On Thu, Oct 30, 2014 at 12:28:14PM -0700, Florian Fainelli wrote:

On 10/30/2014 09:54 AM, Will Deacon wrote:

quoted

To speed up decompression, the decompressor sets up a flat, cacheable
mapping of memory. However, when there is insufficient space to hold
the page tables for this mapping, we don't bother to enable the caches
and subsequently skip all the cache maintenance hooks.

Skipping the cache maintenance before jumping to the relocated code
allows the processor to predict the branch and populate the I-cache
with stale data before the relocation loop has completed (since a
bootloader may have SCTLR.I set, which permits normal, cacheable
instruction fetches regardless of SCTLR.M).

This patch moves the cache maintenance check into the maintenance
routines themselves, allowing the v6/v7 versions to invalidate the
I-cache regardless of the MMU state.

Cc: Julien Grall <redacted>
Signed-off-by: Will Deacon <redacted>

I guess we could credit Marc as well for reporting and providing early
patches addressing this?

If we're going to start doing that, then it should also have:

Suggested-by: Russell King <redacted>

since Will and myself discussed it earlier today and I suggested moving
the tst check into the cache_clean_flush methods as a way to solve this
issue.

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