From: "Kweh, Hock Leong" <hock.leong.kweh@xxxxxxxxx>
Introducing a kernel module to expose capsule loader interface
(misc char device file note) for user to upload capsule binaries.
Example method to load the capsule binary:
cat firmware.bin > /dev/efi_capsule_loader
Cc: Matt Fleming <matt.fleming@xxxxxxxxx>
Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@xxxxxxxxx>
---
drivers/firmware/efi/Kconfig | 10 ++
drivers/firmware/efi/Makefile | 1 +
drivers/firmware/efi/efi-capsule-loader.c | 246 +++++++++++++++++++++++++++++
3 files changed, 257 insertions(+)
create mode 100644 drivers/firmware/efi/efi-capsule-loader.c
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index f712d47..0be8ee3 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -60,6 +60,16 @@ config EFI_RUNTIME_WRAPPERS
config EFI_ARMSTUB
bool
+config EFI_CAPSULE_LOADER
+ tristate "EFI capsule loader"
+ depends on EFI
+ help
+ This option exposes a loader interface "/dev/efi_capsule_loader" for
+ user to load EFI capsule binary and update the EFI firmware through
+ system reboot.
+
+ If unsure, say N.
+
endmenu
config UEFI_CPER
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index 698846e..5ab031a 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_UEFI_CPER) += cper.o
obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o
obj-$(CONFIG_EFI_RUNTIME_WRAPPERS) += runtime-wrappers.o
obj-$(CONFIG_EFI_STUB) += libstub/
+obj-$(CONFIG_EFI_CAPSULE_LOADER) += efi-capsule-loader.o
diff --git a/drivers/firmware/efi/efi-capsule-loader.c b/drivers/firmware/efi/efi-capsule-loader.c
new file mode 100644
index 0000000..571e0c8
--- /dev/null
+++ b/drivers/firmware/efi/efi-capsule-loader.c
@@ -0,0 +1,246 @@
+/*
+ * 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) KBUILD_MODNAME ": " 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 DEV_NAME "efi_capsule_loader"
+
+static struct capsule_info {
+ char header_obtained;
+ long index;
+ unsigned long count;
+ unsigned long total_size;
+ struct page **pages;
+ unsigned long page_count_remain;
+} cap_info;
+
+static DEFINE_MUTEX(capsule_loader_lock);
+
+/*
+ * This function will free the current & all previous allocated buffer pages.
+ * The input parameter is the allocated buffer page for current execution which
+ * has not yet assigned to pages array. The input param can be NULL if the
+ * current execution has not allocated any buffer page.
+ */
+static void efi_free_all_buff_pages(struct page *kbuff_page)
+{
+ if (!kbuff_page)
+ __free_page(kbuff_page);
+
+ if (cap_info.index > 0)
+ while (cap_info.index > 0)
+ __free_page(cap_info.pages[--cap_info.index]);
+
+ if (cap_info.header_obtained)
+ kfree(cap_info.pages);
+
+ /* indicate to the next that error had occurred */
+ cap_info.index = -2;
+}
+
+/*
+ * This function will store the capsule binary and pass it to
+ * efi_capsule_update() API in capsule.c.
+ *
+ * Expectation:
+ * - userspace tool should start at the beginning of capsule binary and pass
+ * data in sequential.
+ * - user should close and re-open this file note in order to upload more
+ * capsules.
+ * - any error occurred, user should close the file and restart the operation
+ * for the next try otherwise -EIO will be returned until the file is closed.
