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\ Hypervisor Software File: catchexc.fth
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id: @(#)catchexc.fth 2.10 07/06/05
copyright: Copyright 2007 Sun Microsystems, Inc. All Rights Reserved
copyright: Use is subject to license terms.
\ Copyright 1985-1990 Bradley Forthware
\ Save the SPARC processor state after a signal.
\ This code is entered as a result of a Unix signal.
\ It saves the processor state and the register windows, then
\ enters Forth so that the state may be examined, and possibly
\ Because our dictionary is independent of the ELF binary
\ that loads it we can concievably end up with a 32-bit
\ dictionary running in a 32-bit process environment, a 64-bit
\ dictionary running in a 64-bit process environment, a 64-bit
\ dictionary running in a 32-bit process environment, or
\ concievably a 32-bit dictionary running in a 64-bit environment,
\ (Note: the last one will only work if the dictionary is located
\ entirely within the 32-bit address space, and our forth binary
\ currently does not ensure that.)
\ So we really should determine the size of the sigcontext structure
\ dynamically based on the stack bias. However, to fully support
\ this we need to always allocate space for 64-bit registers in
\ our user save area and change the code to always save all 64-bits
\ of registers even on a 32-bit dictionarey. But that's a project
\ for the future. Right now I'll continue to use nget and nput.
only forth also hidden also forth definitions
3 global-regs %signal# %signal-code %fault-addr
3 global-regs %psr %asi %fprs
\ ?insane prevents endless occurrences of the same exception.
\ The variable "insane" is cleared after "expect" returns,
\ which is indicative of a human being somewhat in control.
: ?insane ( -- ) insane @ if bye then insane on ;
: enterforth ( -- ) init-window ?insane handle-breakpoint ;
\ Offset from the %o6 stack pointer of saved %g2.
\ This depends in detail on the code in sigtramp.s
\ Here is what is on the stack below the globals:
\ word# 0 16 17 23 24 56 57 58
\ windowregs struct-ret args align fpregs fsr y (total)
16 1 + 6 + even 32 + 1 + 1 + /l*
constant %g2-offset ( -- offset )
: exception ( -- adr ) addr %signal# ;
\ This is the second level save routine. The first level is called
\ from the signal handler, saving the globals and processor state registers.
\ This second level is called after the handler returns, to save the
\ window registers and the stacks.
\ Align the start of window registers ( %o's %l's and %i's ) to 16 bytes
window-registers h# 10 round-up is window-registers
spc ( %o7 ) %g1 move \ save a copy of %o7
here 8 + call \ address of next instruction in spc
here 8 - origin - base set \ relative address of current instruction
spc base base sub \ subtract them to find the base address
32\ \t32 'body main-task up set
32\ \t32 base up up ld \ Address of main task's user area
64\ \t32 'body main-task up set
64\ \t32 scr th 20 scr sllx
32\ \t16 'body main-task up set
32\ \t16 tos th 10 tos sll
64\ \t16 'body main-task up set
64\ \t16 tos th 10 tos sll
%g1 spc move \ restore %o7
'user unix-cpu-state %g4 nget \ Base address of save area
%g0 3 always trapif \ Flush window registers to memory
\ Save the ins, outs, locals
window-registers ( offset )
0 + %o0 %g4 2 pick nput \ %o0
/n + %o1 %g4 2 pick nput \ %o1
/n + %o2 %g4 2 pick nput \ %o2
/n + %o3 %g4 2 pick nput \ %o3
/n + %o4 %g4 2 pick nput \ %o4
/n + %o5 %g4 2 pick nput \ %o5
/n + %o6 %g4 2 pick nput \ %o6
/n + %o7 %g4 2 pick nput \ %o7
/n + %l0 %g4 2 pick nput \ %l0
/n + %l1 %g4 2 pick nput \ %l1
/n + %l2 %g4 2 pick nput \ %l2
/n + %l3 %g4 2 pick nput \ %l3
/n + %l4 %g4 2 pick nput \ %l4
/n + %l5 %g4 2 pick nput \ %l5
/n + %l6 %g4 2 pick nput \ %l6
/n + %l7 %g4 2 pick nput \ %l7
/n + %i0 %g4 2 pick nput \ %i0
/n + %i1 %g4 2 pick nput \ %i1
/n + %i2 %g4 2 pick nput \ %i2
/n + %i3 %g4 2 pick nput \ %i3
/n + %i4 %g4 2 pick nput \ %i4
/n + %i5 %g4 2 pick nput \ %i5
/n + %i6 %g4 2 pick nput \ %i6
/n + %i7 %g4 2 pick nput \ %i7
\ Establish the Data and Return stacks
\ Validate the saved state
%l0 %g4 offset-of %state-valid nput
%l0 %g4 offset-of %restartable? nput
\ Copy the entire Forth Data and Return stacks areas to a save area.
