efi: runtime-maps: Clarify purpose and enable by default for kexec

The current Kconfig logic for CONFIG_EFI_RUNTIME_MAPS does not convey
that without it, a kexec kernel is not able to boot in EFI mode at all.
So clarify this, and make the option only configurable via the menu
system if CONFIG_EXPERT is set.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dave Young <dyoung@redhat.com>

diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 0d5201e4984189bca7933efdd4bd1e960614109d..552512f211a1f5e7535a5de83e24a8f1739e872f 100644 (file)
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -27,13 +27,13 @@ config EFI_VARS_PSTORE_DEFAULT_DISABLE
          using the efivars module's pstore_disable parameter.
 
 config EFI_RUNTIME_MAP
-       bool "Export efi runtime maps to sysfs"
-       depends on X86 && EFI && KEXEC_CORE
-       default y
+       bool "Export EFI runtime maps to sysfs" if EXPERT
+       depends on X86 && EFI
+       default KEXEC_CORE
        help
-         Export efi runtime memory maps to /sys/firmware/efi/runtime-map.
-         That memory map is used for example by kexec to set up efi virtual
-         mapping the 2nd kernel, but can also be used for debugging purposes.
+         Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
+         That memory map is required by the 2nd kernel to set up EFI virtual
+         mappings after kexec, but can also be used for debugging purposes.
 
          See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.