14 files changed, 494 insertions, 328 deletions

diff --git a/sys/arm/arm/machdep.c b/sys/arm/arm/machdep.c
index e5edace..eacdec1 100644
--- a/sys/arm/arm/machdep.c
+++ b/sys/arm/arm/machdep.c
@@ -97,6 +97,7 @@ __FBSDID("$FreeBSD$");
 #include <machine/md_var.h>
 #include <machine/metadata.h>
 #include <machine/pcb.h>
+#include <machine/physmem.h>
 #include <machine/reg.h>
 #include <machine/trap.h>
 #include <machine/undefined.h>
@@ -122,8 +123,6 @@ uint32_t cpu_reset_address = 0;
 int cold = 1;
 vm_offset_t vector_page;
 
-long realmem = 0;
-
 int (*_arm_memcpy)(void *, void *, int, int) = NULL;
 int (*_arm_bzero)(void *, int, int) = NULL;
 int _min_memcpy_size = 0;
@@ -144,9 +143,6 @@ extern vm_offset_t ksym_start, ksym_end;
 
 static struct pv_addr kernel_pt_table[KERNEL_PT_MAX];
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
-
 extern u_int data_abort_handler_address;
 extern u_int prefetch_abort_handler_address;
 extern u_int undefined_handler_address;
@@ -356,6 +352,7 @@ static void
 cpu_startup(void *dummy)
 {
 	struct pcb *pcb = thread0.td_pcb;
+	const unsigned int mbyte = 1024 * 1024;
 #ifdef ARM_TP_ADDRESS
 #ifndef ARM_CACHE_LOCK_ENABLE
 	vm_page_t m;
@@ -364,36 +361,21 @@ cpu_startup(void *dummy)
 
 	identify_arm_cpu();
 
-	printf("real memory  = %ju (%ju MB)\n", (uintmax_t)ptoa(physmem),
-	    (uintmax_t)ptoa(physmem) / 1048576);
-	realmem = physmem;
+	vm_ksubmap_init(&kmi);
 
 	/*
 	 * Display the RAM layout.
 	 */
-	if (bootverbose) {
-		int indx;
-
-		printf("Physical memory chunk(s):\n");
-		for (indx = 0; phys_avail[indx + 1] != 0; indx += 2) {
-			vm_paddr_t size;
-
-			size = phys_avail[indx + 1] - phys_avail[indx];
-			printf("  0x%08jx - 0x%08jx, %ju KBytes (%ju pages)\n",
-			    (uintmax_t)phys_avail[indx],
-			    (uintmax_t)phys_avail[indx + 1] - 1,
-			    (uintmax_t)size / 1024, (uintmax_t)size / PAGE_SIZE);
-		}
-	}
-
-	vm_ksubmap_init(&kmi);
-
+	printf("real memory  = %ju (%ju MB)\n", 
+	    (uintmax_t)arm32_ptob(realmem),
+	    (uintmax_t)arm32_ptob(realmem) / mbyte);
 	printf("avail memory = %ju (%ju MB)\n",
-	    (uintmax_t)ptoa(cnt.v_free_count),
-	    (uintmax_t)ptoa(cnt.v_free_count) / 1048576);
-
-	if (bootverbose)
+	    (uintmax_t)arm32_ptob(cnt.v_free_count),
+	    (uintmax_t)arm32_ptob(cnt.v_free_count) / mbyte);
+	if (bootverbose) {
+		arm_physmem_print_tables();
 		arm_devmap_print_table();
+	}
 
 	bufinit();
 	vm_pager_bufferinit();
@@ -780,44 +762,6 @@ makectx(struct trapframe *tf, struct pcb *pcb)
 }
 
 /*
- * Make a standard dump_avail array.  Can't make the phys_avail
- * since we need to do that after we call pmap_bootstrap, but this
- * is needed before pmap_boostrap.
- */
-void
-arm_dump_avail_init(vm_paddr_t physaddr, vm_offset_t ramsize, size_t max)
-{
-#ifdef LINUX_BOOT_ABI
-	/*
-	 * Linux boot loader passes us the actual banks of memory, so use them
-	 * to construct the dump_avail array.
-	 */
-	if (membanks > 0) 
-	{
-		int i, j;
-
-		if (max < (membanks + 1) * 2)
-			panic("dump_avail[%d] too small for %d banks\n",
-			    max, membanks);
-		for (j = 0, i = 0; i < membanks; i++) {
-			dump_avail[j++] = round_page(memstart[i]);
-			dump_avail[j++] = trunc_page(memstart[i] + memsize[i]);
-		}
-		dump_avail[j++] = 0;
-		dump_avail[j++] = 0;
-		return;
-	}
-#endif
-	if (max < 4)
-		panic("dump_avail too small\n");
-
-	dump_avail[0] = round_page(physaddr);
-	dump_avail[1] = trunc_page(physaddr + ramsize);
-	dump_avail[2] = 0;
-	dump_avail[3] = 0;
-}
-
-/*
  * Fake up a boot descriptor table
  */
 vm_offset_t
@@ -910,11 +854,8 @@ linux_parse_boot_param(struct arm_boot_params *abp)
 		case ATAG_CORE:
 			break;
 		case ATAG_MEM:
-			if (membanks < LBABI_MAX_BANKS) {
-				memstart[membanks] = walker->u.tag_mem.start;
-				memsize[membanks] = walker->u.tag_mem.size;
-			}
-			membanks++;
+			arm_physmem_hardware_region(walker->u.tag_mem.start,
+			    walker->u.tag_mem.size);
 			break;
 		case ATAG_INITRD2:
 			break;
@@ -1077,120 +1018,10 @@ print_kenv(void)
 		debugf(" %x %s\n", (uint32_t)cp, cp);
 }
 