'user pssave scr nget \ Address of data stack save area
sp ps-size sc1 sub \ Bottom of data stack area
ps-size sc2 move \ Size of data stack area in sc2
sc3 scr sc2 nput \ Delay slot
'user rssave scr nget \ Address of return stack save area
rp rs-size sc1 sub \ Bottom of return stack area
rs-size sc2 move \ Size of return stack area in sc2
sc3 scr sc2 nput \ Delay slot
\ Adjust the stack pointer to account for the top of stack register
\ Restart the Forth interpreter.
\itc 'acf enterforth sc1 set
\dtc 'acf enterforth scr set
\ getexc is executed in the signal handler context. It is called
\ from _sigtramp with a bunch of machine state on the %o6 stack.
\ %o2 points to the sigcontext structure.
\ If this is entered as a result of a breakpoint, there are two case:
\ a) The breakpoint was unimplemented instruction = 0
\ This is a breakpoint that was placed in the code.
\ We save the state and return to Forth.
\ b) The breakpoint was unimplemented instruction = 1
\ This occurs at the end of the (restart routine.
\ (restart has restored all the state except for PC and nPC
\ We have a fresh set of local registers as a result of the
spc %l4 move \ Save the return address
here 8 + call \ address of next instruction in spc
here 8 - origin - base set \ relative address of current instruction
spc base base sub \ subtract them to find the base address
32\ \t32 'body main-task up set
32\ \t32 base up up ld \ Address of main task's user area
64\ \t32 'body main-task up set
64\ \t32 scr th 20 scr sllx
32\ \t16 'body main-task up set
32\ \t16 tos th 10 tos sll
64\ \t16 'body main-task up set
64\ \t16 tos th 10 tos sll
'user unix-cpu-state %l3 nget \ Base address of save area
\ Now we need to properly handle the sigcontext structure.
\ We don't know what size of structure we're looking at
\ since the size of the Forth dictionary is independent of
\ the ABI of the ELF executable that loaded it. We need to
\ make that decision based on the stack bias.
\ One thing that is probably still incorrect is that we should
\ not be using nget and nput to save and restore register values
\ from the user area, we should always try to save all 64-bits
\ if possible. That's a bit of a problem until I make sure we
\ allocate enough space in the user structure to store the regs
\ and add code to DTRT on both V8 and V9 instruction set machines.
\ 32-bit aligned stack frame indicates a 32-bit context
%o2 11 /l* %l0 ld \ Get the PC of the breakpoint instruction
%l0 0 %l0 ld \ Get the instruction
%l0 1 %g0 subcc \ Was it unimp=1 ?
