| /* |
| * EFI capsule loader driver. |
| * |
| * Copyright 2015 Intel Corporation |
| * |
| * This file is part of the Linux kernel, and is made available under |
| * the terms of the GNU General Public License version 2. |
| */ |
| |
| #define pr_fmt(fmt) "efi: " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/miscdevice.h> |
| #include <linux/highmem.h> |
| #include <linux/slab.h> |
| #include <linux/mutex.h> |
| #include <linux/efi.h> |
| #include <linux/vmalloc.h> |
| |
| #define NO_FURTHER_WRITE_ACTION -1 |
| |
| /** |
| * efi_free_all_buff_pages - free all previous allocated buffer pages |
| * @cap_info: pointer to current instance of capsule_info structure |
| * |
| * In addition to freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION |
| * to cease processing data in subsequent write(2) calls until close(2) |
| * is called. |
| **/ |
| static void efi_free_all_buff_pages(struct capsule_info *cap_info) |
| { |
| while (cap_info->index > 0) |
| __free_page(cap_info->pages[--cap_info->index]); |
| |
| cap_info->index = NO_FURTHER_WRITE_ACTION; |
| } |
| |
| int __efi_capsule_setup_info(struct capsule_info *cap_info) |
| { |
| size_t pages_needed; |
| int ret; |
| void *temp_page; |
| |
| pages_needed = ALIGN(cap_info->total_size, PAGE_SIZE) / PAGE_SIZE; |
| |
| if (pages_needed == 0) { |
| pr_err("invalid capsule size"); |
| return -EINVAL; |
| } |
| |
| /* Check if the capsule binary supported */ |
| ret = efi_capsule_supported(cap_info->header.guid, |
| cap_info->header.flags, |
| cap_info->header.imagesize, |
| &cap_info->reset_type); |
| if (ret) { |
| pr_err("capsule not supported\n"); |
| return ret; |
| } |
| |
| temp_page = krealloc(cap_info->pages, |
| pages_needed * sizeof(void *), |
| GFP_KERNEL | __GFP_ZERO); |
| if (!temp_page) |
| return -ENOMEM; |
| |
| cap_info->pages = temp_page; |
| |
| temp_page = krealloc(cap_info->phys, |
| pages_needed * sizeof(phys_addr_t *), |
| GFP_KERNEL | __GFP_ZERO); |
| if (!temp_page) |
| return -ENOMEM; |
| |
| cap_info->phys = temp_page; |
| |
| return 0; |
| } |
| |
| /** |
| * efi_capsule_setup_info - obtain the efi capsule header in the binary and |
| * setup capsule_info structure |
| * @cap_info: pointer to current instance of capsule_info structure |
| * @kbuff: a mapped first page buffer pointer |
| * @hdr_bytes: the total received number of bytes for efi header |
| * |
| * Platforms with non-standard capsule update mechanisms can override |
| * this __weak function so they can perform any required capsule |
| * image munging. See quark_quirk_function() for an example. |
| **/ |
| int __weak efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff, |
| size_t hdr_bytes) |
| { |
| /* Only process data block that is larger than efi header size */ |
| if (hdr_bytes < sizeof(efi_capsule_header_t)) |
| return 0; |
| |
| memcpy(&cap_info->header, kbuff, sizeof(cap_info->header)); |
| cap_info->total_size = cap_info->header.imagesize; |
| |
| return __efi_capsule_setup_info(cap_info); |
| } |
| |
| /** |
| * efi_capsule_submit_update - invoke the efi_capsule_update API once binary |
| * upload done |
| * @cap_info: pointer to current instance of capsule_info structure |
| **/ |
| static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info) |
| { |
| bool do_vunmap = false; |
| int ret; |
| |
| /* |
| * cap_info->capsule may have been assigned already by a quirk |
| * handler, so only overwrite it if it is NULL |
| */ |
| if (!cap_info->capsule) { |
| cap_info->capsule = vmap(cap_info->pages, cap_info->index, |
| VM_MAP, PAGE_KERNEL); |
| if (!cap_info->capsule) |
| return -ENOMEM; |
| do_vunmap = true; |
| } |
| |
| ret = efi_capsule_update(cap_info->capsule, cap_info->phys); |
| if (do_vunmap) |
| vunmap(cap_info->capsule); |
| if (ret) { |
| pr_err("capsule update failed\n"); |
| return ret; |
| } |
| |
| /* Indicate capsule binary uploading is done */ |
| cap_info->index = NO_FURTHER_WRITE_ACTION; |
| pr_info("Successfully upload capsule file with reboot type '%s'\n", |
| !cap_info->reset_type ? "RESET_COLD" : |
| cap_info->reset_type == 1 ? "RESET_WARM" : |
| "RESET_SHUTDOWN"); |
| return 0; |
| } |
| |
| /** |
| * efi_capsule_write - store the capsule binary and pass it to |
| * efi_capsule_update() API |
| * @file: file pointer |
| * @buff: buffer pointer |
| * @count: number of bytes in @buff |
| * @offp: not used |
| * |
| * Expectation: |
| * - A user space tool should start at the beginning of capsule binary and |
| * pass data in sequentially. |
| * - Users should close and re-open this file note in order to upload more |
| * capsules. |
| * - After an error returned, user should close the file and restart the |
| * operation for the next try otherwise -EIO will be returned until the |
| * file is closed. |
| * - An EFI capsule header must be located at the beginning of capsule |
| * binary file and passed in as first block data of write operation. |
| **/ |
| static ssize_t efi_capsule_write(struct file *file, const char __user *buff, |
| size_t count, loff_t *offp) |
| { |
