Re: [RFC PATCH v2 1/8] FWU: Add FWU metadata structure and functions for accessing metadata

[Sughosh Ganu <sughosh.ganu@linaro.org>]

On Tue, 21 Dec 2021 at 10:33, AKASHI Takahiro <takahiro.akashi@linaro.org>
wrote:

> On Tue, Dec 21, 2021 at 10:05:57AM +0530, Sughosh Ganu wrote:
> > hi Masami,
> >
> > On Tue, 21 Dec 2021 at 05:40, Masami Hiramatsu <
> masami.hiramatsu@linaro.org>
> > wrote:
> >
> > > Hi Sughosh,
> > >
> > > 2021年12月19日(日) 16:06 Sughosh Ganu <sughosh.ganu@linaro.org>:
> > > >
> > > > In the FWU Multi Bank Update feature, the information about the
> > > > updatable images is stored as part of the metadata, which is stored
> on
> > > > a dedicated partition. Add the metadata structure, and functions to
> > > > access the metadata. These are generic API's, and implementations can
> > > > be added based on parameters like how the metadata partition is
> > > > accessed and what type of storage device houses the metadata.
> > > >
> > > > Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> > > > ---
> > > > Changes since V1:
> > > > * Move all function declarations to a separate header fwu.h
> > > > * Rename metadata with mdata for all symbols
> > > > * Drop the parameter in the function fwu_revert_boot_index
> > > >   as suggested by Etienne
> > > >
> > > >  include/fwu.h               |  28 +++++
> > > >  include/fwu_mdata.h         | 102 ++++++++++++++++
> > > >  lib/fwu_updates/fwu_mdata.c | 236
> ++++++++++++++++++++++++++++++++++++
> > > >  3 files changed, 366 insertions(+)
> > > >  create mode 100644 include/fwu.h
> > > >  create mode 100644 include/fwu_mdata.h
> > > >  create mode 100644 lib/fwu_updates/fwu_mdata.c
> > > >
> > > > diff --git a/include/fwu.h b/include/fwu.h
> > > > new file mode 100644
> > > > index 0000000000..e6bc3e6b73
> > > > --- /dev/null
> > > > +++ b/include/fwu.h
> > > > @@ -0,0 +1,28 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0+ */
> > > > +/*
> > > > + * Copyright (c) 2021, Linaro Limited
> > > > + */
> > > > +
> > > > +#if !defined _FWU_H_
> > > > +#define _FWU_H_
> > > > +
> > > > +#include <efi.h>
> > > > +
> > > > +#include <linux/types.h>
> > > > +
> > > > +#define FWU_MDATA_VERSION      0x1
> > > > +
> > > > +#define FWU_MDATA_GUID \
> > > > +       EFI_GUID(0x8a7a84a0, 0x8387, 0x40f6, 0xab, 0x41, \
> > > > +                0xa8, 0xb9, 0xa5, 0xa6, 0x0d, 0x23)
> > > > +
> > > > +int fwu_get_active_index(u32 *active_idx);
> > > > +int fwu_update_active_index(u32 active_idx);
> > > > +int fwu_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank,
> > > > +                         int *alt_num);
> > > > +int fwu_mdata_check(void);
> > > > +int fwu_revert_boot_index(void);
> > > > +int fwu_accept_image(efi_guid_t *img_type_id);
> > > > +int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank);
> > > > +
> > > > +#endif /* _FWU_H_ */
> > > > diff --git a/include/fwu_mdata.h b/include/fwu_mdata.h
> > > > new file mode 100644
> > > > index 0000000000..11eb570012
> > > > --- /dev/null
> > > > +++ b/include/fwu_mdata.h
> > > > @@ -0,0 +1,102 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0+ */
> > > > +/*
> > > > + * Copyright (c) 2021, Linaro Limited
> > > > + */
> > > > +
> > > > +#if !defined _FWU_MDATA_H_
> > > > +#define _FWU_MDATA_H_
> > > > +
> > > > +#include <efi.h>
> > > > +#include <uuid.h>
> > > > +
> > > > +#include <linux/types.h>
> > > > +
> > > > +/**
> > > > + * struct fwu_image_bank_info - firmware image information
> > > > + * @image_uuid: Guid value of the image in this bank
> > > > + * @accepted: Acceptance status of the image
> > > > + * @reserved: Reserved
> > > > + *
> > > > + * The structure contains image specific fields which are
> > > > + * used to identify the image and to specify the image's
> > > > + * acceptance status
> > > > + */
> > > > +struct fwu_image_bank_info {
> > > > +       efi_guid_t  image_uuid;
> > > > +       u32 accepted;
> > > > +       u32 reserved;
> > > > +};
> > >
> > > Could you explicitly pack these metadata data structures?
> > > Since these metadata will be shared among bootloaders (TF-A,
> SCP-firmware),
