image: Add support for 32bit UEFI.

* gnu/bootloader/grub.scm (grub-efi32-bootloader): New variable.
(install-grub-efi32): New variable.
* gnu/build/bootloader.scm (install-efi): Add a 'targets' keyword
argument.
(install-efi-loader): Likewise.
* gnu/build/image.scm (initialize-efi32-partition): New procedure.
* gnu/packages/bootloaders.scm (grub-efi32): New variable.
* gnu/system/image.scm (esp32-partition): New variable
(efi32-disk-image): New variable.
(efi32-raw-image-type): New variable.
(system-disk-image)[partition-image]: Set '#:grub-efi32' when
calling the partition initializer.

Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>

5 files changed, 102 insertions, 13 deletions

diff --git a/gnu/bootloader/grub.scm b/gnu/bootloader/grub.scm
index 65d7171432c..4f18c9b5183 100644
--- a/gnu/bootloader/grub.scm
+++ b/gnu/bootloader/grub.scm
@@ -8,6 +8,7 @@
 ;;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;; Copyright © 2020 Stefan <stefan-guix@vodafonemail.de>
 ;;; Copyright © 2022 Karl Hallsby <karl@hallsby.com>
+;;; Copyright © 2022 Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -57,6 +58,7 @@
             grub-bootloader
             grub-efi-bootloader
             grub-efi-removable-bootloader
+            grub-efi32-bootloader
             grub-efi-netboot-bootloader
             grub-mkrescue-bootloader
             grub-minimal-bootloader
@@ -636,6 +638,29 @@ fi~%"))))
                         "--bootloader-id=Guix"
                         "--efi-directory" target-esp)))))
 
+(define install-grub-efi32
+  #~(lambda (bootloader efi-dir mount-point)
+      ;; There is nothing useful to do when called in the context of a disk
+      ;; image generation.
+      (when efi-dir
+        ;; Install GRUB onto the EFI partition mounted at EFI-DIR, for the
+        ;; system whose root is mounted at MOUNT-POINT.
+        (let ((grub-install (string-append bootloader "/sbin/grub-install"))
+              (install-dir (string-append mount-point "/boot"))
+              ;; When installing Guix, it's common to mount EFI-DIR below
+              ;; MOUNT-POINT rather than /boot/efi on the live image.
+              (target-esp (if (file-exists? (string-append mount-point efi-dir))
+                              (string-append mount-point efi-dir)
+                              efi-dir)))
+          ;; Tell 'grub-install' that there might be a LUKS-encrypted /boot or
+          ;; root partition.
+          (setenv "GRUB_ENABLE_CRYPTODISK" "y")
+          (invoke/quiet grub-install "--boot-directory" install-dir
+                        "--bootloader-id=Guix"
+                        (cond ((target-x86?) "--target=i386-efi")
+                              ((target-arm?) "--target=arm-efi"))
+                        "--efi-directory" target-esp)))))
+
 (define (install-grub-efi-netboot subdir)
   "Define a grub-efi-netboot bootloader installer for installation in SUBDIR,
 which is usually efi/Guix or efi/boot."
@@ -768,6 +793,13 @@ considered for security aspects."
    (name 'grub-efi-removable-bootloader)
    (installer install-grub-efi-removable)))
 
+(define grub-efi32-bootloader
+  (bootloader
+   (inherit grub-efi-bootloader)
+   (installer install-grub-efi32)
+   (name 'grub-efi32)
+   (package grub-efi32)))
+
 (define grub-efi-netboot-bootloader
   (bootloader
    (inherit grub-efi-bootloader)
diff --git a/gnu/build/bootloader.scm b/gnu/build/bootloader.scm
index 9a89fe55cbe..af6063a884a 100644
--- a/gnu/build/bootloader.scm
+++ b/gnu/build/bootloader.scm
@@ -1,6 +1,8 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
 ;;; Copyright © 2019 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2022 Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
+;;; Copyright © 2022 Timothy Sample <samplet@ngyro.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -54,8 +56,12 @@
 ;;; EFI bootloader.
 ;;;
 
