drivers/firmware/efi/libstub/fdt.c - kernel/bruno - Git at Google

 /*
  * FDT related Helper functions used by the EFI stub on multiple
  * architectures. This should be #included by the EFI stub
  * implementation files.
  *
  * Copyright 2013 Linaro Limited; author Roy Franz
  *
  * This file is part of the Linux kernel, and is made available
  * under the terms of the GNU General Public License version 2.
  *
  */

 #include <linux/efi.h>
 #include <linux/libfdt.h>
 #include <asm/efi.h>

 #include "efistub.h"

 efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
 			unsigned long orig_fdt_size,
 			void *fdt, int new_fdt_size, char *cmdline_ptr,
 			u64 initrd_addr, u64 initrd_size,
 			efi_memory_desc_t *memory_map,
 			unsigned long map_size, unsigned long desc_size,
 			u32 desc_ver)
 {
 	int node, prev, num_rsv;
 	int status;
 	u32 fdt_val32;
 	u64 fdt_val64;

 	/* Do some checks on provided FDT, if it exists*/
 	if (orig_fdt) {
 		if (fdt_check_header(orig_fdt)) {
 			pr_efi_err(sys_table, "Device Tree header not valid!\n");
 			return EFI_LOAD_ERROR;
 		}
 		/*
 		 * We don't get the size of the FDT if we get if from a
 		 * configuration table.
 		 */
 		if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
 			pr_efi_err(sys_table, "Truncated device tree! foo!\n");
 			return EFI_LOAD_ERROR;
 		}
 	}

 	if (orig_fdt)
 		status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
 	else
 		status = fdt_create_empty_tree(fdt, new_fdt_size);

 	if (status != 0)
 		goto fdt_set_fail;

 	/*
 	 * Delete any memory nodes present. We must delete nodes which
 	 * early_init_dt_scan_memory may try to use.
 	 */
 	prev = 0;
 	for (;;) {
 		const char *type;
 		int len;

 		node = fdt_next_node(fdt, prev, NULL);
 		if (node < 0)
 			break;

 		type = fdt_getprop(fdt, node, "device_type", &len);
 		if (type && strncmp(type, "memory", len) == 0) {
 			fdt_del_node(fdt, node);
 			continue;
 		}

 		prev = node;
 	}

 	/*
 	 * Delete all memory reserve map entries. When booting via UEFI,
 	 * kernel will use the UEFI memory map to find reserved regions.
 	 */
 	num_rsv = fdt_num_mem_rsv(fdt);
 	while (num_rsv-- > 0)
 		fdt_del_mem_rsv(fdt, num_rsv);

 	node = fdt_subnode_offset(fdt, 0, "chosen");
 	if (node < 0) {
 		node = fdt_add_subnode(fdt, 0, "chosen");
 		if (node < 0) {
 			status = node; /* node is error code when negative */
 			goto fdt_set_fail;
 		}
 	}

 	if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
 		status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
 				     strlen(cmdline_ptr) + 1);
 		if (status)
 			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(fdt, node, "linux,initrd-start",
 				     &initrd_image_start, sizeof(u64));
 		if (status)
 			goto fdt_set_fail;
 		initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
 		status = fdt_setprop(fdt, node, "linux,initrd-end",
 				     &initrd_image_end, sizeof(u64));
 		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)sys_table);
 	status = fdt_setprop(fdt, node, "linux,uefi-system-table",
 			     &fdt_val64, sizeof(fdt_val64));
 	if (status)
 		goto fdt_set_fail;