+ */
+static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
+ size_t count, loff_t *offp)
+{
+ int ret = 0;
+ struct page *kbuff_page;
+ void *kbuff;
+ size_t write_byte;
+
+ pr_debug("%s: Entering Write()\n", __func__);
+ if (count == 0)
+ return 0;
+
+ /* return error while error had occurred or capsule uploading is done */
+ if (cap_info.index < 0)
+ return -EIO;
+
+ /* only alloc a new page when the current page is full */
+ if (!cap_info.page_count_remain) {
+ kbuff_page = alloc_page(GFP_KERNEL);
+ if (!kbuff_page) {
+ pr_debug("%s: alloc_page() failed\n", __func__);
+ efi_free_all_buff_pages(NULL);
+ return -ENOMEM;
+ }
+ cap_info.page_count_remain = PAGE_SIZE;
+ } else {
+ kbuff_page = cap_info.pages[--cap_info.index];
+ }
+ kbuff = kmap(kbuff_page);
+ if (!kbuff) {
+ pr_debug("%s: kmap() failed\n", __func__);
+ efi_free_all_buff_pages(kbuff_page);
+ return -EFAULT;
+ }
+ kbuff += PAGE_SIZE - cap_info.page_count_remain;
+
+ /* copy capsule binary data from user space to kernel space buffer */
+ write_byte = min_t(size_t, count, cap_info.page_count_remain);
+ if (copy_from_user(kbuff, buff, write_byte)) {
+ pr_debug("%s: copy_from_user() failed\n", __func__);
+ kunmap(kbuff_page);
+ efi_free_all_buff_pages(kbuff_page);
+ return -EFAULT;
+ }
+ cap_info.page_count_remain -= write_byte;
+
+ /* setup capsule binary info structure */
+ if (cap_info.header_obtained == 0 && cap_info.index == 0) {
+ efi_capsule_header_t *cap_hdr = kbuff;
+ int reset_type;
+ size_t pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >>
+ PAGE_SHIFT;
+
+ if (pages_needed == 0) {
+ pr_err("%s: pages count invalid\n", __func__);
+ kunmap(kbuff_page);
+ efi_free_all_buff_pages(kbuff_page);
+ return -EINVAL;
+ }
+
+ /* check if the capsule binary supported */
+ ret = efi_capsule_supported(cap_hdr->guid, cap_hdr->flags,
+ cap_hdr->imagesize, &reset_type);
+ if (ret) {
+ pr_err("%s: efi_capsule_supported() failed\n",
+ __func__);
+ kunmap(kbuff_page);
+ efi_free_all_buff_pages(kbuff_page);
+ return ret;
+ }
+
+ cap_info.total_size = cap_hdr->imagesize;
+ cap_info.pages = kmalloc_array(pages_needed, sizeof(void *),
+ GFP_KERNEL);
+ if (!cap_info.pages) {
+ pr_debug("%s: kmalloc_array() failed\n", __func__);
+ kunmap(kbuff_page);
+ efi_free_all_buff_pages(kbuff_page);
+ return -ENOMEM;
+ }
+
+ cap_info.header_obtained = 1;
+ }
+
+ cap_info.pages[cap_info.index++] = kbuff_page;
+ cap_info.count += write_byte;
+ kunmap(kbuff_page);
+
+ /* submit the full binary to efi_capsule_update() API */
+ if (cap_info.count >= cap_info.total_size) {
+ void *cap_hdr_temp;
+
+ cap_hdr_temp = kmap(cap_info.pages[0]);
+ if (!cap_hdr_temp) {
+ pr_debug("%s: kmap() failed\n", __func__);
+ efi_free_all_buff_pages(NULL);
+ 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__);
+ efi_free_all_buff_pages(NULL);
+ return ret;
+ }
+ /* indicate capsule binary uploading is done */
+ cap_info.index = -1;
+ }
+
+ return write_byte;
+}
+
+static int efi_capsule_release(struct inode *inode, struct file *file)
+{
+ int ret = 0;
+
+ pr_debug("%s: Exit in Release()\n", __func__);
+ /* release uncompleted capsule upload */
+ if (cap_info.index > 0) {
+ pr_err("%s: capsule upload not complete\n", __func__);
+ efi_free_all_buff_pages(NULL);
+ ret = -ECANCELED;
+ }
+ mutex_unlock(&capsule_loader_lock);
+
+ /*
+ * we would not free the successful submitted buffer pages here due to
+ * efi update require system reboot with data maintained.
+ */
+ return ret;
+}
+
+static int efi_capsule_open(struct inode *inode, struct file *file)
+{
+ pr_debug("%s: Entering Open()\n", __func__);
+ if (!mutex_trylock(&capsule_loader_lock))
+ return -EBUSY;
+
+ memset(&cap_info, 0, sizeof(cap_info));
+ return 0;
+}
+
+static const struct file_operations efi_capsule_fops = {
+ .owner = THIS_MODULE,
+ .open = efi_capsule_open,
+ .write = efi_capsule_write,
+ .release = efi_capsule_release,
+ .llseek = no_llseek,
+};
+
+static struct miscdevice efi_capsule_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = DEV_NAME,
+ .fops = &efi_capsule_fops,
+};
+
+static int __init efi_capsule_loader_init(void)
+{
+ int ret;
+
+ mutex_init(&capsule_loader_lock);
+
+ 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)
+{
+ mutex_destroy(&capsule_loader_lock);
+ misc_deregister(&efi_capsule_misc);
+}
+module_exit(efi_capsule_loader_exit);
+
+MODULE_DESCRIPTION("EFI capsule firmware binary loader");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5
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