Precompute the userland process apr cache bits into a global variable.

On AViiON systems with the 6:1 CMMU:CPU configuration, force cached
mappings to be writethrough - this probably hides a bug in the code, but
that's the only way so far to get such a system running stably.

3 files changed, 20 insertions, 7 deletions

diff --git a/sys/arch/aviion/aviion/m8820x.c b/sys/arch/aviion/aviion/m8820x.c
index 518bb28cf95..e52b9fabcdb 100644
--- a/sys/arch/aviion/aviion/m8820x.c
+++ b/sys/arch/aviion/aviion/m8820x.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: m8820x.c,v 1.8 2010/04/25 21:03:51 miod Exp $	*/
+/*	$OpenBSD: m8820x.c,v 1.9 2010/05/02 22:01:43 miod Exp $	*/
 /*
  * Copyright (c) 2004, 2006, 2010 Miodrag Vallat.
  *
@@ -34,6 +34,7 @@
 #include <machine/cmmu.h>
 #include <machine/cpu.h>
 #include <machine/m8820x.h>
+#include <machine/pmap.h>
 #include <machine/prom.h>
 
 extern	u_int32_t pfsr_straight[];
@@ -152,6 +153,15 @@ hardprobe:
 			max_cmmus = ncpusfound << cmmu_shift;
 			scc.isplit = scc.dsplit = 0;	/* XXX unknown */
 			m8820x_pfsr = pfsr_six;
+
+			/*
+			 * We can't use writeback userland mappings until
+			 * the CMMU split scheme is known, as the current
+			 * pessimistic behaviour is not good enough to
+			 * prevent out-of-sync cache lines from occuring.
+			 */
+			default_apr |= CACHE_WT;
+
 			goto done;
 			break;
 		default:
diff --git a/sys/arch/m88k/include/pmap.h b/sys/arch/m88k/include/pmap.h
index 7561a9a5e78..f3a2b82e812 100644
--- a/sys/arch/m88k/include/pmap.h
+++ b/sys/arch/m88k/include/pmap.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.h,v 1.14 2009/05/02 14:32:27 miod Exp $	*/
+/*	$OpenBSD: pmap.h,v 1.15 2010/05/02 22:01:46 miod Exp $	*/
 /*
  * Mach Operating System
  * Copyright (c) 1991 Carnegie Mellon University
@@ -48,6 +48,7 @@ typedef struct pv_entry *pv_entry_t;
 extern	pmap_t		kernel_pmap;
 extern	struct pmap	kernel_pmap_store;
 extern	caddr_t		vmmap;
+extern	apr_t		default_apr;
 
 #define	pmap_kernel()			(&kernel_pmap_store)
 #define pmap_resident_count(pmap)	((pmap)->pm_stats.resident_count)
diff --git a/sys/arch/m88k/m88k/pmap.c b/sys/arch/m88k/m88k/pmap.c
index 4a90268a8d4..9d630d456d1 100644
--- a/sys/arch/m88k/m88k/pmap.c
+++ b/sys/arch/m88k/m88k/pmap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.c,v 1.49 2009/09/27 19:16:10 miod Exp $	*/
+/*	$OpenBSD: pmap.c,v 1.50 2010/05/02 22:01:47 miod Exp $	*/
 /*
  * Copyright (c) 2001-2004, Miodrag Vallat
  * Copyright (c) 1998-2001 Steve Murphree, Jr.
@@ -115,6 +115,8 @@ pt_entry_t *vmpte, *msgbufmap;
 struct pmap kernel_pmap_store;
 pmap_t kernel_pmap = &kernel_pmap_store;
 
+apr_t	default_apr = CACHE_GLOBAL | APR_V;
+
 typedef struct kpdt_entry *kpdt_entry_t;
 struct kpdt_entry {
 	kpdt_entry_t	next;
@@ -751,12 +753,12 @@ pmap_bootstrap(vaddr_t load_start)
 	 * Switch to using new page tables
 	 */
 
-	kernel_pmap->pm_apr = (atop((paddr_t)kmap) << PG_SHIFT) |
-	    CACHE_GLOBAL | CACHE_WT | APR_V;
 #if !defined(MULTIPROCESSOR) && defined(M88110)
 	if (CPU_IS88110)
-		kernel_pmap->pm_apr &= ~CACHE_GLOBAL;
+		default_apr &= ~CACHE_GLOBAL;
 #endif
+	kernel_pmap->pm_apr = (atop((paddr_t)kmap) << PG_SHIFT) | default_apr |
+	    CACHE_WT;
 
 	pmap_bootstrap_cpu(cpu_number());
 }
@@ -894,7 +896,7 @@ pmap_create(void)
 	if (pmap_extract(kernel_pmap, (vaddr_t)segdt,
 	    (paddr_t *)&stpa) == FALSE)
 		panic("pmap_create: pmap_extract failed!");
-	pmap->pm_apr = (atop(stpa) << PG_SHIFT) | CACHE_GLOBAL | APR_V;
+	pmap->pm_apr = (atop(stpa) << PG_SHIFT) | default_apr;
 #if !defined(MULTIPROCESSOR) && defined(M88110)
 	if (CPU_IS88110)
 		pmap->pm_apr &= ~CACHE_GLOBAL;