> > > it is better to ensure that those are packed and fixed offset for each
> > > field.
> > >
> >
> > Okay. WIll do it.
> >
> >
> > >
> > > > +
> > > > +/**
> > > > + * struct fwu_image_entry - information for a particular type of
> image
> > > > + * @image_type_uuid: Guid value for identifying the image type
> > > > + * @location_uuid: Guid of the storage volume where the image is
> located
> > > > + * @img_bank_info: Array containing properties of images
> > > > + *
> > > > + * This structure contains information on various types of updatable
> > > > + * firmware images. Each image type then contains an array of image
> > > > + * information per bank.
> > > > + */
> > > > +struct fwu_image_entry {
> > > > +       efi_guid_t image_type_uuid;
> > > > +       efi_guid_t location_uuid;
> > > > +       struct fwu_image_bank_info
> img_bank_info[CONFIG_FWU_NUM_BANKS];
> > > > +};
> > > > +
> > > > +/**
> > > > + * struct fwu_mdata - FWU metadata structure for multi-bank updates
> > > > + * @crc32: crc32 value for the FWU metadata
> > > > + * @version: FWU metadata version
> > > > + * @active_index: Index of the bank currently used for booting
> images
> > > > + * @previous_active_inde: Index of the bank used before the current
> bank
> > > > + *                        being used for booting
> > > > + * @img_entry: Array of information on various firmware images that
> can
> > > > + *             be updated
> > > > + *
> > > > + * This structure is used to store all the needed information for
> > > performing
> > > > + * multi bank updates on the platform. This contains info on the
> bank
> > > being
> > > > + * used to boot along with the information needed for
> identification of
> > > > + * individual images
> > > > + */
> > > > +struct fwu_mdata {
> > > > +       u32 crc32;
> > > > +       u32 version;
> > > > +       u32 active_index;
> > > > +       u32 previous_active_index;
> > > > +
> > > > +       struct fwu_image_entry
> img_entry[CONFIG_FWU_NUM_IMAGES_PER_BANK];
> > > > +};
> > > > +
> > > > +/**
> > > > + * @get_active_index: get the current active_index value
> > > > + * @update_active_index: update the active_index value
> > > > + * @get_image_alt_num: get the alt number to be used for the image
> > > > + * @mdata_check: check the validity of the FWU metadata partitions
> > > > + * @revert_boot_index: set the active_index to previous_active_index
> > > > + * @set_accept_image: set the accepted bit for the image
> > > > + * @clear_accept_image: clear the accepted bit for the image
> > > > + * @get_mdata() - Get a FWU metadata copy
> > > > + */
> > > > +struct fwu_mdata_ops {
> > > > +       int (*get_active_index)(u32 *active_idx);
> > > > +
> > > > +       int (*update_active_index)(u32 active_idx);
> > > > +
> > > > +       int (*get_image_alt_num)(efi_guid_t image_type_id, u32
> > > update_bank,
> > > > +                                int *alt_num);
> > > > +
> > > > +       int (*mdata_check)(void);
> > > > +
> > > > +       int (*revert_boot_index)(void);
> > > > +
> > > > +       int (*set_accept_image)(efi_guid_t *img_type_id);
> > > > +
> > > > +       int (*clear_accept_image)(efi_guid_t *img_type_id, u32 bank);
> > > > +
> > > > +       int (*get_mdata)(struct fwu_mdata **mdata);
> > > > +};
> > > > +
> > > > +int fwu_get_mdata(struct fwu_mdata **mdata);
> > > > +struct fwu_mdata_ops *get_plat_fwu_mdata_ops(void);
> > >
> > > Also, could you also move these function prototypes and operators to
> > > fwu? I would like to copy this header file to the boot loaders as is.
> > > In that case, I just need the definition of the metadata data
> structure,
> > > but no function prototypes.
> > >
> >
> > I have moved the function declarations to fwu.h. The one function
> prototype
> > that I have in fwu_mdata.h is the one which has the metadata structure as
> > one of it's parameters. Same for the ops as well. The get_mdata function
> > has the metadata structure as its parameter. Are you facing any issues
> with
> > the current structure of the files.
>
> struct fwu_mdata;
> int fwu_get_mdata(struct fwu_**mdata);
>
> would be good enough?
>

