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Add support for emulating the RDMSR and WRMSR instructions into BTX. In

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theory, this should allow the K7V Athlon motherboard to boot ok with boot
virus protection enabled.  However, I have no hardware to test this.  It
shouldn't break anything though. :)

Prodded by:	Kelly Yancey <kbyanc@posi.net>
This commit is contained in:
John Baldwin 2000-06-17 06:45:40 +00:00
parent 2d43b347ec
commit 1ddb0ab555
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=61743
2 changed files with 48 additions and 4 deletions
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26
sys/boot/i386/btx/btx/btx.S
View file

@ -479,11 +479,15 @@ v86mon.2: cmpb $0xf4,%al # HLT?
jne v86mon.7 # No (ignore)
jmp intrtn # Return to user mode
v86mon.3: cmpb $0xf,%al # Is
jne v86mon.4 # this
jne v86mon.3.1 # this
cmpb $0x20,(%esi) # a
jne v86mon.4 # MOV EAX,CR0
jne v86mon.3.1 # MOV EAX,CR0
cmpb $0xc0,0x1(%esi) # instruction?
je v86mov # Yes
v86mon.3.1: cmpb $0x30,(%esi) # Is it a WRMSR?
je v86wrmsr # Yes
cmpb $0x32,(%esi) # Is it a RDMSR?
je v86rdmsr # Yes
v86mon.4: cmpb $0xfa,%al # CLI?
je v86cli # Yes
cmpb $0xfb,%al # STI?
@ -522,6 +526,24 @@ v86mov: movl %cr0,%eax # CR0 to
incl %esi # IP
jmp v86mon.7 # Finish up
#
# Emulate WRMSR
#
v86wrmsr: movl 0x18(%ebp),%ecx # Get user's %ecx (MSR to write)
movl 0x14(%ebp),%edx # Load the value
movl 0x1c(%ebp),%eax # to write
wrmsr # Write MSR
incl %esi # Adjust IP
jmp v86mon.7 # Finish up
#
# Emulate RDMSR
#
v86rdmsr: movl 0x18(%ebp),%ecx # MSR to read
rdmsr # Read the MSR
movl %eax,0x1c(%ebp) # Return the value of
movl %edx,0x14(%ebp) # the MSR to the user
incl %esi # Adjust IP
jmp v86mon.7
#
# Emulate CLI.
#
v86cli: andb $~0x2,0x31(%ebp) # Clear IF

26
sys/boot/i386/btx/btx/btx.s
View file

@ -479,11 +479,15 @@ v86mon.2: cmpb $0xf4,%al # HLT?
jne v86mon.7 # No (ignore)
jmp intrtn # Return to user mode
v86mon.3: cmpb $0xf,%al # Is
jne v86mon.4 # this
jne v86mon.3.1 # this
cmpb $0x20,(%esi) # a
jne v86mon.4 # MOV EAX,CR0
jne v86mon.3.1 # MOV EAX,CR0
cmpb $0xc0,0x1(%esi) # instruction?
je v86mov # Yes
v86mon.3.1: cmpb $0x30,(%esi) # Is it a WRMSR?
je v86wrmsr # Yes
cmpb $0x32,(%esi) # Is it a RDMSR?
je v86rdmsr # Yes
v86mon.4: cmpb $0xfa,%al # CLI?
je v86cli # Yes
cmpb $0xfb,%al # STI?
@ -522,6 +526,24 @@ v86mov: movl %cr0,%eax # CR0 to
incl %esi # IP
jmp v86mon.7 # Finish up
#
# Emulate WRMSR
#
v86wrmsr: movl 0x18(%ebp),%ecx # Get user's %ecx (MSR to write)
movl 0x14(%ebp),%edx # Load the value
movl 0x1c(%ebp),%eax # to write
wrmsr # Write MSR
incl %esi # Adjust IP
jmp v86mon.7 # Finish up
#
# Emulate RDMSR
#
v86rdmsr: movl 0x18(%ebp),%ecx # MSR to read
rdmsr # Read the MSR
movl %eax,0x1c(%ebp) # Return the value of
movl %edx,0x14(%ebp) # the MSR to the user
incl %esi # Adjust IP
jmp v86mon.7
#
# Emulate CLI.
#
v86cli: andb $~0x2,0x31(%ebp) # Clear IF