modules: rename packages/kernel_modules to packages/lkmc

Then inside, split packages/lkmc into kernel_modules and userland,
to keep userland out of the kernel_modules parent path, which makes no
sense.

Copy built modules and userland to the output rootfs overlay.

Document Linux distro tradeoffs.

packages/kernel_modules/Config.in

@@ -1,5 +0,0 @@
-config BR2_PACKAGE_KERNEL_MODULES
-	bool "kernel_modules"
-	depends on BR2_LINUX_KERNEL
-	help
-		Linux Kernel Module Cheat.

packages/kernel_modules/external.desc

@@ -1 +0,0 @@
-name: KERNEL_MODULES

packages/kernel_modules/userland/external.mk

@@ -1,34 +0,0 @@
-################################################################################
-#
-# kernel_modules
-#
-################################################################################
-
-KERNEL_MODULES_VERSION = 1.0
-KERNEL_MODULES_SITE = $(BR2_EXTERNAL_KERNEL_MODULES_PATH)
-KERNEL_MODULES_SITE_METHOD = local
-
-ifeq ($(BR2_PACKAGE_EIGEN),y)
-	KERNEL_MODULES_DEPENDENCIES += eigen
-endif
-ifeq ($(BR2_PACKAGE_LIBDRM),y)
-	KERNEL_MODULES_DEPENDENCIES += libdrm
-endif
-ifeq ($(BR2_PACKAGE_OPENBLAS),y)
-	KERNEL_MODULES_DEPENDENCIES += openblas
-endif
-
-define KERNEL_MODULES_BUILD_CMDS
-	$(MAKE) -C '$(@D)' $(TARGET_CONFIGURE_OPTS) \
-	  BR2_PACKAGE_EIGEN="$(BR2_PACKAGE_EIGEN)" \
-	  BR2_PACKAGE_LIBDRM="$(BR2_PACKAGE_LIBDRM)" \
-	  BR2_PACKAGE_OPENBLAS="$(BR2_PACKAGE_OPENBLAS)" \
-	;
-endef
-
-define KERNEL_MODULES_INSTALL_TARGET_CMDS
-	$(INSTALL) -D -m 0755 $(@D)/*.out '$(TARGET_DIR)'
-endef
-
-$(eval $(kernel-module))
-$(eval $(generic-package))

packages/lkmc/Config.in

@@ -0,0 +1,5 @@
+config BR2_PACKAGE_LKMC
+	bool "lkmc"
+	depends on BR2_LINUX_KERNEL
+	help
+		Linux Kernel Module Cheat kernel modules and compiled userland examples.

packages/lkmc/external.desc

@@ -0,0 +1 @@
+name: LKMC

packages/lkmc/external.mk

@@ -4,21 +4,22 @@
 #
 ################################################################################
 
-KERNEL_MODULES_VERSION = 1.0
-KERNEL_MODULES_SITE = $(BR2_EXTERNAL_KERNEL_MODULES_PATH)
-KERNEL_MODULES_SITE_METHOD = local
+LKMC_VERSION = 1.0
+LKMC_SITE = $(BR2_EXTERNAL_LKMC_PATH)
+LKMC_SITE_METHOD = local
+LKMC_MODULE_SUBDIRS = kernel_modules
 
 ifeq ($(BR2_PACKAGE_EIGEN),y)
-	KERNEL_MODULES_DEPENDENCIES += eigen
+	LKMC_DEPENDENCIES += eigen
 endif
 ifeq ($(BR2_PACKAGE_LIBDRM),y)
-	KERNEL_MODULES_DEPENDENCIES += libdrm
+	LKMC_DEPENDENCIES += libdrm
 endif
 ifeq ($(BR2_PACKAGE_OPENBLAS),y)
-	KERNEL_MODULES_DEPENDENCIES += openblas
+	LKMC_DEPENDENCIES += openblas
 endif
 
-define KERNEL_MODULES_BUILD_CMDS
+define LKMC_BUILD_CMDS
 	$(MAKE) -C '$(@D)/userland' $(TARGET_CONFIGURE_OPTS) \
 	  HAS_EIGEN="$(BR2_PACKAGE_EIGEN)" \
 	  HAS_LIBDRM="$(BR2_PACKAGE_LIBDRM)" \
@@ -26,13 +27,12 @@ define KERNEL_MODULES_BUILD_CMDS
 	;
 endef
 
-define KERNEL_MODULES_INSTALL_TARGET_CMDS
+define LKMC_INSTALL_TARGET_CMDS
 	# The modules are already installed by the kernel-module package type
 	# under /lib/modules/**, but let's also copy the modules to the root
 	# for insmod convenience.
 	#
 	# Modules can be still be easily inserted with "modprobe module" however.
-	$(INSTALL) -D -m 0655 $(@D)/*.ko '$(TARGET_DIR)'
 	$(INSTALL) -D -m 0755 $(@D)/userland/*.out '$(TARGET_DIR)'
 endef
 

packages/lkmc/kernel_modules/Makefile

@@ -1,5 +1,6 @@
 ifeq ($(OBJECT_FILES),)
-obj-m += $(addsuffix .o, $(notdir $(basename $(filter-out %.mod.c, $(wildcard $(BR2_EXTERNAL_KERNEL_MODULES_PATH)/*.c)))))
+# Hardcoding  LKMC_MODULE_SUBDIRS here because is not defined.
+obj-m += $(addsuffix .o, $(notdir $(basename $(filter-out %.mod.c, $(wildcard $(BR2_EXTERNAL_LKMC_PATH)/kernel_modules/*.c)))))
 else
 # Trying to do:
 # $(MAKE) -C '$(LINUX_DIR)' M='$(M)' hello.ko hello2.ko

packages/lkmc/kernel_modules/anonymous_inode.c

@@ -9,7 +9,7 @@
 #include <linux/printk.h> /* printk */
 #include <linux/uaccess.h> /* copy_from_user */
 
-#include "anonymous_inode.h"
+#include "../anonymous_inode.h"
 
 static struct dentry *debugfs_file;
 static u32 myval = 1;

packages/lkmc/kernel_modules/hello.c

@@ -5,7 +5,7 @@
 
 static int myinit(void)
 {
-	pr_info("hello init\n");
+	pr_info("hello init 2\n");
 	/* 0 for success, any negative value means failure,
 	 * E* consts if you want to specify failure cause.
 	 * https://www.linux.com/learn/kernel-newbie-corner-loadable-kernel-modules-coming-and-going */

packages/lkmc/kernel_modules/ioctl.c

@@ -5,7 +5,7 @@
 #include <linux/printk.h> /* printk */
 #include <linux/uaccess.h> /* copy_from_user, copy_to_user */
 
-#include "ioctl.h"
+#include "../ioctl.h"
 
 static struct dentry *debugfs_file;
 

packages/lkmc/kernel_modules/netlink.c

@@ -6,7 +6,7 @@
 #include <linux/skbuff.h>
 #include <net/sock.h>
 
-#include "netlink.h"
+#include "../netlink.h"
 
 struct sock *nl_sk = NULL;
 

packages/lkmc/kernel_modules/ring0.c

@@ -3,7 +3,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 
-#include "ring0.h"
+#include "../ring0.h"
 
 static int myinit(void)
 {