Martin Roth has uploaded this change for review.
Kconfig: Display a warning if the board is updated incorrectly
Even though we have a comment to run make distclean before switching
mainboards, people still ignore this and end up with confusing results.
To try to fix this, save the mainboard directory in a Kconfig symbol
that will not get updated when the mainboard gets changed. This allows
us to compare it to the actual mainboard directory which will be updated
when the platform changes and put up an obnoxious warning in the
mainboard directory. Add another warning in the main menu, because
the initial warning is probably going to be ignored. The main menu
points to some documentation on how to fix the problem.
Note that this will only catch issues going forward, and won't catch
any already saved config that has a problem.
Signed-off-by: Martin Roth <martinroth@chromium.org>
Change-Id: I2a1ccb62c7678f264015c87b9004be6a106f804a
---
A Documentation/getting_started/fix_dot_config.md
M src/Kconfig
M src/mainboard/Kconfig
3 files changed, 78 insertions(+), 0 deletions(-)
git pull ssh://review.coreboot.org:29418/coreboot refs/changes/41/33641/1
diff --git a/Documentation/getting_started/fix_dot_config.md b/Documentation/getting_started/fix_dot_config.md
new file mode 100644
index 0000000..17d89d0
--- /dev/null
+++ b/Documentation/getting_started/fix_dot_config.md
@@ -0,0 +1,50 @@
+# How to repair your .config file
+
+## Overview
+Many people rely on a saved .config file for building their
+platform. This is reasonable, but can create unanticipated
+problems.
+
+## TLDR
+* Backup your .config: "cp .config .config_bak"
+* Create the defconfig file: "make savedefconfig"
+* Edit defconfig & delete unknown config lines: "vi defconfig"
+* To just get rid of the warning about a bad .config, remove
+* the CONFIG_MAINBOARD_CHECK line.
+* The SMBIOS lines are probably incorrect as well. The ROM size
+* is very suspect. Check the correct default for your platform.
+* Save the defconfig
+* Generate a new full config:
+* "make -B defconfig KBUILD_DEFCONFIG=defconfig"
+
+## defconfig or "Mini config"
+Instead of saving a "full" config, people should use a defconfig.
+This is just the changes from a default coreboot configuration
+file. It's significantly smaller, and when a new configuration option
+gets added, it just takes the default value for that option when
+expanded into a full .config.
+
+### Generating the defconfig file
+To create the defconfig file, run "make savedefconfig". By default
+this will generate the file in the root coreboot directory and call
+it "defconfig". If there was already a file named "defconfig", this
+will overwrite that file.
+
+### Contents of the defconfig file
+As the defconfig file contains just the differences between the
+platform and the default choices for the platform. For the current
+default platform, the defconfig can actually be an empty file.
+
+Typically the defconfig will contain at least 2 lines - a
+CONFIG_VENDOR_ line and a CONFIG_BOARD_ line. Again though, if you
+are building the default board for any particular vendor, that line
+may not be present.
+
+All additional lines in a defconfig file are options that the user
+has specifically chosen to update in their config.
+
+### Generating a .config from a defconfig
+To expand the defconfig so that can be used, run:
+ DFILE=defconfig; make -B defconfig KBUILD_DEFCONFIG=$DFILE
+
+You can point DFILE to any saved defconfig.
diff --git a/src/Kconfig b/src/Kconfig
index 72d826f..8eae329 100644
--- a/src/Kconfig
+++ b/src/Kconfig
@@ -16,6 +16,15 @@
mainmenu "coreboot configuration"
+if MAINBOARD_CHECK != MAINBOARD_DIR
+comment "***********************************************************************"
+comment "WARNING: Your config is using defaults from a different mainboard "
+comment "than you currently have set. We'd recommend that you delete your "
+comment ".config file and start over, but if you want to try to repair the "
+comment "file, see Documentation/getting_started/fix_dot_config.md "
+comment "***********************************************************************"
+endif
+
menu "General setup"
config COREBOOT_BUILD
@@ -1062,6 +1071,14 @@
mainboard code supports this. On supported Intel platforms this works
by changing the settings in the descriptor.bin file.
+config MAINBOARD_CHECK
+ string "Mainboard dir - Do not change manually"
+ default MAINBOARD_DIR
+ help
+ Check the platform. If this symbol doesn't match the currently
+ selected mainboard directory, give the user warnings that they're
+ probably doing something wrong.
+
endmenu
diff --git a/src/mainboard/Kconfig b/src/mainboard/Kconfig
index c88d317..d9216a9 100644
--- a/src/mainboard/Kconfig
+++ b/src/mainboard/Kconfig
@@ -1,5 +1,16 @@
comment "Important: Run 'make distclean' before switching boards"
+if MAINBOARD_CHECK != MAINBOARD_DIR
+comment "***********************************************************************"
+comment "WARNING: Your config is using defaults from a different mainboard "
+comment "than you currently have set. We'd recommend that you delete your "
+comment ".config file and start over. "
+comment "* *"
+comment "If you ignore this warning and build anyway, you will almost certainly "
+comment "get a bad rom with undefined results. "
+comment "***********************************************************************"
+endif
+
choice
prompt "Mainboard vendor"
default VENDOR_EMULATION
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