Logging boot messages from the loader

[Bjoern A. Zeeb]

On 21 Nov 2019, at 9:51, Eugene Grosbein wrote:

> Hi!
>
> How do I get boot messages generated by loader itself written to some 
> log after successfull boot?
> This is generic BIOS-based 11.3-STABLE/amd64 system with syscons 
> console driver.
>
> /var/run/dmesg.boot starts with kernel messages without previous lines 
> from the loader.
> Specifically, I need messages about loading kernel modules with full 
> paths.

loader cannot write to the kernel message buffer as there is no kernel 
yet.  There might be possible ways to preserve that but I doubt loader 
is fit for that task.

A boot -v (boot_verbose=“YES”) might spit the information out from 
the kernel as well.   Not sure if that helps you.  However on modern 
server machines a boot -v often overflows the message buffer.. so you 
might have to tune that as well.

Extracted from an older console log of a random lab machine of someone 
else:
..
WARNING: WITNESS option enabled, expect reduced performance.^M^@
WARNING: DIAGNOSTIC option enabled, expect reduced performance.^M^@
Preloaded elf kernel "/boot/kernel/kernel" at 0xffffffff80e66000.^M^@
Preloaded elf obj module "/boot/kernel/if_igb.ko" at 
0xffffffff80e66968.^M^@
Preloaded elf obj module "/boot/kernel/nfscl.ko" at 
0xffffffff80e66fd0.^M^@
Preloaded elf obj module "/boot/kernel/nfslock.ko" at 
0xffffffff80e67638.^M^@
Preloaded elf obj module "/boot/kernel/nfssvc.ko" at 
0xffffffff80e67ba0.^M^@
Preloaded elf obj module "/boot/kernel/krpc.ko" at 
0xffffffff80e68088.^M^@
Preloaded elf obj module "/boot/kernel/nfscommon.ko" at 
0xffffffff80e686b0.^M^@
Preloaded elf obj module "/boot/kernel/ahci.ko" at 
0xffffffff80e68d20.^M^@
Preloaded elf obj module "/boot/kernel/cam.ko" at 
0xffffffff80e69308.^M^@
Preloaded elf obj module "/boot/kernel/mfi.ko" at 
0xffffffff80e699f0.^M^@
Preloaded elf obj module "/boot/kernel/geom_part_gpt.ko" at 
0xffffffff80e6a058.^M^@
Preloaded elf obj module "/boot/kernel/sysvsem.ko" at 
0xffffffff80e6a648.^M^@
Preloaded elf obj module "/boot/kernel/sysvshm.ko" at 
0xffffffff80e6acb0.^M^@
Calibrating TSC clock ... TSC clock: 3400185886 Hz^M^@
CPU: Intel(R) Xeon(R) CPU           X5272  @ 3.40GHz (3400.19-MHz 
K8-class CPU)^M^@
..