[PATCH v13 10/15] FWU: Add support for the FWU Multi Bank Update feature

Ilias Apalodimas ilias.apalodimas at linaro.org
Fri Oct 14 09:31:27 CEST 2022


On Fri, 14 Oct 2022 at 10:06, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
>
> On Fri, 14 Oct 2022 at 12:12, Ilias Apalodimas
> <ilias.apalodimas at linaro.org> wrote:
> >
> > On Thu, Oct 06, 2022 at 02:36:24PM +0530, Sughosh Ganu wrote:
> > > The FWU Multi Bank Update feature supports updation of firmware images
> >
> > s/updation/updating
> >
> > > to one of multiple sets(also called banks) of images. The firmware
> > > images are clubbed together in banks, with the system booting images
> > > from the active bank. Information on the images such as which bank
> > > they belong to is stored as part of the metadata structure, which is
> > > stored on the same storage media as the firmware images on a dedicated
> > > partition.
> > >
> > > At the time of update, the metadata is read to identify the bank to
> > > which the images need to be flashed(update bank). On a successful
> > > update, the metadata is modified to set the updated bank as active
> > > bank to subsequently boot from.
> > >
> > > Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> > > ---
> > > Changes since V12: None
> > >
> > >  drivers/Kconfig               |   2 +
> > >  drivers/Makefile              |   1 +
> > >  include/fwu.h                 |  30 +++++
> > >  lib/Kconfig                   |   6 +
> > >  lib/Makefile                  |   1 +
> > >  lib/efi_loader/efi_capsule.c  | 207 +++++++++++++++++++++++++++++++++-
> > >  lib/efi_loader/efi_firmware.c |  14 +++
> > >  lib/fwu_updates/Kconfig       |  33 ++++++
> > >  lib/fwu_updates/Makefile      |   7 ++
> > >  lib/fwu_updates/fwu.c         |  22 ++++
> > >  10 files changed, 321 insertions(+), 2 deletions(-)
> > >  create mode 100644 lib/fwu_updates/Kconfig
> > >  create mode 100644 lib/fwu_updates/Makefile
> > >
> > > diff --git a/drivers/Kconfig b/drivers/Kconfig
> > > index 8b6fead351..75ac149d31 100644
> > > --- a/drivers/Kconfig
> > > +++ b/drivers/Kconfig
> > > @@ -44,6 +44,8 @@ source "drivers/fuzz/Kconfig"
> > >
> > >  source "drivers/fpga/Kconfig"
> > >
> > > +source "drivers/fwu-mdata/Kconfig"
> > > +
> > >  source "drivers/gpio/Kconfig"
> > >
> > >  source "drivers/hwspinlock/Kconfig"
> > > diff --git a/drivers/Makefile b/drivers/Makefile
> > > index 9d9f69a3c9..253cbfb71d 100644
> > > --- a/drivers/Makefile
> > > +++ b/drivers/Makefile
> > > @@ -85,6 +85,7 @@ obj-y += cache/
> > >  obj-$(CONFIG_CPU) += cpu/
> > >  obj-y += crypto/
> > >  obj-$(CONFIG_FASTBOOT) += fastboot/
> > > +obj-$(CONFIG_FWU_MDATA) += fwu-mdata/
> > >  obj-y += misc/
> > >  obj-$(CONFIG_MMC) += mmc/
> > >  obj-$(CONFIG_NVME) += nvme/
> > > diff --git a/include/fwu.h b/include/fwu.h
> > > index 2effa7da38..b5c59dc161 100644
> > > --- a/include/fwu.h
> > > +++ b/include/fwu.h
> > > @@ -60,6 +60,7 @@ struct fwu_mdata_ops {
> > >  };
> > >
> > > @@ -388,6 +395,130 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
> > >  }
> > >  #endif /* CONFIG_EFI_CAPSULE_AUTHENTICATE */
> > >
> > > +static __maybe_unused bool fwu_empty_capsule(struct efi_capsule_header *capsule)
> > > +{
> > > +     return !guidcmp(&capsule->capsule_guid,
> > > +                     &fwu_guid_os_request_fw_revert) ||
> > > +             !guidcmp(&capsule->capsule_guid,
> > > +                      &fwu_guid_os_request_fw_accept);
> > > +}
> > > +
> > > +static __maybe_unused efi_status_t fwu_to_efi_error(int err)
> > > +{
> > > +     efi_status_t ret;
> > > +
> > > +     switch(err) {
> > > +     case 0:
> > > +             ret = EFI_SUCCESS;
> > > +             break;
> > > +     case -ENODEV:
> >
> > ENODEV should return EFI_INVALID_PARAMETER.  The device was not found,
> > EFI_DEVICE_ERROR usually means something bad happened to the device
> >
> > > +     case -ERANGE:
> > > +     case -EIO:
> > > +             ret = EFI_DEVICE_ERROR;
> > > +             break;
> > > +     case -EINVAL:
> > > +             ret = EFI_INVALID_PARAMETER;
> > > +             break;
> > > +     default:
> > > +             ret = EFI_OUT_OF_RESOURCES;
> > > +     }
> > > +
> > > +     return ret;
> > > +}
> > > +
> > > +static __maybe_unused efi_status_t fwu_empty_capsule_process(
> > > +     struct efi_capsule_header *capsule)
> > > +{
> > > +     int status;
> > > +     u32 active_idx;
> > > +     efi_status_t ret;
> > > +     efi_guid_t *image_guid;
> > > +
> > > +     if (!guidcmp(&capsule->capsule_guid,
> > > +                  &fwu_guid_os_request_fw_revert)) {
> > > +             /*
> > > +              * One of the previously updated image has
> > > +              * failed the OS acceptance test. OS has
> > > +              * requested to revert back to the earlier
> > > +              * boot index
> > > +              */
> > > +             status = fwu_revert_boot_index();
> > > +             ret = fwu_to_efi_error(status);
> > > +             if (ret == EFI_SUCCESS)
> > > +                     log_info("Reverted the FWU active_index. Recommend rebooting the system\n");
> > > +             else
> > > +                     log_err("Failed to revert the FWU boot index\n");
> > > +     } else {
> >
> > We should be explicit on the GUID checking here.  IOW if someone hands you
> > over and empty capsule with a guid !fwu_guid_os_request_fw_revert you'll
> > accept the capsule
>
> This won't happen since this function is called only for empty
> capsules. Will handle the other two review comments.

