[PATCH 3/3] Kconfig: add a default allrandom.config

[Arnd Bergmann <arnd@arndb.de>]

Building randconfig kernels frequently leads to build errors from
drivers that have additional build dependencies, or that we don't
want to build for compile-testing for some other reason.

We already have a couple of compile-time options that can deal with this
problem, but the complete set is not documented well.  We also have a
method to override some options during 'make randconfig' and a couple
of other make targets. However, we don't yet combine those two.

This adds a new allrandom.config file to turn on CONFIG_COMPILE_TEST,
CONFIG_STANDALONE and CONFIG_PREVENT_FIRMWARE_BUILD for all randconfig
builds. This in turn disables some other options that we already try
to avoid in 'allmodconfig' builds and that make no sense in a general
randconfig build.

Building with 'make randconfig KCONFIG_ALLCONFIG=1' should now always
succeed without warnings on x86 and arm64, aside from recent regressions.
Other architectures probably need additional bugfixes.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 kernel/configs/allrandom.config | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 kernel/configs/allrandom.config

diff --git a/kernel/configs/allrandom.config b/kernel/configs/allrandom.config
new file mode 100644
index 000000000000..67294ef2e3a2
--- /dev/null
+++ b/kernel/configs/allrandom.config
@@ -0,0 +1,6 @@
+# maximize search space, disable options not worth testing
+CONFIG_COMPILE_TEST=y
+
+# reduce compile-time dependencies
+CONFIG_STANDALONE=y
+CONFIG_PREVENT_FIRMWARE_BUILD=y
-- 
2.9.0