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Use a critical region to protect almost everything in npxinit().

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npxinit() didn't have the usual race because it doesn't save to curpcb,
but it may have had a worse form of it since it uses the npx when it
doesn't "own" it.  I'm not sure if locking prevented this.  npxinit()
is normally caled with the proc lock but not sched_lock.

Use a critical region to protect pushing of curproc's npx state to
curpcb in npxexit().  Not doing so was harmless since it at worst
saved a wrong state to a dieing pcb.
This commit is contained in:
bde 2001-05-20 18:05:44 +00:00
parent fe3ed5cadc
commit e37c5b4039
3 changed files with 18 additions and 0 deletions
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6
sys/amd64/amd64/fpu.c
View File

@ -484,6 +484,7 @@ npxinit(control)
u_short control;
{
struct save87 dummy;
critical_t savecrit;
if (!npx_exists)
return;
@ -492,12 +493,14 @@ npxinit(control)
* fnsave to throw away any junk in the fpu. npxsave() initializes
* the fpu and sets npxproc = NULL as important side effects.
*/
savecrit = critical_enter();
npxsave(&dummy);
stop_emulating();
fldcw(&control);
if (PCPU_GET(curpcb) != NULL)
fnsave(&PCPU_GET(curpcb)->pcb_savefpu);
start_emulating();
critical_exit(savecrit);
}
/*
@ -507,9 +510,12 @@ void
npxexit(p)
struct proc *p;
{
critical_t savecrit;
savecrit = critical_enter();
if (p == PCPU_GET(npxproc))
npxsave(&PCPU_GET(curpcb)->pcb_savefpu);
critical_exit(savecrit);
#ifdef NPX_DEBUG
if (npx_exists) {
u_int masked_exceptions;

6
sys/amd64/isa/npx.c
View File

@ -484,6 +484,7 @@ npxinit(control)
u_short control;
{
struct save87 dummy;
critical_t savecrit;
if (!npx_exists)
return;
@ -492,12 +493,14 @@ npxinit(control)
* fnsave to throw away any junk in the fpu. npxsave() initializes
* the fpu and sets npxproc = NULL as important side effects.
*/
savecrit = critical_enter();
npxsave(&dummy);
stop_emulating();
fldcw(&control);
if (PCPU_GET(curpcb) != NULL)
fnsave(&PCPU_GET(curpcb)->pcb_savefpu);
start_emulating();
critical_exit(savecrit);
}
/*
@ -507,9 +510,12 @@ void
npxexit(p)
struct proc *p;
{
critical_t savecrit;
savecrit = critical_enter();
if (p == PCPU_GET(npxproc))
npxsave(&PCPU_GET(curpcb)->pcb_savefpu);
critical_exit(savecrit);
#ifdef NPX_DEBUG
if (npx_exists) {
u_int masked_exceptions;

6
sys/i386/isa/npx.c
View File

@ -484,6 +484,7 @@ npxinit(control)
u_short control;
{
struct save87 dummy;
critical_t savecrit;
if (!npx_exists)
return;
@ -492,12 +493,14 @@ npxinit(control)
* fnsave to throw away any junk in the fpu. npxsave() initializes
* the fpu and sets npxproc = NULL as important side effects.
*/
savecrit = critical_enter();
npxsave(&dummy);
stop_emulating();
fldcw(&control);
if (PCPU_GET(curpcb) != NULL)
fnsave(&PCPU_GET(curpcb)->pcb_savefpu);
start_emulating();
critical_exit(savecrit);
}
/*
@ -507,9 +510,12 @@ void
npxexit(p)
struct proc *p;
{
critical_t savecrit;
savecrit = critical_enter();
if (p == PCPU_GET(npxproc))
npxsave(&PCPU_GET(curpcb)->pcb_savefpu);
critical_exit(savecrit);
#ifdef NPX_DEBUG
if (npx_exists) {
u_int masked_exceptions;