There is absolutely no need to double map DVMA addresses into the kernel address

space on SRMMU systems (i.e. sun4m), so don't do it anymore and update
misleading comments.

5 files changed, 31 insertions, 80 deletions

diff --git a/sys/arch/sparc/include/param.h b/sys/arch/sparc/include/param.h
index 4eb288b689b..71cc97bf954 100644
--- a/sys/arch/sparc/include/param.h
+++ b/sys/arch/sparc/include/param.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: param.h,v 1.40 2007/11/28 16:33:20 martin Exp $	*/
+/*	$OpenBSD: param.h,v 1.41 2010/06/29 21:26:09 miod Exp $	*/
 /*	$NetBSD: param.h,v 1.29 1997/03/10 22:50:37 pk Exp $ */
 
 /*
@@ -112,16 +112,6 @@
 #define	btodb(x)	((x) >> DEV_BSHIFT)
 #define	dbtob(x)	((x) << DEV_BSHIFT)
 
-/*
- * dvmamap manages a range of DVMA addresses intended to create double
- * mappings of physical memory. In a way, `dvmamap' is a submap of the
- * VM map `phys_map'. The difference is the use of the `resource map'
- * routines to manage page allocation, allowing DVMA addresses to be
- * allocated and freed from within interrupt routines.
- *
- * Note that `phys_map' can still be used to allocate memory-backed pages
- * in DVMA space.
- */
 #ifdef _KERNEL
 #ifndef _LOCORE
 extern vaddr_t		dvma_base;
diff --git a/sys/arch/sparc/include/pmap.h b/sys/arch/sparc/include/pmap.h
index 9c6a85917b2..e4c1c780dc8 100644
--- a/sys/arch/sparc/include/pmap.h
+++ b/sys/arch/sparc/include/pmap.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.h,v 1.46 2010/06/06 10:04:33 miod Exp $	*/
+/*	$OpenBSD: pmap.h,v 1.47 2010/06/29 21:26:09 miod Exp $	*/
 /*	$NetBSD: pmap.h,v 1.30 1997/08/04 20:00:47 pk Exp $ */
 
 /*
@@ -58,8 +58,8 @@
  * both into the same structure.  Fortunately, they are almost the same.
  *
  * The kernel begins at 0xf8000000 and runs to 0xffffffff (although
- * some of this is not actually used).  Kernel space, including DVMA
- * space (for now?), is mapped identically into all user contexts.
+ * some of this is not actually used).  Kernel space is mapped identically
+ * into all user contexts.
  * There is no point in duplicating this mapping in each user process
  * so they do not appear in the user structures.
  *
@@ -72,8 +72,8 @@
  * makes no such distinction.
  *
  * Since each virtual segment covers 256 kbytes, the user space
- * requires 3584 segments, while the kernel (including DVMA) requires
- * only 512 segments.
+ * requires 3584 segments, while the kernel (including DVMA on 4/4c)
+ * requires only 512 segments.
  *
  *
  ** FOR THE SUN4/SUN4C
diff --git a/sys/arch/sparc/sparc/machdep.c b/sys/arch/sparc/sparc/machdep.c
index 4ed5029fe22..ead377a6ad5 100644
--- a/sys/arch/sparc/sparc/machdep.c
+++ b/sys/arch/sparc/sparc/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.126 2010/06/27 13:28:47 miod Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.127 2010/06/29 21:26:12 miod Exp $	*/
 /*	$NetBSD: machdep.c,v 1.85 1997/09/12 08:55:02 pk Exp $ */
 
 /*
@@ -100,7 +100,6 @@
 #endif
 
 struct vm_map *exec_map = NULL;
-struct vm_map *phys_map = NULL;
 
 /*
  * Declare these as initialized data so we can patch them.
@@ -128,11 +127,10 @@ int	sparc_led_blink = 0;
  * safepri is a safe priority for sleep to set for a spin-wait
  * during autoconfiguration or after a panic.
  */
-int   safepri = 0;
+int	safepri = 0;
 
