On Thu, Oct 1, 2015 at 2:05 PM, Kweh, Hock Leong <hock.leong.kweh@xxxxxxxxx> wrote: > 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; > + Why is this static? > +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 -2 to too magical. > +} > + > +/* > + * 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__); Unnecessary. > + 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); And what if cap_hdr isn't written yet? > + 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; I don't see how you know that the header is obtained. > + } > + > + cap_info.pages[cap_info.index++] = kbuff_page; Huh? You might now have allocated a whole 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; Should count > cap_info.total_size be an error? --Andy > +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); Holding mutexes in userspace seems like an error. In fact, doesn't lockdep warn when you do that? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html