efi: libstub: unify initrd loading between architectures

Use a EFI configuration table to pass the initrd to the core kernel,
instead of per-arch methods. This cleans up the code considerably, and
should make it easier for architectures to get rid of their reliance on
DT for doing EFI boot in the future.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Documentation/arm/uefi.rst

@@ -65,10 +65,6 @@ linux,uefi-mmap-desc-size   32-bit   Size in bytes of each entry in the UEFI
 
 linux,uefi-mmap-desc-ver    32-bit   Version of the mmap descriptor format.
 
-linux,initrd-start          64-bit   Physical start address of an initrd
-
-linux,initrd-end            64-bit   Physical end address of an initrd
-
 kaslr-seed                  64-bit   Entropy used to randomize the kernel image
                                      base address location.
 ==========================  ======   ===========================================

drivers/firmware/efi/efi.c

@@ -21,6 +21,7 @@
 #include <linux/device.h>
 #include <linux/efi.h>
 #include <linux/of.h>
+#include <linux/initrd.h>
 #include <linux/io.h>
 #include <linux/kexec.h>
 #include <linux/platform_device.h>
@@ -55,6 +56,7 @@ EXPORT_SYMBOL(efi);
 unsigned long __ro_after_init efi_rng_seed = EFI_INVALID_TABLE_ADDR;
 static unsigned long __initdata mem_reserve = EFI_INVALID_TABLE_ADDR;
 static unsigned long __initdata rt_prop = EFI_INVALID_TABLE_ADDR;
+static unsigned long __initdata initrd = EFI_INVALID_TABLE_ADDR;
 
 struct mm_struct efi_mm = {
 	.mm_rb			= RB_ROOT,
@@ -532,6 +534,7 @@ static const efi_config_table_type_t common_tables[] __initconst = {
 	{LINUX_EFI_TPM_EVENT_LOG_GUID,		&efi.tpm_log,		"TPMEventLog"	},
 	{LINUX_EFI_TPM_FINAL_LOG_GUID,		&efi.tpm_final_log,	"TPMFinalLog"	},
 	{LINUX_EFI_MEMRESERVE_TABLE_GUID,	&mem_reserve,		"MEMRESERVE"	},
+	{LINUX_EFI_INITRD_MEDIA_GUID,		&initrd,		"INITRD"	},
 	{EFI_RT_PROPERTIES_TABLE_GUID,		&rt_prop,		"RTPROP"	},
 #ifdef CONFIG_EFI_RCI2_TABLE
 	{DELLEMC_EFI_RCI2_TABLE_GUID,		&rci2_table_phys			},
@@ -674,6 +677,18 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
 		}
 	}
 
+	if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) &&
+	    initrd != EFI_INVALID_TABLE_ADDR && phys_initrd_size == 0) {
+		struct linux_efi_initrd *tbl;
+
+		tbl = early_memremap(initrd, sizeof(*tbl));
+		if (tbl) {
+			phys_initrd_start = tbl->base;
+			phys_initrd_size = tbl->size;
+			early_memunmap(tbl, sizeof(*tbl));
+		}
+	}
+
 	return 0;
 }
 

drivers/firmware/efi/libstub/efi-stub-helper.c

@@ -550,20 +550,16 @@ static const struct {
  * * %EFI_SUCCESS if the initrd was loaded successfully, in which
  *   case @load_addr and @load_size are assigned accordingly
  * * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd device path
- * * %EFI_INVALID_PARAMETER if load_addr == NULL or load_size == NULL
  * * %EFI_OUT_OF_RESOURCES if memory allocation failed
  * * %EFI_LOAD_ERROR in all other cases
  */
 static
-efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr,
-				      unsigned long *load_size,
+efi_status_t efi_load_initrd_dev_path(struct linux_efi_initrd *initrd,
 				      unsigned long max)
 {
 	efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID;
 	efi_device_path_protocol_t *dp;
 	efi_load_file2_protocol_t *lf2;
-	unsigned long initrd_addr;
-	unsigned long initrd_size;
 	efi_handle_t handle;
 	efi_status_t status;
 
@@ -577,42 +573,37 @@ efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr,
 	if (status != EFI_SUCCESS)
 		return status;
 
-	status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, NULL);
+	initrd->size = 0;
+	status = efi_call_proto(lf2, load_file, dp, false, &initrd->size, NULL);
 	if (status != EFI_BUFFER_TOO_SMALL)
 		return EFI_LOAD_ERROR;
 