 	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map);
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
 			     &fdt_val64,  sizeof(fdt_val64));
 	if (status)
 		goto fdt_set_fail;

 	fdt_val32 = cpu_to_fdt32(map_size);
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
 			     &fdt_val32,  sizeof(fdt_val32));
 	if (status)
 		goto fdt_set_fail;

 	fdt_val32 = cpu_to_fdt32(desc_size);
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
 			     &fdt_val32, sizeof(fdt_val32));
 	if (status)
 		goto fdt_set_fail;

 	fdt_val32 = cpu_to_fdt32(desc_ver);
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
 			     &fdt_val32, sizeof(fdt_val32));
 	if (status)
 		goto fdt_set_fail;

 	return EFI_SUCCESS;

 fdt_set_fail:
 	if (status == -FDT_ERR_NOSPACE)
 		return EFI_BUFFER_TOO_SMALL;

 	return EFI_LOAD_ERROR;
 }

 #ifndef EFI_FDT_ALIGN
 #define EFI_FDT_ALIGN EFI_PAGE_SIZE
 #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.
  */

 efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
 					    void *handle,
 					    unsigned long *new_fdt_addr,
 					    unsigned long max_addr,
 					    u64 initrd_addr, u64 initrd_size,
 					    char *cmdline_ptr,
 					    unsigned long fdt_addr,
 					    unsigned long fdt_size)
 {
 	unsigned long map_size, desc_size;
 	u32 desc_ver;
 	unsigned long mmap_key;
 	efi_memory_desc_t *memory_map, *runtime_map;
 	unsigned long new_fdt_size;
 	efi_status_t status;
 	int runtime_entry_count = 0;

 	/*
 	 * Get a copy of the current memory map that we will use to prepare
 	 * the input for SetVirtualAddressMap(). We don't have to worry about
 	 * subsequent allocations adding entries, since they could not affect
 	 * the number of EFI_MEMORY_RUNTIME regions.
 	 */
 	status = efi_get_memory_map(sys_table, &runtime_map, &map_size,
 				    &desc_size, &desc_ver, &mmap_key);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
 		return status;
 	}

 	pr_efi(sys_table,
 	       "Exiting boot services and installing virtual address map...\n");

 	/*
 	 * Estimate size of new FDT, and allocate memory for it. We
 	 * will allocate a bigger buffer if this ends up being too
 	 * small, so a rough guess is OK here.
 	 */
 	new_fdt_size = fdt_size + EFI_PAGE_SIZE;
 	while (1) {
 		status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN,
 					new_fdt_addr, max_addr);
 		if (status != EFI_SUCCESS) {
 			pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");
 			goto fail;
 		}

 		/*
 		 * Now that we have done our final memory allocation (and free)
 		 * we can get the memory map key  needed for
 		 * exit_boot_services().
 		 */
 		status = efi_get_memory_map(sys_table, &memory_map, &map_size,
 					    &desc_size, &desc_ver, &mmap_key);
 		if (status != EFI_SUCCESS)
 			goto fail_free_new_fdt;

 		status = update_fdt(sys_table,
 				    (void *)fdt_addr, fdt_size,
 				    (void *)*new_fdt_addr, new_fdt_size,
 				    cmdline_ptr, initrd_addr, initrd_size,
 				    memory_map, map_size, desc_size, desc_ver);

 		/* Succeeding the first time is the expected case. */
 		if (status == EFI_SUCCESS)
 			break;

 		if (status == EFI_BUFFER_TOO_SMALL) {
 			/*
 			 * We need to allocate more space for the new
 			 * device tree, so free existing buffer that is
 			 * too small.  Also free memory map, as we will need
 			 * to get new one that reflects the free/alloc we do
 			 * on the device tree buffer.
 			 */
 			efi_free(sys_table, new_fdt_size, *new_fdt_addr);
 			sys_table->boottime->free_pool(memory_map);
 			new_fdt_size += EFI_PAGE_SIZE;
 		} else {
 			pr_efi_err(sys_table, "Unable to constuct new device tree.\n");
 			goto fail_free_mmap;
 		}
 	}

 	/*
 	 * Update the memory map with virtual addresses. The function will also
 	 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
 	 * entries so that we can pass it straight into SetVirtualAddressMap()
 	 */
 	efi_get_virtmap(memory_map, map_size, desc_size, runtime_map,
 			&runtime_entry_count);