 /*
- * dvmamap is used to manage DVMA memory. Note: this coincides with
- * the memory range in `phys_map' (which is mostly a place-holder).
+ * dvmamap_extent is used to manage DVMA memory.
  */
 vaddr_t dvma_base, dvma_end;
 struct extent *dvmamap_extent;
@@ -192,38 +190,11 @@ cpu_startup()
 	 * map, but we want one completely separate, even though it uses
 	 * the same pmap.
 	 */
-	dvma_base = CPU_ISSUN4M ? DVMA4M_BASE : DVMA_BASE;
-	dvma_end = CPU_ISSUN4M ? DVMA4M_END : DVMA_END;
-#if defined(SUN4M)
-	if (CPU_ISSUN4M) {
-		/*
-		 * The DVMA space we want partially overrides kernel_map.
-		 * Allocate it in kernel_map as well to prevent it from being
-		 * used for other things.
-		 */
-		if (uvm_map(kernel_map, &dvma_base,
-		    vm_map_max(kernel_map) - dvma_base,
-                    NULL, UVM_UNKNOWN_OFFSET, 0,
-                    UVM_MAPFLAG(UVM_PROT_NONE, UVM_PROT_NONE, UVM_INH_NONE,
-                                UVM_ADV_NORMAL, UVM_FLAG_FIXED)))
-			panic("startup: can not steal dvma map");
-	}
-#endif
-	phys_map = uvm_map_create(pmap_kernel(), dvma_base, dvma_end,
-	    VM_MAP_INTRSAFE);
-	if (phys_map == NULL)
-		panic("unable to create DVMA map");
-
-	/*
-	 * Allocate DVMA space and dump into a privately managed
-	 * resource map for double mappings which is usable from
-	 * interrupt contexts.
-	 */
-	if (uvm_km_valloc_wait(phys_map, (dvma_end-dvma_base)) != dvma_base)
-		panic("unable to allocate from DVMA map");
+	dvma_base = CPU_ISSUN4DOR4M ? DVMA4M_BASE : DVMA_BASE;
+	dvma_end = CPU_ISSUN4DOR4M ? DVMA4M_END : DVMA_END;
 	dvmamap_extent = extent_create("dvmamap", dvma_base, dvma_end,
 				       M_DEVBUF, NULL, 0, EX_NOWAIT);
-	if (dvmamap_extent == 0)
+	if (dvmamap_extent == NULL)
 		panic("unable to allocate extent for dvma");
 
 #ifdef DEBUG
diff --git a/sys/arch/sparc/sparc/vaddrs.h b/sys/arch/sparc/sparc/vaddrs.h
index e833b72416e..5afd25688dc 100644
--- a/sys/arch/sparc/sparc/vaddrs.h
+++ b/sys/arch/sparc/sparc/vaddrs.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vaddrs.h,v 1.7 2005/04/17 18:47:51 miod Exp $	*/
+/*	$OpenBSD: vaddrs.h,v 1.8 2010/06/29 21:26:12 miod Exp $	*/
 /*	$NetBSD: vaddrs.h,v 1.8 1997/03/10 23:54:41 pk Exp $ */
 
