Reimplement the lazy FP context switching:

o   Move all code into a single file for easier maintenance.
o   Use a single global lock to avoid having to handle either
    multiple locks or race conditions.
o   Make sure to disable the high FP registers after saving
    or dropping them.
o   use msleep() to wait for the other CPU to save the high
    FP registers.

This change fixes the high FP inconsistency panics.

A single global lock typically serializes too much, which may
be noticable when a lot of threads use the high FP registers,
but in that case it's probably better to switch the high FP
context synchronuously. Put differently: cpu_switch() should
switch the high FP registers if the incoming and outgoing
threads both use the high FP registers.

1 files changed, 0 insertions, 75 deletions

diff --git a/sys/ia64/ia64/machdep.c b/sys/ia64/ia64/machdep.c
index 299c9ec..e578e8b 100644
--- a/sys/ia64/ia64/machdep.c
+++ b/sys/ia64/ia64/machdep.c
@@ -1461,81 +1461,6 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
 	return (0);
 }
 
-/*
- * High FP register functions.
- */
-
-int
-ia64_highfp_drop(struct thread *td)
-{
-	struct pcb *pcb;
-	struct pcpu *cpu;
-	struct thread *thr;
-
-	mtx_lock_spin(&td->td_md.md_highfp_mtx);
-	pcb = td->td_pcb;
-	cpu = pcb->pcb_fpcpu;
-	if (cpu == NULL) {
-		mtx_unlock_spin(&td->td_md.md_highfp_mtx);
-		return (0);
-	}
-	pcb->pcb_fpcpu = NULL;
-	thr = cpu->pc_fpcurthread;
-	cpu->pc_fpcurthread = NULL;
-	mtx_unlock_spin(&td->td_md.md_highfp_mtx);
-
-	/* Post-mortem sanity checking. */
-	KASSERT(thr == td, ("Inconsistent high FP state"));
-	return (1);
-}
-
-int
-ia64_highfp_save(struct thread *td)
-{
-	struct pcb *pcb;
-	struct pcpu *cpu;
-	struct thread *thr;
-
-	/* Don't save if the high FP registers weren't modified. */
-	if ((td->td_frame->tf_special.psr & IA64_PSR_MFH) == 0)
-		return (ia64_highfp_drop(td));
-
-	mtx_lock_spin(&td->td_md.md_highfp_mtx);
-	pcb = td->td_pcb;
-	cpu = pcb->pcb_fpcpu;
-	if (cpu == NULL) {
-		mtx_unlock_spin(&td->td_md.md_highfp_mtx);
-		return (0);
-	}
-#ifdef SMP
-	if (td == curthread)
-		sched_pin();
-	if (cpu != pcpup) {
-		mtx_unlock_spin(&td->td_md.md_highfp_mtx);
-		ipi_send(cpu, IPI_HIGH_FP);
-		if (td == curthread)
-			sched_unpin();
-		while (pcb->pcb_fpcpu == cpu)
-			DELAY(100);
-		return (1);
-	} else {
-		save_high_fp(&pcb->pcb_high_fp);
-		if (td == curthread)
-			sched_unpin();
-	}
-#else
-	save_high_fp(&pcb->pcb_high_fp);
-#endif
-	pcb->pcb_fpcpu = NULL;
-	thr = cpu->pc_fpcurthread;
-	cpu->pc_fpcurthread = NULL;
-	mtx_unlock_spin(&td->td_md.md_highfp_mtx);
-
-	/* Post-mortem sanity cxhecking. */
-	KASSERT(thr == td, ("Inconsistent high FP state"));
-	return (1);
-}
-
 void
 ia64_sync_icache(vm_offset_t va, vm_offset_t sz)
 {