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Patrick Georgi 7333a116b3 util/: Replace GPLv2 boiler plate with SPDX header Used commands: perl -i -p0e 's\|\/\[\s].is free software[:;][\s]you[\s]can[\s]redistribute[\s]it[\s]and\/or[\s]modify[\s]it[\s]under[\s]the[\s]terms[\s]of[\s]the[\s]GNU[\s]General[\s]Public[\s]License[\s]as[\s]published[\s]by[\s]the[\s]Free[\s]Software[\s]Foundation[;,][\s]version[\s]2[\s]of[\s]the[\s]License.[\s]This[\s]program[\s]is[\s]distributed[\s]in[\s]the[\s]hope[\s]that[\s]it[\s]will[\s]be[\s]useful,[\s]but[\s]WITHOUT[\s]ANY[\s]WARRANTY;[\s]without[\s]even[\s]the[\s]implied[\s]warranty[\s]of[\s]MERCHANTABILITY[\s]or[\s]FITNESS[\s]FOR[\s]A[\s]PARTICULAR[\s]PURPOSE.[\s]See[\s]the[\s]GNU[\s]General[\s]Public[\s]License[\s]for[\s]more[\s]details.[\s]\\/\|/ SPDX-License-Identifier: GPL-2.0-only /\|' $(cat filelist) perl -i -p0e 's\|This[\s]program[\s]is[\s]free[\s]software[:;][\s]you[\s]can[\s]redistribute[\s]it[\s]and/or[\s]modify[\s]it[\s]under[\s]the[\s]terms[\s]of[\s]the[\s]GNU[\s]General[\s]Public[\s]License[\s]as[\s]published[\s]by[\s]the[\s]Free[\s]Software[\s]Foundation[;,][\s]either[\s]version[\s]2[\s]of[\s]the[\s]License,[\s]or[\s].at[\s]your[\s]option.[\s]any[\s]later[\s]version.[\s]This[\s]program[\s]is[\s]distributed[\s]in[\s]the[\s]hope[\s]that[\s]it[\s]will[\s]be[\s]useful,[\s]but[\s]WITHOUT[\s]ANY[\s]WARRANTY;[\s]without[\s]even[\s]the[\s]implied[\s]warranty[\s]of[\s]MERCHANTABILITY[\s]or[\s]FITNESS[\s]FOR[\s]A[\s]PARTICULAR[\s]PURPOSE.[\s]See[\s]the[\s]GNU[\s]General[\s]Public[\s]License[\s]for[\s]more[\s]details.[\s]\\/\|/ SPDX-License-Identifier: GPL-2.0-or-later /\|' $(cat filelist) perl -i -p0e 's\|\/\[\s].This[\s#]program[\s#]is[\s#]free[\s#]software[;:,][\s#]you[\s#]can[\s#]redistribute[\s#]it[\s#]and/or[\s#]modify[\s#]it[\s#]under[\s#]the[\s#]terms[\s#]of[\s#]the[\s#]GNU[\s#]General[\s#]Public[\s#]License[\s#]as[\s#]published[\s#]by[\s#]the[\s#]Free[\s#]Software[\s#]Foundation[;:,][\s#]either[\s#]version[\s#]3[\s#]of[\s#]the[\s#]License[;:,][\s#]or[\s#].at[\s#]your[\s#]option.[\s#]any[\s#]later[\s#]version.[\s#]This[\s#]program[\s#]is[\s#]distributed[\s#]in[\s#]the[\s#]hope[\s#]that[\s#]it[\s#]will[\s#]be[\s#]useful[;:,][\s#]but[\s#]WITHOUT[\s#]ANY[\s#]WARRANTY[;:,][\s#]without[\s#]even[\s#]the[\s#]implied[\s#]warranty[\s#]of[\s#]MERCHANTABILITY[\s#]or[\s#]FITNESS[\s#]FOR[\s#]A[\s#]PARTICULAR[\s#]PURPOSE.[\s#]See[\s#]the[\s#]GNU[\s#]General[\s#]Public[\s#]License[\s#]for[\s#]more[\s#]details.[\s]\\/\|/ SPDX-License-Identifier: GPL-3.0-or-later /\|' $(cat filelist) perl -i -p0e 's\|(\#\#)[\w].is free software[:;][\#\s]you[\#\s]can[\#\s]redistribute[\#\s]it[\#\s]and\/or[\#\s]modify[\#\s]it[\s\#]under[\s \#]the[\s\#]terms[\s\#]of[\s\#]the[\s\#]GNU[\s\#]General[\s\#]Public[\s\#]License[\s\#]as[\s\#]published[\s\#]by[\s\#]the[\s\#]Free[\s\#]Software[\s\#]Foundation[;,][\s\#]version[\s\#]2[\s\#]of[\s\#]the[\s\#]License.[\s\#]This[\s\#]program[\s\#]is[\s\#]distributed[\s\#]in[\s\#]the[\s\#]hope[\s\#]that[\s\#]it[\s\#]will[\#\s]be[\#\s]useful,[\#\s]but[\#\s]WITHOUT[\#\s]ANY[\#\s]WARRANTY;[\#\s]without[\#\s]even[\#\s]the[\#\s]implied[\#\s]warranty[\#\s]of[\#\s]MERCHANTABILITY[\#\s]or[\#\s]FITNESS[\#\s]FOR[\#\s]A[\#\s]PARTICULAR[\#\s]PURPOSE.[\#\s]See[\#\s]the[\#\s]GNU[\#\s]General[\#\s]Public[\#\s]License[\#\s]for[\#\s]more[\#\s]details.\s(# \n)\|\1 SPDX-License-Identifier: GPL-2.0-only\n\n\|' $(cat filelist) perl -i -p0e 's\|(\#\#)[\w].is free software[:;][\s]you[\s]can[\s]redistribute[\s]it[\s]and\/or[\s]modify[\s]it[\s]under[\s]the[\s]terms[\s]of[\s]the[\s]GNU[\s]General[\s]Public[\s]License[\s]as[\s]published[\s]by[\s]the[\s]Free[\s]Software[\s]Foundation[;,][\s]version[\s]2[\s]of[\s]the[\s]License.[\s]This[\s]program[\s]is[\s]distributed[\s]in[\s]the[\s]hope[\s]that[\s]it[\s]will[\s]be[\s]useful,[\s]but[\s]WITHOUT[\s]ANY[\s]WARRANTY;[\s]without[\s]even[\s]the[\s]implied[\s]warranty[\s]of[\s]MERCHANTABILITY[\s]or[\s]FITNESS[\s]FOR[\s]A[\s]PARTICULAR[\s]PURPOSE.[\s]See[\s]the[\s]GNU[\s]General[\s]Public[\s]License[\s]for[\s]more[\s]details.\s(#* \n)\|\1 SPDX-License-Identifier: GPL-2.0-only\n\n\|' $(cat filelist) Change-Id: I1008a63b804f355a916221ac994701d7584f60ff Signed-off-by: Patrick Georgi <pgeorgi@google.com> Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr> Reviewed-on: https://review.coreboot.org/c/coreboot/+/41177 Tested-by: build bot (Jenkins) <no-reply@coreboot.org>		2020-05-09 21:22:08 +00:00
..
Makefile	…
bucts.c	util/: Replace GPLv2 boiler plate with SPDX header	2020-05-09 21:22:08 +00:00
description.md	…
readme.md	…

