Merge pull request #220 from mfld-fr/gnu

[kernel] Move to full GNU toolchain:
- Rewrite some assembly sources to ATT syntax
- Tune GCC options: small model, no relocations...
- Add LD scripts to output ELKS a.out
- Rework build scripts for full GNU
- Add RAW option for target image
- Warnings and glitches fixes
- Wipe out some BCC related stuff

README

@@ -1,20 +1,25 @@
                ELKS, the Embeddable Linux Kernel Subset
                ----------------------------------------
 
-This is a project to write a Linux-like operating system for ancient
-computers running an Intel 8086-compatible processor.
+This is a project to write a Linux-like operating system for systems based on
+the Intel IA16 architecture (16 bits processors: i8088, i8086, i80188, i80186,
+i80286, V20, V30 and compatibles).
 
-To build ELKS, you will need a cross build chain, mainly based on DEV86, and
-also on GCC-IA16 if you select that latest in place of BCC to build the kernel.
+Such systems are ancient computers (IBM-PC XT/AT and clones) or more recent
+embedded ones that reuse their huge hardware & software legacy.
+
+To build ELKS, you need a cross build chain, mainly based on DEV86 (still used
+for the user land) and GCC-IA16 (now used for the kernel).
 
 A script is provided to automatically download and build that cross chain:
 
   'tools/build.sh'
 
-Note: all the scripts must be executed with top folder 'elks/' as the current one.
+Note: all the scripts must be executed with the top folder 'elks/' as the
+current one.
 
-A script that attempts to automate the whole build process and make it easier
-for ELKS newbies has been provided:
+A script is provided to automate the whole build process (configuration,
+kernel, user land and target image) and make it easier for ELKS newbies:
 
   './build.sh'
 
@@ -29,29 +34,24 @@ The general build procedure for ELKS is as follows:
 
   '. tools/env.sh' (note the '.' before the script)
 
-* Configure the build chain, the kernel, the commands and select the target
-  image format (the default configuration is for an IBM PC/XT/AT):
+* Configure the build chain, the kernel, the user land and the target image
+  format:
 
   'make menuconfig'
 
-* Build the kernel and the commands:
+* Build the kernel, the user land and the target image:
 
   'make all'
 
-* Build the target image as a user with the 'sudoer' privilege:
-
-  'cd elkscmd'
-  'make image'
-
 The target root folder is built in 'target/', and depending on your
 configuration, that folder is packed as either a floppy disk image (fd1440,
 fd1680, fd1200, fd720, fd360, without MBR), a hard-disk image (hd, with MBR),
 or a file image (rom, tar), into the '/image' folder.
 
-Before writting the image on the real device, you can test it first on QEMU with
-'./qemu.sh' (will configure QEMU to be close as possible to an ISA system).
+Before writting the image on the real device, you can test it first on QEMU
+with './qemu.sh' (will configure QEMU for an ISA system).
 
 Questions? Problems? Patches? Open an issue in this project! You can also join
-and email the 'Linux-8086' mailing list at [email protected]. 
+and email the 'Linux-8086' list at [email protected].
 
 More information in the Documentation folder: Documentation/index.html

elks/Makefile-rules

@@ -115,42 +115,26 @@ DISTDIR 	= $(shell $(BASEDIR)/scripts/setdir $(TOPDIR)/elks-$(DIST)/$(MYDIR))
 #########################################################################
 # Specify the standard definitions to be given to system programs.
 
-ifdef USEIA16
-CCDEFS_IA16= -DUSE_IA16
-else
-CCDEFS_IA16=
-endif
-
 CCDEFS		= -DELKS_VERSION_CODE=$(VSNCODE)		\
 		  -DUTS_RELEASE=\"$(DIST)\"			\
-		  -D__KERNEL__ $(CCDEFS_IA16)
+		  -D__KERNEL__ -DUSE_IA16
 
 #########################################################################
 # Set the target environment and the compiler to use.
 
