Re: kernelversion distinction
From: Axel Weiss
Date: Mon Apr 12 2004 - 10:04:33 EST
Am Montag, 12. April 2004 15:20 schrieb sam@xxxxxxxxxxxx:
> Date: Man, 12 Apr 2004 12:21:44 +0200 skrev Axel Weiss <aweiss@xxxxxxxxxxxxxxxxxxxxxxx> :
> Why you cannot use the same Makefile for 2.4 and 2.6?
On SuSE-9.0 the build simply fails:
rantanplan:/home/axel/freeSP-1.0.3 # make -C drivers/linux/harmonie/
make: Entering directory `/home/axel/freeSP-1.0.3/drivers/linux/harmonie'
make -C driver all
make[1]: Entering directory `/home/axel/freeSP-1.0.3/drivers/linux/harmonie/driver'
make -C /lib/modules/2.4.21-199-axel/build SUBDIRS=/home/axel/freeSP-1.0.3/drivers/linux/harmonie/driver modules
make[2]: Entering directory `/usr/src/linux-2.4.21-199'
make -C /home/axel/freeSP-1.0.3/drivers/linux/harmonie/driver CFLAGS="-D__KERNEL__ -I/usr/src/linux-2.4.21-199/include -Wall -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer -fno-unit-at-a-time -pipe -msoft-float -mpreferred-stack-boundary=2 -march=athlon -DMODULE" MAKING_MODULES=1 modules
make[3]: Entering directory `/home/axel/freeSP-1.0.3/drivers/linux/harmonie/driver'
make[3]: *** Keine Regel, um »modules« zu erstellen. Schluss.
make[3]: Leaving directory `/home/axel/freeSP-1.0.3/drivers/linux/harmonie/driver'
make[2]: *** [_mod_/home/axel/freeSP-1.0.3/drivers/linux/harmonie/driver] Fehler 2
make[2]: Leaving directory `/usr/src/linux-2.4.21-199'
make[1]: *** [all] Fehler 2
make[1]: Leaving directory `/home/axel/freeSP-1.0.3/drivers/linux/harmonie/driver'
make: *** [module] Fehler 2
make: Leaving directory `/home/axel/freeSP-1.0.3/drivers/linux/harmonie'
>
> A simple Makefile like you outline:
> >EXTRA_CFLAGS := -I/usr/include
> >obj-m += <my_module>.o
> ><my_module>-objs = <my module object files>
>
> Will work flawlessly with both 2.4 and 2.6.
> I know people for a long time have hardcoded the gcc commandline
> to build modules for 2.4 - but thats just wrong.
> In this way you do not catch differences in gcc options.
> For 2.4 we have seen only few of these config related flags to gcc,
> in 2.6 we have a lot.
>
> Please next time post the full Makefile.
(see eom)
>
> Btw, a module that is dependent on /usr/include looks wrong...
This is because I include the ioctl-definitions, and I put them to /usr/include/dsp, so the kernel module and user-space-lib see the identical file.
Perhaps it would be better to include the local source (in this case ../system_include), I will think over it.
> >clean:
> > rm -f *.o *.ko .*.cmd <my_module>.mod.c
>
> For the new external module support implemented in -mc4 you
> do not have to hardcode the clean: target, and no attempts will
> be made to update the kernel stuff.
> Documentation soon to arrive...
Do you think, it would be better to write
clean:
$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) clean
?
There are still some inconsistencies, especially when I try to compile a second module. I will investigate this tonight and post cognitions here.
The next problem arises when I have to ditinguish the kernel version within C source. For now I do it like this:
// fw-declaration of /proc-read functions:
#ifdef LINUX_VERSION_CODE
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 4, 18)
int harmonie_read_proc(char *buf, char **start, off_t offset, int len, int unused);
#else // 2.4.19 ... < 2.5
int harmonie_read_proc(char *buf, char **start, off_t offset, int cnt, int *eof, void *data);
#endif
#else // >= 2.5
int harmonie_read_proc(char *buf, char **start, off_t offset, int cnt, int *eof, void *data);
#endif
This looks really ugly, so what is the recommended way to get kernel version information? As the interface for ISRs has changed, too, there is a need for getting kernel version at compile time.
For now, I have a running module for 2.2 - 2.6 :)
Now the complete Makefile:
# ***************************************************************************
# makefile - description
#
# This is the harmonie device driver makefile.
#
# -------------------
# begin : Wed May 29 2002
# copyright : (C) 2002 by Axel Weiss
# email : aweiss@xxxxxxxxxxxxxxxxxxxxxxx
# ***************************************************************************/
#
# ***************************************************************************
# * *
# * This program is free software; you can redistribute it and/or modify *
# * it under the terms of the GNU General Public License as published by *
# * the Free Software Foundation; either version 2 of the License, or *
# * (at your option) any later version. *
# * *
# ***************************************************************************/
KERNELVERSION := $(shell uname -r)
KERNELBASE := $(basename $(KERNELVERSION))
KERNELMINOR := $(suffix $(KERNELBASE))
KERNELMAJOR := $(basename $(KERNELBASE))
OLD_MODULES := $(strip $(foreach V, .0 .1 .2 .3 .4, $(shell [ "$(V)" = "$(KERNELMINOR)" ] && echo yes)))
ifeq ($(KERNELMAJOR),2)
ifeq ($(OLD_MODULES),yes) # old style make
DEBUG := yes
CC := gcc
SOURCES := $(wildcard *.c)
HEADERS := $(wildcard *.h)
OBJS := $(SOURCES:%.c=%.o)
CC_FLAGS := -c -Wall -I/lib/modules/`uname -r`/build/include -DMODULE -D__KERNEL__
ifeq ($(DEBUG),yes)
CC_FLAGS += -DHARMONIE_DEBUG
endif
all: harmonie.o
harmonie.o: $(OBJS)
$(LD) -r -o $@ $(OBJS)
$(OBJS): %.o:%.c
$(CC) $(CC_FLAGS) $<
$(OBJS): $(HEADERS) $(SYSTEM_HEADERS_INSTALL)
clean:
@rm -f $(OBJS) *% *.bak harmonie.o
else #ifeq ($(OLD_MODULES),yes) new style make
ifneq ($(KERNELRELEASE),)
EXTRA_CFLAGS := -I/usr/include
obj-m += harmonie.o
harmonie-objs = harmonie_buffer.o harmonie_device.o harmonie_module.o harmonie_procio.o harmonie_io.o
else #ifneq ($(KERNELRELEASE),)
KDIR := /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
all:
$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
clean:
rm -f *.o *.ko .*.cmd harmonie.mod.c
endif #ifneq ($(KERNELRELEASE),)
endif #ifeq ($(OLD_MODULES),yes)
else #ifeq ($(KERNELMAJOR),2) # kernel 1.x ?
all:
@echo kernel $(KERNELVERSION) not supported
endif #ifeq ($(KERNELMAJOR),2)
-
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