diff --git a/ChangeLog b/ChangeLog
index cdb3f3d33..097ef0de1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-01-07  Colin Watson  <cjwatson@ubuntu.com>
+
+	* docs/grub.texi (grub_cpu): New subsection.
+	(grub_platform): Likewise.
+
 2013-01-07  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/fs/minix.c (grub_minix_read_file): Simplify arithmetics.
diff --git a/docs/grub.texi b/docs/grub.texi
index e23ceccb4..a92bd969e 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -2674,6 +2674,8 @@ These variables have special meaning to GRUB.
 * gfxmode::
 * gfxpayload::
 * gfxterm_font::
+* grub_cpu::
+* grub_platform::
 * icondir::
 * lang::
 * locale_dir::
@@ -2857,6 +2859,20 @@ If this variable is set, it names a font to use for text on the
 available font.
 
 
+@node grub_cpu
+@subsection grub_cpu
+
+In normal mode (@pxref{normal}), GRUB sets the @samp{grub_cpu} variable to
+the CPU type for which GRUB was built (e.g. @samp{i386} or @samp{powerpc}).
+
+
+@node grub_platform
+@subsection grub_platform
+
+In normal mode (@pxref{normal}), GRUB sets the @samp{grub_platform} variable
+to the platform for which GRUB was built (e.g. @samp{pc} or @samp{efi}).
+
+
 @node icondir
 @subsection icondir