0= if \ If so, we fix PC and nPC
%l3 offset-of %pc %l0 nget \ PC from Forth save area
%l0 %o2 11 /l* st \ fix PC in sigcontext
%l3 offset-of %npc %l0 nget \ nPC from Forth save area
%l0 %o2 12 /l* st \ fix nPC in sigcontext
\ Save the State Registers
%o0 %l3 offset-of %signal# nput \ Signo
%o1 %l3 offset-of %signal-code nput \ Sigcode
%o3 %l3 offset-of %fault-addr nput \ Fault address
%o2 11 /l* %l0 ld %l0 %l3 offset-of %pc nput \ PC
%o2 12 /l* %l0 ld %l0 %l3 offset-of %npc nput \ nPC
%l0 rdy %l0 %l3 offset-of %y nput \ Y
%o2 10 /l* %l0 ld %l0 %l3 offset-of %psr nput \ PSR
\ Save the Globals (sigtramp put them on the C stack)
%g0 %l3 offset-of %g0 nput \ g0 is immutable
%o2 14 /l* %l0 ld %l0 %l3 offset-of %g1 nput \ g1 is in sigcontext
drop 15 /l* \ Note: we don't use %g2-offset, rather a constant
%o2 over %l0 ld %l0 %l3 offset-of %g2 nput \ g2
4 + %o2 over %l0 ld %l0 %l3 offset-of %g3 nput \ g3
4 + %o2 over %l0 ld %l0 %l3 offset-of %g4 nput \ g4
4 + %o2 over %l0 ld %l0 %l3 offset-of %g5 nput \ g5
4 + %o2 over %l0 ld %l0 %l3 offset-of %g6 nput \ g6
4 + %o2 swap %l0 ld %l0 %l3 offset-of %g7 nput \ g7
\ Now we set the saved PC to point to the rest of the state save
\ routine, the return to the signal dispatcher, which will clean
\ up its stack frame and execute the Unix signal cleanup call.
\ sigcleanup will restore the process to the context that existed
\ at the time of the signal, except that the PC will be set to the
\ We have to do it this way to prevent nesting of the signal handler.
finish-save origin- %l0 set
%l0 %o2 11 /l* st \ Change saved PC
%l0 %o2 12 /l* st \ Change saved nPC
\ Unaligned stack, so read out a 64-bit context
%l0 0 %l0 ld \ Get the instruction
%l0 1 %g0 subcc \ Was it unimp=1 ?
0= if \ If so, we fix PC and nPC
%l3 offset-of %pc %l0 nget \ PC from Forth save area
%l0 %o2 h# 48 stx \ fix PC in sigcontext
%l3 offset-of %npc %l0 nget \ nPC from Forth save area
%l0 %o2 h# 50 stx \ fix nPC in sigcontext
%o0 %l3 offset-of %signal# nput \ Signo
%o1 %l3 offset-of %signal-code nput \ Sigcode
%o3 %l3 offset-of %fault-addr nput \ Fault address
%o2 h# 48 %l0 ldx %l0 %l3 offset-of %pc nput \ PC
%o2 h# 50 %l0 ldx %l0 %l3 offset-of %npc nput \ nPC
%l0 rdy %l0 %l3 offset-of %y nput \ Y
%o2 h# 40 %l0 ldx %l0 %l3 offset-of %psr nput \ CCR
%o2 h# d8 %l0 ldx %l0 %l3 offset-of %asi nput \ ASI
%o2 h# e0 %l0 ldx %l0 %l3 offset-of %fprs nput \ FPRS
\ Save the Globals (sigtramp put them on the C stack)
%g0 %l3 offset-of %g0 nput \ g0 is immutable
%o2 h# 60 %l0 ldx %l0 %l3 offset-of %g1 nput \ g1 is in sigcontext
drop h# 68 \ Note: we don't use %g2-offset, rather a constant
%o2 over %l0 ldx %l0 %l3 offset-of %g2 nput \ g2
8 + %o2 over %l0 ldx %l0 %l3 offset-of %g3 nput \ g3
8 + %o2 over %l0 ldx %l0 %l3 offset-of %g4 nput \ g4
8 + %o2 over %l0 ldx %l0 %l3 offset-of %g5 nput \ g5
8 + %o2 over %l0 ldx %l0 %l3 offset-of %g6 nput \ g6
8 + %o2 swap %l0 ldx %l0 %l3 offset-of %g7 nput \ g7
\ Now we set the saved PC to point to the rest of the state save
\ routine, the return to the signal dispatcher, which will clean
\ up its stack frame and execute the Unix signal cleanup call.
\ sigcleanup will restore the process to the context that existed
\ at the time of the signal, except that the PC will be set to the
\ We have to do it this way to prevent nesting of the signal handler.
finish-save origin- %l0 set
%l0 %o2 h# 48 stx \ Change saved PC
%l0 %o2 h# 50 stx \ Change saved nPC
code (restart-unix ( -- )
\ Restore the Forth stacks.
