drivers/firmware/efi/libstub/arm32-stub.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2013 Linaro Ltd;  <roy.franz@linaro.org>
  */
 #include <linux/efi.h>
 #include <asm/efi.h>

 #include "efistub.h"

 efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
 {
 	int block;

 	/* non-LPAE kernels can run anywhere */
 	if (!IS_ENABLED(CONFIG_ARM_LPAE))
 		return EFI_SUCCESS;

 	/* LPAE kernels need compatible hardware */
 	block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
 	if (block < 5) {
 		pr_efi_err(sys_table_arg, "This LPAE kernel is not supported by your CPU\n");
 		return EFI_UNSUPPORTED;
 	}
 	return EFI_SUCCESS;
 }

 static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;

 struct screen_info *alloc_screen_info(efi_system_table_t *sys_table_arg)
 {
 	struct screen_info *si;
 	efi_status_t status;

 	/*
 	 * Unlike on arm64, where we can directly fill out the screen_info
 	 * structure from the stub, we need to allocate a buffer to hold
 	 * its contents while we hand over to the kernel proper from the
 	 * decompressor.
 	 */
 	status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
 				sizeof(*si), (void **)&si);

 	if (status != EFI_SUCCESS)
 		return NULL;

 	status = efi_call_early(install_configuration_table,
 				&screen_info_guid, si);
 	if (status == EFI_SUCCESS)
 		return si;

 	efi_call_early(free_pool, si);
 	return NULL;
 }

 void free_screen_info(efi_system_table_t *sys_table_arg, struct screen_info *si)
 {
 	if (!si)
 		return;

 	efi_call_early(install_configuration_table, &screen_info_guid, NULL);
 	efi_call_early(free_pool, si);
 }

 static efi_status_t reserve_kernel_base(efi_system_table_t *sys_table_arg,
 					unsigned long dram_base,
 					unsigned long *reserve_addr,
 					unsigned long *reserve_size)
 {
 	efi_physical_addr_t alloc_addr;
 	efi_memory_desc_t *memory_map;
 	unsigned long nr_pages, map_size, desc_size, buff_size;
 	efi_status_t status;
 	unsigned long l;

 	struct efi_boot_memmap map = {
 		.map		= &memory_map,
 		.map_size	= &map_size,
 		.desc_size	= &desc_size,
 		.desc_ver	= NULL,
 		.key_ptr	= NULL,
 		.buff_size	= &buff_size,
 	};

 	/*
 	 * Reserve memory for the uncompressed kernel image. This is
 	 * all that prevents any future allocations from conflicting
 	 * with the kernel. Since we can't tell from the compressed
 	 * image how much DRAM the kernel actually uses (due to BSS
 	 * size uncertainty) we allocate the maximum possible size.
 	 * Do this very early, as prints can cause memory allocations
 	 * that may conflict with this.
 	 */
 	alloc_addr = dram_base + MAX_UNCOMP_KERNEL_SIZE;
 	nr_pages = MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE;
 	status = efi_call_early(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
 				EFI_BOOT_SERVICES_DATA, nr_pages, &alloc_addr);
 	if (status == EFI_SUCCESS) {
 		if (alloc_addr == dram_base) {
 			*reserve_addr = alloc_addr;
 			*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
 			return EFI_SUCCESS;
 		}
 		/*
 		 * If we end up here, the allocation succeeded but starts below
 		 * dram_base. This can only occur if the real base of DRAM is
 		 * not a multiple of 128 MB, in which case dram_base will have
 		 * been rounded up. Since this implies that a part of the region
 		 * was already occupied, we need to fall through to the code
 		 * below to ensure that the existing allocations don't conflict.
 		 * For this reason, we use EFI_BOOT_SERVICES_DATA above and not
 		 * EFI_LOADER_DATA, which we wouldn't able to distinguish from
 		 * allocations that we want to disallow.
 		 */
 	}

