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

Sughosh Ganu
2022-10-14T07:06:50Z

On Fri, 14 Oct 2022 at 12:12, Ilias Apalodimas
<ilias.apalodimas@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@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.

-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