[PATCH 2/2] efi_loader: remove non vital devices first

[Simon Glass]

Hi Heinrich,

On Wed, 13 Nov 2024 at 08:17, Heinrich Schuchardt <xypron.glpk at gmx.de>
wrote:
>
> Am 13. November 2024 15:39:22 MEZ schrieb Simon Glass <sjg at chromium.org>:
> >Hi,
> >
> >On Wed, 13 Nov 2024 at 05:52, Heinrich Schuchardt <xypron.glpk at gmx.de>
wrote:
> >>
> >> On 11/1/24 21:29, Mark Kettenis wrote:
> >> >> From: Janne Grunau <j at jannau.net>
> >> >> Date: Thu, 31 Oct 2024 23:48:02 +0100
> >> >>
> >> >> DM_FLAG_VITAL marks devices which are essential for the operation of
> >> >> other devices. Removing these devices before their users can result
in
> >> >> hangs or crashes.
> >> >> This potentially fixes EFI boot of Renesas rcar3 devices. Their
clock
> >> >> devices (and with this series the dart iommu) are the only devices
> >> >> markes as vital.
> >> >> The arm boot code already handles devioce removal in this way.
> >> >
> >> > There is a typo in that last sentence of the commit message
(devioce).
> >> > Otherwise:
> >> >
> >> >> Signed-off-by: Janne Grunau <j at jannau.net>
> >> >
> >> > Reviewed-by: Mark Kettenis <kettenis at openbsd.org>
> >> >
> >> >> ---
> >> >>   lib/efi_loader/efi_boottime.c | 1 +
> >> >>   1 file changed, 1 insertion(+)
> >> >>
> >> >> diff --git a/lib/efi_loader/efi_boottime.c
b/lib/efi_loader/efi_boottime.c
> >> >> index
4f52284b4c653c252b0ed6c0c87da8901448d4b4..7db3c95782970f8c06a970a8ee86b1804cd848b6
100644
> >> >> --- a/lib/efi_loader/efi_boottime.c
> >> >> +++ b/lib/efi_loader/efi_boottime.c
> >> >> @@ -2234,6 +2234,7 @@ static efi_status_t EFIAPI
efi_exit_boot_services(efi_handle_t image_handle,
> >> >>              if (IS_ENABLED(CONFIG_USB_DEVICE))
> >> >>                      udc_disconnect();
> >> >>              board_quiesce_devices();
> >> >> +            dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL |
DM_REMOVE_NON_VITAL);
> >> >>              dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL);
> >>
> >> Simon's patch 6224dc9ba428 ("arm: Remove vital devices last") addressed
> >> the same issue for bootm on arm. But what about about other
architectures?
> >>
> >> This logic should be moved to drivers/core/root.c instead of
replicating
> >> code.
> >
> >We could have a common helper, but it should not be in driver/core as
> >this ordering is more of a policy decision. Unless we can add a
> >parameter telling dm exactly what to do...
> >
> >BTW, Heinrich, this behaviour is exactly what my bootflow_efi() test
> >was supposed to check. But since it doesn't have the
> >exit-boot-services piece at your request...
> >
> >Regards,
> >Simon
>
>
> Why can't we generally remove non-vital devices first if all are to be
removed?
>
> I cannot see anything device specific here.

No objection to that...but it needs to be in a new function, not become the
default behaviour of dm_remove_devices_flags(), which is supposed to do
what it is told and in one pass.

Regards,
Simon