 	/*
 	 * If the allocation above failed, we may still be able to proceed:
 	 * if the only allocations in the region are of types that will be
 	 * released to the OS after ExitBootServices(), the decompressor can
 	 * safely overwrite them.
 	 */
 	status = efi_get_memory_map(sys_table_arg, &map);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table_arg,
 			   "reserve_kernel_base(): Unable to retrieve memory map.\n");
 		return status;
 	}

 	for (l = 0; l < map_size; l += desc_size) {
 		efi_memory_desc_t *desc;
 		u64 start, end;

 		desc = (void *)memory_map + l;
 		start = desc->phys_addr;
 		end = start + desc->num_pages * EFI_PAGE_SIZE;

 		/* Skip if entry does not intersect with region */
 		if (start >= dram_base + MAX_UNCOMP_KERNEL_SIZE ||
 		    end <= dram_base)
 			continue;

 		switch (desc->type) {
 		case EFI_BOOT_SERVICES_CODE:
 		case EFI_BOOT_SERVICES_DATA:
 			/* Ignore types that are released to the OS anyway */
 			continue;

 		case EFI_CONVENTIONAL_MEMORY:
 			/* Skip soft reserved conventional memory */
 			if (efi_soft_reserve_enabled() &&
 			    (desc->attribute & EFI_MEMORY_SP))
 				continue;

 			/*
 			 * Reserve the intersection between this entry and the
 			 * region.
 			 */
 			start = max(start, (u64)dram_base);
 			end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE);

 			status = efi_call_early(allocate_pages,
 						EFI_ALLOCATE_ADDRESS,
 						EFI_LOADER_DATA,
 						(end - start) / EFI_PAGE_SIZE,
 						&start);
 			if (status != EFI_SUCCESS) {
 				pr_efi_err(sys_table_arg,
 					"reserve_kernel_base(): alloc failed.\n");
 				goto out;
 			}
 			break;

 		case EFI_LOADER_CODE:
 		case EFI_LOADER_DATA:
 			/*
 			 * These regions may be released and reallocated for
 			 * another purpose (including EFI_RUNTIME_SERVICE_DATA)
 			 * at any time during the execution of the OS loader,
 			 * so we cannot consider them as safe.
 			 */
 		default:
 			/*
 			 * Treat any other allocation in the region as unsafe */
 			status = EFI_OUT_OF_RESOURCES;
 			goto out;
 		}
 	}

 	status = EFI_SUCCESS;
 out:
 	efi_call_early(free_pool, memory_map);
 	return status;
 }

 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
 				 unsigned long *image_addr,
 				 unsigned long *image_size,
 				 unsigned long *reserve_addr,
 				 unsigned long *reserve_size,
 				 unsigned long dram_base,
 				 efi_loaded_image_t *image)
 {
 	unsigned long kernel_base;
 	efi_status_t status;

 	/*
 	 * Verify that the DRAM base address is compatible with the ARM
 	 * boot protocol, which determines the base of DRAM by masking
 	 * off the low 27 bits of the address at which the zImage is
 	 * loaded. These assumptions are made by the decompressor,
 	 * before any memory map is available.
 	 */
 	kernel_base = round_up(dram_base, SZ_128M);

 	/*
 	 * Note that some platforms (notably, the Raspberry Pi 2) put
 	 * spin-tables and other pieces of firmware at the base of RAM,
 	 * abusing the fact that the window of TEXT_OFFSET bytes at the
 	 * base of the kernel image is only partially used at the moment.
 	 * (Up to 5 pages are used for the swapper page tables)
 	 */
 	kernel_base += TEXT_OFFSET - 5 * PAGE_SIZE;

 	status = reserve_kernel_base(sys_table, kernel_base, reserve_addr,
 				     reserve_size);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
 		return status;
 	}

 	/*
 	 * Relocate the zImage, so that it appears in the lowest 128 MB
 	 * memory window.
 	 */
 	*image_size = image->image_size;
 	status = efi_relocate_kernel(sys_table, image_addr, *image_size,
 				     *image_size,
 				     kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0, 0);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Failed to relocate kernel.\n");
 		efi_free(sys_table, *reserve_size, *reserve_addr);
 		*reserve_size = 0;
 		return status;
 	}

