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Date: Mon, 8 Feb 2016 15:13:42 +0000
From: Matt Fleming <matt@...sole-pimps.org>
To: "Kweh, Hock Leong" <hock.leong.kweh@...el.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Ong Boon Leong <boon.leong.ong@...el.com>,
LKML <linux-kernel@...r.kernel.org>, linux-efi@...r.kernel.org,
Sam Protsenko <semen.protsenko@...aro.org>,
Peter Jones <pjones@...hat.com>,
Andy Lutomirski <luto@...capital.net>,
Roy Franz <roy.franz@...aro.org>,
Borislav Petkov <bp@...en8.de>,
James Bottomley <James.Bottomley@...senpartnership.com>,
Linux FS Devel <linux-fsdevel@...r.kernel.org>,
Anvin H Peter <h.peter.anvin@...el.com>,
Bryan O'Donoghue <pure.logic@...us-software.ie>
Subject: Re: [PATCH v11 1/1] efi: a misc char interface for user to update
efi firmware
On Fri, 29 Jan, at 12:39:54PM, Kweh Hock Leong wrote:
> From: "Kweh, Hock Leong" <hock.leong.kweh@...el.com>
>
> Introducing a kernel module to expose capsule loader interface
> (misc char device file note) for users to upload capsule binaries.
>
> Example:
> cat firmware.bin > /dev/efi_capsule_loader
>
> This patch also export efi_capsule_supported() function symbol for
> verifying the submitted capsule header in this kernel module.
>
> Cc: Matt Fleming <matt@...eblueprint.co.uk>
> Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@...el.com>
> ---
> drivers/firmware/efi/Kconfig | 9 +
> drivers/firmware/efi/Makefile | 1 +
> drivers/firmware/efi/capsule-loader.c | 334 +++++++++++++++++++++++++++++++++
> drivers/firmware/efi/capsule.c | 1 +
> 4 files changed, 345 insertions(+)
> create mode 100644 drivers/firmware/efi/capsule-loader.c
OK, I've picked this up. I did make some modifications based on
Bryan's comments from v10 of this patch.
You can see a diff of the changes below, but roughly,
1. Use Bryan's comments for changelog and expand it a bit
2. Add more detail to Kconfig entry, most people don't need this
3. Sprinkled comments from Bryan in the kerneldoc comments
4. Deleted a level of indentation in efi_capsule_setup_info()
5. Local variable instead of indexing ->pages in efi_capsule_write()
6. Fix memory leak in efi_capsule_open()
My plan is to include this patch in the EFI capsule series, and resend
the whole thing out.
---
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 73c14af00c19..de221bbde9c9 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -92,9 +92,10 @@ config EFI_CAPSULE_LOADER
depends on EFI
help
This option exposes a loader interface "/dev/efi_capsule_loader" for
- users to load EFI capsules.
+ users to load EFI capsules. This driver requires working runtime
+ capsule support in the firmware, which many OEMs do not provide.
- If unsure, say N.
+ Most users should say N.
endmenu
diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
index acffd767223e..9a43b1568234 100644
--- a/drivers/firmware/efi/capsule-loader.c
+++ b/drivers/firmware/efi/capsule-loader.c
@@ -33,7 +33,7 @@ struct capsule_info {
* efi_free_all_buff_pages - free all previous allocated buffer pages
* @cap_info: pointer to current instance of capsule_info structure
*
- * In addition of freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION
+ * 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.
**/
@@ -46,7 +46,7 @@ static void efi_free_all_buff_pages(struct capsule_info *cap_info)
}
/**
- * efi_capsule_setup_info - to obtain the efi capsule header in the binary and
+ * 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
@@ -55,44 +55,46 @@ static void efi_free_all_buff_pages(struct capsule_info *cap_info)
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 a efi header size */
- if (hdr_bytes >= sizeof(efi_capsule_header_t)) {
- /* Reset back to the correct offset of header */
- efi_capsule_header_t *cap_hdr = kbuff - cap_info->count;
- size_t pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >>
- PAGE_SHIFT;
+ /* Only process data block that is larger than efi header size */
+ if (hdr_bytes < sizeof(efi_capsule_header_t))
+ return 0;
- if (pages_needed == 0) {
- pr_err("%s: pages count invalid\n", __func__);
- return -EINVAL;
- }
+ /* Reset back to the correct offset of header */
+ cap_hdr = kbuff - cap_info->count;
+ pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >> PAGE_SHIFT;
- /* 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;
- }
+ if (pages_needed == 0) {
+ pr_err("%s: pages count invalid\n", __func__);
+ return -EINVAL;
+ }
- 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;
- }
+ /* 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->pages = temp_page;
- cap_info->header_obtained = true;
+ 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;
}
@@ -137,21 +139,22 @@ static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
* @offp: not used
*
* Expectation:
- * - User space tool should start at the beginning of capsule binary and
+ * - 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.
- * - EFI capsule header must be located at the beginning of capsule binary
- * file and passed in as first block data of write operation.
+ * - 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;
@@ -164,16 +167,20 @@ static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
/* Only alloc a new page when previous page is full */
if (!cap_info->page_bytes_remain) {
- cap_info->pages[cap_info->index++] = alloc_page(GFP_KERNEL);
- if (!cap_info->pages[cap_info->index - 1]) {
+ 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;
}
- kbuff = kmap(cap_info->pages[cap_info->index - 1]);
+ page = cap_info->pages[cap_info->index - 1];
+
+ kbuff = kmap(page);
if (!kbuff) {
pr_debug("%s: kmap() failed\n", __func__);
ret = -EFAULT;
@@ -199,7 +206,7 @@ static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
}
cap_info->count += write_byte;
- kunmap(cap_info->pages[cap_info->index - 1]);
+ kunmap(page);
/* Submit the full binary to efi_capsule_update() API */
if (cap_info->header_obtained &&
@@ -219,7 +226,7 @@ static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
return write_byte;
fail_unmap:
- kunmap(cap_info->pages[cap_info->index - 1]);
+ kunmap(page);
failed:
efi_free_all_buff_pages(cap_info);
return ret;
@@ -253,8 +260,8 @@ static int efi_capsule_flush(struct file *file, fl_owner_t id)
* @inode: not used
* @file: file pointer
*
- * We would not free successfully submitted pages since efi update require
- * data to be maintained across system reboot.
+ * 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)
{
@@ -285,8 +292,10 @@ static int efi_capsule_open(struct inode *inode, struct file *file)
return -ENOMEM;
cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL);
- if (!cap_info->pages)
+ if (!cap_info->pages) {
+ kfree(cap_info);
return -ENOMEM;
+ }
file->private_data = cap_info;
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