 	/* Now we are ready to exit_boot_services.*/
 	status = sys_table->boottime->exit_boot_services(handle, mmap_key);

 	if (status == EFI_SUCCESS) {
 		efi_set_virtual_address_map_t *svam;

 		/* Install the new virtual address map */
 		svam = sys_table->runtime->set_virtual_address_map;
 		status = svam(runtime_entry_count * desc_size, desc_size,
 			      desc_ver, runtime_map);

 		/*
 		 * We are beyond the point of no return here, so if the call to
 		 * SetVirtualAddressMap() failed, we need to signal that to the
 		 * incoming kernel but proceed normally otherwise.
 		 */
 		if (status != EFI_SUCCESS) {
 			int l;

 			/*
 			 * Set the virtual address field of all
 			 * EFI_MEMORY_RUNTIME entries to 0. This will signal
 			 * the incoming kernel that no virtual translation has
 			 * been installed.
 			 */
 			for (l = 0; l < map_size; l += desc_size) {
 				efi_memory_desc_t *p = (void *)memory_map + l;

 				if (p->attribute & EFI_MEMORY_RUNTIME)
 					p->virt_addr = 0;
 			}
 		}
 		return EFI_SUCCESS;
 	}

 	pr_efi_err(sys_table, "Exit boot services failed.\n");

 fail_free_mmap:
 	sys_table->boottime->free_pool(memory_map);

 fail_free_new_fdt:
 	efi_free(sys_table, new_fdt_size, *new_fdt_addr);

 fail:
 	sys_table->boottime->free_pool(runtime_map);
 	return EFI_LOAD_ERROR;
 }

 void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
 {
 	efi_guid_t fdt_guid = DEVICE_TREE_GUID;
 	efi_config_table_t *tables;
 	void *fdt;
 	int i;

 	tables = (efi_config_table_t *) sys_table->tables;
 	fdt = NULL;

 	for (i = 0; i < sys_table->nr_tables; i++)
 		if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
 			fdt = (void *) tables[i].table;
 			if (fdt_check_header(fdt) != 0) {
 				pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
 				return NULL;
 			}
 			*fdt_size = fdt_totalsize(fdt);
 			break;
 	 }

 	return fdt;
 }
	/*
	* FDT related Helper functions used by the EFI stub on multiple
	* architectures. This should be #included by the EFI stub
	* implementation files.
	*
	* Copyright 2013 Linaro Limited; author Roy Franz
	*
	* This file is part of the Linux kernel, and is made available
	* under the terms of the GNU General Public License version 2.
	*
	*/

	#include <linux/efi.h>
	#include <linux/libfdt.h>
	#include <asm/efi.h>

	#include "efistub.h"

	efi_status_t update_fdt(efi_system_table_t sys_table, void orig_fdt,
	unsigned long orig_fdt_size,
	void fdt, int new_fdt_size, char cmdline_ptr,
	u64 initrd_addr, u64 initrd_size,
	efi_memory_desc_t *memory_map,
	unsigned long map_size, unsigned long desc_size,
	u32 desc_ver)
	{
	int node, prev, num_rsv;
	int status;
	u32 fdt_val32;
	u64 fdt_val64;

	/* Do some checks on provided FDT, if it exists*/
	if (orig_fdt) {
	if (fdt_check_header(orig_fdt)) {
	pr_efi_err(sys_table, "Device Tree header not valid!\n");
	return EFI_LOAD_ERROR;
	}
	/*
	* We don't get the size of the FDT if we get if from a
	* configuration table.
	*/
	if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
	pr_efi_err(sys_table, "Truncated device tree! foo!\n");
	return EFI_LOAD_ERROR;
	}
	}

	if (orig_fdt)
	status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
	else
	status = fdt_create_empty_tree(fdt, new_fdt_size);

	if (status != 0)
	goto fdt_set_fail;

