efi: Add misc char driver interface to update EFI firmware
This patch introduces a kernel module to expose a capsule loader interface (misc char device file note) for users to upload capsule binaries. Example: cat firmware.bin > /dev/efi_capsule_loader Any upload error will be returned while doing "cat" through file operation write() function call. Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@intel.com> [ Update comments and Kconfig text ] Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Reviewed-by: Bryan O'Donoghue <pure.logic@nexus-software.ie> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Peter Jones <pjones@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sam Protsenko <semen.protsenko@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: joeyli <jlee@suse.com> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1461614832-17633-30-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kweh, Hock Leong
Ingo Molnar
parent
87615a34d5
commit
65117f1aa1
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@ -102,6 +102,16 @@ config EFI_BOOTLOADER_CONTROL
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bootloader reads this reboot reason and takes particular
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bootloader reads this reboot reason and takes particular
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action according to its policy.
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action according to its policy.
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config EFI_CAPSULE_LOADER
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tristate "EFI capsule loader"
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depends on EFI
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help
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This option exposes a loader interface "/dev/efi_capsule_loader" for
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users to load EFI capsules. This driver requires working runtime
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capsule support in the firmware, which many OEMs do not provide.
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Most users should say N.
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endmenu
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endmenu
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config UEFI_CPER
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config UEFI_CPER
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@ -24,3 +24,4 @@ obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o
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arm-obj-$(CONFIG_EFI) := arm-init.o arm-runtime.o
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arm-obj-$(CONFIG_EFI) := arm-init.o arm-runtime.o
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obj-$(CONFIG_ARM) += $(arm-obj-y)
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obj-$(CONFIG_ARM) += $(arm-obj-y)
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obj-$(CONFIG_ARM64) += $(arm-obj-y)
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obj-$(CONFIG_ARM64) += $(arm-obj-y)
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obj-$(CONFIG_EFI_CAPSULE_LOADER) += capsule-loader.o
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@ -0,0 +1,343 @@
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/*
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* EFI capsule loader driver.
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*
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* Copyright 2015 Intel Corporation
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*
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* This file is part of the Linux kernel, and is made available under
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* the terms of the GNU General Public License version 2.
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*/
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#define pr_fmt(fmt) "efi: " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/miscdevice.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/efi.h>
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#define NO_FURTHER_WRITE_ACTION -1
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struct capsule_info {
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bool header_obtained;
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int reset_type;
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long index;
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size_t count;
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size_t total_size;
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struct page **pages;
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size_t page_bytes_remain;
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};
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/**
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* efi_free_all_buff_pages - free all previous allocated buffer pages
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* @cap_info: pointer to current instance of capsule_info structure
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*
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* In addition to freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION
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* to cease processing data in subsequent write(2) calls until close(2)
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* is called.
