Introduction

+Introduction + + +

+When you read about kernel configurations, you will often see that setti= ngs are +described as CONFIG_<something>. This short-hand notation i= s what +the kernel configuration actually uses internally, and is what you will = find in +the kernel configuration file (be it /usr/src/linux/.config= or in +the auto-generated /proc/config.gz file). Of course, using +short-hand notation wouldn't do much good if you cannot translate this t= o the +real location in the kernel configuration. Luckily, the make menuconf= ig +tool allows you to do just that. +

+ + +

+Translating CONFIG_FOO to the real configuration location + + +

+Suppose you need to enable CONFIG_TMPFS_XATTR, launch the kernel +configuration menu (make menuconfig) and type in /. This w= ill open +the search box. In this search box, type CONFIG_TMPFS_XATTR (you = can even +drop the CONFIG_). The next code listing shows the result of this= search. +

+ +

+Symbol: TMPFS_XATTR [=3Dn]
+Type  : boolean
+Prompt: Tmpfs extended attributes
+  Defined at fs/Kconfig:138
+  Depends on: TMPFS [=3Dy]
+  Location:
+    -> File systems
+      -> Pseudo filesystems
+        -> Virtual memory file system support (former shm fs) (TMPFS [=3D=
y])
+  Selected by: TMPFS_POSIX_ACL [=3Dn] && TMPFS [=3Dy]
+

+ +

+This output yields lots of interesting information. +

+ + + + + + + + Symbol: TMPFS_XATTR [=3Dn] + + This identifies the kernel configuration entry you are looking for. = It also + already tells you that the setting is currently not enabled (= [=3Dn]). + + + + Type: boolean + + The setting you looked for is a boolean (which means you can enable = or + disable it). Some settings are numbers or strings. + + + + Prompt: Tmpfs extended attributes + + This is the text you will find in make menuconfig and as such= , is the + entry that you are looking for in a more human readable format. + + + + Depends on: TMPFS [=3Dy] + + Before you can even see this entry, you need to have CONFIG_TMPFS= + enabled. In this case, this is done (hence the [=3Dy]) but if this i= s not the + case, you will first need to look (and enable) CONFIG_TMPFS. + + + + Location: ... + + This is the location in the make menuconfig structure where y= ou can + find the setting. Remember, the setting you are looking for is Tm= pfs + extended attributes. + + + + Selected by: TMPFS_POSIX_ACL [=3Dn] && TMPFS [=3Dy] + + If the settings described here are both enabled (in our case, the fi= rst one + isn't), then CONFIG_TMPFS_XATTR will be automatically enabled= as well + and you will not be able to disable it. + + +

Entry	Description

+ +

+With this information, you should be able to translate any CONFIG_* +requirements tossed at you easily. In short, it means you +

+ +

need to enable the settings described in the Depends on fie= ld
navigate where Location: points you towards
toggle the value referred to by Prompt:

+ + +