languages/go
languages/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-10-14 03:43:28 +00:00
Code Issues Packages Projects Releases Wiki Activity

runtime: fix fault during arm software floating point

Browse source 
The software floating point runs with m->locks++
to avoid being preempted; recognize this case in panic
and undo it so that m->locks is maintained correctly
when panicking.

Fixes #7553.

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/84030043
This commit is contained in:
Russ Cox 2014-04-03 15:39:48 -04:00
parent 9dbb185fb6
commit b2cbf49343
3 changed files with 20 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
src/pkg/runtime/panic.c
View file

@ -498,7 +498,7 @@ runtime·canpanic(G *gp)
// and not stuck in a system call.
if(gp == nil || gp != m->curg)
return false;
if(m->locks != 0 || m->mallocing != 0 || m->throwing != 0 || m->gcing != 0 || m->dying != 0)
if(m->locks-m->softfloat != 0 || m->mallocing != 0 || m->throwing != 0 || m->gcing != 0 || m->dying != 0)
return false;
if(gp->status != Grunning || gp->syscallsp != 0)
return false;
@ -526,6 +526,16 @@ runtime·panicstring(int8 *s)
{
Eface err;
// m->softfloat is set during software floating point,
// which might cause a fault during a memory load.
// It increments m->locks to avoid preemption.
// If we're panicking, the software floating point frames
// will be unwound, so decrement m->locks as they would.
if(m->softfloat) {
m->locks--;
m->softfloat = 0;
}
if(m->mallocing) {
runtime·printf("panic: %s\n", s);
runtime·throw("panic during malloc");
@ -534,6 +544,10 @@ runtime·panicstring(int8 *s)
runtime·printf("panic: %s\n", s);
runtime·throw("panic during gc");
}
if(m->locks) {
runtime·printf("panic: %s\n", s);
runtime·throw("panic holding locks");
}
runtime·newErrorCString(s, &err);
runtime·panic(err);
}

1
src/pkg/runtime/runtime.h
View file

@ -312,6 +312,7 @@ struct M
int32 throwing;
int32 gcing;
int32 locks;
int32 softfloat;
int32 dying;
int32 profilehz;
int32 helpgc;

4
src/pkg/runtime/vlop_arm.s
View file

@ -75,10 +75,14 @@ TEXT _sfloat(SB), NOSPLIT, $64-0 // 4 arg + 14*4 saved regs + cpsr
MOVW m_locks(m), R1
ADD $1, R1
MOVW R1, m_locks(m)
MOVW $1, R1
MOVW R1, m_softfloat(m)
BL runtime·_sfloat2(SB)
MOVW m_locks(m), R1
SUB $1, R1
MOVW R1, m_locks(m)
MOVW $0, R1
MOVW R1, m_softfloat(m)
MOVW R0, 0(R13)
MOVW 64(R13), R1
WORD $0xe128f001 // msr cpsr_f, r1