Re: i386/amd64 image generated trough mkimage stuck on primary bootsrap at boot

[RVP <rvp%SDF.ORG@localhost>]

On Sun, 10 Jul 2022, Izumi Tsutsui wrote:

> IIRC libsa/sa/ufs.c requires large heapsize to read blocksize,
> from ffs, so sometimes it fails to load on blocksize=65536 fs.
> (but I'm nots sure 64KB blocksize is valied on FFS because
> newfs(8) man page just says 4KB-32KB for it)

On Mon, 11 Jul 2022, matthew green wrote:

> FWIW, i've been using 64K block *and frag size FFS for over
> a decade without any problem, on a file system that almost
> always has extremely large files on it.

I think what's happening here on x86/amd64 systems with a 64k
or larger FS block-sizes is that:

a) the no. of sectors exceeds the count allowed in the INT 13h
   disk-read call (less likely), or,

b) the buffer allocated in sys/lib/libsa/ufs.c:724 crosses a
   64k x86 segment boundary (more likely).

I see that sys/arch/i386/stand/lib/biosdisk_ll.c:242 sets cold=1
which will most likely result in situation b) for any of the
bootxx_* bootloaders.

It should be documented somewhere that block-sizes > 32k are a
problem for the BIOS bootloaders on the x86/amd64 arch...

-RVP