 ifeq ($(wildcard $(TOPDIR)/.config),)
     MK_ARCH	= ibmpc
     MK_CPU	= 8086
-    MK_CC	= bcc
 else
     MK_ARCH	= $(shell grep '^CONFIG_ARCH_' $(TOPDIR)/.config \
 			| cut -d = -f 1 | cut -d _ -f 3- | tr A-Z a-z)
     MK_CPU	= $(shell grep '^CONFIG_CPU_' $(TOPDIR)/.config \
 			| cut -d = -f 1 | cut -d _ -f 3- | tr A-Z a-z)
-    MK_CCN	= $(shell grep '^CONFIG_COMPILER_' $(TOPDIR)/.config \
-			| cut -d = -f 1 | cut -d _ -f 3- )
-ifeq ($(MK_CCN), 1)
-    MK_CC	= bcc
-else
-ifeq ($(MK_CCN), 2)
-    MK_CC	= ia16-elf-gcc
-else
-    MK_CC	= ia16-unknown-elks-gcc
-endif
-    USEIA16	= y
-endif
 endif
 
+CROSS_CC = ia16-elf-gcc
+CROSS_CFLAGS = -fno-inline -mcmodel=small -mno-segment-relocation-stuff -ffreestanding
+
 #########################################################################
 # Define architecture-specific flags.
 
@@ -170,39 +154,21 @@ endif
 # Define CPU-specific flags.
 
 ifeq ($(MK_CPU), 8086)
-ifeq ($(USEIA16), y)
-    CPU_AS	= -0 -O
-    CPU_CC	= -mtune=i8086 -fno-inline -fdata-sections -ffunction-sections -fleading-underscore -mseparate-code-segment -Wl,--gc-sections
-    CPU_LD	= -0
-else
-    CPU_AS	= -0 -O
-    CPU_CC	= -0
-    CPU_LD	= -0
-endif
+    CPU_AS	= -mtune=i8086
+    CPU_CC	= -mtune=i8086
+    CPU_LD	=
 endif
 
 ifeq ($(MK_CPU), 80186)
-ifeq ($(USEIA16), y)
-    CPU_AS	= -1 -O
-    CPU_CC	= -mtune=i80186 -fno-inline -fdata-sections -ffunction-sections -fleading-underscore -mseparate-code-segment -Wl,--gc-sections
-    CPU_LD	= -0
-else
-    CPU_AS	= -1 -O
-    CPU_CC	= -0
-    CPU_LD	= -0
-endif
+    CPU_AS	= -mtune=i18086
+    CPU_CC	= -mtune=i80186
+    CPU_LD	=
 endif
 
 ifeq ($(MK_CPU), 80286)
-ifeq ($(USEIA16), y)
-    CPU_AS	= -2 -O
-    CPU_CC	= -mtune=i80286 -fno-inline -fdata-sections -ffunction-sections -fleading-underscore -mseparate-code-segment -Wl,--gc-sections
-    CPU_LD	= -0
-else
-    CPU_AS	= -2 -O
-    CPU_CC	= -0
-    CPU_LD	= -0
-endif
+    CPU_AS	= -mtune=i80286
+    CPU_CC	= -mtune=i80286
+    CPU_LD	=
 endif
 
 #########################################################################
@@ -216,7 +182,6 @@ endif
 ################################
 # Common definitions
 
-AR		= ar
 CC_PROTO	= gcc $(INCLUDES) -M -MG $(CCDEFS)
 CFLBASE 	= $(INCLUDES) $(CCDEFS)
 CPP		= $(CC) $(INCLUDES) -E $(CCDEFS) -ansi
@@ -229,41 +194,29 @@ LHFLAGS 	= $(LCFLAGS) -exportfcn -declundef -fcnuse -fielduse \
 
 ifneq ($(USEBCC), N)
 
-ifeq ($(USEIA16), y)
 ################################
 # Definitions using ia16-unknown-elks-gcc compiler
 
