BTX halted trying to boot X4100 from disk

[Remy Nonnenmacher]

Michiel Boland wrote:
> Ok here is a patch for /sys/boot/i386/btx/btx/btx.S that will get X4100s
> to boot.
> 
> It extends the v86 monitor in the BTX so that it catches INT3 and treats
> it like any other interrupt. Not sure if it's a great idea, but it's
> better than nothing at this point.
> 
> You will need to update the bootblock and /boot/loader since they both
> appear to be linking in their own copy of BTX.
> 
> --- btx.S.orig	Thu Oct  5 17:30:51 2006
> +++ btx.S	Sun Nov 26 16:26:12 2006
> @@ -510,6 +510,8 @@
>  		je v86popf			# Yes
>  		cmpb $0xcd,%al			# INT imm8?
>  		je v86intn			# Yes
> +		cmpb $0xcc,%al			# INT3?
> +		je v86int3			# Yes
>  		cmpb $0xcf,%al			# IRET/IRETD?
>  		je v86iret			# Yes
>  		popl %ebx			# Restore
> @@ -651,6 +653,11 @@
>  reboot:		orb $0x1,btx_hdr+0x7		# Set the reboot flag
>  		jmp exit			# Terminate BTX and reboot
> 
> +/*
> + * Emulate INT3
> + */
> +v86int3:	movb $3,%al
> +		jmp v86intn.1
>  /*
>   * Emulate INT imm8... also make sure to check if it's int 15/87
>   */
> 
> _______________________________________________

I confirm this patch fixes the same 'BTX Halted' problem on LSI1068 
SAS/IME (mpt) on Fujitsu/Siemens RX200-S3.

This will probably helps the BTX syndrome on recent LSI bioses on a few 
machines.