[RFC PATCH v2 6/8] FWU: Add boot time checks as highlighted by the FWU specification
AKASHI Takahiro
takahiro.akashi at linaro.org
Mon Dec 20 11:25:11 CET 2021
Hi Sughosh,
On Mon, Dec 20, 2021 at 03:36:37PM +0530, Sughosh Ganu wrote:
> hi Takahiro,
>
> On Mon, 20 Dec 2021 at 11:39, AKASHI Takahiro <takahiro.akashi at linaro.org>
> wrote:
>
> > Sughosh,
> >
> > On Sun, Dec 19, 2021 at 12:36:03PM +0530, Sughosh Ganu wrote:
> > > The FWU Multi Bank Update specification requires the Update Agent to
> > > carry out certain checks at the time of platform boot. The Update
> > > Agent is the component which is responsible for updating the firmware
> > > components and maintaining and keeping the metadata in sync.
> > >
> > > The spec requires that the Update Agent perform the following checks
> > > at the time of boot
> > > * Sanity check of both the metadata copies maintained by the platform.
> > > * Get the boot index passed to U-Boot by the prior stage bootloader
> > > and use this value for metadata bookkeeping.
> > > * Check if the system is booting in Trial State. If the system boots
> > > in the Trial State for more than a specified number of boot counts,
> > > change the Active Bank to be booting the platform from.
> > >
> > > Add these checks in the board initialisation sequence, invoked after
> > > relocation.
> > >
> > > Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> > > ---
> > > Changes since V1:
> > > * Define a funtion fwu_update_checks_pass to do the checks
> > > before initiating the update
> > > * Log the status of the boottime checks using boottime_check
> > > variable and allow system to boot instead of hanging the
> > > platform(fwu_boottime_checks)
> > >
> > > common/board_r.c | 6 ++
> > > include/fwu.h | 3 +
> > > lib/fwu_updates/fwu.c | 163 ++++++++++++++++++++++++++++++++++++++++++
> > > 3 files changed, 172 insertions(+)
> > > create mode 100644 lib/fwu_updates/fwu.c
> > >
> > > diff --git a/common/board_r.c b/common/board_r.c
> > > index 31a59c585a..81678870b9 100644
> > > --- a/common/board_r.c
> > > +++ b/common/board_r.c
> > > @@ -78,6 +78,9 @@
> > > #ifdef CONFIG_EFI_SETUP_EARLY
> > > #include <efi_loader.h>
> > > #endif
> > > +#ifdef CONFIG_FWU_MULTI_BANK_UPDATE
> > > +#include <fwu.h>
> > > +#endif
> > >
> > > DECLARE_GLOBAL_DATA_PTR;
> > >
> > > @@ -805,6 +808,9 @@ static init_fnc_t init_sequence_r[] = {
> > > #endif
> > > #ifdef CONFIG_EFI_SETUP_EARLY
> > > (init_fnc_t)efi_init_obj_list,
> > > +#endif
> > > +#ifdef CONFIG_FWU_MULTI_BANK_UPDATE
> > > + fwu_boottime_checks,
> > > #endif
> >
> > Maybe I don't understand your code well.
> > Why do you want to call fwu_boottime_checks() here?
> > Why not in CONFIG_EFI_CAPSULE_UPDATE_EARLY (i.e. efi_launch_capsules()
> > in main_loop())?
> >
>
> These are boot time checks which are to be carried out during platform
> boot. Do you see any issue if we place the call to fwu_boottime_checks in
> the init_sequence.
No, I don't see any specific issue right now.
> I would like to avoid having the fwu boot time checks
> tied up with CONFIG_EFI_CAPSULE_ON_DISK_EARLY.
My question was why you want to avoid that.
In main_loop(), update_tftp(), as well as efi capsule code, is put there.
It would be a good practice to have similar functionality called in one place.