I am not sure I am following.  Why can't it happen?  If someone create
an empty capsule with an invalid (by invalid I mean none of the 2
GUIDs the spec expects), you'll end up trying to accept the firmware
no?

Thanks
/Ilias
>
> -sughosh
>
> >
> > > +             /*
> > > +              * Image accepted by the OS. Set the acceptance
> > > +              * status for the image.
> > > +              */
> > > +             image_guid = (void *)(char *)capsule +
> > > +                     capsule->header_size;
> > > +
> > > +             status = fwu_get_active_index(&active_idx);
> > > +             ret = fwu_to_efi_error(status);
> > > +             if (ret != EFI_SUCCESS) {
> > > +                     log_err("Unable to get the active_index from the FWU metadata\n");
> > > +                     return ret;
> > > +             }
> > > +
> > > +             status = fwu_accept_image(image_guid, active_idx);
> > > +             ret = fwu_to_efi_error(status);
> > > +             if (ret != EFI_SUCCESS)
> > > +                     log_err("Unable to set the Accept bit for the image %pUs\n",
> > > +                             image_guid);
> > > +     }
> > > +
> > > +     return ret;
> > > +}
> > > +
> > > +static __maybe_unused void fwu_post_update_checks(
> > > +     struct efi_capsule_header *capsule,
> > > +     bool *fw_accept_os, bool *capsule_update)
> > > +{
> > > +     if (fwu_empty_capsule(capsule))
> > > +             *capsule_update = false;
> > > +     else
> > > +             if (!*fw_accept_os)
> >
> > This line should fold to the upper one
> >
> > > +                     *fw_accept_os =
> > > +                             capsule->flags & FW_ACCEPT_OS ? true : false;
> > > +}
> > > +
> > > +static __maybe_unused efi_status_t fwu_post_update_process(bool fw_accept_os)
> > > +{
> > > +     int status;
> > > +     u32 update_index;
> > > +     efi_status_t ret;
> > > +
> > > +     status = fwu_plat_get_update_index(&update_index);
> > > +     if (status < 0) {
> > > +             log_err("Failed to get the FWU update_index value\n");
> > > +             return EFI_DEVICE_ERROR;
> > > +     }
> > > +
> > > +     /*
> > > +      * All the capsules have been updated successfully,
> > > +      * update the FWU metadata.
> > > +      */
> > > +     log_debug("Update Complete. Now updating active_index to %u\n",
> > > +               update_index);
> > > +     status = fwu_set_active_index(update_index);
> > > +     ret = fwu_to_efi_error(status);
> > > +     if (ret != EFI_SUCCESS) {
> > > +             log_err("Failed to update FWU metadata index values\n");
> > > +     } else {
> > > +             log_debug("Successfully updated the active_index\n");
> >
> > [...]
> >
> > Thanks
> > /Ilias


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