-AS		= as86
-ASFLAGS 	= $(CPU_AS) $(ARCH_AS)
-CC		= $(MK_CC)
-CFLAGS		= $(CPU_CC) $(ARCH_CC) -Os $(CFLBASE) -Wall
-LD		= ld86
-LDFLAGS 	= $(CPU_LD) -s
-
-else
-################################
-# Definitions using BCC compiler
-
-AS		= as86
-ASFLAGS 	= $(CPU_AS) $(ARCH_AS)
-CC		= bcc
-CFLAGS		= $(CPU_CC) $(ARCH_CC) -O $(CFLBASE) -ansi
-LD		= ld86
-LDFLAGS 	= $(CPU_LD) -s
-
-endif
+AS      = ia16-elf-as
+ASFLAGS = $(CPU_AS) $(ARCH_AS)
+CC      = $(CROSS_CC) -Os
+CFLAGS  = $(CROSS_CFLAGS) $(CPU_CC) $(ARCH_CC) $(CFLBASE) -Wall
+LD      = ia16-elf-ld
+LDFLAGS = $(CPU_LD) -s
+AR      = ia16-elf-ar
 
 else
 
 ################################
-# Definitions using GCC compiler
+# Definitions using GCC host compiler
 
 AS      = as
 ASFLAGS =
 CC      = gcc
 CFLAGS  = -Wall $(CFLBASE)
 LD      = ld
 LDFLAGS =
+AR      = ar
 
 endif
 
@@ -279,18 +232,8 @@ endif
 	$(AS) $(ASFLAGS) -o $*.o $<
 
 ifneq ($(USEBCC), N)
-ifeq ($(USEIA16), y)
-.c.o:
-	$(CC) $(CFLAGS) -S -o $*.s $<
-	att2as86 < $*.s > $*.asm
-	$(AS) $(ASFLAGS) -u -o $*.o $*.asm
-	rm $*.s $*.asm
-
-else
 .c.o:
 	$(CC) $(CFLAGS) -c -o $*.o $<
-
-endif
 endif
 
 #########################################################################

elks/arch/i86/Makefile

@@ -39,8 +39,6 @@ SIBOFLAGS	=
 
 endif
 
-LDFLAGS 	= -0 -i $(SIBOFLAGS)
-
 #########################################################################
 # Objects to be compiled.
 
@@ -62,62 +60,42 @@ XINCLUDE = $(BASEDIR)/include/arch/asm-offsets.h
 #########################################################################
 # Things to make.
 
-.PHONY: 		boot/system toolkit
-
-boot/bootsect:		boot/bootsect.o
-	$(LD) -0 -M $(ARCH_LD) -s -o boot/bootsect boot/bootsect.o > boot/bootsect.map
-
-boot/bootsect.o:	boot/bootsect.s
+.PHONY: toolkit
 
-boot/crt0.o:		boot/crt0.s
-
-boot/crt1.o:		boot/crt1.c
+boot/bootsect.o: boot/bootsect.S
+boot/bootsect.o: boot/bootsect.s
+boot/bootsect:   boot/bootsect.o
+	$(LD) $(LDFLAGS) $(SIBOFLAGS) -M -T $(TOPDIR)/elks/elks-tiny.ld -o boot/bootsect boot/bootsect.o > boot/bootsect.map
 
 boot/netbootsect:	boot/netbootsect.o
-	$(LD) $(LDFLAGS) -M $(ARCH_LD) -s -o boot/netbootsect boot/netbootsect.o > boot/netbootsect.map
+	$(LD) $(LDFLAGS) $(SIBOFLAGS) -M $(ARCH_LD) -s -o boot/netbootsect boot/netbootsect.o > boot/netbootsect.map
 
 boot/netbootsect.o:	boot/netbootsect.s
 
-boot/setup:		boot/setup.o
-	$(LD) -0 -M $(ARCH_LD) -s -o boot/setup boot/setup.o > boot/setup.tmp
-	sort -k3,4 boot/setup.tmp > boot/setup.map
-	rm -f boot/setup.tmp
+boot/setup.s: boot/setup.S
+boot/setup.o: boot/setup.s
+boot/setup:   boot/setup.o
+	$(LD) $(LDFLAGS) $(SIBOFLAGS) -M -T $(TOPDIR)/elks/elks-tiny.ld -o boot/setup boot/setup.o > boot/setup.map
 
