Messages in this thread |  | | From | Arnd Bergmann <> | Date | Sat, 27 Jan 2018 01:15:49 +0100 | Subject | Re: [PATCH 20/21] Kbuild, lto: Add Link Time Optimization support |
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On Mon, Nov 27, 2017 at 10:34 PM, Andi Kleen <andi@firstfloor.org> wrote: > From: Andi Kleen <ak@linux.intel.com> > - Add a new LDFINAL variable that controls the final link > for vmlinux or module. In this case we call gcc-ld instead > of ld, to run the LTO step.
When I tried this out on allmodconfig (following the lwn article), I ran into a number of warnings:
WARNING: modpost: missing MODULE_LICENSE() in drivers/isdn/hardware/eicon/diva_mnt.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/isdn/hysdn/hysdn.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/vhost/vhost_scsi.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/scsi/pcmcia/qlogic_cs.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/scsi/pcmcia/fdomain_cs.o ...
These are apparently all compound modules that do have a valid license, and modinfo shows it correctly:
modinfo build/tmp/drivers/isdn/hardware/eicon/diva_mnt.ko filename: /home/arnd/arm-soc/build/tmp/drivers/isdn/hardware/eicon/diva_mnt.ko license: GPL author: Cytronics & Melware, Eicon Networks description: Maint driver for Eicon DIVA Server cards ...
but something in the LTO build conuses modpost to the point that it doesn't see it.
I also get 131 errors in x86 allmodconfig along the lines of
/git/arm-soc/include/linux/slab.h:298:0: error: type of 'kmalloc_caches' does not match original declaration [-Werror=lto-type-mismatch] extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; /git/arm-soc/mm/slab_common.c:958:1: note: 'kmalloc_caches' was previously declared here EXPORT_SYMBOL(kmalloc_caches);
/git/arm-soc/include/linux/seq_file.h:109:5: error: type of 'seq_open' does not match original declaration [-Werror=lto-type-mismatc h] int seq_open(struct file *, const struct seq_operations *); ^ /git/arm-soc/fs/seq_file.c:48:0: note: 'seq_open' was previously declared here int seq_open(struct file *file, const struct seq_operations *op)
I found a fix for some of these issues attached to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83954 but am still doing more randconfig build testing.
Arnd
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