linux: ignore FDT unless we need to modify itloadfile2-v4

Now that we implemented support for the LoadFile2 protocol for initrd
loading, there is no longer a need to pass the initrd parameters via
the device tree. This means that when the LoadFile2 protocol is being
used, there is no reason to update the device tree in the first place,
and so we can ignore it entirely.

The only remaining reason to deal with the devicetree is if we are
using the 'devicetree' command to load one from disk, so tweak the
logic in grub_fdt_install() to take that into account.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>

2 files changed, 16 insertions, 13 deletions

diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c
index 8b7fbb35f..36396e9f7 100644
--- a/grub-core/loader/arm64/linux.c
+++ b/grub-core/loader/arm64/linux.c
@@ -133,21 +133,21 @@ finalize_params_linux (void)
 
   void *fdt;
 
-  fdt = grub_fdt_load (GRUB_EFI_LINUX_FDT_EXTRA_SPACE);
+  /* Set initrd info */
+  if (initrd_start && initrd_end > initrd_start)
+    {
+      fdt = grub_fdt_load (GRUB_EFI_LINUX_FDT_EXTRA_SPACE);
 
-  if (!fdt)
-    goto failure;
+      if (!fdt)
+       goto failure;
 
-  node = grub_fdt_find_subnode (fdt, 0, "chosen");
-  if (node < 0)
-    node = grub_fdt_add_subnode (fdt, 0, "chosen");
+      node = grub_fdt_find_subnode (fdt, 0, "chosen");
+      if (node < 0)
+       node = grub_fdt_add_subnode (fdt, 0, "chosen");
 
-  if (node < 1)
-    goto failure;
+      if (node < 1)
+       goto failure;
 
-  /* Set initrd info */
-  if (initrd_start && initrd_end > initrd_start)
-    {
       grub_dprintf ("linux", "Initrd @ %p-%p\n",
 		    (void *) initrd_start, (void *) initrd_end);
 
diff --git a/grub-core/loader/efi/fdt.c b/grub-core/loader/efi/fdt.c
index 80d708874..fd8093ac8 100644
--- a/grub-core/loader/efi/fdt.c
+++ b/grub-core/loader/efi/fdt.c
@@ -89,13 +89,16 @@ grub_fdt_install (void)
   static grub_efi_guid_t fdt_guid = GRUB_EFI_DEVICE_TREE_GUID;
   grub_efi_status_t status;
 
+  if (!fdt && !loaded_fdt)
+    return GRUB_ERR_NONE;
+
   b = grub_efi_system_table->boot_services;
-  status = b->install_configuration_table (&fdt_guid, fdt);
+  status = b->install_configuration_table (&fdt_guid, fdt ?: loaded_fdt);
   if (status != GRUB_EFI_SUCCESS)
     return grub_error (GRUB_ERR_IO, "failed to install FDT");
 
   grub_dprintf ("fdt", "Installed/updated FDT configuration table @ %p\n",
-		fdt);
+		fdt ?: loaded_fdt);
   return GRUB_ERR_NONE;
 }