I wrote:

> Maybe we should check virtual cache index in pmap_pv_enter() and
> allow multiple mappings if VA pages being mapped have the same
> virtual indexes like mips pmap?

Here is an unreliable patch:
---
Index: include/cache.h
===================================================================
RCS file: /cvsroot/src/sys/arch/sh3/include/cache.h,v
retrieving revision 1.7
diff -u -r1.7 cache.h
--- include/cache.h	21 Jan 2006 00:46:36 -0000	1.7
+++ include/cache.h	23 Aug 2006 16:14:26 -0000
@@ -156,6 +156,9 @@
 extern int sh_cache_index_mode_icache;
 extern int sh_cache_index_mode_dcache;
 
+extern int sh_cache_alias_mask;
+#define	sh_cache_indexof(x)	(sh_cache_alias_mask & (x))
+
 extern struct sh_cache_ops sh_cache_ops;
 
 #define	sh_icache_sync_all()						\
Index: sh3/cache.c
===================================================================
RCS file: /cvsroot/src/sys/arch/sh3/sh3/cache.c,v
retrieving revision 1.11
diff -u -r1.11 cache.c
--- sh3/cache.c	2 Jan 2006 23:37:34 -0000	1.11
+++ sh3/cache.c	23 Aug 2006 16:14:26 -0000
@@ -77,6 +77,7 @@
 int sh_cache_ram_mode;
 int sh_cache_index_mode_icache;
 int sh_cache_index_mode_dcache;
+int sh_cache_alias_mask;
 
 void
 sh_cache_init()
Index: sh3/cache_sh4.c
===================================================================
RCS file: /cvsroot/src/sys/arch/sh3/sh3/cache_sh4.c,v
retrieving revision 1.15
diff -u -r1.15 cache_sh4.c
--- sh3/cache_sh4.c	24 Dec 2005 23:24:02 -0000	1.15
+++ sh3/cache_sh4.c	23 Aug 2006 16:14:27 -0000
@@ -44,6 +44,7 @@
 
 #include <sh3/cache.h>
 #include <sh3/cache_sh4.h>
+#include <sh3/vmparam.h>
 
 #define	round_line(x)		(((x) + 31) & ~31)
 #define	trunc_line(x)		((x) & ~31)
@@ -134,6 +135,7 @@
 	sh_cache_enable_dcache = (r & SH4_CCR_OCE);
 	sh_cache_ways = ways;
 	sh_cache_line_size = SH4_CACHE_LINESZ;
+	sh_cache_alias_mask = (dcache_size / ways - 1) & ~PAGE_MASK;
 	sh_cache_write_through_p0_u0_p3 = (r & SH4_CCR_WT);
 	sh_cache_write_through_p1 = !(r & SH4_CCR_CB);
 	sh_cache_write_through = sh_cache_write_through_p0_u0_p3 &&
Index: sh3/pmap.c
===================================================================
RCS file: /cvsroot/src/sys/arch/sh3/sh3/pmap.c,v
retrieving revision 1.55
diff -u -r1.55 pmap.c
--- sh3/pmap.c	7 Aug 2006 23:19:36 -0000	1.55
+++ sh3/pmap.c	23 Aug 2006 16:14:27 -0000
@@ -457,10 +457,15 @@
 	s = splvm();
 	if (SH_HAS_VIRTUAL_ALIAS) {
 		/* Remove all other mapping on this physical page */
+ again:
 		pvh = &pg->mdpage;
-		while ((pv = SLIST_FIRST(&pvh->pvh_head)) != NULL) {
-			pmap_remove(pv->pv_pmap, pv->pv_va,
-			    pv->pv_va + PAGE_SIZE);
+		SLIST_FOREACH(pv, &pvh->pvh_head, pv_link) {
+			if (sh_cache_indexof(va) !=
+			    sh_cache_indexof(pv->pv_va)) {
+				pmap_remove(pv->pv_pmap, pv->pv_va,
+				    pv->pv_va + PAGE_SIZE);
+				goto again;
+			}
 		}
 	}
 
---
Izumi Tsutsui