Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756373Ab2FYUc7 (ORCPT ); Mon, 25 Jun 2012 16:32:59 -0400 Received: from georges.telenet-ops.be ([195.130.137.68]:53070 "EHLO georges.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755900Ab2FYUc5 (ORCPT ); Mon, 25 Jun 2012 16:32:57 -0400 Date: Mon, 25 Jun 2012 22:32:53 +0200 (CEST) From: Geert Uytterhoeven To: Andreas Schwab cc: =?ISO-8859-15?Q?Bj=F8rn_Mork?= , Greg Kroah-Hartman , USB list , linux-kernel@vger.kernel.org, Linux-Next , linux-kbuild , Linux/m68k Subject: Re: [PATCH] mod/file2alias: make modalias generation safe for cross compiling In-Reply-To: Message-ID: References: <20120615201021.GB14544@kroah.com> <20120615231220.GC8205@kroah.com> <87lijns84s.fsf@nemi.mork.no> <87fw9urqau.fsf@nemi.mork.no> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4253 Lines: 113 Hi Andreas, On Mon, 25 Jun 2012, Andreas Schwab wrote: > Use the target compiler to compute the offsets of the fields of the > device_id structures, so that it won't be broken by different alignments > between the host and target ABIs. Thanks, very nice! > --- a/include/linux/mod_devicetable.h > +++ b/include/linux/mod_devicetable.h > @@ -33,8 +33,7 @@ struct ieee1394_device_id { > __u32 model_id; > __u32 specifier_id; > __u32 version; > - kernel_ulong_t driver_data > - __attribute__((aligned(sizeof(kernel_ulong_t)))); > + kernel_ulong_t driver_data; After this, we can also get rid of kernel_ulong_t, but that's a more intruisive patch all over the place. > --- /dev/null > +++ b/scripts/mod/devicetable-offsets.c > @@ -0,0 +1,171 @@ > +#include > +#include > + > +#define DEVID(devid) DEFINE(SIZE_##devid, sizeof(struct devid)) > +#define DEVID_FIELD(devid, field) \ > + DEFINE(OFF_##devid##_##field, offsetof(struct devid, field)) > + > +int main(void) > +{ > + DEVID(usb_device_id); > + DEVID_FIELD(usb_device_id, match_flags); > + DEVID_FIELD(usb_device_id, idVendor); > + DEVID_FIELD(usb_device_id, idProduct); > + DEVID_FIELD(usb_device_id, bcdDevice_lo); > + DEVID_FIELD(usb_device_id, bcdDevice_hi); > + DEVID_FIELD(usb_device_id, bDeviceClass); > + DEVID_FIELD(usb_device_id, bDeviceSubClass); > + DEVID_FIELD(usb_device_id, bDeviceProtocol); > + DEVID_FIELD(usb_device_id, bInterfaceClass); > + DEVID_FIELD(usb_device_id, bInterfaceSubClass); > + DEVID_FIELD(usb_device_id, bInterfaceProtocol); These are all duplicates of the structures in . Can't you get rid of the duplication by putting e.g. the following in : DEVID_START(usb_device_id); DEVID_FIELD(usb_device_id, __u16, match_flags); DEVID_FIELD(usb_device_id, __u16, idVendor); DEVID_FIELD(usb_device_id, __u16, idProduct); DEVID_FIELD(usb_device_id, __u16, bcdDevice_lo); DEVID_FIELD(usb_device_id, __u16, bcdDevice_hi); DEVID_FIELD(usb_device_id, __u8, bDeviceClass); DEVID_FIELD(usb_device_id, __u8, bDeviceSubClass); DEVID_FIELD(usb_device_id, __u8, bDeviceProtocol); DEVID_FIELD(usb_device_id, __u8, bInterfaceClass); DEVID_FIELD(usb_device_id, __u8, bInterfaceSubClass); DEVID_FIELD(usb_device_id, __u8, bInterfaceProtocol); DEVID_END(); and redefining the DEVID_*() macros depending on 1. __KERNEL__, to generate the C struct definitions for kernel builds, 2. first inclusion by devicetable-offsets.c, also to generate C struct definitions, 3. second inclusion by devicetable-offsets.c, to generate the sizes and offset definitions for modalias? > --- a/scripts/mod/file2alias.c > +++ b/scripts/mod/file2alias.c > @@ -116,7 +129,6 @@ static inline void add_wildcard(char *str) > strcat(str + len, "*"); > } > > -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 > @@ -131,8 +143,6 @@ 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 " Funny, I didn't know there was a check for cross-compiling, supposedly to ignore the warnings. And it didn't work, as the problem was noticed originally on the linux-next build service (which uses cross-compiling), and also showed up for my own cross-builds. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/