docs: Document the cutmem command

The command is not present in the docs/grub.texi user documentation.

Reported-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

diff --git a/docs/grub.texi b/docs/grub.texi
index 91666781bf2263fed6bc6be9d0df728c8e607b26..c5fc3904faeab200838713f9b73cfe868e03a567 100644 (file)
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -3981,6 +3981,7 @@ you forget a command, you can run the command @command{help}
 * cpuid::                       Check for CPU features
 * crc::                         Compute or check CRC32 checksums
 * cryptomount::                 Mount a crypto device
+* cutmem::                      Remove memory regions
 * date::                        Display or set current date and time
 * devicetree::                  Load a device tree blob
 * distrust::                    Remove a pubkey from trusted keys
@@ -4139,6 +4140,8 @@ this page is to be filtered.  This syntax makes it easy to represent patterns
 that are often result of memory damage, due to physical distribution of memory
 cells.
 
+The command is similar to @command{cutmem} command.
+
 Note: The command is not allowed when lockdown is enforced (@pxref{Lockdown}).
       This prevents removing EFI memory regions to potentially subvert the
       security mechanisms provided by the UEFI secure boot.
@@ -4303,6 +4306,24 @@ modules (@var{luks}, @var{luks2} and @var{geli}) have to be loaded manually
 before this command can be used.
 @end deffn
 
+@node cutmem
+@subsection cutmem
+
+@deffn Command cutmem from[K|M|G] to[K|M|G]
+Remove any memory regions in specified range.
+@end deffn
+
+This command notifies the memory manager that specified regions of RAM ought to
+be filtered out. This remains in effect after a payload kernel has been loaded
+by GRUB, as long as the loaded kernel obtains its memory map from GRUB. Kernels
+that support this include Linux, GNU Mach, the kernel of FreeBSD and Multiboot
+kernels in general.
+
+The command is similar to @command{badram} command.
+
+Note: The command is not allowed when lockdown is enforced (@pxref{Lockdown}).
+      This prevents removing EFI memory regions to potentially subvert the
+      security mechanisms provided by the UEFI secure boot.
 
 @node date
 @subsection date