-	status = efi_allocate_pages(initrd_size, &initrd_addr, max);
+	status = efi_allocate_pages(initrd->size, &initrd->base, max);
 	if (status != EFI_SUCCESS)
 		return status;
 
-	status = efi_call_proto(lf2, load_file, dp, false, &initrd_size,
-				(void *)initrd_addr);
+	status = efi_call_proto(lf2, load_file, dp, false, &initrd->size,
+				(void *)initrd->base);
 	if (status != EFI_SUCCESS) {
-		efi_free(initrd_size, initrd_addr);
+		efi_free(initrd->size, initrd->base);
 		return EFI_LOAD_ERROR;
 	}
-
-	*load_addr = initrd_addr;
-	*load_size = initrd_size;
 	return EFI_SUCCESS;
 }
 
 static
 efi_status_t efi_load_initrd_cmdline(efi_loaded_image_t *image,
-				     unsigned long *load_addr,
-				     unsigned long *load_size,
+				     struct linux_efi_initrd *initrd,
 				     unsigned long soft_limit,
 				     unsigned long hard_limit)
 {
 	if (!IS_ENABLED(CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER) ||
-	    (IS_ENABLED(CONFIG_X86) && (!efi_is_native() || image == NULL))) {
-		*load_addr = *load_size = 0;
-		return EFI_SUCCESS;
-	}
+	    (IS_ENABLED(CONFIG_X86) && (!efi_is_native() || image == NULL)))
+		return EFI_UNSUPPORTED;
 
 	return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2,
 				    soft_limit, hard_limit,
-				    load_addr, load_size);
+				    &initrd->base, &initrd->size);
 }
 
 static const struct {
@@ -659,42 +650,60 @@ static void efi_measure_initrd(unsigned long load_addr, unsigned long load_size)
 /**
  * efi_load_initrd() - Load initial RAM disk
  * @image:	EFI loaded image protocol
- * @load_addr:	pointer to loaded initrd
- * @load_size:	size of loaded initrd
  * @soft_limit:	preferred address for loading the initrd
  * @hard_limit:	upper limit address for loading the initrd
  *
  * Return:	status code
  */
 efi_status_t efi_load_initrd(efi_loaded_image_t *image,
-			     unsigned long *load_addr,
-			     unsigned long *load_size,
 			     unsigned long soft_limit,
-			     unsigned long hard_limit)
+			     unsigned long hard_limit,
+			     const struct linux_efi_initrd **out)
 {
-	efi_status_t status;
+	efi_guid_t tbl_guid = LINUX_EFI_INITRD_MEDIA_GUID;
+	efi_status_t status = EFI_SUCCESS;
+	struct linux_efi_initrd initrd, *tbl;
 
-	if (efi_noinitrd) {
-		*load_addr = *load_size = 0;
-		status = EFI_SUCCESS;
-	} else {
-		status = efi_load_initrd_dev_path(load_addr, load_size, hard_limit);
-		if (status == EFI_SUCCESS) {
-			efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n");
-			if (*load_size > 0)
-				efi_measure_initrd(*load_addr, *load_size);
-		} else if (status == EFI_NOT_FOUND) {
-			status = efi_load_initrd_cmdline(image, load_addr, load_size,
-							 soft_limit, hard_limit);
-			if (status == EFI_SUCCESS && *load_size > 0)
-				efi_info("Loaded initrd from command line option\n");
-		}
-		if (status != EFI_SUCCESS) {
-			efi_err("Failed to load initrd: 0x%lx\n", status);
-			*load_addr = *load_size = 0;
-		}
+	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD) || efi_noinitrd)
+		return EFI_SUCCESS;
+
+	status = efi_load_initrd_dev_path(&initrd, hard_limit);
+	if (status == EFI_SUCCESS) {
+		efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n");
+		if (initrd.size > 0)
+			efi_measure_initrd(initrd.base, initrd.size);
+	} else if (status == EFI_NOT_FOUND) {
+		status = efi_load_initrd_cmdline(image, &initrd, soft_limit,
+						 hard_limit);
+		/* command line loader disabled or no initrd= passed? */
+		if (status == EFI_UNSUPPORTED || status == EFI_NOT_READY)
+			return EFI_SUCCESS;
+		if (status == EFI_SUCCESS)
+			efi_info("Loaded initrd from command line option\n");
 	}
+	if (status != EFI_SUCCESS)
+		goto failed;
+
+	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(initrd),
+			     (void **)&tbl);
+	if (status != EFI_SUCCESS)
+		goto free_initrd;
+
+	*tbl = initrd;
+	status = efi_bs_call(install_configuration_table, &tbl_guid, tbl);
+	if (status != EFI_SUCCESS)
+		goto free_tbl;
+
+	if (out)
+		*out = tbl;
+	return EFI_SUCCESS;
 