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**/
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static void efi_free_all_buff_pages(struct capsule_info *cap_info)
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{
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while (cap_info->index > 0)
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__free_page(cap_info->pages[--cap_info->index]);
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cap_info->index = NO_FURTHER_WRITE_ACTION;
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}
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/**
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* efi_capsule_setup_info - obtain the efi capsule header in the binary and
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* setup capsule_info structure
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* @cap_info: pointer to current instance of capsule_info structure
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* @kbuff: a mapped first page buffer pointer
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* @hdr_bytes: the total received number of bytes for efi header
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**/
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static ssize_t efi_capsule_setup_info(struct capsule_info *cap_info,
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void *kbuff, size_t hdr_bytes)
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{
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efi_capsule_header_t *cap_hdr;
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size_t pages_needed;
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int ret;
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void *temp_page;
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/* Only process data block that is larger than efi header size */
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if (hdr_bytes < sizeof(efi_capsule_header_t))
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return 0;
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/* Reset back to the correct offset of header */
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cap_hdr = kbuff - cap_info->count;
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pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >> PAGE_SHIFT;
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if (pages_needed == 0) {
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pr_err("%s: pages count invalid\n", __func__);
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return -EINVAL;
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}
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/* Check if the capsule binary supported */
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ret = efi_capsule_supported(cap_hdr->guid, cap_hdr->flags,
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cap_hdr->imagesize,
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&cap_info->reset_type);
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if (ret) {
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pr_err("%s: efi_capsule_supported() failed\n",
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__func__);
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return ret;
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}
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cap_info->total_size = cap_hdr->imagesize;
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temp_page = krealloc(cap_info->pages,
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pages_needed * sizeof(void *),
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GFP_KERNEL | __GFP_ZERO);
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if (!temp_page) {
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pr_debug("%s: krealloc() failed\n", __func__);
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return -ENOMEM;
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}
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cap_info->pages = temp_page;
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cap_info->header_obtained = true;
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return 0;
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}
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/**
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* efi_capsule_submit_update - invoke the efi_capsule_update API once binary
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* upload done
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* @cap_info: pointer to current instance of capsule_info structure
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**/
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static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
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{
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int ret;
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void *cap_hdr_temp;
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cap_hdr_temp = kmap(cap_info->pages[0]);
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if (!cap_hdr_temp) {
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pr_debug("%s: kmap() failed\n", __func__);
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return -EFAULT;
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}
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ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
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kunmap(cap_info->pages[0]);
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if (ret) {
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pr_err("%s: efi_capsule_update() failed\n", __func__);
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return ret;
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}
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/* Indicate capsule binary uploading is done */
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cap_info->index = NO_FURTHER_WRITE_ACTION;
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pr_info("%s: Successfully upload capsule file with reboot type '%s'\n",
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__func__, !cap_info->reset_type ? "RESET_COLD" :
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cap_info->reset_type == 1 ? "RESET_WARM" :
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"RESET_SHUTDOWN");
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return 0;
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}
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/**
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* efi_capsule_write - store the capsule binary and pass it to
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* efi_capsule_update() API
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* @file: file pointer
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* @buff: buffer pointer
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* @count: number of bytes in @buff
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* @offp: not used
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*
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* Expectation:
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* - A user space tool should start at the beginning of capsule binary and
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* pass data in sequentially.
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* - Users should close and re-open this file note in order to upload more
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* capsules.
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* - After an error returned, user should close the file and restart the
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* operation for the next try otherwise -EIO will be returned until the
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* file is closed.
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* - An EFI capsule header must be located at the beginning of capsule
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* binary file and passed in as first block data of write operation.
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**/
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static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
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size_t count, loff_t *offp)
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{
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int ret = 0;
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struct capsule_info *cap_info = file->private_data;
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struct page *page;
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void *kbuff = NULL;
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size_t write_byte;
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if (count == 0)
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return 0;
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/* Return error while NO_FURTHER_WRITE_ACTION is flagged */
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if (cap_info->index < 0)
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return -EIO;
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/* Only alloc a new page when previous page is full */
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if (!cap_info->page_bytes_remain) {
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page = alloc_page(GFP_KERNEL);
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if (!page) {
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pr_debug("%s: alloc_page() failed\n", __func__);
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ret = -ENOMEM;
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goto failed;
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}
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cap_info->pages[cap_info->index++] = page;
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cap_info->page_bytes_remain = PAGE_SIZE;
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}
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page = cap_info->pages[cap_info->index - 1];
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kbuff = kmap(page);
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if (!kbuff) {
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pr_debug("%s: kmap() failed\n", __func__);
