On Mon, Sep 9, 2013 at 10:06 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>> [*] Why does m68k allmodconfig still succeed on kissb???
>> It does fail for me, as m68k's copy_from_user_page() calls
>> flush_icache_user_range(), which is not exported.
>>
> I don't see a build failure in m68k:allmodconfig either.
>
> flush_icache_user_range() is called from copy_to_user_page(), not from
> copy_from_user_page(). copy_from_user_page() calls flush_cache_page()
> which calls __flush_cache_030(). The first is inline, the second is
> assembler, so I would expect it to work. Which doesn't answer
> the question why it fails for you.
Sorry, I meant copy_to_user_page().
I tried with 2.6.3 from crosstool, and it succeeded, too.
Turns out cfs_access_process_vm() is called with write=0 only.
Gcc 2.6.3 optimizes away the write != 0 branch (which calls copy_to_user_page()
and thus flush_icache_user_range()), while gcc 4.1.2 doesn't do that.
Mystery solved.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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
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