	/*
	* Delete any memory nodes present. We must delete nodes which
	* early_init_dt_scan_memory may try to use.
	*/
	prev = 0;
	for (;;) {
	const char *type;
	int len;

	node = fdt_next_node(fdt, prev, NULL);
	if (node < 0)
	break;

	type = fdt_getprop(fdt, node, "device_type", &len);
	if (type && strncmp(type, "memory", len) == 0) {
	fdt_del_node(fdt, node);
	continue;
	}

	prev = node;
	}

	/*
	* Delete all memory reserve map entries. When booting via UEFI,
	* kernel will use the UEFI memory map to find reserved regions.
	*/
	num_rsv = fdt_num_mem_rsv(fdt);
	while (num_rsv-- > 0)
	fdt_del_mem_rsv(fdt, num_rsv);

	node = fdt_subnode_offset(fdt, 0, "chosen");
	if (node < 0) {
	node = fdt_add_subnode(fdt, 0, "chosen");
	if (node < 0) {
	status = node; /* node is error code when negative */
	goto fdt_set_fail;
	}
	}

	if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
	status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
	strlen(cmdline_ptr) + 1);
	if (status)
	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(fdt, node, "linux,initrd-start",
	&initrd_image_start, sizeof(u64));
	if (status)
	goto fdt_set_fail;
	initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
	status = fdt_setprop(fdt, node, "linux,initrd-end",
	&initrd_image_end, sizeof(u64));
	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)sys_table);
	status = fdt_setprop(fdt, node, "linux,uefi-system-table",
	&fdt_val64, sizeof(fdt_val64));
	if (status)
	goto fdt_set_fail;

	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map);
	status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
	&fdt_val64, sizeof(fdt_val64));
	if (status)
	goto fdt_set_fail;

	fdt_val32 = cpu_to_fdt32(map_size);
	status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
	&fdt_val32, sizeof(fdt_val32));
	if (status)
	goto fdt_set_fail;

	fdt_val32 = cpu_to_fdt32(desc_size);
	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
	&fdt_val32, sizeof(fdt_val32));
	if (status)
	goto fdt_set_fail;

	fdt_val32 = cpu_to_fdt32(desc_ver);
	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
	&fdt_val32, sizeof(fdt_val32));
	if (status)
	goto fdt_set_fail;

	return EFI_SUCCESS;

	fdt_set_fail:
	if (status == -FDT_ERR_NOSPACE)
	return EFI_BUFFER_TOO_SMALL;

	return EFI_LOAD_ERROR;
	}

	#ifndef EFI_FDT_ALIGN
	#define EFI_FDT_ALIGN EFI_PAGE_SIZE
	#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.
	*/

	efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
	void *handle,
	unsigned long *new_fdt_addr,
	unsigned long max_addr,
	u64 initrd_addr, u64 initrd_size,
	char *cmdline_ptr,
	unsigned long fdt_addr,
	unsigned long fdt_size)
	{
	unsigned long map_size, desc_size;
	u32 desc_ver;
	unsigned long mmap_key;
	efi_memory_desc_t memory_map, runtime_map;
	unsigned long new_fdt_size;
	efi_status_t status;
	int runtime_entry_count = 0;

	/*
	* Get a copy of the current memory map that we will use to prepare
	* the input for SetVirtualAddressMap(). We don't have to worry about
	* subsequent allocations adding entries, since they could not affect
	* the number of EFI_MEMORY_RUNTIME regions.
	*/
	status = efi_get_memory_map(sys_table, &runtime_map, &map_size,
	&desc_size, &desc_ver, &mmap_key);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
	return status;
	}

	pr_efi(sys_table,
	"Exiting boot services and installing virtual address map...\n");

