From ac24a8ea24a65307c036d88eeefe18b9a95d69cb Mon Sep 17 00:00:00 2001
From: Alan Cox <alc@FreeBSD.org>
Date: Mon, 11 Jan 2010 16:01:20 +0000
Subject: [PATCH] Simplify pmap_init().  Additionally, correct a harmless
 misbehavior on i386. Specifically, where locore had created large page
 mappings for the kernel, the wrong vm page array entries were being
 initialized.  The vm page array entries for the pages containing the kernel
 were being initialized instead of the vm page array entries for page table
 pages.

MFC after:	1 week
---
 sys/amd64/amd64/pmap.c | 10 ++--------
 sys/i386/i386/locore.s |  2 --
 sys/i386/i386/pmap.c   |  7 ++++---
 3 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 44b71f387231..889a06a7f55e 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -664,7 +664,6 @@ pmap_page_init(vm_page_t m)
 void
 pmap_init(void)
 {
-	pd_entry_t *pd;
 	vm_page_t mpte;
 	vm_size_t s;
 	int i, pv_npg;
@@ -673,18 +672,13 @@ pmap_init(void)
 	 * Initialize the vm page array entries for the kernel pmap's
 	 * page table pages.
 	 */ 
-	pd = pmap_pde(kernel_pmap, KERNBASE);
 	for (i = 0; i < NKPT; i++) {
-		if ((pd[i] & (PG_PS | PG_V)) == (PG_PS | PG_V))
-			continue;
-		KASSERT((pd[i] & PG_V) != 0,
-		    ("pmap_init: page table page is missing"));
-		mpte = PHYS_TO_VM_PAGE(pd[i] & PG_FRAME);
+		mpte = PHYS_TO_VM_PAGE(KPTphys + (i << PAGE_SHIFT));
 		KASSERT(mpte >= vm_page_array &&
 		    mpte < &vm_page_array[vm_page_array_size],
 		    ("pmap_init: page table page is out of range"));
 		mpte->pindex = pmap_pde_pindex(KERNBASE) + i;
-		mpte->phys_addr = pd[i] & PG_FRAME;
+		mpte->phys_addr = KPTphys + (i << PAGE_SHIFT);
 	}
 
 	/*
diff --git a/sys/i386/i386/locore.s b/sys/i386/i386/locore.s
index eee9fdb8903b..170aaf139997 100644
--- a/sys/i386/i386/locore.s
+++ b/sys/i386/i386/locore.s
@@ -104,9 +104,7 @@ IdlePTD:	.long	0		/* phys addr of kernel PTD */
 IdlePDPT:	.long	0		/* phys addr of kernel PDPT */
 #endif
 
-#ifdef SMP
 	.globl	KPTphys
-#endif
 KPTphys:	.long	0		/* phys addr of kernel page tables */
 
 	.globl	proc0kstack
diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c
index 794aa02e5ae2..993b13e03b3a 100644
--- a/sys/i386/i386/pmap.c
+++ b/sys/i386/i386/pmap.c
@@ -206,6 +206,7 @@ int pseflag = 0;		/* PG_PS or-in */
 static int nkpt;
 vm_offset_t kernel_vm_end;
 extern u_int32_t KERNend;
+extern u_int32_t KPTphys;
 
 #ifdef PAE
 pt_entry_t pg_nx;
@@ -659,13 +660,13 @@ pmap_init(void)
 	 * Initialize the vm page array entries for the kernel pmap's
 	 * page table pages.
 	 */ 
-	for (i = 0; i < nkpt; i++) {
-		mpte = PHYS_TO_VM_PAGE(PTD[i + KPTDI] & PG_FRAME);
+	for (i = 0; i < NKPT; i++) {
+		mpte = PHYS_TO_VM_PAGE(KPTphys + (i << PAGE_SHIFT));
 		KASSERT(mpte >= vm_page_array &&
 		    mpte < &vm_page_array[vm_page_array_size],
 		    ("pmap_init: page table page is out of range"));
 		mpte->pindex = i + KPTDI;
-		mpte->phys_addr = PTD[i + KPTDI] & PG_FRAME;
+		mpte->phys_addr = KPTphys + (i << PAGE_SHIFT);
 	}
 
 	/*