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

3 files changed, 29 insertions, 12 deletions

diff --git a/drivers/firmware/efi/libstub/loongarch-stub.c b/drivers/firmware/efi/libstub/loongarch-stub.c
index 72c71ae201f0..d6ec5d4b8dbe 100644
--- a/drivers/firmware/efi/libstub/loongarch-stub.c
+++ b/drivers/firmware/efi/libstub/loongarch-stub.c
@@ -35,9 +35,9 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 	return status;
 }
 
-unsigned long kernel_entry_address(void)
+unsigned long kernel_entry_address(unsigned long kernel_addr)
 {
 	unsigned long base = (unsigned long)&kernel_offset - kernel_offset;
 
-	return (unsigned long)&kernel_entry - base + VMLINUX_LOAD_ADDRESS;
+	return (unsigned long)&kernel_entry - base + kernel_addr;
 }
diff --git a/drivers/firmware/efi/libstub/loongarch.c b/drivers/firmware/efi/libstub/loongarch.c
index 807cba2693fc..0e0aa6cda73f 100644
--- a/drivers/firmware/efi/libstub/loongarch.c
+++ b/drivers/firmware/efi/libstub/loongarch.c
@@ -37,9 +37,9 @@ static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv)
 	return EFI_SUCCESS;
 }
 
-unsigned long __weak kernel_entry_address(void)
+unsigned long __weak kernel_entry_address(unsigned long kernel_addr)
 {
-	return *(unsigned long *)(PHYSADDR(VMLINUX_LOAD_ADDRESS) + 8);
+	return *(unsigned long *)(kernel_addr + 8) - VMLINUX_LOAD_ADDRESS + kernel_addr;
 }
 
 efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,
@@ -73,7 +73,7 @@ efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,
 	csr_write64(CSR_DMW0_INIT, LOONGARCH_CSR_DMWIN0);
 	csr_write64(CSR_DMW1_INIT, LOONGARCH_CSR_DMWIN1);
 
-	real_kernel_entry = (void *)kernel_entry_address();
+	real_kernel_entry = (void *)kernel_entry_address(kernel_addr);
 
 	real_kernel_entry(true, (unsigned long)cmdline_ptr,
 			  (unsigned long)efi_system_table);
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,