readme.md

What is bucts?

Many Intel southbridges provide a mechanism called Back Up Control Top Swap (BUC.TS). This functionality allows to have the southbridge fetch the reset vector or the beginning of the bootblock at a 64K/128/256K offset from the usual top of flash.

This can be useful in different ways:

Have a backup bootblock in case of bootblock hacking;
Some vendor BIOS only write protect their bootblock so this tool makes it possible to circumvent this protection to allow flashing and booting coreboot.

The BUC.TS status is stored in a nvram bit. To clear it one has to remove the RTC battery.

Operation Description

First compile bucts by running make:

$ make

Then you can view the current system settings:

$ ./bucts --print

To flip the decode address of the bootblock, by setting BUC.TS to 1:

$ ./bucts --set

To set the behavior the regular mapping, by setting BUC.TS to 0

$ ./bucts --unset

Details

Example Bootblock size of 64KB (this is only configurable to be something else like 128 or 256K on PCH Intel targets).

    +-------------+ -> 0x200000         +-------------+ -> 0xFFFFFFFF       +-------------+ -> 0xFFFFFFFF
    |             |                     |             |                     |             |
    | bootblock_0 |                     | bootblock_0 |                     | bootblock_1 |
    |             |                     |             |                     |             |
    +-------------+ -> 0x1F0000         +-------------+ -> 0xFFFF0000       +-------------+ -> 0xFFFF0000
    |             |                     |             |                     |             |
    | bootblock_1 |                     | bootblock_1 |                     | bootblock_0 |
    |             |                     |             |                     |             |
    +-------------+ -> 0x1E0000         +-------------+ -> 0xFFFE0000       +-------------+ -> 0xFFFE0000
    |             |                     |             |                     |             |
    |             |                     |             |                     |             |
    Z             Z                     Z             Z                     Z             Z
    Z             Z                     Z             Z                     Z             Z
    |             |                     |             |                     |             |
    |             |                     |             |                     |             |
    FLASH (2M)                          Memory Map BUC.TS=0               Memory Map BUC.TS=1