 	/*
 	 * Check to see if we were able to allocate memory low enough
 	 * in memory. The kernel determines the base of DRAM from the
 	 * address at which the zImage is loaded.
 	 */
 	if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
 		pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
 		efi_free(sys_table, *reserve_size, *reserve_addr);
 		*reserve_size = 0;
 		efi_free(sys_table, *image_size, *image_addr);
 		*image_size = 0;
 		return EFI_LOAD_ERROR;
 	}
 	return EFI_SUCCESS;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (C) 2013 Linaro Ltd; <roy.franz@linaro.org>
	*/
	#include <linux/efi.h>
	#include <asm/efi.h>

	#include "efistub.h"

	efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
	{
	int block;

	/* non-LPAE kernels can run anywhere */
	if (!IS_ENABLED(CONFIG_ARM_LPAE))
	return EFI_SUCCESS;

	/* LPAE kernels need compatible hardware */
	block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
	if (block < 5) {
	pr_efi_err(sys_table_arg, "This LPAE kernel is not supported by your CPU\n");
	return EFI_UNSUPPORTED;
	}
	return EFI_SUCCESS;
	}

	static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;

	struct screen_info alloc_screen_info(efi_system_table_t sys_table_arg)
	{
	struct screen_info *si;
	efi_status_t status;

	/*
	* Unlike on arm64, where we can directly fill out the screen_info
	* structure from the stub, we need to allocate a buffer to hold
	* its contents while we hand over to the kernel proper from the
	* decompressor.
	*/
	status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
	sizeof(si), (void *)&si);

	if (status != EFI_SUCCESS)
	return NULL;

	status = efi_call_early(install_configuration_table,
	&screen_info_guid, si);
	if (status == EFI_SUCCESS)
	return si;

	efi_call_early(free_pool, si);
	return NULL;
	}

	void free_screen_info(efi_system_table_t sys_table_arg, struct screen_info si)
	{
	if (!si)
	return;

	efi_call_early(install_configuration_table, &screen_info_guid, NULL);
	efi_call_early(free_pool, si);
	}

	static efi_status_t reserve_kernel_base(efi_system_table_t *sys_table_arg,
	unsigned long dram_base,
	unsigned long *reserve_addr,
	unsigned long *reserve_size)
	{
	efi_physical_addr_t alloc_addr;
	efi_memory_desc_t *memory_map;
	unsigned long nr_pages, map_size, desc_size, buff_size;
	efi_status_t status;
	unsigned long l;

	struct efi_boot_memmap map = {
	.map = &memory_map,
	.map_size = &map_size,
	.desc_size = &desc_size,
	.desc_ver = NULL,
	.key_ptr = NULL,
	.buff_size = &buff_size,
	};

	/*
	* Reserve memory for the uncompressed kernel image. This is
	* all that prevents any future allocations from conflicting
	* with the kernel. Since we can't tell from the compressed
	* image how much DRAM the kernel actually uses (due to BSS
	* size uncertainty) we allocate the maximum possible size.
	* Do this very early, as prints can cause memory allocations
	* that may conflict with this.
	*/
	alloc_addr = dram_base + MAX_UNCOMP_KERNEL_SIZE;
	nr_pages = MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE;
	status = efi_call_early(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
	EFI_BOOT_SERVICES_DATA, nr_pages, &alloc_addr);
	if (status == EFI_SUCCESS) {
	if (alloc_addr == dram_base) {
	*reserve_addr = alloc_addr;
	*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
	return EFI_SUCCESS;
	}
	/*
	* If we end up here, the allocation succeeded but starts below
	* dram_base. This can only occur if the real base of DRAM is
	* not a multiple of 128 MB, in which case dram_base will have
	* been rounded up. Since this implies that a part of the region
	* was already occupied, we need to fall through to the code
	* below to ensure that the existing allocations don't conflict.
	* For this reason, we use EFI_BOOT_SERVICES_DATA above and not
	* EFI_LOADER_DATA, which we wouldn't able to distinguish from
	* allocations that we want to disallow.
	*/
	}

