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cpu_simple_lock: on spin out, check whether we've already panicked. If so,

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just take the lock on the assumption that in panic mode, we run on a single
CPU anyway.
This commit is contained in:
pk 2004-07-04 09:54:20 +00:00
parent 94e2ec5a8b
commit ce03cf29a9
1 changed files with 19 additions and 8 deletions
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27
sys/arch/sparc/sparc/locore.s
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@ -1,4 +1,4 @@
/* $NetBSD: locore.s,v 1.213 2004/07/04 09:11:33 pk Exp $ */
/* $NetBSD: locore.s,v 1.214 2004/07/04 09:54:20 pk Exp $ */
/*
* Copyright (c) 1996 Paul Kranenburg
@ -6606,19 +6606,30 @@ _ENTRY(_C_LABEL(__cpu_simple_lock))
0:
ldstub [%o0], %o1
tst %o1
bnz 1f
set 0x1000000, %o2 ! set spinout counter
bnz,a 2f
ldub [%o0], %o1
1:
retl
EMPTY
1:
ldub [%o0], %o1
2:
set 0x1000000, %o2 ! set spinout counter
3:
tst %o1
bz 0b ! lock has been released; try again
deccc %o2
bcc 1b ! repeat until counter < 0
nop
bcc,a 3b ! repeat until counter < 0
ldub [%o0], %o1
! spun out; set up stack frame and call panic
! spun out; check if already panicking
sethi %hi(_C_LABEL(panicstr)), %o2
ld [%o2 + %lo(_C_LABEL(panicstr))], %o1
tst %o1
! if so, just take the lock and return on the assumption that
! in panic mode we're running on a single CPU anyway.
bnz,a 1b
ldstub [%o0], %g0
! set up stack frame and call panic
save %sp, -CCFSZ, %sp
sethi %hi(CPUINFO_VA + CPUINFO_CPUNO), %o0
ld [%o0 + %lo(CPUINFO_VA + CPUINFO_CPUNO)], %o1