-boot/setup.o:		boot/setup.s
+boot/crt0.s:		boot/crt0.S
+boot/crt0.o:		boot/crt0.s
+
+boot/crt1.o:		boot/crt1.c
 
 toolkit:
 	${MAKE} -C tools all
 
-ifeq ($(USEIA16), y)
 $(BASEDIR)/include/arch/asm-offsets.h: kernel/asm-offsets.c
 	echo '#ifndef ASM_OFFSETS_H' > $(BASEDIR)/include/arch/asm-offsets.h
 	echo '#define ASM_OFFSETS_H' >> $(BASEDIR)/include/arch/asm-offsets.h
 	$(CC) $(CFLAGS) -S -o asm-offsets.s kernel/asm-offsets.c
 	sed -e '/^\tm/ !d' \
 	-e "s/\(.*\t\\$$\)/\#define /" \
-	-e "s/\([0-9][0-9]*\),\t_\([a-zA-Z][_0-9a-zA-Z]*\)/\2 \1/" \
+	-e "s/\([0-9][0-9]*\),\t\([a-zA-Z][_0-9a-zA-Z]*\)/\2 \1/" \
 	< asm-offsets.s >> $(BASEDIR)/include/arch/asm-offsets.h
 	echo '#endif' >> $(BASEDIR)/include/arch/asm-offsets.h
 	rm asm-offsets.s
 
-else
-$(BASEDIR)/include/arch/asm-offsets.h: kernel/asm-offsets.c
-	echo '#ifndef ASM_OFFSETS_H' > $(BASEDIR)/include/arch/asm-offsets.h
-	echo '#define ASM_OFFSETS_H' >> $(BASEDIR)/include/arch/asm-offsets.h
-	$(CC) $(CFLAGS) -S -o asm-offsets.s kernel/asm-offsets.c
-	sed -e '/^[^m].*/ d' \
-	-e 's/\],/  /' \
-	-e 's/ #/ /' \
-	-e 's/ \*/ /' \
-	-e 's/ \$$/0x/' \
-	-e 's/^.*\[_/#define /' \
-	-e 's/ax/0/' \
-	< asm-offsets.s | grep -e define >> $(BASEDIR)/include/arch/asm-offsets.h
-	echo '#endif' >> $(BASEDIR)/include/arch/asm-offsets.h
-	rm asm-offsets.s
-
-endif
-
 #########################################################################
 # Image selection.
 
@@ -126,7 +104,7 @@ ifeq ($(CONFIG_ARCH_SIBO), y)
 # Begin SIBO image build
 
 boot/system: $(XINCLUDE) $(AARCHIVES) $(ADRIVERS) sibo/crt1.o sibo/crt0.o
-	(cd $(BASEDIR) ; $(LD) $(LDFLAGS) -t -M $(ARCH_LD) \
+	(cd $(BASEDIR) ; $(LD) $(LDFLAGS) $(SIBOFLAGS) -M $(ARCH_LD) \
 		$(ARCH_DIR)/sibo/crt0.o $(ARCH_DIR)/sibo/crt1.o \
 		init/main.o $(ARCHIVES) $(DRIVERS) \
 		-o $(ARCH_DIR)/boot/system > $(ARCH_DIR)/boot/system.tmp ; \
@@ -143,12 +121,12 @@ else
 # Begin PC image build
 
 boot/system:	$(XINCLUDE) $(AARCHIVES) $(ADRIVERS) boot/crt1.o boot/crt0.o
-	(cd $(BASEDIR) ; $(LD) $(LDFLAGS) -t -M $(ARCH_LD) \
+	(cd $(BASEDIR) ; $(LD) $(LDFLAGS) -M $(ARCH_LD) -T $(TOPDIR)/elks/elks-small.ld \
 		$(ARCH_DIR)/boot/crt0.o $(ARCH_DIR)/boot/crt1.o \
-		init/main.o $(ARCHIVES) $(DRIVERS) \
-		-o $(ARCH_DIR)/boot/system > $(ARCH_DIR)/boot/system.tmp ; \
-		sort -k3,4 $(ARCH_DIR)/boot/system.tmp > $(ARCH_DIR)/boot/system.map ; \
-		rm -f $(ARCH_DIR)/boot/system.tmp )
+		init/main.o '-(' $(ARCHIVES) $(DRIVERS) '-)' \
+		-o $(ARCH_DIR)/boot/system > $(ARCH_DIR)/boot/system.map)
+#		sort -k3,4 $(ARCH_DIR)/boot/system.tmp > $(ARCH_DIR)/boot/system.map ; \
+#		rm -f $(ARCH_DIR)/boot/system.tmp )
 
 ifneq ($(CONFIG_ROMCODE), y)