KALLSYMS_ALL, IKCONFIG

kernel_config_fragment

@@ -1,12 +1,19 @@
-# If you change this file, you need to run:
+# Changes to this file are automatically used in the new kernel
-#     rm -rf buildroot/output/build/linux-*.*.*/
+# after ./run, no need to do anything different.
-# before ./run
+
-CONFIG_DEBUG_KERNEL=y
 CONFIG_DEBUG_FS=y
 CONFIG_DEBUG_INFO=y
+CONFIG_DEBUG_KERNEL=y
 CONFIG_GDB_SCRIPTS=y
 
-# KGDB.
+# grep lkmc_dep /proc/kallsyms
+CONFIG_KALLSYMS_ALL=y
+
+# zcat /proc/config.gz
+CONFIG_IKCONFIG=y
+CONFIG_IKCONFIG_PROC=y
+
+# KGDB
 CONFIG_CONSOLE_POLL=y
 CONFIG_KDB_CONTINUE_CATASTROPHIC=0
 CONFIG_KDB_DEFAULT_ENABLE=0x1

kernel_module/dep.c

@@ -25,6 +25,12 @@ sys visibility:
 	cat refcnt
 	# => 1
 
+proc visibility:
+
+	grep lkmc_dep /proc/kallsyms
+
+Requires "CONFIG_KALLSYMS_ALL=y".
+
 depmod:
 
 	grep dep "/lib/module/"*"/depmod"

kernel_module/ioctl.c

@@ -14,6 +14,9 @@ Documentation/ioctl/ioctl-number.txt has some info:
     _IOW   an ioctl with write parameters (copy_from_user)
     _IOR   an ioctl with read parameters  (copy_to_user)
     _IOWR  an ioctl with both write and read parameters.
+
+- https://stackoverflow.com/questions/2264384/how-do-i-use-ioctl-to-manipulate-my-kernel-module/44613896#44613896
+- https://askubuntu.com/questions/54239/problem-with-ioctl-in-a-simple-kernel-module/926675#926675
 */
 
 #include <asm/uaccess.h> /* copy_from_user, copy_to_user */