linux/drivers/firmware/efi/capsule-loader.c

344 lines
8.6 KiB
C

/*
* 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>
#define NO_FURTHER_WRITE_ACTION -1
struct capsule_info {
bool header_obtained;
int reset_type;
long index;
size_t count;
size_t total_size;
struct page **pages;
size_t page_bytes_remain;
};
/**
* 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;
}
/**
* 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
**/
static ssize_t efi_capsule_setup_info(struct capsule_info *cap_info,
void *kbuff, size_t hdr_bytes)
{
efi_capsule_header_t *cap_hdr;
size_t pages_needed;
int ret;
void *temp_page;
/* Only process data block that is larger than efi header size */
if (hdr_bytes < sizeof(efi_capsule_header_t))
return 0;
/* Reset back to the correct offset of header */
cap_hdr = kbuff - cap_info->count;
pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >> PAGE_SHIFT;
if (pages_needed == 0) {
pr_err("%s: pages count invalid\n", __func__);
return -EINVAL;
}
/* Check if the capsule binary supported */
ret = efi_capsule_supported(cap_hdr->guid, cap_hdr->flags,
cap_hdr->imagesize,
&cap_info->reset_type);
if (ret) {
pr_err("%s: efi_capsule_supported() failed\n",
__func__);
return ret;
}
cap_info->total_size = cap_hdr->imagesize;
temp_page = krealloc(cap_info->pages,
pages_needed * sizeof(void *),
GFP_KERNEL | __GFP_ZERO);
if (!temp_page) {
pr_debug("%s: krealloc() failed\n", __func__);
return -ENOMEM;
}
cap_info->pages = temp_page;
cap_info->header_obtained = true;
return 0;
}
/**
* 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)
{
int ret;
void *cap_hdr_temp;
cap_hdr_temp = kmap(cap_info->pages[0]);
if (!cap_hdr_temp) {
pr_debug("%s: kmap() failed\n", __func__);
return -EFAULT;
}
ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
kunmap(cap_info->pages[0]);
if (ret) {
pr_err("%s: efi_capsule_update() failed\n", __func__);
return ret;
}
/* Indicate capsule binary uploading is done */
cap_info->index = NO_FURTHER_WRITE_ACTION;
pr_info("%s: Successfully upload capsule file with reboot type '%s'\n",
__func__, !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) {
pr_debug("%s: alloc_page() failed\n", __func__);
ret = -ENOMEM;
goto failed;
}
cap_info->pages[cap_info->index++] = page;
cap_info->page_bytes_remain = PAGE_SIZE;
}
page = cap_info->pages[cap_info->index - 1];
kbuff = kmap(page);
if (!kbuff) {
pr_debug("%s: kmap() failed\n", __func__);
ret = -EFAULT;
goto failed;
}
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)) {
pr_debug("%s: copy_from_user() failed\n", __func__);
ret = -EFAULT;
goto fail_unmap;
}
cap_info->page_bytes_remain -= write_byte;
/* Setup capsule binary info structure */
if (!cap_info->header_obtained) {
ret = efi_capsule_setup_info(cap_info, kbuff,
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_obtained &&
cap_info->count >= cap_info->total_size) {
if (cap_info->count > cap_info->total_size) {
pr_err("%s: upload size exceeded header defined size\n",
__func__);
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("%s: capsule upload not complete\n", __func__);
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(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;
}
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("%s: Failed to register misc char file note\n",
__func__);
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");