	/*
	* If the allocation above failed, we may still be able to proceed:
	* if the only allocations in the region are of types that will be
	* released to the OS after ExitBootServices(), the decompressor can
	* safely overwrite them.
	*/
	status = efi_get_memory_map(sys_table_arg, &map);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table_arg,
	"reserve_kernel_base(): Unable to retrieve memory map.\n");
	return status;
	}

	for (l = 0; l < map_size; l += desc_size) {
	efi_memory_desc_t *desc;
	u64 start, end;

	desc = (void *)memory_map + l;
	start = desc->phys_addr;
	end = start + desc->num_pages * EFI_PAGE_SIZE;

	/* Skip if entry does not intersect with region */
	if (start >= dram_base + MAX_UNCOMP_KERNEL_SIZE \|\|
	end <= dram_base)
	continue;

	switch (desc->type) {
	case EFI_BOOT_SERVICES_CODE:
	case EFI_BOOT_SERVICES_DATA:
	/* Ignore types that are released to the OS anyway */
	continue;

	case EFI_CONVENTIONAL_MEMORY:
	/* Skip soft reserved conventional memory */
	if (efi_soft_reserve_enabled() &&
	(desc->attribute & EFI_MEMORY_SP))
	continue;

	/*
	* Reserve the intersection between this entry and the
	* region.
	*/
	start = max(start, (u64)dram_base);
	end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE);

	status = efi_call_early(allocate_pages,
	EFI_ALLOCATE_ADDRESS,
	EFI_LOADER_DATA,
	(end - start) / EFI_PAGE_SIZE,
	&start);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table_arg,
	"reserve_kernel_base(): alloc failed.\n");
	goto out;
	}
	break;

	case EFI_LOADER_CODE:
	case EFI_LOADER_DATA:
	/*
	* These regions may be released and reallocated for
	* another purpose (including EFI_RUNTIME_SERVICE_DATA)
	* at any time during the execution of the OS loader,
	* so we cannot consider them as safe.
	*/
	default:
	/*
	* Treat any other allocation in the region as unsafe */
	status = EFI_OUT_OF_RESOURCES;
	goto out;
	}
	}

	status = EFI_SUCCESS;
	out:
	efi_call_early(free_pool, memory_map);
	return status;
	}

	efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
	unsigned long *image_addr,
	unsigned long *image_size,
	unsigned long *reserve_addr,
	unsigned long *reserve_size,
	unsigned long dram_base,
	efi_loaded_image_t *image)
	{
	unsigned long kernel_base;
	efi_status_t status;

	/*
	* Verify that the DRAM base address is compatible with the ARM
	* boot protocol, which determines the base of DRAM by masking
	* off the low 27 bits of the address at which the zImage is
	* loaded. These assumptions are made by the decompressor,
	* before any memory map is available.
	*/
	kernel_base = round_up(dram_base, SZ_128M);

	/*
	* Note that some platforms (notably, the Raspberry Pi 2) put
	* spin-tables and other pieces of firmware at the base of RAM,
	* abusing the fact that the window of TEXT_OFFSET bytes at the
	* base of the kernel image is only partially used at the moment.
	* (Up to 5 pages are used for the swapper page tables)
	*/
	kernel_base += TEXT_OFFSET - 5 * PAGE_SIZE;

	status = reserve_kernel_base(sys_table, kernel_base, reserve_addr,
	reserve_size);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
	return status;
	}

	/*
	* Relocate the zImage, so that it appears in the lowest 128 MB
	* memory window.
	*/
	*image_size = image->image_size;
	status = efi_relocate_kernel(sys_table, image_addr, *image_size,
	*image_size,
	kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0, 0);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Failed to relocate kernel.\n");
	efi_free(sys_table, reserve_size, reserve_addr);
	*reserve_size = 0;
	return status;
	}

	/*
	* Check to see if we were able to allocate memory low enough
	* in memory. The kernel determines the base of DRAM from the
	* address at which the zImage is loaded.
	*/
	if (image_addr + image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
	pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
	efi_free(sys_table, reserve_size, reserve_addr);
	*reserve_size = 0;
	efi_free(sys_table, image_size, image_addr);
	*image_size = 0;
	return EFI_LOAD_ERROR;
	}
	return EFI_SUCCESS;
	}