From: Julian Andres Klode <julian.klode@canonical.com>
Date: Wed, 19 Jul 2023 15:52:09 +0200
Subject: Disable fallback to legacy mode if shim is loaded on x86 archs

This reverts commits
- 6425c12cd77ad51ad24be84c092aefacf0875089:
  this originally adds the fallback
- e60015f574024584e43d1b3b245551e864aa8c4d:
  this triggers it in another case
---
 grub-core/kern/efi/sb.c      | 18 ------------------
 grub-core/loader/efi/linux.c | 17 -----------------
 include/grub/efi/sb.h        |  5 +----
 3 files changed, 1 insertion(+), 39 deletions(-)

diff --git a/grub-core/kern/efi/sb.c b/grub-core/kern/efi/sb.c
index 8d3e413..80cfa08 100644
--- a/grub-core/kern/efi/sb.c
+++ b/grub-core/kern/efi/sb.c
@@ -32,8 +32,6 @@
 
 static grub_guid_t shim_lock_guid = GRUB_EFI_SHIM_LOCK_GUID;
 
-static bool shim_lock_enabled = false;
-
 /*
  * Determine whether we're in secure boot mode.
  *
@@ -95,14 +93,6 @@ grub_efi_get_secureboot (void)
   if (!(attr & GRUB_EFI_VARIABLE_RUNTIME_ACCESS) && *moksbstate == 1)
     {
       secureboot = GRUB_EFI_SECUREBOOT_MODE_DISABLED;
-      /*
-       * TODO: Replace this all with shim's LoadImage protocol, delegating policy to it.
-       *
-       * We need to set shim_lock_enabled here because we disabled secure boot
-       * validation *inside* shim but not in the firmware, so we set this variable
-       * here to trigger that code path, whereas the actual verifier is not enabled.
-       */
-      shim_lock_enabled = true;
       goto out;
     }
 
@@ -225,14 +215,6 @@ grub_shim_lock_verifier_setup (void)
   /* Enforce shim_lock_verifier. */
   grub_verifier_register (&shim_lock_verifier);
 
-  shim_lock_enabled = true;
-
   grub_env_set ("shim_lock", "y");
   grub_env_export ("shim_lock");
 }
-
-bool
-grub_is_shim_lock_enabled (void)
-{
-  return shim_lock_enabled;
-}
diff --git a/grub-core/loader/efi/linux.c b/grub-core/loader/efi/linux.c
index bfbd95a..dd6ca47 100644
--- a/grub-core/loader/efi/linux.c
+++ b/grub-core/loader/efi/linux.c
@@ -29,7 +29,6 @@
 #include <grub/efi/fdtload.h>
 #include <grub/efi/memory.h>
 #include <grub/efi/pe32.h>
-#include <grub/efi/sb.h>
 #include <grub/i18n.h>
 #include <grub/lib/cmdline.h>
 #include <grub/verify.h>
@@ -462,22 +461,6 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
 
   grub_dl_ref (my_mod);
 
-  if (grub_is_shim_lock_enabled () == true)
-    {
-#if defined(__i386__) || defined(__x86_64__)
-      grub_dprintf ("linux", "shim_lock enabled, falling back to legacy Linux kernel loader\n");
-
-      err = grub_cmd_linux_x86_legacy (cmd, argc, argv);
-
-      if (err == GRUB_ERR_NONE)
-	return GRUB_ERR_NONE;
-      else
-	goto fail;
-#else
-      grub_dprintf ("linux", "shim_lock enabled, trying Linux kernel EFI stub loader\n");
-#endif
-    }
-
   if (argc == 0)
     {
       grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
diff --git a/include/grub/efi/sb.h b/include/grub/efi/sb.h
index 49a9ad0..30c4335 100644
--- a/include/grub/efi/sb.h
+++ b/include/grub/efi/sb.h
@@ -22,7 +22,7 @@
 #include <grub/types.h>
 #include <grub/dl.h>
 
-#define GRUB_EFI_SECUREBOOT_MODE_UNSET		0
+#define GRUB_EFI_SECUREBOOT_MODE_UNSET	0
 #define GRUB_EFI_SECUREBOOT_MODE_UNKNOWN	1
 #define GRUB_EFI_SECUREBOOT_MODE_DISABLED	2
 #define GRUB_EFI_SECUREBOOT_MODE_ENABLED	3
@@ -31,9 +31,6 @@
 extern grub_uint8_t
 EXPORT_FUNC (grub_efi_get_secureboot) (void);
 
-extern bool
-EXPORT_FUNC (grub_is_shim_lock_enabled) (void);
-
 extern void
 grub_shim_lock_verifier_setup (void);
 #else