On Fri, Jul 31, 2026 at 7:30 PM Alexey Charkov <[email protected]> wrote: > > On Fri, Jul 31, 2026 at 4:40 PM Alexey Charkov <[email protected]> wrote: > > > > The GPT partition entry array is sized in bytes by the spec, so the > > number of blocks it takes up depends on the block size of the device. > > U-Boot got that wrong in gpt_fill_header(), which reserved a fixed 34 > > blocks at each end of the disk. On a device with 4096-byte native > > sectors, such as UFS flash, the backup entry array ended up 28 blocks > > short of the backup GPT header instead of immediately before it, and > > roughly 114 KiB was wasted at each end of the disk. > > > > Patch 1 calculates the count from the block size and makes the four > > places that need it share one helper, since they disagreed with each > > other in different ways. Note that it also changes the 512-byte layout > > for boards that do not use the default entry count: > > CONFIG_EFI_PARTITION_ENTRIES_NUMBERS is "default 56 if ARCH_SUNXI" and > > is set to 64 by a number of Rockchip defconfigs, and on those > > first_usable_lba moves from 34 to 16 and 18 respectively. Existing > > tables stay readable, since the entry array is always located from the > > on-disk partition_entry_lba, and only newly written tables are > > affected. Partitions given without an explicit start= will be placed > > lower, though, and on sunxi first_usable_lba lands exactly on the 8 KiB > > SPL offset, so sunxi and Rockchip folks may want to look at patch 1 > > specifically (none of the devices I have override the default). > > > > Patch 2 is an unrelated big-endian correctness fix in the same file, > > noticed while auditing it: a few header fields are read without > > converting from little-endian, and one already-converted value is > > swapped a second time. > > > > Patch 3 is another unrelated bug that has to be fixed before any of this > > can be tested: part_test_mac() reads one block into a 512-byte on-stack > > buffer, so it corrupts the stack on any device with larger blocks. Since > > it runs during partition probing on every device, sandbox crashes on any > > access at all to a device bound with a 4096-byte block size. > > > > Patches 4 and 6 add the tests. The C test sweeps block sizes from 512 to > > 32768 against gpt_fill_header()/gpt_fill_pte() with a synthetic > > descriptor, and the Python test writes a real GPT to a host device with > > 4096-byte blocks and checks the resulting on-disk headers. Both fail > > without patch 1. > > > > Patch 5 is a prerequisite for patch 6: test_gpt_write_part_type() never > > binds its own disk image and has only worked because an earlier test > > left host 0 bound, so it breaks as soon as a test binding a different > > image is added above it. > > > > One known gap: test_gpt_write and test_gpt_write_part_type hardcode the > > 128-entry 512-byte layout, so they fail if sandbox is configured with a > > different CONFIG_EFI_PARTITION_ENTRIES_NUMBERS. The new tests derive > > their expectations instead, and pass at 56 and 64 entries. No sandbox > > defconfig upstream uses anything but 128, so I have left the old tests > > alone. > > > > Tested by building sandbox (default, flattree, sandbox64, gcc and > > clang), generic-rk3576 (gcc and clang), sonoff-ihost-rv1126 and > > A20-OLinuXino_MICRO-eMMC on armv7, and boston32r2 and boston64r2 for > > MIPS32/MIPS64 big-endian, which is what patch 2 is there for. > > > > Signed-off-by: Alexey Charkov <[email protected]> > > --- > > Alexey Charkov (6): > > disk: part_efi: Size the partition entry array from the block size > > disk: part_efi: Add missing endianness conversions > > disk: part_mac: Fix stack corruption on devices with large blocks > > test: dm: part: Check the GPT layout for large sector sizes > > test: py: gpt: Bind the disk image in test_gpt_write_part_type() > > test: py: gpt: Test the GPT layout on a device with 4096-byte blocks > > > > disk/part_efi.c | 55 +++++++++++++++------- > > disk/part_mac.c | 12 ++--- > > test/dm/part.c | 100 +++++++++++++++++++++++++++++++++++++++ > > test/py/tests/test_gpt.py | 116 > > ++++++++++++++++++++++++++++++++++++++++++++++ > > 4 files changed, 261 insertions(+), 22 deletions(-) > > NB: the CI passes all green: > https://git.u-boot-project.org/u-boot/contributors/alchark/u-boot/-/pipelines/841
Gentle ping regarding this series. All patches got R-b, can this please be applied? get_maintainer.pl says these fall under "THE REST" - Tom, can you please pick it up? Thanks a lot! Best regards, Alexey
