[PATCH 05/10] bootm: Do bootstage processing in bootm_final()

[Simon Glass]

Hi Heinrich,

On Wed, 7 Jan 2026 at 12:14, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> Am 7. Januar 2026 20:02:39 MEZ schrieb Simon Glass <sjg at chromium.org>:
> >Hi Heinrich,
> >
> >On Tue, 6 Jan 2026 at 20:58, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> >>
> >> Am 7. Januar 2026 01:31:22 MEZ schrieb Simon Glass <sjg at chromium.org>:
> >> >From: Simon Glass <sjg at chromium.org>
> >> >
> >> >Mark kernel start before booting. If enabled, show a bootstage report.
> >> >
> >> >Signed-off-by: Simon Glass <sjg at chromium.org>
> >> >Signed-off-by: Simon Glass <simon.glass at canonical.com>
> >> >---
> >> >
> >> > boot/bootm_final.c   | 6 ++++++
> >> > test/boot/bootflow.c | 2 +-
> >> > 2 files changed, 7 insertions(+), 1 deletion(-)
> >> >
> >> >diff --git a/boot/bootm_final.c b/boot/bootm_final.c
> >> >index 71661334e11..dd7cac55f1e 100644
> >> >--- a/boot/bootm_final.c
> >> >+++ b/boot/bootm_final.c
> >> >@@ -6,11 +6,17 @@
> >> >  */
> >> >
> >> > #include <bootm.h>
> >> >+#include <bootstage.h>
> >> > #include <dm/root.h>
> >> >
> >> > void bootm_final(enum bootm_final_t flags)
> >> > {
> >> >       printf("\nStarting kernel ...\n\n");
> >>
> >> This noisy message makes no sense for EFI booting. The kernel in not started in ExitBootServices().
> >
> >Can you explain that a bit more? I believe that's exactly when the
> >kernel starts.
> >
> >>
> >> Operating systems like Ubuntu tend to boot the kernel with argument "quiet" for aesthetic reasons. We should not disrupt this.
> >
> >When I boot (with this patch) I see these messages on the serial console:
> >>>>
> >Scanning for bootflows in all bootdevs
> >Seq  Method       State   Uclass    Part  E  Name                      Filename
> >---  -----------  ------  --------  ----  -  ------------------------
> >----------------
> >Scanning global bootmeth 'efi_mgr':
> >  0  efi_mgr      ready   (none)       0     <NULL>
> >** Booting bootflow '<NULL>' with efi_mgr
> >      try_load_entry() Booting: Label: Ubuntu Device path:
> >/HD(1,GPT,eccaac1c-b634-441b-a788-ab0f959111af,0x800,0x165800)/\EFI\ubuntu\shimx64.efi
>
> Here GRUB is running. If you don't see output, then because purposefully it has been quieted.

OK, so there is no problem, right?

>
> >
> >Starting kernel ...
>
> ExitBootServices is called in the middle of the Linux kernel EFI stub and not when entering the kernel.

Oh I see. To my mind the kernel EFI stub is a bit like a bootloader
tacked onto the front of Linux. Linux doesn't properly start until it
has control of the machine and actually starts its init.

So we definitely want to get bootstage output (for example) covering
that period, otherwise there is a significant uncounted time between
the EFI app starting and Linux starting.

Regards,
Simon

>
> Best regards
>
> Heinrich
>
> ><<<
> >
> >So it is not silent today. The last line is the new one. Every other
> >boot method writes this line.
> >
> >However, the video display is silent once grub has finished and I just
> >noticed that this patch draws some pixels on the display, as if the
> >EFI display is set to a different mode from what U-Boot expects. I
> >suppose this is understandable, as grub has run by then and has
> >probably changed the mode.
> >
> >So I wonder what would be best here. We don't support dynamic video
> >sizing right now and I don't feel the urge to implement it just for
> >this. Perhaps with EFI we could disable the vidconsole when
> >exit-boot-services is called, on the basis that we cannot deal with
> >whatever has happened to the display in the interim?
> >
> >Regards,
> >Simon
> >
> >>
> >> Best regards
> >>
> >> Heinrich
> >>
> >> >
> >> >+      bootstage_mark_name(BOOTSTAGE_ID_BOOTM_HANDOFF, "start_kernel");
> >> >+
> >> >+      if (IS_ENABLED(CONFIG_BOOTSTAGE_REPORT))
> >> >+              bootstage_report();
> >> >+
> >> >       dm_remove_devices_active();
> >> > }
> >> >diff --git a/test/boot/bootflow.c b/test/boot/bootflow.c
> >> >index a56435d053f..80adc074070 100644
> >> >--- a/test/boot/bootflow.c
> >> >+++ b/test/boot/bootflow.c
> >> >@@ -1381,7 +1381,7 @@ static int bootflow_efi(struct unit_test_state *uts)
> >> >
> >> >       /* TODO: Why the \r ? */
> >> >       ut_assert_nextline("U-Boot test app for EFI_LOADER\r");
> >> >-      ut_assert_nextline("Exiting test app");
> >> >+      ut_assert_skip_to_line("Exiting test app");
> >> >       ut_assert_nextline("Boot failed (err=-14)");
> >> >
> >> >       ut_assert_console_end();
> >>
> >
> >Regards,
> >Simon
>