Yes, I had considered putting this kind of declaration in fwu.h. But I
decided against it thinking that any function declaration that involved the
fwu metadata structure can be put in one file. But I just want to
understand if there is some issue in putting these declarations in the
fwu_mdata.h. The rest of the function declarations and symbols are put in
the fwu.h header. If you see, I only include the fwu.h in the
efi_firmware.c and efi_capsule.c.


>
> I'm not sure whether it is a good idea that we re-use the *same* file
> in other software, but I would suggest you to use standard POSIX types
> like 'uint32_t' instead of 'u32' anyway.
>

Hmm, this is on the same lines to the types used in the capsule code. That
was the primary reason that I stuck with u<size> types. Any issue with
using the short type? The Linux kernel seems to be using it.

-sughosh


>
> -Takahiro Akashi
>
>
> > -sughosh
> >
> >
> > > Thank you,
> > >
> > > > +
> > > > +#endif /* _FWU_MDATA_H_ */
> > > > diff --git a/lib/fwu_updates/fwu_mdata.c
> b/lib/fwu_updates/fwu_mdata.c
> > > > new file mode 100644
> > > > index 0000000000..348e9c85f7
> > > > --- /dev/null
> > > > +++ b/lib/fwu_updates/fwu_mdata.c
> > > > @@ -0,0 +1,236 @@
> > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > +/*
> > > > + * Copyright (c) 2021, Linaro Limited
> > > > + */
> > > > +
> > > > +#include <fwu_mdata.h>
> > > > +
> > > > +#include <linux/errno.h>
> > > > +#include <linux/types.h>
> > > > +
> > > > +static struct fwu_mdata_ops *get_fwu_mdata_ops(void)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops =  get_plat_fwu_mdata_ops();
> > > > +       if (!ops) {
> > > > +               log_err("Unable to get fwu ops\n");
> > > > +               return NULL;
> > > > +       }
> > > > +
> > > > +       return ops;
> > > > +}
> > > > +
> > > > +/**
> > > > + * fwu_get_active_index() - Get active_index from the FWU metadata
> > > > + * @active_idx: active_index value to be read
> > > > + *
> > > > + * Read the active_index field from the FWU metadata and place it in
> > > > + * the variable pointed to be the function argument.
> > > > + *
> > > > + * Return: 0 if OK, -ve on error
> > > > + *
> > > > + */
> > > > +int fwu_get_active_index(u32 *active_idx)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops = get_fwu_mdata_ops();
> > > > +       if (!ops)
> > > > +               return -EPROTONOSUPPORT;
> > > > +
> > > > +       if (!ops->get_active_index) {
> > > > +               log_err("get_active_index() method not defined for
> the
> > > platform\n");
> > > > +               return -ENOSYS;
> > > > +       }
> > > > +
> > > > +       return ops->get_active_index(active_idx);
> > > > +}
> > > > +
> > > > +/**
> > > > + * fwu_update_active_index() - Update active_index from the FWU
> metadata
> > > > + * @active_idx: active_index value to be updated
> > > > + *
> > > > + * Update the active_index field in the FWU metadata
> > > > + *
> > > > + * Return: 0 if OK, -ve on error
> > > > + *
> > > > + */
> > > > +int fwu_update_active_index(u32 active_idx)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops = get_fwu_mdata_ops();
> > > > +       if (!ops)
> > > > +               return -EPROTONOSUPPORT;
> > > > +
> > > > +       if (!ops->update_active_index) {
> > > > +               log_err("update_active_index() method not defined for
> > > the platform\n");
> > > > +               return -ENOSYS;
> > > > +       }
> > > > +
> > > > +       return ops->update_active_index(active_idx);
> > > > +}
> > > > +
> > > > +/**
> > > > + * fwu_get_image_alt_num() - Get the dfu alt number to be used for
> > > capsule update
> > > > + * @image_type_id: image guid as passed in the capsule
> > > > + * @update_bank: Bank to which the update is to be made
> > > > + * @alt_num: The alt_num for the image
> > > > + *
> > > > + * Based on the guid value passed in the capsule, along with the
> bank
> > > to which the
> > > > + * image needs to be updated, get the dfu alt number which will be
> used
> > > for the
> > > > + * capsule update
> > > > + *
> > > > + * Return: 0 if OK, -ve on error
> > > > + *
> > > > + */
> > > > +int fwu_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank,
> > > > +                         int *alt_num)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops = get_fwu_mdata_ops();
> > > > +       if (!ops)
> > > > +               return -EPROTONOSUPPORT;
> > > > +
> > > > +       if (!ops->get_image_alt_num) {
> > > > +               log_err("get_image_alt_num() method not defined for
> the
> > > platform\n");
> > > > +               return -ENOSYS;
> > > > +       }
> > > > +
> > > > +       return ops->get_image_alt_num(image_type_id, update_bank,
