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Message-ID: <20080302115828.GA15820@uranus.ravnborg.org>
Date: Sun, 2 Mar 2008 12:58:28 +0100
From: Sam Ravnborg <sam@...nborg.org>
To: Michael Buesch <mb@...sch.de>
Cc: "John W. Linville" <linville@...driver.com>,
Johannes Berg <johannes@...solutions.net>,
David Miller <davem@...emloft.net>,
gordonfarquharson@...il.com, netdev@...r.kernel.org,
linux-wireless@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: pull request: wireless-2.6 2008-02-27
On Sat, Mar 01, 2008 at 04:51:12PM +0100, Michael Buesch wrote:
> On Saturday 01 March 2008, Sam Ravnborg wrote:
> > > This version seems to work, but it is a bit chatty when CROSS_COMPILE
> > > is set and you build lots of modules...thoughts?
> >
> > We cannot use CROSS_COMPILE to detect a cross build as CROSS_COMPILE
> > is used used to select different gcc versions, cccache etc.
> > The only relaiably way to detect a cross build is to check
> > is ARCH != modified uname -m arch.
> > So this check would have to be done in the top-level Makefile.
> >
> > And that for shaving 6 bytes of a structure..
>
> Wrong. For maintaining userspace ABI compatibility.
NEws to me - that argument I did not see when I posted my previous mail
about possible worarounds.
Find below a patch that detect when we do a cross build and thus ignore
the check.
This is NOT tested as I do not have access to my dev box atm.
I have only tested I could build a i386 kernel.
So please let me know if this works and then I can push it upstrem
hopefully already by tomorrow.
Note: I decided to name the variable KBUILD_BUILDHOST as this is more
descriptive then SUBARCH. We can later clean up the naming and get rid
of SUBARCH but I refrained from this to make the pacht minimal.
Sam
diff --git a/Makefile b/Makefile
index a229784..de28306 100644
--- a/Makefile
+++ b/Makefile
@@ -189,7 +189,7 @@ SUBARCH := $(shell uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
# Alternatively CROSS_COMPILE can be set in the environment.
# Default value for CROSS_COMPILE is not to prefix executables
# Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
-
+export KBUILD_BUILDHOST := $(SUBARCH)
ARCH ?= $(SUBARCH)
CROSS_COMPILE ?=
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index cfc004e..2d20640 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -58,6 +58,9 @@ modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
+ifneq ($(KBUILD_BUILDHOST),$(ARCH))
+ cross_build := 1
+endif
# Step 2), invoke modpost
# Includes step 3,4
@@ -70,7 +73,8 @@ modpost = scripts/mod/modpost \
$(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \
$(if $(CONFIG_MARKERS),-K $(kernelmarkersfile)) \
$(if $(CONFIG_MARKERS),-M $(markersfile)) \
- $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
+ $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
+ $(if $(cross_build),-c)
quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
cmd_modpost = $(modpost) -s
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 9ddf944..348d868 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -51,11 +51,13 @@ do { \
sprintf(str + strlen(str), "*"); \
} while(0)
+unsigned int cross_build = 0;
/**
* Check that sizeof(device_id type) are consistent with size of section
* in .o file. If in-consistent then userspace and kernel does not agree
* on actual size which is a bug.
* Also verify that the final entry in the table is all zeros.
+ * Ignore both checks if build host differ from target host and size differs.
**/
static void device_id_check(const char *modname, const char *device_id,
unsigned long size, unsigned long id_size,
@@ -64,6 +66,8 @@ static void device_id_check(const char *modname, const char *device_id,
int i;
if (size % id_size || size < id_size) {
+ if (cross_build != 0)
+ return;
fatal("%s: sizeof(struct %s_device_id)=%lu is not a modulo "
"of the size of section __mod_%s_device_table=%lu.\n"
"Fix definition of struct %s_device_id "
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 695b5d6..110cf24 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2026,7 +2026,7 @@ int main(int argc, char **argv)
int opt;
int err;
- while ((opt = getopt(argc, argv, "i:I:msSo:awM:K:")) != -1) {
+ while ((opt = getopt(argc, argv, "i:I:cmsSo:awM:K:")) != -1) {
switch (opt) {
case 'i':
kernel_read = optarg;
@@ -2035,6 +2035,9 @@ int main(int argc, char **argv)
module_read = optarg;
external_module = 1;
break;
+ case 'c':
+ cross_build = 1;
+ break;
case 'm':
modversions = 1;
break;
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 565c587..09f58e3 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -135,6 +135,7 @@ struct elf_info {
};
/* file2alias.c */
+extern unsigned int cross_build;
void handle_moddevtable(struct module *mod, struct elf_info *info,
Elf_Sym *sym, const char *symname);
void add_moddevtable(struct buffer *buf, struct module *mod);
--
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