+free_tbl:
+	efi_bs_call(free_pool, tbl);
+free_initrd:
+	efi_free(initrd.size, initrd.base);
+failed:
+	efi_err("Failed to load initrd: 0x%lx\n", status);
 	return status;
 }
 

drivers/firmware/efi/libstub/efi-stub.c

@@ -132,8 +132,6 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	unsigned long image_addr;
 	unsigned long image_size = 0;
 	/* addr/point and size pairs for memory management*/
-	unsigned long initrd_addr = 0;
-	unsigned long initrd_size = 0;
 	unsigned long fdt_addr = 0;  /* Original DTB */
 	unsigned long fdt_size = 0;
 	char *cmdline_ptr = NULL;
@@ -231,7 +229,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	} else {
 		status = efi_load_dtb(image, &fdt_addr, &fdt_size);
 
-		if (status != EFI_SUCCESS) {
+		if (status != EFI_SUCCESS && status != EFI_NOT_READY) {
 			efi_err("Failed to load device tree!\n");
 			goto fail_free_image;
 		}
@@ -249,8 +247,8 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	if (!fdt_addr)
 		efi_info("Generating empty DTB\n");
 
-	efi_load_initrd(image, &initrd_addr, &initrd_size, ULONG_MAX,
-			efi_get_max_initrd_addr(image_addr));
+	efi_load_initrd(image, ULONG_MAX, efi_get_max_initrd_addr(image_addr),
+			NULL);
 
 	efi_random_get_seed();
 
@@ -292,11 +290,10 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 
 	install_memreserve_table();
 
-	status = allocate_new_fdt_and_exit_boot(handle, &fdt_addr,
-						initrd_addr, initrd_size,
-						cmdline_ptr, fdt_addr, fdt_size);
+	status = allocate_new_fdt_and_exit_boot(handle, &fdt_addr, cmdline_ptr,
+						fdt_addr, fdt_size);
 	if (status != EFI_SUCCESS)
-		goto fail_free_initrd;
+		goto fail_free_fdt;
 
 	if (IS_ENABLED(CONFIG_ARM))
 		efi_handle_post_ebs_state();
@@ -304,10 +301,9 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	efi_enter_kernel(image_addr, fdt_addr, fdt_totalsize((void *)fdt_addr));
 	/* not reached */
 
-fail_free_initrd:
+fail_free_fdt:
 	efi_err("Failed to update FDT and exit boot services\n");
 
-	efi_free(initrd_size, initrd_addr);
 	efi_free(fdt_size, fdt_addr);
 
 fail_free_image:

drivers/firmware/efi/libstub/efistub.h

@@ -846,7 +846,6 @@ efi_status_t efi_exit_boot_services(void *handle, void *priv,
 
 efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 					    unsigned long *new_fdt_addr,
-					    u64 initrd_addr, u64 initrd_size,
 					    char *cmdline_ptr,
 					    unsigned long fdt_addr,
 					    unsigned long fdt_size);
@@ -923,10 +922,9 @@ static inline efi_status_t efi_load_dtb(efi_loaded_image_t *image,
 }
 
 efi_status_t efi_load_initrd(efi_loaded_image_t *image,
-			     unsigned long *load_addr,
-			     unsigned long *load_size,
 			     unsigned long soft_limit,
-			     unsigned long hard_limit);
+			     unsigned long hard_limit,
+			     const struct linux_efi_initrd **out);
 /*
  * This function handles the architcture specific differences between arm and
  * arm64 regarding where the kernel image must be loaded and any memory that

drivers/firmware/efi/libstub/fdt.c

@@ -28,8 +28,7 @@ static void fdt_update_cell_size(void *fdt)
 }
 
 static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size,
-			       void *fdt, int new_fdt_size, char *cmdline_ptr,
-			       u64 initrd_addr, u64 initrd_size)
+			       void *fdt, int new_fdt_size, char *cmdline_ptr)
 {
 	int node, num_rsv;
 	int status;
@@ -93,21 +92,6 @@ static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size,
 			goto fdt_set_fail;
 	}
 
