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authorPatrick Rudolph <patrick.rudolph@9elements.com>2019-04-17 11:51:25 +0200
committerPatrick Rudolph <siro@das-labor.org>2019-04-19 11:36:53 +0000
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tree5cea980621185dd546a45c0a6be29819fc6d82f4 /Documentation/lib/abi-data-consumption.md
parent8f702676071ab3e62a9c07d5bdc75f5c92e58946 (diff)
Documentation: Add small fixes
* Remove empty security.md * Remove second H1 header from lib/index.md * Move two documents in appropriate subfolders * Fix file path * Drop document overview Change-Id: I0e9df6203e82003c01b84967ea6bd779d7583fef Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/32340 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Reviewed-by: Hung-Te Lin <hungte@chromium.org> Reviewed-by: Martin Roth <martinroth@google.com>
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+# ABI data consumption
+
+This text describes the ABI coreboot presents to downstream users. Such
+users are payloads and/or operating systems. Therefore, this text serves
+at what can be relied on for downstream consumption. Anything not explicitly
+listed as consumable is subject to change without notice.
+
+## Background and Usage
+
+coreboot passes information to downstream users using coreboot tables. These
+table definitions can be found in
+`./src/commonlib/include/commonlib/coreboot_tables.h` and
+`./payloads/libpayload/include/coreboot_tables.h` respectively within coreboot
+and libpayload. One of the most vital and important pieces of information
+found within these tables is the memory map of the system indicating
+available and reserved memory.
+
+In 2009 cbmem was added to coreboot. The "CBMEM high table memory manager"
+serves a way for coreboot to bookkeep its own internal data. While some
+of this data may be exposed through the coreboot tables the data structures
+used to manage the data within the cbmem area is subject to change.
+
+Provided the above, if one needs a piece of data exposed to the OS
+or payload it should reside within the coreboot tables. If it isn't there
+then a code change will be required to add it to the coreboot tables.