amd64/182740: BTX halted on Jetway NF81 motherboard when RAID is enabled

[John Baldwin]

The following reply was made to PR amd64/182740; it has been noted by GNATS.

From: John Baldwin <jhb at freebsd.org>
To: freebsd-amd64 at freebsd.org
Cc: Julian Pidancet <julian.pidancet at gmail.com>,
 freebsd-gnats-submit at freebsd.org
Subject: Re: amd64/182740: BTX halted on Jetway NF81 motherboard when RAID is enabled
Date: Mon, 7 Oct 2013 11:47:32 -0400

 On Sunday, October 06, 2013 7:28:31 am Julian Pidancet wrote:
 > 
 > >Number:         182740
 > >Category:       amd64
 > >Synopsis:       BTX halted on Jetway NF81 motherboard when RAID is enabled
 > >Confidential:   no
 > >Severity:       non-critical
 > >Priority:       low
 > >Responsible:    freebsd-amd64
 > >State:          open
 > >Quarter:        
 > >Keywords:       
 > >Date-Required:
 > >Class:          sw-bug
 > >Submitter-Id:   current-users
 > >Arrival-Date:   Sun Oct 06 11:30:00 UTC 2013
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     Julian Pidancet
 > >Release:        8.2
 > >Organization:
 > >Environment:
 > >Description:
 > Just got this brand new motherboard with an AMD APU and an AMD chipset.
 > 
 > Whenever I try to boot FreeBSD and AHCI or RAID is enabled in the BIOS, I am 
 getting this message:
 > 
 > BTX loader 1.00  BTX version is 1.02
 > int=0000000a  err=00000000  efl=00006402  eip=000093e0
 > eax=534d4150  ebx=00000001  ecx=00000014  edx=534d4150
 > esi=00000000  edi=00000004  ebp=00000000  esp=0000004e
 > cs=0008  ds=0033  es=0033    fs=0033  gs=0033  ss=0010
 > cs:eip=cf 83 f8 01 75 1a 16 87-86 1f 1e 0f a1 0f a0 0f
 >        a9 b8 00 a0 00 00 03 44-24 0c 8d 60 04 58 ff d0
 > ss:esp=00 f0 39 e7 00 f0 e3 21-80 ce 2e e8 00 f0 d2 ef
 >        00 f0 00 e0 00 f0 f2 e6-00 f0 6e fe 00 f0 53 ff
 > BTX halted
 > 
 > It looks like to me the BTX is taking an "Invalid TSS" exception while 
 executing an iret instruction.
 > >How-To-Repeat:
 > I tried: - Booting from the install cdrom
 >          - Booting from an USB install disk
 >          - Booting from boot/pxeboot in PXE mode
 > 
 > All exhibit the same issue.
 > >Fix:
 > Selecting "Legacy IDE" mode in the BIOS configuration instead of AHCI/RAID.
 
 Ok, can you take this patch and use it to build an updated pxeboot and test
 if it fixes disk access with AHCI enabled?
 
 Index: boot/i386/btx/btx/btx.S
 ===================================================================
 --- boot/i386/btx/btx/btx.S	(revision 247010)
 +++ boot/i386/btx/btx/btx.S	(working copy)
 @@ -41,6 +41,8 @@
  		.set PSL_RESERVED_DEFAULT,0x00000002
  		.set PSL_T,0x00000100		# Trap flag
  		.set PSL_I,0x00000200		# Interrupt enable flag
 +		.set PSL_D,0x00000400		# String instruction direction
 +		.set PSL_NT,0x00004000		# Nested task flag
  		.set PSL_VM,0x00020000		# Virtual 8086 mode flag
  		.set PSL_AC,0x00040000		# Alignment check flag
  /*
 @@ -611,8 +613,8 @@
  		pushl %ds			#  regs
  		pushl %es
  		pushfl				# Save %eflags
 -		cli				# Disable interrupts
 -		std				# String ops dec
 +		pushl $PSL_RESERVED_DEFAULT|PSL_D # Use clean %eflags with
 +		popfl				#  string ops dec
  		xorw %ax,%ax			# Reset seg 
  		movw %ax,%ds			#  regs
  		movw %ax,%es			#  (%ss is already 0)
 @@ -675,6 +677,7 @@
  		testl $V86F_FLAGS,%edx		# User wants flags?
  		jz rret_tramp.3			# No
  		movl MEM_ESPR-0x3c,%eax		# Read real mode flags
 +		andl $~(PSL_T|PSL_NT),%eax	# Clear unsafe flags
  		movw %ax,-0x08(%esi)		# Update user flags (low 16)
  /*
   * Return to the user task
 
 -- 
 John Baldwin