> > > alt_num);
> > > > +}
> > > > +
> > > > +/**
> > > > + * fwu_mdata_check() - Check if the FWU metadata is valid
> > > > + *
> > > > + * Validate both copies of the FWU metadata. If one of the copies
> > > > + * has gone bad, restore it from the other bad copy.
> > > > + *
> > > > + * Return: 0 if OK, -ve on error
> > > > + *
> > > > + */
> > > > +int fwu_mdata_check(void)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops = get_fwu_mdata_ops();
> > > > +       if (!ops)
> > > > +               return -EPROTONOSUPPORT;
> > > > +
> > > > +       if (!ops->mdata_check) {
> > > > +               log_err("mdata_check() method not defined for the
> > > platform\n");
> > > > +               return -ENOSYS;
> > > > +       }
> > > > +
> > > > +       return ops->mdata_check();
> > > > +}
> > > > +
> > > > +/**
> > > > + * fwu_revert_boot_index() - Revert the active index in the FWU
> metadata
> > > > + *
> > > > + * Revert the active_index value in the FWU metadata, by swapping
> the
> > > values
> > > > + * of active_index and previous_active_index in both copies of the
> > > > + * FWU metadata.
> > > > + *
> > > > + * Return: 0 if OK, -ve on error
> > > > + *
> > > > + */
> > > > +int fwu_revert_boot_index(void)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops = get_fwu_mdata_ops();
> > > > +       if (!ops)
> > > > +               return -EPROTONOSUPPORT;
> > > > +
> > > > +       if (!ops->revert_boot_index) {
> > > > +               log_err("revert_boot_index() method not defined for
> the
> > > platform\n");
> > > > +               return -ENOSYS;
> > > > +       }
> > > > +
> > > > +       return ops->revert_boot_index();
> > > > +}
> > > > +
> > > > +/**
> > > > + * fwu_accept_image() - Set the Acceptance bit for the image
> > > > + * @img_type_id: Guid of the image type for which the accepted bit
> is
> > > to be
> > > > + *               cleared
> > > > + *
> > > > + * Set the accepted bit for the image specified by the img_guid
> > > parameter. This
> > > > + * indicates acceptance of image for subsequent boots by some
> governing
> > > component
> > > > + * like OS(or firmware).
> > > > + *
> > > > + * Return: 0 if OK, -ve on error
> > > > + *
> > > > + */
> > > > +int fwu_accept_image(efi_guid_t *img_type_id)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops = get_fwu_mdata_ops();
> > > > +       if (!ops)
> > > > +               return -EPROTONOSUPPORT;
> > > > +
> > > > +       if (!ops->set_accept_image) {
> > > > +               log_err("set_accept_image() method not defined for
> the
> > > platform\n");
> > > > +               return -ENOSYS;
> > > > +       }
> > > > +
> > > > +       return ops->set_accept_image(img_type_id);
> > > > +}
> > > > +
> > > > +/**
> > > > + * fwu_clear_accept_image() - Clear the Acceptance bit for the image
> > > > + * @img_type_id: Guid of the image type for which the accepted bit
> is
> > > to be
> > > > + *               cleared
> > > > + *
> > > > + * Clear the accepted bit for the image type specified by the
> > > img_type_id parameter.
> > > > + * This function is called after the image has been updated. The
> > > accepted bit is
> > > > + * cleared to be set subsequently after passing the image acceptance
> > > criteria, by
> > > > + * either the OS(or firmware)
> > > > + *
> > > > + * Return: 0 if OK, -ve on error
> > > > + *
> > > > + */
> > > > +int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops = get_fwu_mdata_ops();
> > > > +       if (!ops)
> > > > +               return -EPROTONOSUPPORT;
> > > > +
> > > > +       if (!ops->clear_accept_image) {
> > > > +               log_err("clear_accept_image() method not defined for
> the
> > > platform\n");
> > > > +               return -ENOSYS;
> > > > +       }
> > > > +
> > > > +       return ops->clear_accept_image(img_type_id, bank);
> > > > +}
> > > > +
> > > > +/**
> > > > + * fwu_get_mdata() - Get a FWU metadata copy
> > > > + * @mdata: Copy of the FWU metadata
> > > > + *
> > > > + * Get a valid copy of the FWU metadata.
> > > > + *
> > > > + * Return: 0 if OK, -ve on error
> > > > + *
> > > > + */
> > > > +int fwu_get_mdata(struct fwu_mdata **mdata)
> > > > +{
> > > > +       struct fwu_mdata_ops *ops;
> > > > +
> > > > +       ops = get_fwu_mdata_ops();
> > > > +       if (!ops)
> > > > +               return -EPROTONOSUPPORT;
> > > > +
> > > > +       if (!ops->get_mdata) {
> > > > +               log_err("get_mdata() method not defined for the
> > > platform\n");
> > > > +               return -ENOSYS;
> > > > +       }
> > > > +
> > > > +       return ops->get_mdata(mdata);
> > > > +}
> > > > --
> > > > 2.17.1
> > > >
> > >
> > >
> > > --
> > > Masami Hiramatsu
> > >
>