[RFC 1/8] boot: EFI boot manager does not depend on BootOrder

[Simon Glass]

Hi Heinrich,

On Fri, 2 May 2025 at 10:09, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> On 5/2/25 16:49, Simon Glass wrote:
> > Hi Heinrich,
> >
> > On Mon, 21 Apr 2025 at 10:26, Heinrich Schuchardt
> > <heinrich.schuchardt at canonical.com> wrote:
> >>
> >> The EFI boot manager bootmeth does not require variable BootOrder to be
> >> preexisting. It creates this variable.
> >>
> >> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> >> ---
> >>   boot/bootmeth_efi_mgr.c | 21 +++------------------
> >>   1 file changed, 3 insertions(+), 18 deletions(-)
> >>
> >> diff --git a/boot/bootmeth_efi_mgr.c b/boot/bootmeth_efi_mgr.c
> >> index 42b8863815e..1669cbed5bd 100644
> >> --- a/boot/bootmeth_efi_mgr.c
> >> +++ b/boot/bootmeth_efi_mgr.c
> >> @@ -47,30 +47,15 @@ static int efi_mgr_check(struct udevice *dev, struct bootflow_iter *iter)
> >>
> >>   static int efi_mgr_read_bootflow(struct udevice *dev, struct bootflow *bflow)
> >>   {
> >> -       struct efi_mgr_priv *priv = dev_get_priv(dev);
> >> -       efi_status_t ret;
> >> -       efi_uintn_t size;
> >> -       u16 *bootorder;
> >> -
> >> -       if (priv->fake_dev) {
> >> -               bflow->state = BOOTFLOWST_READY;
> >> -               return 0;
> >> -       }
> >> +       int ret
> >>
> >>          ret = efi_init_obj_list();
> >>          if (ret)
> >>                  return log_msg_ret("init", ret);
> >>
> >> -       /* Enable this method if the "BootOrder" UEFI exists. */
> >> -       bootorder = efi_get_var(u"BootOrder", &efi_global_variable_guid,
> >> -                               &size);
> >> -       if (bootorder) {
> >> -               free(bootorder);
> >> -               bflow->state = BOOTFLOWST_READY;
> >> -               return 0;
> >> -       }
> >> +       bflow->state = BOOTFLOWST_READY;
> >>
> >> -       return -EINVAL;
> >> +       return 0;
> >>   }
> >>
> >>   static int efi_mgr_read_file(struct udevice *dev, struct bootflow *bflow,
> >> --
> >> 2.48.1
> >>
> >
> > How do we know if the board is using EFI bootmgr? My understanding was
> > that this was a way to find out?
>
> The boot manager must always run.

Are you sure that is true? It seems false to me, e.g.

- if we are booting FEL on suxi, it must not run.
- none of the boards in my lab use it
- the Ubuntu 24.04 test in my lab doesn't use it

So how can we say that it must always run?

>
> The check for the BootOrder variable introduced in commit f2bfa0cb1794
> is a bug.
>
> The boot manager handles in sequence:
>
> * Try to boot as indicated by BootNext.
> * Try to boot as indicated by BootOrder.
> * Try to boot default path for available media.
>    This will add Boot#### entries and update BootOrder.

Regards,
Simon