	/*
	* Estimate size of new FDT, and allocate memory for it. We
	* will allocate a bigger buffer if this ends up being too
	* small, so a rough guess is OK here.
	*/
	new_fdt_size = fdt_size + EFI_PAGE_SIZE;
	while (1) {
	status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN,
	new_fdt_addr, max_addr);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");
	goto fail;
	}

	/*
	* Now that we have done our final memory allocation (and free)
	* we can get the memory map key needed for
	* exit_boot_services().
	*/
	status = efi_get_memory_map(sys_table, &memory_map, &map_size,
	&desc_size, &desc_ver, &mmap_key);
	if (status != EFI_SUCCESS)
	goto fail_free_new_fdt;

	status = update_fdt(sys_table,
	(void *)fdt_addr, fdt_size,
	(void )new_fdt_addr, new_fdt_size,
	cmdline_ptr, initrd_addr, initrd_size,
	memory_map, map_size, desc_size, desc_ver);

	/* Succeeding the first time is the expected case. */
	if (status == EFI_SUCCESS)
	break;

	if (status == EFI_BUFFER_TOO_SMALL) {
	/*
	* We need to allocate more space for the new
	* device tree, so free existing buffer that is
	* too small. Also free memory map, as we will need
	* to get new one that reflects the free/alloc we do
	* on the device tree buffer.
	*/
	efi_free(sys_table, new_fdt_size, *new_fdt_addr);
	sys_table->boottime->free_pool(memory_map);
	new_fdt_size += EFI_PAGE_SIZE;
	} else {
	pr_efi_err(sys_table, "Unable to constuct new device tree.\n");
	goto fail_free_mmap;
	}
	}

	/*
	* Update the memory map with virtual addresses. The function will also
	* populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
	* entries so that we can pass it straight into SetVirtualAddressMap()
	*/
	efi_get_virtmap(memory_map, map_size, desc_size, runtime_map,
	&runtime_entry_count);

	/* Now we are ready to exit_boot_services.*/
	status = sys_table->boottime->exit_boot_services(handle, mmap_key);

	if (status == EFI_SUCCESS) {
	efi_set_virtual_address_map_t *svam;

	/* Install the new virtual address map */
	svam = sys_table->runtime->set_virtual_address_map;
	status = svam(runtime_entry_count * desc_size, desc_size,
	desc_ver, runtime_map);

	/*
	* We are beyond the point of no return here, so if the call to
	* SetVirtualAddressMap() failed, we need to signal that to the
	* incoming kernel but proceed normally otherwise.
	*/
	if (status != EFI_SUCCESS) {
	int l;

	/*
	* Set the virtual address field of all
	* EFI_MEMORY_RUNTIME entries to 0. This will signal
	* the incoming kernel that no virtual translation has
	* been installed.
	*/
	for (l = 0; l < map_size; l += desc_size) {
	efi_memory_desc_t p = (void )memory_map + l;

	if (p->attribute & EFI_MEMORY_RUNTIME)
	p->virt_addr = 0;
	}
	}
	return EFI_SUCCESS;
	}

	pr_efi_err(sys_table, "Exit boot services failed.\n");

	fail_free_mmap:
	sys_table->boottime->free_pool(memory_map);

	fail_free_new_fdt:
	efi_free(sys_table, new_fdt_size, *new_fdt_addr);

	fail:
	sys_table->boottime->free_pool(runtime_map);
	return EFI_LOAD_ERROR;
	}

	void get_fdt(efi_system_table_t sys_table, unsigned long *fdt_size)
	{
	efi_guid_t fdt_guid = DEVICE_TREE_GUID;
	efi_config_table_t *tables;
	void *fdt;
	int i;

	tables = (efi_config_table_t *) sys_table->tables;
	fdt = NULL;

	for (i = 0; i < sys_table->nr_tables; i++)
	if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
	fdt = (void *) tables[i].table;
	if (fdt_check_header(fdt) != 0) {
	pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
	return NULL;
	}
	*fdt_size = fdt_totalsize(fdt);
	break;
	}

	return fdt;
	}