| int ret = 0; |
| struct capsule_info *cap_info = file->private_data; |
| struct page *page; |
| void *kbuff = NULL; |
| size_t write_byte; |
| |
| if (count == 0) |
| return 0; |
| |
| /* Return error while NO_FURTHER_WRITE_ACTION is flagged */ |
| if (cap_info->index < 0) |
| return -EIO; |
| |
| /* Only alloc a new page when previous page is full */ |
| if (!cap_info->page_bytes_remain) { |
| page = alloc_page(GFP_KERNEL); |
| if (!page) { |
| ret = -ENOMEM; |
| goto failed; |
| } |
| |
| cap_info->pages[cap_info->index] = page; |
| cap_info->phys[cap_info->index] = page_to_phys(page); |
| cap_info->page_bytes_remain = PAGE_SIZE; |
| cap_info->index++; |
| } else { |
| page = cap_info->pages[cap_info->index - 1]; |
| } |
| |
| kbuff = kmap(page); |
| kbuff += PAGE_SIZE - cap_info->page_bytes_remain; |
| |
| /* Copy capsule binary data from user space to kernel space buffer */ |
| write_byte = min_t(size_t, count, cap_info->page_bytes_remain); |
| if (copy_from_user(kbuff, buff, write_byte)) { |
| ret = -EFAULT; |
| goto fail_unmap; |
| } |
| cap_info->page_bytes_remain -= write_byte; |
| |
| /* Setup capsule binary info structure */ |
| if (cap_info->header.headersize == 0) { |
| ret = efi_capsule_setup_info(cap_info, kbuff - cap_info->count, |
| cap_info->count + write_byte); |
| if (ret) |
| goto fail_unmap; |
| } |
| |
| cap_info->count += write_byte; |
| kunmap(page); |
| |
| /* Submit the full binary to efi_capsule_update() API */ |
| if (cap_info->header.headersize > 0 && |
| cap_info->count >= cap_info->total_size) { |
| if (cap_info->count > cap_info->total_size) { |
| pr_err("capsule upload size exceeded header defined size\n"); |
| ret = -EINVAL; |
| goto failed; |
| } |
| |
| ret = efi_capsule_submit_update(cap_info); |
| if (ret) |
| goto failed; |
| } |
| |
| return write_byte; |
| |
| fail_unmap: |
| kunmap(page); |
| failed: |
| efi_free_all_buff_pages(cap_info); |
| return ret; |
| } |
| |
| /** |
| * efi_capsule_flush - called by file close or file flush |
| * @file: file pointer |
| * @id: not used |
| * |
| * If a capsule is being partially uploaded then calling this function |
| * will be treated as upload termination and will free those completed |
| * buffer pages and -ECANCELED will be returned. |
| **/ |
| static int efi_capsule_flush(struct file *file, fl_owner_t id) |
| { |
| int ret = 0; |
| struct capsule_info *cap_info = file->private_data; |
| |
| if (cap_info->index > 0) { |
| pr_err("capsule upload not complete\n"); |
| efi_free_all_buff_pages(cap_info); |
| ret = -ECANCELED; |
| } |
| |
| return ret; |
| } |
| |
| /** |
| * efi_capsule_release - called by file close |
| * @inode: not used |
| * @file: file pointer |
| * |
| * We will not free successfully submitted pages since efi update |
| * requires data to be maintained across system reboot. |
| **/ |
| static int efi_capsule_release(struct inode *inode, struct file *file) |
| { |
| struct capsule_info *cap_info = file->private_data; |
| |
| kfree(cap_info->pages); |
| kfree(cap_info->phys); |
| kfree(file->private_data); |
| file->private_data = NULL; |
| return 0; |
| } |
| |
| /** |
| * efi_capsule_open - called by file open |
| * @inode: not used |
| * @file: file pointer |
| * |
| * Will allocate each capsule_info memory for each file open call. |
| * This provided the capability to support multiple file open feature |
| * where user is not needed to wait for others to finish in order to |
| * upload their capsule binary. |
| **/ |
| static int efi_capsule_open(struct inode *inode, struct file *file) |
| { |
| struct capsule_info *cap_info; |
| |
| cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL); |
| if (!cap_info) |
| return -ENOMEM; |
| |
| cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL); |
| if (!cap_info->pages) { |
| kfree(cap_info); |
| return -ENOMEM; |
| } |
| |
| cap_info->phys = kzalloc(sizeof(void *), GFP_KERNEL); |
| if (!cap_info->phys) { |
| kfree(cap_info->pages); |
| kfree(cap_info); |
| return -ENOMEM; |
| } |
| |
| file->private_data = cap_info; |
| |
| return 0; |
| } |
| |
| static const struct file_operations efi_capsule_fops = { |
| .owner = THIS_MODULE, |
| .open = efi_capsule_open, |
| .write = efi_capsule_write, |
| .flush = efi_capsule_flush, |
| .release = efi_capsule_release, |
| .llseek = no_llseek, |
| }; |
| |
| static struct miscdevice efi_capsule_misc = { |
| .minor = MISC_DYNAMIC_MINOR, |
| .name = "efi_capsule_loader", |
| .fops = &efi_capsule_fops, |
| }; |
| |
| static int __init efi_capsule_loader_init(void) |
| { |
| int ret; |
| |
| if (!efi_enabled(EFI_RUNTIME_SERVICES)) |
| return -ENODEV; |
| |
| ret = misc_register(&efi_capsule_misc); |
| if (ret) |
| pr_err("Unable to register capsule loader device\n"); |
| |
| return ret; |
| } |
| module_init(efi_capsule_loader_init); |
| |
| static void __exit efi_capsule_loader_exit(void) |
| { |
| misc_deregister(&efi_capsule_misc); |
| } |
| module_exit(efi_capsule_loader_exit); |
| |
| MODULE_DESCRIPTION("EFI capsule firmware binary loader"); |
| MODULE_LICENSE("GPL v2"); |