[src/trunk]: src/sys/arch/sparc/sparc ctx_alloc: set context before flushing ...

[pk <pk%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8c863e37110a
branches:  trunk
changeset: 485147:8c863e37110a
user:      pk <pk%NetBSD.org@localhost>
date:      Thu Apr 20 13:59:02 2000 +0000

description:
ctx_alloc: set context before flushing a stolen context's cache

diffstat:

 sys/arch/sparc/sparc/pmap.c |  34 +++++++++++++++++++++++-----------
 1 files changed, 23 insertions(+), 11 deletions(-)

diffs (72 lines):

diff -r 19b705b76ded -r 8c863e37110a sys/arch/sparc/sparc/pmap.c
--- a/sys/arch/sparc/sparc/pmap.c       Thu Apr 20 13:52:35 2000 +0000
+++ b/sys/arch/sparc/sparc/pmap.c       Thu Apr 20 13:59:02 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.156 2000/04/17 20:32:00 pk Exp $ */
+/*     $NetBSD: pmap.c,v 1.157 2000/04/20 13:59:02 pk Exp $ */
 
 /*
  * Copyright (c) 1996
@@ -1915,11 +1915,21 @@
 
                /* Do any cache flush needed on context switch */
                (*cpuinfo.pure_vcache_flush)();
-#ifdef DEBUG
-               if (pm->pm_reg_ptps_pa[0] == 0)
-                       panic("ctx_alloc: no region table in current pmap");
-#endif
-               /*setcontext(0); * paranoia? can we modify curr. ctx? */
+
+               /*
+                * We need to flush the cache only when stealing a context
+                * from another pmap. In that case it's Ok to switch the
+                * context and leave it set, since it the context table
+                * will have a valid region table entry for this context
+                * number.
+                *
+                * Otherwise, we switch to the new context after loading
+                * the context table entry with the new pmap's region.
+                */
+               if (doflush) {
+                       setcontext4m(cnum);
+                       cache_flush_context();
+               }
 
                /*
                 * The context allocated to a process is the same on all CPUs.
@@ -1945,9 +1955,10 @@
                                        SRMMU_TEPTD);
                }
 
-               setcontext4m(cnum);
-               if (doflush)
-                       cache_flush_context();
+               /* Set context if not yet done above to flush the cache */
+               if (!doflush)
+                       setcontext4m(cnum);
+
                tlb_flush_context(); /* remove any remnant garbage from tlb */
 #endif
                splx(s);
@@ -3923,9 +3934,10 @@
                n = 0;
 #endif
                {
-                       pool_put(&L1_pool, pm->pm_reg_ptps[n]);
+                       int *pt = pm->pm_reg_ptps[n];
                        pm->pm_reg_ptps[n] = NULL;
                        pm->pm_reg_ptps_pa[n] = 0;
+                       pool_put(&L1_pool, pt);
                }
        }
 #endif
@@ -4550,8 +4562,8 @@
                if (pm->pm_ctx)
                        tlb_flush_segment(vr, vs);      /* Paranoia? */
                setpgt4m(&rp->rg_seg_ptps[vs], SRMMU_TEINVALID);
+               sp->sg_pte = NULL;
                pool_put(&L23_pool, pte0);
-               sp->sg_pte = NULL;
 
                if (--rp->rg_nsegmap == 0) {
                        int n;