From e2bd3b65536e140fd1432ff6eb959ca304691d79 Mon Sep 17 00:00:00 2001
From: kettenis <kettenis@openbsd.org>
Date: Mon, 8 Aug 2016 14:47:52 +0000
Subject: [PATCH] Mapping non-cachable memory as cachable and subsequently
 changing the mapping to non-cachable is retarded.  Fix this by introducing
 PMAP_NOCACHE and PMAP_DEVICE flags that can be or'ed into the physical
 address passed to pmap_kenter(9), like we have on many of our other
 architectures.  This way we can also properly distinguish between device
 memory and normal (non-cachable) memory.

ok visa@
---
 sys/arch/arm/arm/pmap7.c         | 48 +++++++++++---------------------
 sys/arch/arm/armv7/armv7_space.c | 23 ++++++---------
 sys/arch/arm/include/pmap.h      |  9 +++++-
 3 files changed, 32 insertions(+), 48 deletions(-)

diff --git a/sys/arch/arm/arm/pmap7.c b/sys/arch/arm/arm/pmap7.c
index e0631efc365..a283779e482 100644
--- a/sys/arch/arm/arm/pmap7.c
+++ b/sys/arch/arm/arm/pmap7.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap7.c,v 1.34 2016/08/08 09:06:47 kettenis Exp $	*/
+/*	$OpenBSD: pmap7.c,v 1.35 2016/08/08 14:47:52 kettenis Exp $	*/
 /*	$NetBSD: pmap.c,v 1.147 2004/01/18 13:03:50 scw Exp $	*/
 
 /*
@@ -927,33 +927,6 @@ pmap_l2ptp_ctor(void *v)
 	PTE_SYNC_RANGE(v, L2_TABLE_SIZE_REAL / sizeof(pt_entry_t));
 }
 
-/*
- * Make a pmap_kernel() mapping uncached. Used by bus_dma for coherent pages.
- */
-void
-pmap_uncache_page(paddr_t va, vaddr_t pa)
-{
-	struct vm_page *pg;
-	struct pv_entry *pv;
-	pt_entry_t *pte;
-
-	if ((pg = PHYS_TO_VM_PAGE(pa)) != NULL) {
-		pv = pmap_find_pv(pg, pmap_kernel(), va);
-		if (pv != NULL)
-			pv->pv_flags |= PVF_NC;	/* XXX ought to be pg attr */
-	}
-
-	pte = vtopte(va);
-	*pte &= ~L2_S_CACHE_MASK;
-	*pte |= L2_B; /* device memory */
-	PTE_SYNC(pte);
-	cpu_tlb_flushD_SE(va);
-	cpu_cpwait();
-
-	cpu_dcache_wbinv_range(va, PAGE_SIZE);
-	cpu_sdcache_wbinv_range(va, pa, PAGE_SIZE);
-}
-
 /*
  * Modify pte bits for all ptes corresponding to the given physical address.
  * We use `maskbits' rather than `clearbits' because we're always passing
@@ -1514,6 +1487,7 @@ pmap_kenter_pa(vaddr_t va, paddr_t pa, vm_prot_t prot)
 {
 	struct l2_bucket *l2b;
 	pt_entry_t *ptep, opte, npte;
+	pt_entry_t cache_mode = pte_l2_s_cache_mode;
 
 	NPDEBUG(PDB_KENTER,
 	    printf("pmap_kenter_pa: va 0x%08lx, pa 0x%08lx, prot 0x%x\n",
@@ -1528,22 +1502,32 @@ pmap_kenter_pa(vaddr_t va, paddr_t pa, vm_prot_t prot)
 	if (opte == 0)
 		l2b->l2b_occupancy++;
 