\ Establish the Data and Return stack pointers
'user pssave scr nget \ Address of data stack save area
sp ps-size sc1 sub \ Bottom of data stack area
ps-size sc2 move \ Size of data stack area in sc2
sc3 sc1 sc2 nput \ Delay slot
'user rssave scr nget \ Address of return stack save area
rp rs-size sc1 sub \ Bottom of return stack area
rs-size sc2 move \ Size of return stack area in sc2
sc3 sc1 sc2 nput \ Delay slot
\ Restore the Window Registers.
'user unix-cpu-state %g1 nget
window-registers ( offset )
0 + %g1 over %o0 nget \ %o0
/n + %g1 over %o1 nget \ %o1
/n + %g1 over %o2 nget \ %o2
/n + %g1 over %o3 nget \ %o3
/n + %g1 over %o4 nget \ %o4
/n + %g1 over %o5 nget \ %o5
/n + %g1 over %o6 nget \ %o6
/n + %g1 over %o7 nget \ %o7
/n + %g1 over %l0 nget \ %l0
/n + %g1 over %l1 nget \ %l1
/n + %g1 over %l2 nget \ %l2
/n + %g1 over %l3 nget \ %l3
/n + %g1 over %l4 nget \ %l4
/n + %g1 over %l5 nget \ %l5
/n + %g1 over %l6 nget \ %l6
/n + %g1 over %l7 nget \ %l7
/n + %g1 over %i0 nget \ %i0
/n + %g1 over %i1 nget \ %i1
/n + %g1 over %i2 nget \ %i2
/n + %g1 over %i3 nget \ %i3
/n + %g1 over %i4 nget \ %i4
/n + %g1 over %i5 nget \ %i5
/n + %g1 over %i6 nget \ %i6
/n + %g1 over %i7 nget \ %i7
\ Restore the State Registers.
'user unix-cpu-state %g7 nget
%g7 offset-of %y %g4 nget %g4 0 wry \ Y
32\ %g7 offset-of %psr %g1 nget \ PSR
32\ %g1 8 %g1 sll %g1 28 %g1 srl \ Extract icc bits
64\ %g7 offset-of %psr %g1 nget \ CCR
64\ %g1 h# f %g1 and %g1 d# 20 %g1 srl \ Extract icc bits
%g0 d# 33 always trapif \ Set icc
64\ %g7 offset-of %asi %g1 nget \ ASI
64\ %g7 offset-of %fprs %g1 nget \ FPRS
%g7 offset-of %g0 %g0 nget
%g7 offset-of %g1 %g1 nget
%g7 offset-of %g2 %g2 nget
%g7 offset-of %g3 %g3 nget
%g7 offset-of %g4 %g4 nget
%g7 offset-of %g5 %g5 nget
%g7 offset-of %g6 %g6 nget
%g7 offset-of %g7 %g7 nget
\ Take another trap, so we can fix up the PC's in the signal handler
\ %g0 %g0 %g0 restore \ Do we need to do something with nPC ?
' (restart-unix is restart
SIGINT of ." Interrupt" endof
SIGILL of ." Illegal Instruction" endof
SIGTRAP of ." Trace Trap" endof
SIGIOT of ." IO Trap" endof
SIGEMT of ." Emulator Trap" endof
SIGSEGV of ." Segmentation Violation" endof
SIGBUS of ." Bus Error" endof
SIGFPE of ." Numeric Exception" endof
interactive? 0= if bye then \ Restart only if a human is at the controls
' print-breakpoint is handle-breakpoint
: unix-catch-exceptions ( -- )
['] print-breakpoint is handle-breakpoint
['] (restart-unix is restart
ps-size alloc-mem to pssave
rs-size alloc-mem to rssave
h# 400 alloc-mem is unix-cpu-state
['] unix-cpu-state is cpu-state
[ window-registers literal ] to window-registers
['] yes-accessible is accessible?
getexc SIGILL signal drop
getexc SIGINT signal drop
getexc SIGBUS signal drop
getexc SIGSEGV signal drop
getexc SIGTRAP signal drop
getexc SIGIOT signal drop
getexc SIGEMT signal drop
getexc SIGFPE signal drop
['] .signal is .exception
: unix-init ( -- ) unix-init unix-catch-exceptions ;
only forth also definitions
projects / OpenSPARC-T2-SAM / blob