 /*
@@ -52,10 +52,10 @@
  * Special (fixed) virtual addresses on the SPARC.
  *
  * IO virtual space begins at 0xfe000000 (a segment boundary) and
- * continues up to the DVMA edge at 0xff000000.  (The upper all-1s
- * byte is special since some of the hardware supplies this to pad
- * a 24-bit address space out to 32 bits.  This is a legacy of the
- * IBM PC AT bus, actually, just so you know who to blame.)
+ * continues up to the DVMA edge at 0xff000000 (on non-SRMMU systems only).
+ * (The upper all-1s byte is special anyway since some of the hardware
+ * supplies this to pad a 24-bit address space out to 32 bits.  This is a
+ * legacy of the IBM PC AT bus, actually, just so you know who to blame.)
  *
  * We reserve several pages at the base of our IO virtual space
  * for `oft-used' devices which must be present anyway in order to
@@ -100,20 +100,9 @@
  * Note that pagetables must be allocated at a cost of 1k per MB of DVMA
  * space, plus severe alignment restrictions. So don't make DVMA4M_BASE too
  * low (max space = 2G).
- *
- * Since DVMA space overlaps with normal kernel address space (notably
- * the device mappings and the PROM), we don't want to put any DVMA
- * mappings where any of this useful stuff is (i.e. if we dvma_malloc
- * a buffer, we want to still have a SRMMU mapping to it, and we can't
- * have that if its on top of kernel code). Thus the last two
- * constants define the actual DVMA addresses used. These can be anything
- * as long as they are within the bounds setup by the first 2 constants.
- * This is especially important on MP systems with cache coherency: to
- * avoid consistency problems, DVMA addresses must map to the same place
- * in both processor and IOMMU space.
  */
 #define DVMA4M_BASE	0xfc000000	/* can change subject to above rule */
-#define DVMA4M_END	0xfffff000	/* XXX is this enough? */
+#define DVMA4M_END	0xfffff000
 #define DVMA_D24_BASE	0xff000000
 #define DVMA_D24_END	0xfffff000
 
diff --git a/sys/arch/sparc/sparc/vm_machdep.c b/sys/arch/sparc/sparc/vm_machdep.c
index 7c3f8617c94..912be7ddf40 100644
--- a/sys/arch/sparc/sparc/vm_machdep.c
+++ b/sys/arch/sparc/sparc/vm_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vm_machdep.c,v 1.52 2010/06/22 20:27:32 oga Exp $	*/
+/*	$OpenBSD: vm_machdep.c,v 1.53 2010/06/29 21:26:12 miod Exp $	*/
 /*	$NetBSD: vm_machdep.c,v 1.30 1997/03/10 23:55:40 pk Exp $ */
 
 /*
@@ -140,7 +140,8 @@ u_long dvma_cachealign = 0;
 
 /*
  * Map a range [va, va+len] of wired virtual addresses in the given map
- * to a kernel address in DVMA space.
+ * to a valid DVMA address. On non-SRMMU systems, this establish a
+ * second mapping of that range.
  */
 vaddr_t
 dvma_mapin_space(map, va, len, canwait, space)
@@ -222,33 +223,33 @@ dvma_mapin_space(map, va, len, canwait, space)
 }
 
 /*
- * Remove double map of `va' in DVMA space at `kva'.
+ * Remove DVMA mapping of `va' in DVMA space at `dva'.
  */
 void
-dvma_mapout(kva, va, len)
-	vaddr_t	kva, va;
+dvma_mapout(dva, va, len)
+	vaddr_t	dva, va;
 	int		len;
 {
 	int s, off;
 	int error;
-	int klen;
+	int dlen;
 
-	off = (int)kva & PGOFSET;
-	kva -= off;
-	klen = round_page(len + off);
+	off = (int)dva & PGOFSET;
+	dva -= off;
+	dlen = round_page(len + off);
 
 #if defined(SUN4M)
 	if (CPU_ISSUN4M)
-		iommu_remove(kva, klen);
+		iommu_remove(dva, dlen);
 	else
 #endif
 	{
-		pmap_kremove(kva, klen);
+		pmap_kremove(dva, dlen);
 		pmap_update(pmap_kernel());
 	}
 
 	s = splhigh();
-	error = extent_free(dvmamap_extent, kva, klen, EX_NOWAIT);
+	error = extent_free(dvmamap_extent, dva, dlen, EX_NOWAIT);
 	if (error)
 		printf("dvma_mapout: extent_free failed\n");
 	splx(s);