Randall Spangler ad2adc4022 Invalidate hash if flash operation changes the hashed region ...

This prevents the EC from returning a stale hash.

BUG=chrome-os-partner:16668
BRANCH=link,snow
TEST=manual, with WP disabled

From EC console
- Boot system and wait a second
- hash --> prints valid hash
- flasherase 0x20000 0x1000
- hash --> invalid
- hash rw
- hash --> prints valid hash
- flashwrite 0x20000 0x1000
- hash --> invalid
- hash rw
- flasherase 0x38000 0x1000
- flashwrite 0x38000 0x1000
- hash --> still valid (since 0x38000 is outside the rw section)

From root shell
- ectool hash --> prints valid hash
- ectool flasherase 0x20000 0x1000
- ectool hash --> invalid
- ectool hash recalc RW
- ectool hash --> prints valid hash
- echo 'Making a hash of this' > /tmp/hashofthis
- ectool flashwrite 0x20000 /tmp/hashofthis
- ectool hash --> invalid
- ectool hash recalc RW
- ectool flasherase 0x38000 0x1000
- ectool flashwrite 0x38000 /tmp/hashofthis
- ectool hash --> still valid (since 0x38000 is outside the rw section)

Change-Id: Id915a504a7bc70b8b8c339b5ce55dc5bad5838fe
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/39484
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

2012-12-10 15:14:38 -08:00

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