Merge tag 'efi-urgent-for-v6.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI fixes from Ard Biesheuvel:

 - Deal with a regression in the recently refactored x86 EFI stub code
   on older Dell systems by disabling randomization of the physical load
   address

 - Use the correct load address for relocatable Loongarch kernels

* tag 'efi-urgent-for-v6.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/x86: Avoid physical KASLR on older Dell systems
  efi/loongarch: Use load address to calculate kernel entry address

1 files changed, 24 insertions, 7 deletions

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 1bfdae34df39..da9b7b8d0716 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -307,17 +307,20 @@ static void setup_unaccepted_memory(void)
 		efi_err("Memory acceptance protocol failed\n");
 }
 
+static efi_char16_t *efistub_fw_vendor(void)
+{
+	unsigned long vendor = efi_table_attr(efi_system_table, fw_vendor);
+
+	return (efi_char16_t *)vendor;
+}
+
 static const efi_char16_t apple[] = L"Apple";
 
 static void setup_quirks(struct boot_params *boot_params)
 {
-	efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
-		efi_table_attr(efi_system_table, fw_vendor);
-
-	if (!memcmp(fw_vendor, apple, sizeof(apple))) {
-		if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
-			retrieve_apple_device_properties(boot_params);
-	}
+	if (IS_ENABLED(CONFIG_APPLE_PROPERTIES) &&
+	    !memcmp(efistub_fw_vendor(), apple, sizeof(apple)))
+		retrieve_apple_device_properties(boot_params);
 }
 
 /*
@@ -765,11 +768,25 @@ static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry)
 
 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
 		u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size;
+		static const efi_char16_t ami[] = L"American Megatrends";
 
 		efi_get_seed(seed, sizeof(seed));
 
 		virt_addr += (range * seed[1]) >> 32;
 		virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1);
+
+		/*
+		 * Older Dell systems with AMI UEFI firmware v2.0 may hang
+		 * while decompressing the kernel if physical address
+		 * randomization is enabled.
+		 *
+		 * https://bugzilla.kernel.org/show_bug.cgi?id=218173
+		 */
+		if (efi_system_table->hdr.revision <= EFI_2_00_SYSTEM_TABLE_REVISION &&
+		    !memcmp(efistub_fw_vendor(), ami, sizeof(ami))) {
+			efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n");
+			seed[0] = 0;
+		}
 	}
 
 	status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,