arm64: mm: ensure that the zero page is visible to the page table walker

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commit 32d6397805 upstream.

In paging_init, we allocate the zero page, memset it to zero and then
point TTBR0 to it in order to avoid speculative fetches through the
identity mapping.

In order to guarantee that the freshly zeroed page is indeed visible to
the page table walker, we need to execute a dsb instruction prior to
writing the TTBR.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Will Deacon 2015-12-10 16:05:36 +00:00 • committed by Greg Kroah-Hartman

parent c01afb9239

commit 8182d4cf11

1 changed files with 3 additions and 0 deletions

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arch/arm64/mm/mmu.c

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