdata-sections \
           -ffunction-sections \
+          --specs=nosys.specs \
           -D$(MCU_CORE)=1 \
           -DCORE_$(MCU_CORE) \
           -DALIF_CMSIS_H="\"$(MCU_CORE).h\""
@@ -95,17 +95,16 @@ CFLAGS += $(CFLAGS_EXTRA)
 
 AFLAGS = -mthumb -march=armv8.1-m.main+fp+mve.fp $(CFLAGS_FPU)
 
-LDFLAGS += -nostdlib \
-           -T$(BUILD)/ensemble.ld \
-           -Map=$@.map \
-           --cref \
-           --gc-sections \
-           --print-memory-usage
-ifeq ($(MCU_CORE),M55_HP)
-LDFLAGS += --wrap=dcd_event_handler
-endif
+CFLAGS += -Wl,-T$(BUILD)/ensemble.ld \
+          -Wl,-Map=$@.map \
+          -Wl,--cref \
+          -Wl,--gc-sections \
+          -Wl,--print-memory-usage \
+          -Wl,--no-warn-rwx-segment
 
-LIBS += "$(shell $(CC) $(CFLAGS) -print-libgcc-file-name)"
+ifeq ($(MCU_CORE),M55_HP)
+CFLAGS += -Wl,--wrap=dcd_event_handler
+endif
 
 ################################################################################
 # Source files and libraries
@@ -126,6 +125,7 @@ SRC_C = \
 	mpu.c \
 	mpuart.c \
 	msc_disk.c \
+	nosys_stubs.c \
 	ospi_ext.c \
 	ospi_flash.c \
 	pendsv.c \
@@ -256,7 +256,7 @@ $(BUILD)/ensemble.ld: $(LD_FILE)
 
 $(BUILD)/firmware.elf: $(OBJ) $(BUILD)/ensemble.ld
 	$(ECHO) "Link $@"
-	$(Q)$(LD) $(LDFLAGS) -o $@ $(OBJ) $(LIBS)
+	$(Q)$(CC) $(CFLAGS) -o $@ $(OBJ) $(LIBS)
 	$(Q)$(SIZE) $@
 
 $(BUILD)/firmware.bin: $(BUILD)/firmware.elf

ports/alif/main.c

@@ -55,7 +55,7 @@ NORETURN void panic(const char *msg) {
     }
 }
 
-void _start(void) {
+int main(void) {
     system_tick_init();
 
     MICROPY_BOARD_STARTUP();

ports/alif/nosys_stubs.c

@@ -0,0 +1,46 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2024 OpenMV LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include <errno.h>
+
+int _write(int handle, char *buffer, int size) {
+    errno = ENOSYS;
+    return -1;
+}
+
+int _read(int handle, char *buffer, int size) {
+    errno = ENOSYS;
+    return -1;
+}
+
+int _close(int f) {
+    errno = ENOSYS;
+    return -1;
+}
+
+int _lseek(int f, int ptr, int dir) {
+    errno = ENOSYS;
+    return -1;
+}