Add a level of indirection to the kernel PTE table. The old

scheme allowed for 1024 PTE pages, each containing 256 PTEs.
This yielded 2GB of KVA. This is not enough to boot a kernel
on a 16GB box and in general too low for a 64-bit machine.
By adding a level of indirection we now have 1024 2nd-level
directory pages, each capable of supporting 2GB of KVA. This
brings the grand total to 2TB of KVA.

2 files changed, 61 insertions, 37 deletions

diff --git a/sys/ia64/ia64/exception.S b/sys/ia64/ia64/exception.S
index 96ed2de..52b5e97 100644
--- a/sys/ia64/ia64/exception.S
+++ b/sys/ia64/ia64/exception.S
@@ -866,37 +866,45 @@ IVT_ENTRY(Data_Nested_TLB, 0x1400)
 {	.mii
 	srlz.d
 	dep		r27=0,r27,61,3
-	extr.u		r28=r30,PAGE_SHIFT,61-PAGE_SHIFT
 	;;
+	extr.u		r28=r30,3*PAGE_SHIFT-8, PAGE_SHIFT-3	// dir L0 index
 }
 {	.mii
-	ld8		r27=[r27]
-	shr.u		r29=r28,PAGE_SHIFT-5	// dir index
-	extr.u		r28=r28,0,PAGE_SHIFT-5	// pte index
+	ld8		r27=[r27]				// dir L0 page
+	extr.u		r29=r30,2*PAGE_SHIFT-5, PAGE_SHIFT-3	// dir L1 index
+	;;
+	dep		r27=0,r27,61,3
 	;;
 }
 {	.mmi
-	shladd		r27=r29,3,r27
+	shladd		r27=r28,3,r27
 	;;
-	mov		cr.ifa=r30
-	dep		r27=0,r27,61,3
+	ld8		r27=[r27]				// dir L1 page
+	extr.u		r28=r30,PAGE_SHIFT,PAGE_SHIFT-5		// pte index
 	;;
 }
 {	.mmi
-	ld8		r27=[r27]
+	shladd		r27=r29,3,r27
+	;;
 	mov		r29=rr[r30]
-	shl		r28=r28,5
+	dep		r27=0,r27,61,3
 	;;
 }
 {	.mii
-	add		r27=r27,r28		// address of pte
+	ld8		r27=[r27]				// pte page
+	shl		r28=r28,5
 	dep		r29=0,r29,0,2
 	;;
+}
+{	.mmi
+	add		r27=r28,r27
+	;;
+	mov		cr.ifa=r30
 	dep		r27=0,r27,61,3
 	;;
 }
 {	.mmi
-	ld8		r28=[r27]
+	ld8		r28=[r27]		// pte
 	;;
 	mov		cr.itir=r29
 	or		r28=PTE_DIRTY+PTE_ACCESSED,r28
diff --git a/sys/ia64/ia64/pmap.c b/sys/ia64/ia64/pmap.c
index e88a535..8376914 100644
--- a/sys/ia64/ia64/pmap.c
+++ b/sys/ia64/ia64/pmap.c
@@ -166,11 +166,13 @@ vm_offset_t virtual_end;	/* VA of last avail page (end of kernel AS) */
  * Kernel virtual memory management.
  */
 static int nkpt;
-struct ia64_lpte **ia64_kptdir;
-#define KPTE_DIR_INDEX(va) \
-	((va >> (2*PAGE_SHIFT-5)) & ((1<<(PAGE_SHIFT-3))-1))
+struct ia64_lpte ***ia64_kptdir;
+#define KPTE_DIR0_INDEX(va) \
+	(((va) >> (3*PAGE_SHIFT-8)) & ((1<<(PAGE_SHIFT-3))-1))
+#define KPTE_DIR1_INDEX(va) \
+	(((va) >> (2*PAGE_SHIFT-5)) & ((1<<(PAGE_SHIFT-3))-1))
 #define KPTE_PTE_INDEX(va) \
-	((va >> PAGE_SHIFT) & ((1<<(PAGE_SHIFT-5))-1))
+	(((va) >> PAGE_SHIFT) & ((1<<(PAGE_SHIFT-5))-1))
 #define NKPTEPG		(PAGE_SIZE / sizeof(struct ia64_lpte))
 
 vm_offset_t kernel_vm_end;
@@ -356,12 +358,8 @@ pmap_bootstrap()
 	 * Allocate some memory for initial kernel 'page tables'.
 	 */
 	ia64_kptdir = (void *)pmap_steal_memory(PAGE_SIZE);
-	for (i = 0; i < NKPT; i++) {
-		ia64_kptdir[i] = (void*)pmap_steal_memory(PAGE_SIZE);
-	}
-	nkpt = NKPT;
-	kernel_vm_end = NKPT * PAGE_SIZE * NKPTEPG + VM_MIN_KERNEL_ADDRESS -
-	    VM_GATEWAY_SIZE;
+	nkpt = 0;
+	kernel_vm_end = VM_MIN_KERNEL_ADDRESS - VM_GATEWAY_SIZE;
 
 	for (i = 0; phys_avail[i+2]; i+= 2)
 		;
@@ -749,25 +747,37 @@ pmap_release(pmap_t pmap)
 void
 pmap_growkernel(vm_offset_t addr)
 {
-	struct ia64_lpte *ptepage;
+	struct ia64_lpte **dir1;
+	struct ia64_lpte *leaf;
 	vm_page_t nkpg;
 
