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authorRusty Russell <rusty@rustcorp.com.au>2007-07-26 10:41:02 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-26 11:35:16 -0700
commitf938d2c892db0d80d144253d4a7b7083efdbedeb (patch)
tree1fbc946a9fb59827001a5d4d5224abe5e624e605 /drivers/lguest/segments.c
parentdfb68689bf3e3d31dc9fb5c2bde5379a4ca9b0ec (diff)
lguest: documentation I: Preparation
The netfilter code had very good documentation: the Netfilter Hacking HOWTO. Noone ever read it. So this time I'm trying something different, using a bit of Knuthiness. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/lguest/segments.c')
-rw-r--r--drivers/lguest/segments.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/lguest/segments.c b/drivers/lguest/segments.c
index 1b2cfe89dcd..c4fc7293b84 100644
--- a/drivers/lguest/segments.c
+++ b/drivers/lguest/segments.c
@@ -1,3 +1,14 @@
+/*P:600 The x86 architecture has segments, which involve a table of descriptors
+ * which can be used to do funky things with virtual address interpretation.
+ * We originally used to use segments so the Guest couldn't alter the
+ * Guest<->Host Switcher, and then we had to trim Guest segments, and restore
+ * for userspace per-thread segments, but trim again for on userspace->kernel
+ * transitions... This nightmarish creation was contained within this file,
+ * where we knew not to tread without heavy armament and a change of underwear.
+ *
+ * In these modern times, the segment handling code consists of simple sanity
+ * checks, and the worst you'll experience reading this code is butterfly-rash
+ * from frolicking through its parklike serenity. :*/
#include "lg.h"
static int desc_ok(const struct desc_struct *gdt)