-static void
-physmap_init(struct mem_region *availmem_regions, int availmem_regions_sz,
-    vm_offset_t kernload)
-{
-	int i, j, cnt;
-	vm_offset_t phys_kernelend;
-	uint32_t s, e, sz;
-	struct mem_region *mp, *mp1;
-
-	phys_kernelend = kernload + (virtual_avail - KERNVIRTADDR);
-
-	/*
-	 * Remove kernel physical address range from avail
-	 * regions list. Page align all regions.
-	 * Non-page aligned memory isn't very interesting to us.
-	 * Also, sort the entries for ascending addresses.
-	 */
-	sz = 0;
-	cnt = availmem_regions_sz;
-	debugf("processing avail regions:\n");
-	for (mp = availmem_regions; mp->mr_size; mp++) {
-		s = mp->mr_start;
-		e = mp->mr_start + mp->mr_size;
-		debugf(" %08x-%08x -> ", s, e);
-		/* Check whether this region holds all of the kernel. */
-		if (s < kernload && e > phys_kernelend) {
-			availmem_regions[cnt].mr_start = phys_kernelend;
-			availmem_regions[cnt++].mr_size = e - phys_kernelend;
-			e = kernload;
-		}
-		/* Look whether this regions starts within the kernel. */
-		if (s >= kernload && s < phys_kernelend) {
-			if (e <= phys_kernelend)
-				goto empty;
-			s = phys_kernelend;
-		}
-		/* Now look whether this region ends within the kernel. */
-		if (e > kernload && e <= phys_kernelend) {
-			if (s >= kernload) {
-				goto empty;
-			}
-			e = kernload;
-		}
-		/* Now page align the start and size of the region. */
-		s = round_page(s);
-		e = trunc_page(e);
-		if (e < s)
-			e = s;
-		sz = e - s;
-		debugf("%08x-%08x = %x\n", s, e, sz);
-
-		/* Check whether some memory is left here. */
-		if (sz == 0) {
-		empty:
-			printf("skipping\n");
-			bcopy(mp + 1, mp,
-			    (cnt - (mp - availmem_regions)) * sizeof(*mp));
-			cnt--;
-			mp--;
-			continue;
-		}
-
-		/* Do an insertion sort. */
-		for (mp1 = availmem_regions; mp1 < mp; mp1++)
-			if (s < mp1->mr_start)
-				break;
-		if (mp1 < mp) {
-			bcopy(mp1, mp1 + 1, (char *)mp - (char *)mp1);
-			mp1->mr_start = s;
-			mp1->mr_size = sz;
-		} else {
-			mp->mr_start = s;
-			mp->mr_size = sz;
-		}
-	}
-	availmem_regions_sz = cnt;
-
-	/* Fill in phys_avail table, based on availmem_regions */
-	debugf("fill in phys_avail:\n");
-	for (i = 0, j = 0; i < availmem_regions_sz; i++, j += 2) {
-
-		debugf(" region: 0x%08x - 0x%08x (0x%08x)\n",
-		    availmem_regions[i].mr_start,
-		    availmem_regions[i].mr_start + availmem_regions[i].mr_size,
-		    availmem_regions[i].mr_size);
-
-		/*
-		 * We should not map the page at PA 0x0000000, the VM can't
-		 * handle it, as pmap_extract() == 0 means failure.
-		 */
-		if (availmem_regions[i].mr_start > 0 ||
-		    availmem_regions[i].mr_size > PAGE_SIZE) {
-			vm_size_t size;
-			phys_avail[j] = availmem_regions[i].mr_start;
-
-			size = availmem_regions[i].mr_size;
-			if (phys_avail[j] == 0) {
-				phys_avail[j] += PAGE_SIZE;
-				size -= PAGE_SIZE;
-			}
-			phys_avail[j + 1] = availmem_regions[i].mr_start + size;
-		} else
-			j -= 2;
-	}
-	phys_avail[j] = 0;
-	phys_avail[j + 1] = 0;
-}
-
 void *
 initarm(struct arm_boot_params *abp)
 {
-	struct mem_region memory_regions[FDT_MEM_REGIONS];
-	struct mem_region availmem_regions[FDT_MEM_REGIONS];
-	struct mem_region reserved_regions[FDT_MEM_REGIONS];
+	struct mem_region mem_regions[FDT_MEM_REGIONS];
 	struct pv_addr kernel_l1pt;
 	struct pv_addr dpcpu;
 	vm_offset_t dtbp, freemempos, l2_start, lastaddr;
@@ -1198,13 +1029,7 @@ initarm(struct arm_boot_params *abp)
 	char *env;
 	void *kmdp;
 	u_int l1pagetable;
-	int i = 0, j = 0, err_devmap = 0;
-	int memory_regions_sz;
-	int availmem_regions_sz;
-	int reserved_regions_sz;
-	vm_offset_t start, end;
-	vm_offset_t rstart, rend;
-	int curr;
+	int i, j, err_devmap, mem_regions_sz;
 