-Takahiro Akashi
> -sughosh
>
>
> >
> > -Takahiro Akashi
> >
> > > run_main_loop,
> > > };
> > > diff --git a/include/fwu.h b/include/fwu.h
> > > index 5ba437798d..2d2e674d6a 100644
> > > --- a/include/fwu.h
> > > +++ b/include/fwu.h
> > > @@ -16,6 +16,9 @@
> > > EFI_GUID(0x8a7a84a0, 0x8387, 0x40f6, 0xab, 0x41, \
> > > 0xa8, 0xb9, 0xa5, 0xa6, 0x0d, 0x23)
> > >
> > > +int fwu_boottime_checks(void);
> > > +u8 fwu_update_checks_pass(void);
> > > +
> > > 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,
> > > diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> > > new file mode 100644
> > > index 0000000000..e964f9b0b1
> > > --- /dev/null
> > > +++ b/lib/fwu_updates/fwu.c
> > > @@ -0,0 +1,163 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +/*
> > > + * Copyright (c) 2021, Linaro Limited
> > > + */
> > > +
> > > +#include <efi.h>
> > > +#include <efi_loader.h>
> > > +#include <efi_variable.h>
> > > +#include <fwu.h>
> > > +#include <fwu_mdata.h>
> > > +#include <malloc.h>
> > > +
> > > +#include <linux/errno.h>
> > > +#include <linux/types.h>
> > > +
> > > +static u8 trial_state = 0;
> > > +static u8 boottime_check = 0;
> > > +
> > > +static int fwu_trial_state_check(void)
> > > +{
> > > + int ret, i;
> > > + efi_status_t status;
> > > + efi_uintn_t var_size;
> > > + u16 trial_state_ctr;
> > > + u32 nimages, active_bank, var_attributes, active_idx;
> > > + struct fwu_mdata *mdata = NULL;
> > > + struct fwu_image_entry *img_entry;
> > > + struct fwu_image_bank_info *img_bank_info;
> > > +
> > > + ret = fwu_get_mdata(&mdata);
> > > + if (ret < 0)
> > > + return ret;
> > > +
> > > + ret = 0;
> > > + nimages = CONFIG_FWU_NUM_IMAGES_PER_BANK;
> > > + active_bank = mdata->active_index;
> > > + img_entry = &mdata->img_entry[0];
> > > + for (i = 0; i < nimages; i++) {
> > > + img_bank_info = &img_entry[i].img_bank_info[active_bank];
> > > + if (!img_bank_info->accepted) {
> > > + trial_state = 1;
> > > + break;
> > > + }
> > > + }
> > > +
> > > + if (trial_state) {
> > > + var_size = (efi_uintn_t)sizeof(trial_state_ctr);
> > > + log_info("System booting in Trial State\n");
> > > + var_attributes = EFI_VARIABLE_NON_VOLATILE |
> > > + EFI_VARIABLE_BOOTSERVICE_ACCESS |
> > > + EFI_VARIABLE_RUNTIME_ACCESS;
> > > + status = efi_get_variable_int(L"TrialStateCtr",
> > > + &efi_global_variable_guid,
> > > + &var_attributes,
> > > + &var_size, &trial_state_ctr,
> > > + NULL);
> > > + if (status != EFI_SUCCESS) {
> > > + log_err("Unable to read TrialStateCtr variable\n");
> > > + ret = -1;
> > > + goto out;
> > > + }
> > > +
> > > + ++trial_state_ctr;
> > > + if (trial_state_ctr > CONFIG_FWU_TRIAL_STATE_CNT) {
> > > + log_info("Trial State count exceeded. Revert back
> > to previous_active_index\n");
> > > + active_idx = mdata->active_index;
> > > + ret = fwu_revert_boot_index();
> > > + if (ret < 0) {
> > > + log_err("Unable to revert active_index\n");
> > > + goto out;
> > > + }
> > > +
> > > + trial_state_ctr = 0;
> > > + status = efi_set_variable_int(L"TrialStateCtr",
> > > +
> > &efi_global_variable_guid,
> > > + var_attributes,
> > > + 0,
> > > + &trial_state_ctr,
> > false);
> > > + if (status != EFI_SUCCESS) {
> > > + log_err("Unable to clear TrialStateCtr
> > variable\n");
> > > + ret = -1;
> > > + goto out;
> > > + }
> > > + } else {
> > > + status = efi_set_variable_int(L"TrialStateCtr",
> > > +
> > &efi_global_variable_guid,
> > > + var_attributes,
> > > + var_size,
> > > + &trial_state_ctr,
> > false);
> > > + if (status != EFI_SUCCESS) {
> > > + log_err("Unable to increment TrialStateCtr
> > variable\n");
> > > + ret = -1;
> > > + goto out;
> > > + } else {
> > > + ret = 0;
> > > + }
> > > + }
> > > + }
> > > +
> > > +out:
> > > + free(mdata);
> > > + return ret;
> > > +}
> > > +
> > > +u8 fwu_update_checks_pass(void)
> > > +{
> > > + return !trial_state && boottime_check;
> > > +}
> > > +
> > > +int fwu_boottime_checks(void)
> > > +{
> > > + int ret;
> > > + u32 boot_idx, active_idx;
> > > +
> > > + ret = fwu_mdata_check();
> > > + if (ret < 0) {
> > > + boottime_check = 0;
> > > + return 0;
> > > + }
> > > +
> > > + /*
> > > + * Get the Boot Index, i.e. the bank from
> > > + * which the platform has booted. This value
> > > + * gets passed from the ealier stage bootloader
> > > + * which booted u-boot, e.g. tf-a. If the
> > > + * boot index is not the same as the
> > > + * active_index read from the FWU metadata,
> > > + * update the active_index.
> > > + */
> > > + fwu_plat_get_bootidx(&boot_idx);
> > > + if (boot_idx >= CONFIG_FWU_NUM_BANKS) {
> > > + log_err("Received incorrect value of boot_index\n");
> > > + boottime_check = 0;
> > > + return 0;
> > > + }
> > > +
> > > + ret = fwu_get_active_index(&active_idx);
> > > + if (ret < 0) {
> > > + log_err("Unable to read active_index\n");
> > > + boottime_check = 0;
> > > + return 0;
> > > + }
> > > +
> > > + if (boot_idx != active_idx) {
> > > + log_info("Boot idx %u is not matching active idx %u,
> > changing active_idx\n",
> > > + boot_idx, active_idx);
> > > + ret = fwu_update_active_index(boot_idx);
> > > + if (ret < 0)
> > > + boottime_check = 0;
> > > + else
> > > + boottime_check = 1;
> > > +
> > > + return 0;
> > > + }
> > > +
> > > + ret = fwu_trial_state_check();
> > > + if (ret < 0)
> > > + boottime_check = 0;
> > > + else
> > > + boottime_check = 1;
> > > +
> > > + return 0;
> > > +}
> > > --
> > > 2.17.1
> > >
> >
More information about the U-Boot
mailing list