[PATCH v5 38/46] boot: Consider non-bootable partitions

[Simon Glass]

Hi Tom,

On Thu, 3 Apr 2025 at 03:28, Tom Rini <trini at konsulko.com> wrote:
>
> On Sat, Mar 15, 2025 at 02:25:58PM +0000, Simon Glass wrote:
>
> > Any 'bootable' flag in a DOS partition causes boostd to only scan
> > bootable partitions for that media. This can mean that extlinux.conf
> > files on the root disk are missed.
> >
> > Put this logic behind a flag and update the documentation.
> >
> > For now, the flag is enabled, to preserve existing behaviour. Future
> > work may provide a command (or some other mechanism) to control this.
> >
> > Signed-off-by: Simon Glass <sjg at chromium.org>
> > ---
> >
> > (no changes since v4)
> >
> > Changes in v4:
> > - Rewrite the commit message
> > - Enable the flag by default
> >
> > Changes in v3:
> > - Add new patch to consider non-bootable partitions
> >
> >  boot/bootdev-uclass.c            | 4 +++-
> >  cmd/bootflow.c                   | 2 +-
> >  doc/develop/bootstd/overview.rst | 5 +++--
> >  include/bootflow.h               | 2 ++
> >  test/boot/bootdev.c              | 1 +
> >  test/boot/bootflow.c             | 5 +++--
> >  6 files changed, 13 insertions(+), 6 deletions(-)
>
> Having spent another 10 minutes just now trying to understand things,
> again:
> - The commit message, and the implementation are either in disagreement
>   or just too vague. Saying "to preserve existing behaviour" is unclear
>   about which behavior is being preserved, since we're setting the flag
>   to continue to only check bootable flagged partitions
>   (BOOTFLOWIF_ONLY_BOOTABLE). But then we would continue to miss
>   extlinux.conf files on root filesystems, which would seem to be the
>   bug that needed fixing?

How about 'to preserve the existing behaviour of bootstd which is to
ignore non-bootable partitions so long as there is at least one
bootable partition on the disk"  ?

> - It's still unclear if this makes bootstd match the exiting distro
>   script behavior or not, and from your other emails it sounded like you
>   were expecting someone else to dig around.

The distro scripts include the code below. My reading of it is that it
only considers bootable partitions, except that if there is none, then
it always scans partition 1.

"scan_dev_for_boot_part="                                         \
"part list ${devtype} ${devnum} -bootable devplist; "     \
"env exists devplist || setenv devplist 1; "              \
"for distro_bootpart in ${devplist}; do "                 \
"if fstype ${devtype} "                           \
"${devnum}:${distro_bootpart} "   \
"bootfstype; then "               \
"part uuid ${devtype} "                   \
"${devnum}:${distro_bootpart} "   \
"distro_bootpart_uuid ; "         \
"run scan_dev_for_boot; "                 \
"fi; "                                            \
"done; "                                                  \
"setenv devplist\0"   \
\

Regards,
Simon