Enable EDAC debug mode on Ubuntu bionic kernel

When developing Ubuntu Bionic kernel, you probably notice the EDAC, Error Detection and Correction, is not enabled by default. You may want to enable it for development. This is how it works.

Go and fetch Ubuntu bionic source code via Launchpad, and make a change as the following:

diff --git a/debian.master/config/annotations b/debian.master/config/annotations
index d4ba76f3a350..bf220bf6e729 100644
--- a/debian.master/config/annotations
+++ b/debian.master/config/annotations
@@ -1259,7 +1259,7 @@ CONFIG_OF_UNITTEST                              flag<DEBUG>
 # Menu: Device Drivers >> EDAC (Error Detection And Correction) reporting
 CONFIG_EDAC                                     policy<{'amd64': 'y', 'arm64': 'y', 'armhf': 'y', 'i386': 'y', 'ppc64el': 'y'}>
 CONFIG_EDAC_LEGACY_SYSFS                        policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n'}>
-CONFIG_EDAC_DEBUG                               policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n'}>
+CONFIG_EDAC_DEBUG                               policy<{'amd64': 'n', 'arm64': 'y', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n'}>
 CONFIG_EDAC_DECODE_MCE                          policy<{'amd64': 'm', 'i386': 'm'}>
 CONFIG_EDAC_GHES                                policy<{'amd64': 'y', 'arm64': 'y', 'i386': 'y'}>
 CONFIG_EDAC_AMD64                               policy<{'amd64': 'm', 'i386': 'm'}>
diff --git a/debian.master/config/arm64/config.flavour.generic b/debian.master/config/arm64/config.flavour.generic
index bb7773a235d2..b6d9b685a5a7 100644
--- a/debian.master/config/arm64/config.flavour.generic
+++ b/debian.master/config/arm64/config.flavour.generic
@@ -1,3 +1,4 @@
 #
 # Config options for config.flavour.generic automatically generated by splitconfig.pl
 #
+CONFIG_EDAC_DEBUG=y

For now, if you check the debugfs of EDAC, you should have /sys/kernel/debug/edac folder is generated by default.