Implemented support for building host binaries to test kernel features

Makefile

@@ -60,9 +60,10 @@ $(BUILD_DIR)/%.o: %.c
 	@$(CC) $< -o $@ -c $(CFLAGS) $(ARCH_CFLAGS)
 
 clean:
-	@printf "    \033[1;93mRM\033[0m     Deleting build artefacts.\n"
+	@printf "    \033[1;93mRM\033[0m     Deleting kernel build artefacts.\n"
 	@rm -rf $(BUILD_DIR)
 
+	@$(MAKE) -C sandbox clean
 
 all: $(BUILD_DIR)/$(KERNEL_EXEC)
 
@@ -73,10 +74,13 @@ $(BUILD_DIR)/compile_commands.json:
 
 	@./tools/make/generate_compile_commands.py
 
+sandbox:
+	@$(MAKE) -C sandbox
+
 compile-db: $(BUILD_DIR)/compile_commands.json
 
 include arch/$(ARCH)/extra.mk
 
-.PHONY: all compile-db
+.PHONY: all compile-db sandbox
 
 .INTERMEDIATE: $(ARCH_TEMP_FILES)

sandbox/Makefile

@@ -0,0 +1,13 @@
+SANDBOX_DIR_LIST := hello
+
+all:
+	@for prog in $(SANDBOX_DIR_LIST); do \
+		$(MAKE) -C $$prog; \
+	done
+
+clean:
+	@for prog in $(SANDBOX_DIR_LIST); do \
+		$(MAKE) -C $$prog clean; \
+	done
+
+.PHONY: all clean

sandbox/hello/Makefile

@@ -0,0 +1,4 @@
+SANDBOX_PROG_NAME := hello
+
+include ../sandbox-config.mk
+include ../sandbox-template.mk

sandbox/hello/main.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main(int argc, const char **argv)
+{
+	printf("Hello, world\n");
+	return 0;
+}

sandbox/sandbox-config.mk

@@ -0,0 +1,8 @@
+
+MAKEFILE_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
+SANDBOX_DIR := $(patsubst %/,%,$(dir $(MAKEFILE_PATH)))
+
+include $(SANDBOX_DIR)/../tools/make/gcc-host.mk
+
+SANDBOX_BUILD_DIR := $(SANDBOX_DIR)/../build/sandbox
+BUILD_DIR := $(SANDBOX_BUILD_DIR)/$(SANDBOX_PROG_NAME)

sandbox/sandbox-template.mk

@@ -0,0 +1,22 @@
+BUILD_DIR := $(SANDBOX_BUILD_DIR)/$(SANDBOX_PROG_NAME)
+
+SRC := $(wildcard *.c)
+OBJ := $(addprefix $(BUILD_DIR)/,$(SRC:.c=.o))
+
+$(BUILD_DIR)/$(SANDBOX_PROG_NAME): $(OBJ)
+	@mkdir -p $(@D)
+
+	@printf "    \033[1;36mHOSTLD\033[0m \033[1msandbox/$(SANDBOX_PROG_NAME)\033[0m\n"
+	@$(CC) $< -o $@ $(CFLAGS) $(LDFLAGS)
+
+$(BUILD_DIR)/%.o: %.c
+	@printf "    \033[1;32mHOSTCC\033[0m $(SANDBOX_PROG_NAME)/$^\n"
+	@mkdir -p $(@D)
+
+	@$(CC) $< -o $@ -c $(CFLAGS)
+
+all: $(SANDBOX_PROG_NAME)
+
+clean:
+	@printf "    \033[1;93mRM\033[0m     Deleting sandbox/$(SANDBOX_PROG_NAME)\n"
+	@rm -rf $(BUILD_DIR)

tools/make/gcc-host.mk

@@ -0,0 +1,7 @@
+LD  := gcc
+CC  := gcc
+ASM := gcc
+
+CFLAGS   := -Wall -Werror -pedantic
+ASMFLAGS := $(CFLAGS)
+LDFLAGS  := -O2