[PATCH] machine_kexec.c: Fix the description of segment handling

One of my original comments in machine_kexec was unclear
and this should fix it.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <ak@muc.de>
Acked-by: Horms <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/kernel/machine_kexec.c

@@ -189,14 +189,11 @@ NORET_TYPE void machine_kexec(struct kimage *image)
 	memcpy((void *)reboot_code_buffer, relocate_new_kernel,
 						relocate_new_kernel_size);
 
-	/* The segment registers are funny things, they are
-	 * automatically loaded from a table, in memory wherever you
-	 * set them to a specific selector, but this table is never
-	 * accessed again you set the segment to a different selector.
-	 *
-	 * The more common model is are caches where the behide
-	 * the scenes work is done, but is also dropped at arbitrary
-	 * times.
+	/* The segment registers are funny things, they have both a
+	 * visible and an invisible part.  Whenever the visible part is
+	 * set to a specific selector, the invisible part is loaded
+	 * with from a table in memory.  At no other time is the
+	 * descriptor table in memory accessed.
 	 *
 	 * I take advantage of this here by force loading the
 	 * segments, before I zap the gdt with an invalid value.

arch/x86_64/kernel/machine_kexec.c

@@ -207,14 +207,11 @@ NORET_TYPE void machine_kexec(struct kimage *image)
 	__flush_tlb();
 
 
-	/* The segment registers are funny things, they are
-	 * automatically loaded from a table, in memory wherever you
-	 * set them to a specific selector, but this table is never
-	 * accessed again unless you set the segment to a different selector.
-	 *
-	 * The more common model are caches where the behide
-	 * the scenes work is done, but is also dropped at arbitrary
-	 * times.
+	/* The segment registers are funny things, they have both a
+	 * visible and an invisible part.  Whenever the visible part is
+	 * set to a specific selector, the invisible part is loaded
+	 * with from a table in memory.  At no other time is the
+	 * descriptor table in memory accessed.
 	 *
 	 * I take advantage of this here by force loading the
 	 * segments, before I zap the gdt with an invalid value.