From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Fri, 18 Dec 2009 16:24:34 +0000 (+0000)
Subject: ARM: make_coherent: fix problems with highpte, part 1
X-Git-Tag: v2.6.34-rc1~241^2~4^9~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=56dd47098abe1fdde598a8d8b7c04d775506f456;p=pandora-kernel.git

ARM: make_coherent: fix problems with highpte, part 1

update_mmu_cache() is called with a page table already mapped.  We
call make_coherent(), which then calls adjust_pte() which wants to
map other page tables.  This causes kmap_atomic() to BUG() because
the slot its trying to use is already taken.

Since do_adjust_pte() modifies the page tables, we are also missing
any form of locking, so we're risking corrupting the page tables.

Fix this by using pte_offset_map_nested(), and taking the pte page
table lock around do_adjust_pte().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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