-	npte = L2_S_PROTO | pa | L2_S_PROT(PTE_KERNEL, prot) |
-	    pte_l2_s_cache_mode;
+	if (pa & PMAP_DEVICE)
+		cache_mode = L2_B;
+	else if (pa & PMAP_NOCACHE)
+		cache_mode = L2_V7_S_TEX(1);
+
+	npte = L2_S_PROTO | (pa & PMAP_PA_MASK) |
+	    L2_S_PROT(PTE_KERNEL, prot) | cache_mode;
 	*ptep = npte;
 	PTE_SYNC(ptep);
 	if (l2pte_valid(opte)) {
 		cpu_tlb_flushD_SE(va);
 		cpu_cpwait();
 	}
+
+	if (pa & PMAP_NOCACHE) {
+		cpu_dcache_wbinv_range(va, PAGE_SIZE);
+		cpu_sdcache_wbinv_range(va, (pa & PMAP_PA_MASK), PAGE_SIZE);
+	}
 }
 
 void
 pmap_kenter_cache(vaddr_t va, paddr_t pa, vm_prot_t prot, int cacheable)
 {
-	pmap_kenter_pa(va, pa, prot);
 	if (cacheable == 0)
-		pmap_uncache_page(va, pa);
+		pa |= PMAP_NOCACHE;
+	pmap_kenter_pa(va, pa, prot);
 }
 
 void
diff --git a/sys/arch/arm/armv7/armv7_space.c b/sys/arch/arm/armv7/armv7_space.c
index d61549301da..4f6c1e04e73 100644
--- a/sys/arch/arm/armv7/armv7_space.c
+++ b/sys/arch/arm/armv7/armv7_space.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: armv7_space.c,v 1.7 2016/07/27 21:25:25 patrick Exp $ */
+/*	$OpenBSD: armv7_space.c,v 1.8 2016/08/08 14:47:52 kettenis Exp $ */
 
 /*
  * Copyright (c) 2001, 2002 Wasabi Systems, Inc.
@@ -166,11 +166,11 @@ struct bus_space armv7_bs_tag = {
 
 int
 armv7_bs_map(void *t, bus_addr_t bpa, bus_size_t size,
-	      int flag, bus_space_handle_t *bshp)
+	      int flags, bus_space_handle_t *bshp)
 {
 	u_long startpa, endpa, pa;
 	vaddr_t va;
-	pt_entry_t *pte;
+	int pmap_flags = PMAP_DEVICE;
 
 	startpa = trunc_page(bpa);
 	endpa = round_page(bpa + size);
@@ -183,18 +183,11 @@ armv7_bs_map(void *t, bus_addr_t bpa, bus_size_t size,
 
 	*bshp = (bus_space_handle_t)(va + (bpa - startpa));
 
-	for (pa = startpa; pa < endpa; pa += PAGE_SIZE, va += PAGE_SIZE) {
-		pmap_kenter_pa(va, pa, PROT_READ | PROT_WRITE);
-		if ((flag & BUS_SPACE_MAP_CACHEABLE) == 0) {
-			pte = vtopte(va);
-			*pte &= ~L2_S_CACHE_MASK;
-			*pte |= L2_B;
-			PTE_SYNC(pte);
-			/* XXX: pmap_kenter_pa() also does PTE_SYNC(). a bit of
-			 *      waste.
-			 */
-		}
-	}
+	if (flags & BUS_SPACE_MAP_CACHEABLE)
+		pmap_flags = 0;
+
+	for (pa = startpa; pa < endpa; pa += PAGE_SIZE, va += PAGE_SIZE)
+		pmap_kenter_pa(va, pa | pmap_flags, PROT_READ | PROT_WRITE);
 	pmap_update(pmap_kernel());
 
 	return(0);
diff --git a/sys/arch/arm/include/pmap.h b/sys/arch/arm/include/pmap.h
index b382dc3de8f..393b5484373 100644
--- a/sys/arch/arm/include/pmap.h
+++ b/sys/arch/arm/include/pmap.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.h,v 1.40 2016/03/22 23:35:01 patrick Exp $	*/
+/*	$OpenBSD: pmap.h,v 1.41 2016/08/08 14:47:52 kettenis Exp $	*/
 /*	$NetBSD: pmap.h,v 1.76 2003/09/06 09:10:46 rearnsha Exp $	*/
 
 /*
@@ -180,6 +180,13 @@ struct pmap {
 
 typedef struct pmap *pmap_t;
 
+/*
+ * MD flags that we use for pmap_enter (in the pa):
+ */
+#define PMAP_PA_MASK	~((paddr_t)PAGE_MASK) /* to remove the flags */
+#define PMAP_NOCACHE	0x1 /* non-cacheable memory. */
+#define PMAP_DEVICE	0x2 /* device memory. */
+
 /*
  * Physical / virtual address structure. In a number of places (particularly
  * during bootstrapping) we need to keep track of the physical and virtual
-- 
2.20.1