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ret = -EFAULT;
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goto failed;
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}
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kbuff += PAGE_SIZE - cap_info->page_bytes_remain;
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/* Copy capsule binary data from user space to kernel space buffer */
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write_byte = min_t(size_t, count, cap_info->page_bytes_remain);
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if (copy_from_user(kbuff, buff, write_byte)) {
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pr_debug("%s: copy_from_user() failed\n", __func__);
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ret = -EFAULT;
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goto fail_unmap;
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}
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cap_info->page_bytes_remain -= write_byte;
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/* Setup capsule binary info structure */
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if (!cap_info->header_obtained) {
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ret = efi_capsule_setup_info(cap_info, kbuff,
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cap_info->count + write_byte);
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if (ret)
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goto fail_unmap;
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}
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cap_info->count += write_byte;
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kunmap(page);
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/* Submit the full binary to efi_capsule_update() API */
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if (cap_info->header_obtained &&
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cap_info->count >= cap_info->total_size) {
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if (cap_info->count > cap_info->total_size) {
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pr_err("%s: upload size exceeded header defined size\n",
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__func__);
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ret = -EINVAL;
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goto failed;
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}
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ret = efi_capsule_submit_update(cap_info);
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if (ret)
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goto failed;
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}
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return write_byte;
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fail_unmap:
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kunmap(page);
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failed:
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efi_free_all_buff_pages(cap_info);
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return ret;
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}
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/**
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* efi_capsule_flush - called by file close or file flush
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* @file: file pointer
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* @id: not used
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*
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* If a capsule is being partially uploaded then calling this function
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* will be treated as upload termination and will free those completed
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* buffer pages and -ECANCELED will be returned.
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**/
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static int efi_capsule_flush(struct file *file, fl_owner_t id)
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{
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int ret = 0;
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struct capsule_info *cap_info = file->private_data;
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if (cap_info->index > 0) {
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pr_err("%s: capsule upload not complete\n", __func__);
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efi_free_all_buff_pages(cap_info);
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ret = -ECANCELED;
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}
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return ret;
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}
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/**
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* efi_capsule_release - called by file close
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* @inode: not used
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* @file: file pointer
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*
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* We will not free successfully submitted pages since efi update
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* requires data to be maintained across system reboot.
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**/
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static int efi_capsule_release(struct inode *inode, struct file *file)
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{
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struct capsule_info *cap_info = file->private_data;
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kfree(cap_info->pages);
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kfree(file->private_data);
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file->private_data = NULL;
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return 0;
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}
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/**
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* efi_capsule_open - called by file open
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* @inode: not used
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* @file: file pointer
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*
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* Will allocate each capsule_info memory for each file open call.
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* This provided the capability to support multiple file open feature
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* where user is not needed to wait for others to finish in order to
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* upload their capsule binary.
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**/
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static int efi_capsule_open(struct inode *inode, struct file *file)
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{
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struct capsule_info *cap_info;
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cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL);
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if (!cap_info)
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return -ENOMEM;
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cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL);
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if (!cap_info->pages) {
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kfree(cap_info);
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return -ENOMEM;
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}
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file->private_data = cap_info;
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return 0;
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}
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static const struct file_operations efi_capsule_fops = {
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.owner = THIS_MODULE,
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.open = efi_capsule_open,
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.write = efi_capsule_write,
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.flush = efi_capsule_flush,
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.release = efi_capsule_release,
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.llseek = no_llseek,
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};
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static struct miscdevice efi_capsule_misc = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = "efi_capsule_loader",
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.fops = &efi_capsule_fops,
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};
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static int __init efi_capsule_loader_init(void)
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{
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int ret;
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if (!efi_enabled(EFI_RUNTIME_SERVICES))
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return -ENODEV;
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ret = misc_register(&efi_capsule_misc);
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if (ret)
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pr_err("%s: Failed to register misc char file note\n",
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__func__);
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return ret;
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}
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module_init(efi_capsule_loader_init);
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static void __exit efi_capsule_loader_exit(void)
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{
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misc_deregister(&efi_capsule_misc);
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}
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module_exit(efi_capsule_loader_exit);
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MODULE_DESCRIPTION("EFI capsule firmware binary loader");
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MODULE_LICENSE("GPL v2");
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