-	/* Set initrd address/end in device tree, if present */
-	if (initrd_size != 0) {
-		u64 initrd_image_end;
-		u64 initrd_image_start = cpu_to_fdt64(initrd_addr);
-
-		status = fdt_setprop_var(fdt, node, "linux,initrd-start", initrd_image_start);
-		if (status)
-			goto fdt_set_fail;
-
-		initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
-		status = fdt_setprop_var(fdt, node, "linux,initrd-end", initrd_image_end);
-		if (status)
-			goto fdt_set_fail;
-	}
-
 	/* Add FDT entries for EFI runtime services in chosen node. */
 	node = fdt_subnode_offset(fdt, 0, "chosen");
 	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table);
@@ -226,22 +210,18 @@ static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv)
 #endif
 
 /*
- * Allocate memory for a new FDT, then add EFI, commandline, and
- * initrd related fields to the FDT.  This routine increases the
- * FDT allocation size until the allocated memory is large
- * enough.  EFI allocations are in EFI_PAGE_SIZE granules,
- * which are fixed at 4K bytes, so in most cases the first
- * allocation should succeed.
- * EFI boot services are exited at the end of this function.
- * There must be no allocations between the get_memory_map()
- * call and the exit_boot_services() call, so the exiting of
- * boot services is very tightly tied to the creation of the FDT
- * with the final memory map in it.
+ * Allocate memory for a new FDT, then add EFI and commandline related fields
+ * to the FDT.  This routine increases the FDT allocation size until the
+ * allocated memory is large enough.  EFI allocations are in EFI_PAGE_SIZE
+ * granules, which are fixed at 4K bytes, so in most cases the first allocation
+ * should succeed.  EFI boot services are exited at the end of this function.
+ * There must be no allocations between the get_memory_map() call and the
+ * exit_boot_services() call, so the exiting of boot services is very tightly
+ * tied to the creation of the FDT with the final memory map in it.
  */
 
 efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 					    unsigned long *new_fdt_addr,
-					    u64 initrd_addr, u64 initrd_size,
 					    char *cmdline_ptr,
 					    unsigned long fdt_addr,
 					    unsigned long fdt_size)
@@ -269,8 +249,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 	}
 
 	status = update_fdt((void *)fdt_addr, fdt_size,
-			    (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr,
-			    initrd_addr, initrd_size);
+			    (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr);
 
 	if (status != EFI_SUCCESS) {
 		efi_err("Unable to construct new device tree.\n");

drivers/firmware/efi/libstub/file.c

@@ -238,6 +238,9 @@ efi_status_t handle_cmdline_files(efi_loaded_image_t *image,
 
 	if (volume)
 		volume->close(volume);
+
+	if (*load_size == 0)
+		return EFI_NOT_READY;
 	return EFI_SUCCESS;
 
 err_close_file:

drivers/firmware/efi/libstub/x86-stub.c

@@ -766,7 +766,7 @@ unsigned long efi_main(efi_handle_t handle,
 	unsigned long bzimage_addr = (unsigned long)startup_32;
 	unsigned long buffer_start, buffer_end;
 	struct setup_header *hdr = &boot_params->hdr;
-	unsigned long addr, size;
+	const struct linux_efi_initrd *initrd = NULL;
 	efi_status_t status;
 
 	efi_system_table = sys_table_arg;
@@ -861,17 +861,18 @@ unsigned long efi_main(efi_handle_t handle,
 	 * arguments will be processed only if image is not NULL, which will be
 	 * the case only if we were loaded via the PE entry point.
 	 */
-	status = efi_load_initrd(image, &addr, &size, hdr->initrd_addr_max,
-				 ULONG_MAX);
+	status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX,
+				 &initrd);
 	if (status != EFI_SUCCESS)
 		goto fail;
-	if (size > 0) {
-		efi_set_u64_split(addr, &hdr->ramdisk_image,
+	if (initrd && initrd->size > 0) {
+		efi_set_u64_split(initrd->base, &hdr->ramdisk_image,
 				  &boot_params->ext_ramdisk_image);
-		efi_set_u64_split(size, &hdr->ramdisk_size,
+		efi_set_u64_split(initrd->size, &hdr->ramdisk_size,
 				  &boot_params->ext_ramdisk_size);
 	}
 
+
 	/*
 	 * If the boot loader gave us a value for secure_boot then we use that,
 	 * otherwise we ask the BIOS.

include/linux/efi.h

@@ -1330,6 +1330,11 @@ struct linux_efi_coco_secret_area {
 	u64	size;
 };
 
+struct linux_efi_initrd {
+	unsigned long	base;
+	unsigned long	size;
+};
+
 /* Header of a populated EFI secret area */
 #define EFI_SECRET_TABLE_HEADER_GUID	EFI_GUID(0x1e74f542, 0x71dd, 0x4d66,  0x96, 0x3e, 0xef, 0x42, 0x87, 0xff, 0x17, 0x3b)