From 2bc702613a6a034002e63ec2926667c8fd734751 Mon Sep 17 00:00:00 2001
From: alc <alc@FreeBSD.org>
Date: Mon, 10 Sep 2012 16:11:29 +0000
Subject: Simplify pmap_unmapdev().  Since kmem_free() eventually calls
 pmap_remove(), pmap_unmapdev()'s own direct efforts to destroy the page table
 entries are redundant, so eliminate them.

Don't set PTE_W on the page table entry in pmap_kenter{,_attr}() on MIPS.
Setting PTE_W on MIPS is inconsistent with the implementation of this
function on other architectures.  Moreover, PTE_W should not be set, unless
the pmap's wired mapping count is incremented, which pmap_kenter{,_attr}()
doesn't do.

MFC after:	10 days
---
 sys/amd64/amd64/pmap.c | 5 +----
 sys/i386/i386/pmap.c   | 5 +----
 sys/i386/xen/pmap.c    | 7 +------
 sys/mips/mips/pmap.c   | 6 ++----
 4 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 03d9ae7..a578375 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -4998,7 +4998,7 @@ pmap_mapbios(vm_paddr_t pa, vm_size_t size)
 void
 pmap_unmapdev(vm_offset_t va, vm_size_t size)
 {
-	vm_offset_t base, offset, tmpva;
+	vm_offset_t base, offset;
 
 	/* If we gave a direct map region in pmap_mapdev, do nothing */
 	if (va >= DMAP_MIN_ADDRESS && va < DMAP_MAX_ADDRESS)
@@ -5006,9 +5006,6 @@ pmap_unmapdev(vm_offset_t va, vm_size_t size)
 	base = trunc_page(va);
 	offset = va & PAGE_MASK;
 	size = roundup(offset + size, PAGE_SIZE);
-	for (tmpva = base; tmpva < (base + size); tmpva += PAGE_SIZE)
-		pmap_kremove(tmpva);
-	pmap_invalidate_range(kernel_pmap, va, tmpva);
 	kmem_free(kernel_map, base, size);
 }
 
diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c
index 9e81117..416f895 100644
--- a/sys/i386/i386/pmap.c
+++ b/sys/i386/i386/pmap.c
@@ -5011,16 +5011,13 @@ pmap_mapbios(vm_paddr_t pa, vm_size_t size)
 void
 pmap_unmapdev(vm_offset_t va, vm_size_t size)
 {
-	vm_offset_t base, offset, tmpva;
+	vm_offset_t base, offset;
 
 	if (va >= KERNBASE && va + size <= KERNBASE + KERNLOAD)
 		return;
 	base = trunc_page(va);
 	offset = va & PAGE_MASK;
 	size = roundup(offset + size, PAGE_SIZE);
-	for (tmpva = base; tmpva < (base + size); tmpva += PAGE_SIZE)
-		pmap_kremove(tmpva);
-	pmap_invalidate_range(kernel_pmap, va, tmpva);
 	kmem_free(kernel_map, base, size);
 }
 
diff --git a/sys/i386/xen/pmap.c b/sys/i386/xen/pmap.c
index b0e1624..e6702cd 100644
--- a/sys/i386/xen/pmap.c
+++ b/sys/i386/xen/pmap.c
@@ -3989,18 +3989,13 @@ pmap_mapbios(vm_paddr_t pa, vm_size_t size)
 void
 pmap_unmapdev(vm_offset_t va, vm_size_t size)
 {
-	vm_offset_t base, offset, tmpva;
+	vm_offset_t base, offset;
 
 	if (va >= KERNBASE && va + size <= KERNBASE + KERNLOAD)
 		return;
 	base = trunc_page(va);
 	offset = va & PAGE_MASK;
 	size = roundup(offset + size, PAGE_SIZE);
-	critical_enter();
-	for (tmpva = base; tmpva < (base + size); tmpva += PAGE_SIZE)
-		pmap_kremove(tmpva);
-	pmap_invalidate_range(kernel_pmap, va, tmpva);
-	critical_exit();
 	kmem_free(kernel_map, base, size);
 }
 
diff --git a/sys/mips/mips/pmap.c b/sys/mips/mips/pmap.c
index 1ef55fd..3dd74c5 100644
--- a/sys/mips/mips/pmap.c
+++ b/sys/mips/mips/pmap.c
@@ -814,10 +814,10 @@ pmap_kenter_attr(vm_offset_t va, vm_paddr_t pa, int attr)
 #ifdef PMAP_DEBUG
 	printf("pmap_kenter:  va: %p -> pa: %p\n", (void *)va, (void *)pa);
 #endif
-	npte = TLBLO_PA_TO_PFN(pa) | PTE_D | PTE_V | PTE_G | PTE_W | attr;
 
 	pte = pmap_pte(kernel_pmap, va);
 	opte = *pte;
+	npte = TLBLO_PA_TO_PFN(pa) | attr | PTE_D | PTE_V | PTE_G;
 	*pte = npte;
 	if (pte_test(&opte, PTE_V) && opte != npte)
 		pmap_update_page(kernel_pmap, va, npte);
@@ -2946,7 +2946,7 @@ void
 pmap_unmapdev(vm_offset_t va, vm_size_t size)
 {
 #ifndef __mips_n64
-	vm_offset_t base, offset, tmpva;
+	vm_offset_t base, offset;
 
 	/* If the address is within KSEG1 then there is nothing to do */
 	if (va >= MIPS_KSEG1_START && va <= MIPS_KSEG1_END)
@@ -2955,8 +2955,6 @@ pmap_unmapdev(vm_offset_t va, vm_size_t size)
 	base = trunc_page(va);
 	offset = va & PAGE_MASK;
 	size = roundup(size + offset, PAGE_SIZE);
-	for (tmpva = base; tmpva < base + size; tmpva += PAGE_SIZE)
-		pmap_kremove(tmpva);
 	kmem_free(kernel_map, base, size);
 #endif
 }
-- 
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