-(define (install-efi grub grub-config esp)
-  "Write a self-contained GRUB EFI loader to the mounted ESP using GRUB-CONFIG."
+(define* (install-efi grub grub-config esp #:key targets)
+  "Write a self-contained GRUB EFI loader to the mounted ESP using
+GRUB-CONFIG.
+
+If TARGETS is set, use its car as the GRUB image format and its cdr as
+the output filename.  Otherwise, use defaults for the host platform."
   (let* ((system %host-type)
          ;; Hard code the output location to a well-known path recognized by
          ;; compliant firmware. See "3.5.1.1 Removable Media Boot Behaviour":
@@ -63,14 +69,15 @@
          (grub-mkstandalone (string-append grub "/bin/grub-mkstandalone"))
          (efi-directory (string-append esp "/EFI/BOOT"))
          ;; Map grub target names to boot file names.
-         (efi-targets (cond ((string-prefix? "x86_64" system)
-                             '("x86_64-efi" . "BOOTX64.EFI"))
-                            ((string-prefix? "i686" system)
-                             '("i386-efi" . "BOOTIA32.EFI"))
-                            ((string-prefix? "armhf" system)
-                             '("arm-efi" . "BOOTARM.EFI"))
-                            ((string-prefix? "aarch64" system)
-                             '("arm64-efi" . "BOOTAA64.EFI")))))
+         (efi-targets (or targets
+                          (cond ((string-prefix? "x86_64" system)
+                                 '("x86_64-efi" . "BOOTX64.EFI"))
+                                ((string-prefix? "i686" system)
+                                 '("i386-efi" . "BOOTIA32.EFI"))
+                                ((string-prefix? "armhf" system)
+                                 '("arm-efi" . "BOOTARM.EFI"))
+                                ((string-prefix? "aarch64" system)
+                                 '("arm64-efi" . "BOOTAA64.EFI"))))))
     ;; grub-mkstandalone requires a TMPDIR to prepare the firmware image.
     (setenv "TMPDIR" esp)
 
@@ -81,9 +88,12 @@
             ;; Graft the configuration file onto the image.
             (string-append "boot/grub/grub.cfg=" grub-config))))
 
-(define (install-efi-loader grub-efi esp)
+(define* (install-efi-loader grub-efi esp #:key targets)
   "Install in ESP directory the given GRUB-EFI bootloader.  Configure it to
-load the Grub bootloader located in the 'Guix_image' root partition."
+load the Grub bootloader located in the 'Guix_image' root partition.
+
+If TARGETS is set, use its car as the GRUB image format and its cdr as
+the output filename.  Otherwise, use defaults for the host platform."
   (let ((grub-config "grub.cfg"))
     (call-with-output-file grub-config
       (lambda (port)
@@ -97,5 +107,6 @@ load the Grub bootloader located in the 'Guix_image' root partition."
                insmod part_gpt~@
                search --set=root --label Guix_image~@
                configfile /boot/grub/grub.cfg~%")))
-    (install-efi grub-efi grub-config esp)
+    (install-efi grub-efi grub-config esp #:targets targets)
     (delete-file grub-config)))
+
diff --git a/gnu/build/image.scm b/gnu/build/image.scm
index ddfd34c111a..321be8e4b1a 100644
--- a/gnu/build/image.scm
+++ b/gnu/build/image.scm
@@ -6,6 +6,7 @@
 ;;; Copyright © 2020, 2022 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2020 Mathieu Othacehe <m.othacehe@gmail.com>
 ;;; Copyright © 2022 Pavel Shlyak <p.shlyak@pantherx.org>
+;;; Copyright © 2022 Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -27,6 +28,7 @@
   #:use-module (guix build syscalls)
   #:use-module (guix build utils)
   #:use-module (guix store database)
+  #:use-module (guix utils)
   #:use-module (gnu build bootloader)
   #:use-module (gnu build install)
   #:use-module (gnu build linux-boot)
@@ -41,6 +43,7 @@
             convert-disk-image
             genimage
             initialize-efi-partition
+            initialize-efi32-partition
             initialize-root-partition
 
             make-iso9660-image))
@@ -169,6 +172,17 @@ produced by #:references-graphs.  Pass WAL-MODE? to call-with-database."
   "Install in ROOT directory, an EFI loader using GRUB-EFI."
   (install-efi-loader grub-efi root))
 