-	while (kernel_vm_end < addr) {
-		/* We could handle more by increasing the size of kptdir. */
-		if (nkpt == MAXKPT)
-			panic("pmap_growkernel: out of kernel address space");
+	while (kernel_vm_end <= addr) {
+		if (nkpt == PAGE_SIZE/8 + PAGE_SIZE*PAGE_SIZE/64)
+			panic("%s: out of kernel address space", __func__);
+
+		dir1 = ia64_kptdir[KPTE_DIR0_INDEX(kernel_vm_end)];
+		if (dir1 == NULL) {
+			nkpg = vm_page_alloc(NULL, nkpt++,
+			    VM_ALLOC_NOOBJ|VM_ALLOC_INTERRUPT|VM_ALLOC_WIRED);
+			if (!nkpg)
+				panic("%s: cannot add dir. page", __func__);
+
+			dir1 = (struct ia64_lpte **) 
+			    IA64_PHYS_TO_RR7(VM_PAGE_TO_PHYS(nkpg));
+			bzero(dir1, PAGE_SIZE);
+			ia64_kptdir[KPTE_DIR0_INDEX(kernel_vm_end)] = dir1;
+		}
 
-		nkpg = vm_page_alloc(NULL, nkpt,
-		    VM_ALLOC_NOOBJ | VM_ALLOC_INTERRUPT | VM_ALLOC_WIRED);
+		nkpg = vm_page_alloc(NULL, nkpt++,
+		    VM_ALLOC_NOOBJ|VM_ALLOC_INTERRUPT|VM_ALLOC_WIRED);
 		if (!nkpg)
-			panic("pmap_growkernel: no memory to grow kernel");
+			panic("%s: cannot add PTE page", __func__);
 
-		ptepage = (struct ia64_lpte *)
+		leaf = (struct ia64_lpte *)
 		    IA64_PHYS_TO_RR7(VM_PAGE_TO_PHYS(nkpg));
-		bzero(ptepage, PAGE_SIZE);
-		ia64_kptdir[KPTE_DIR_INDEX(kernel_vm_end)] = ptepage;
+		bzero(leaf, PAGE_SIZE);
+		dir1[KPTE_DIR1_INDEX(kernel_vm_end)] = leaf;
 
-		nkpt++;
 		kernel_vm_end += PAGE_SIZE * NKPTEPG;
 	}
 }
@@ -1094,11 +1104,17 @@ pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
 static struct ia64_lpte *
 pmap_find_kpte(vm_offset_t va)
 {
+	struct ia64_lpte **dir1;
+	struct ia64_lpte *leaf;
+
 	KASSERT((va >> 61) == 5,
 		("kernel mapping 0x%lx not in region 5", va));
-	KASSERT(IA64_RR_MASK(va) < (nkpt * PAGE_SIZE * NKPTEPG),
+	KASSERT(va < kernel_vm_end,
 		("kernel mapping 0x%lx out of range", va));
-	return (&ia64_kptdir[KPTE_DIR_INDEX(va)][KPTE_PTE_INDEX(va)]);
+
+	dir1 = ia64_kptdir[KPTE_DIR0_INDEX(va)];
+	leaf = dir1[KPTE_DIR1_INDEX(va)];
+	return (&leaf[KPTE_PTE_INDEX(va)]);
 }
 
 /*
@@ -1240,7 +1256,7 @@ pmap_kextract(vm_offset_t va)
 		return (IA64_RR_MASK((vm_offset_t)ia64_gateway_page));
 
 	/* Bail out if the virtual address is beyond our limits. */
-	if (IA64_RR_MASK(va) >= nkpt * PAGE_SIZE * NKPTEPG)
+	if (va >= kernel_vm_end)
 		return (0);
 
 	pte = pmap_find_kpte(va);
@@ -2388,7 +2404,7 @@ DB_COMMAND(kpte, db_kpte)
 		db_printf("kpte: error: invalid <kva>\n");
 		return;
 	}
-	pte = &ia64_kptdir[KPTE_DIR_INDEX(addr)][KPTE_PTE_INDEX(addr)];
+	pte = pmap_find_kpte(addr);
 	db_printf("kpte at %p:\n", pte);
 	db_printf("  pte  =%016lx\n", pte->pte);
 	db_printf("  itir =%016lx\n", pte->itir);