From: Paul Mundt <lethal@linux-sh.org>
Date: Wed, 27 Sep 2006 05:38:02 +0000 (+0900)
Subject: sh: Fix fatal oops in copy_user_page() on sh4a (SH7780).
X-Git-Tag: v2.6.19-rc1~902^2~78
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8b395265f81817385f12e62f03f795efb732a445;p=pandora-kernel.git

sh: Fix fatal oops in copy_user_page() on sh4a (SH7780).

We had a pretty interesting oops happening, where copy_user_page()
was down()'ing p3map_sem[] with a bogus offset (particularly, an
offset that hadn't been initialized with sema_init(), due to the
mismatch between cpu_data->dcache.n_aliases and what was assumed
based off of the old CACHE_ALIAS value).

Luckily, spinlock debugging caught this for us, and so we drop
the old hardcoded CACHE_ALIAS for sh4 completely and rely on the
run-time probed cpu_data->dcache.alias_mask. This in turn gets
the p3map_sem[] index right, and everything works again.

While we're at it, also convert to 4-level page tables..

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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