+(define* (initialize-efi32-partition root
+                                     #:key
+                                     grub-efi32
+                                     #:allow-other-keys)
+  "Install in ROOT directory, an EFI 32bit loader using GRUB-EFI32."
+  (install-efi-loader grub-efi32 root
+                      #:targets (cond ((target-x86?)
+                                       '("i386-efi" . "BOOTIA32.EFI"))
+                                      ((target-arm?)
+                                       '("arm-efi" . "BOOTARM.EFI")))))
+
 (define* (initialize-root-partition root
                                     #:key
                                     bootcfg
diff --git a/gnu/packages/bootloaders.scm b/gnu/packages/bootloaders.scm
index 91d259475a4..71a10f54d54 100644
--- a/gnu/packages/bootloaders.scm
+++ b/gnu/packages/bootloaders.scm
@@ -15,6 +15,7 @@
 ;;; Copyright © 2020, 2021 Pierre Langlois <pierre.langlois@gmx.com>
 ;;; Copyright © 2021 Vincent Legoll <vincent.legoll@gmail.com>
 ;;; Copyright © 2021 Brice Waegeneire <brice@waegenei.re>
+;;; Copyright © 2022 Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -332,6 +333,18 @@ menu to select one of the installed operating systems.")
                                        "/bin/mcopy\"")))
                      #t))))))))))
 
+(define-public grub-efi32
+  (package
+    (inherit grub-efi)
+    (name "grub-efi32")
+    (synopsis "GRand Unified Boot loader (UEFI 32bit version)")
+    (arguments
+     `(,@(substitute-keyword-arguments (package-arguments grub-efi)
+           ((#:configure-flags flags
+             ''()) `(cons* ,(cond ((target-x86?) "--target=i386")
+                                  ((target-arm?) "--target=arm"))
+                           ,flags)))))))
+
 ;; Because grub searches hardcoded paths it's easiest to just build grub
 ;; again to make it find both grub-pc and grub-efi.  There is a command
 ;; line argument which allows you to specify ONE platform - but
diff --git a/gnu/system/image.scm b/gnu/system/image.scm
index f02f6e0b8c2..5972a944d7b 100644
--- a/gnu/system/image.scm
+++ b/gnu/system/image.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2020, 2021 Mathieu Othacehe <m.othacehe@gmail.com>
 ;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ;;; Copyright © 2022 Pavel Shlyak <p.shlyak@pantherx.org>
+;;; Copyright © 2022 Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -66,6 +67,7 @@
             root-label
 
             esp-partition
+            esp32-partition
             root-partition
 
             efi-disk-image
@@ -75,6 +77,7 @@
 
             image-with-os
             efi-raw-image-type
+            efi32-raw-image-type
             qcow2-image-type
             iso-image-type
             uncompressed-iso-image-type
@@ -110,6 +113,11 @@
    (flags '(esp))
    (initializer (gexp initialize-efi-partition))))
 
+(define esp32-partition
+  (partition
+   (inherit esp-partition)
+   (initializer (gexp initialize-efi32-partition))))
+
 (define root-partition
   (partition
    (size 'guess)
@@ -123,6 +131,11 @@
    (format 'disk-image)
    (partitions (list esp-partition root-partition))))
 
+(define efi32-disk-image
+  (image
+   (format 'disk-image)
+   (partitions (list esp32-partition root-partition))))
+
 (define iso9660-image
   (image
    (format 'iso9660)
@@ -164,6 +177,11 @@ set to the given OS."
    (name 'efi-raw)
    (constructor (cut image-with-os efi-disk-image <>))))
 
+(define efi32-raw-image-type
+  (image-type
+   (name 'efi32-raw)
+   (constructor (cut image-with-os efi32-disk-image <>))))
+
 (define qcow2-image-type
   (image-type
    (name 'qcow2)
@@ -376,6 +394,7 @@ used in the image."
                                                 #$(image-shared-store? image))
                               #:system-directory #$os
                               #:grub-efi #+grub-efi
+                              #:grub-efi32 #+grub-efi32
                               #:bootloader-package
                               #+(bootloader-package bootloader)
                               #:bootloader-installer