Messages in this thread | | | Date | Thu, 29 Oct 2009 15:43:26 +0100 | From | Tejun Heo <> | Subject | Re: [PATCH -next] ia64/sn: fix percpu warnings |
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Hello,
Luck, Tony wrote: > Ok. x86 doesn't see this because the defconfig has > CONFIG_MODVERSIONS is not set > > If I turn MODVERSION off, then the problem disappears for me. > > If I turn MODVERSIONS on for x86 (and fudge a driver to make use of > softirq_work_list), then x86 gets the CRC warning too.
Right, I can reproduce it here too.
> So this isn't a tool chain problem. Neither x86 nor ia64 > can handle exported per-cpu array objects when CONFIG_MODVERSIONS > is set. > > Looking at the __crc symbols in the vmlinux for x86 with > CONFIG_MODVERSIONS=y I see: > > 000000006dcaeb88 A __crc_per_cpu__kernel_stack > 00000000b3994c7a A __crc_per_cpu__kstat > 00000000d917c158 A __crc_per_cpu__node_number > w __crc_per_cpu__softirq_work_list > 0000000036a1f502 A __crc_per_cpu__softnet_data > 0000000057adf756 A __crc_per_cpu__this_cpu_off > > which explains why "modpost" is unable to find a CRC. > > Maybe the comments in <linux/module.h> are supposed to be a > clue? : > > #ifdef CONFIG_MODVERSIONS > /* Mark the CRC weak since genksyms apparently decides not to > * generate a checksums for some symbols */ > #define __CRC_SYMBOL(sym, sec) \ > extern void *__crc_##sym __attribute__((weak)); \ > static const unsigned long __kcrctab_##sym \ > __used \ > __attribute__((section("__kcrctab" sec), unused)) \ > = (unsigned long) &__crc_##sym; > > But not enough of a clue for me :-(
I have no idea either. I'll dig a bit and try to find out what's going on.
Thanks.
-- tejun
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