 	lastaddr = parse_boot_param(abp);
 	memsize = 0;
@@ -1235,72 +1060,14 @@ initarm(struct arm_boot_params *abp)
 		while (1);
 
 	/* Grab physical memory regions information from device tree. */
-	if (fdt_get_mem_regions(memory_regions, &memory_regions_sz,
-	    &memsize) != 0)
-		while(1);
-
-	/* Grab physical memory regions information from device tree. */
-	if (fdt_get_reserved_regions(reserved_regions, &reserved_regions_sz) != 0)
-		reserved_regions_sz = 0;
-		
-	/*
-	 * Now exclude all the reserved regions
-	 */
-	curr = 0;
-	for (i = 0; i < memory_regions_sz; i++) {
-		start = memory_regions[i].mr_start;
-		end = start + memory_regions[i].mr_size;
-		for (j = 0; j < reserved_regions_sz; j++) {
-			rstart = reserved_regions[j].mr_start;
-			rend = rstart + reserved_regions[j].mr_size;
-			/* 
-			 * Restricted region is before available
-			 * Skip restricted region
-			 */
-			if (rend <= start)
-				continue;
-			/* 
-			 * Restricted region is behind available
-			 * No  further processing required
-			 */
-			if (rstart >= end)
-				break;
-			/*
-			 * Restricted region includes memory region
-			 * skip available region
-			 */
-			if ((start >= rstart) && (rend >= end)) {
-				start = rend;
-				end = rend;
-				break;
-			}
-			/*
-			 * Memory region includes restricted region
-			 */
-			if ((rstart > start) && (end > rend)) {
-				availmem_regions[curr].mr_start = start;
-				availmem_regions[curr++].mr_size = rstart - start;
-				start = rend;
-				break;
-			}
-			/*
-			 * Memory region partially overlaps with restricted
-			 */
-			if ((rstart >= start) && (rstart <= end)) {
-				end = rstart;
-			}
-			else if ((rend >= start) && (rend <= end)) {
-				start = rend;
-			}
-		}
+	if (fdt_get_mem_regions(mem_regions, &mem_regions_sz, &memsize) != 0)
+		panic("Cannot get physical memory regions");
+	arm_physmem_hardware_regions(mem_regions, mem_regions_sz);
 
-		if (end > start) {
-			availmem_regions[curr].mr_start = start;
-			availmem_regions[curr++].mr_size = end - start;
-		}
-	}
-
-	availmem_regions_sz = curr;
+	/* Grab reserved memory regions information from device tree. */
+	if (fdt_get_reserved_regions(mem_regions, &mem_regions_sz) == 0)
+		arm_physmem_exclude_regions(mem_regions, mem_regions_sz, 
+		    EXFLAG_NODUMP | EXFLAG_NOALLOC);
 
 	/* Platform-specific initialisation */
 	initarm_early_init();
@@ -1339,7 +1106,7 @@ initarm(struct arm_boot_params *abp)
 		freemempos += PAGE_SIZE;
 	valloc_pages(kernel_l1pt, L1_TABLE_SIZE / PAGE_SIZE);
 
-	for (i = 0; i < l2size; ++i) {
+	for (i = 0, j = 0; i < l2size; ++i) {
 		if (!(i % (PAGE_SIZE / L2_TABLE_SIZE_REAL))) {
 			valloc_pages(kernel_pt_table[i],
 			    L2_TABLE_SIZE / PAGE_SIZE);
@@ -1498,17 +1265,22 @@ initarm(struct arm_boot_params *abp)
 
 	arm_intrnames_init();
 	arm_vector_init(ARM_VECTORS_HIGH, ARM_VEC_ALL);
-	arm_dump_avail_init(abp->abp_physaddr, memsize,
-	    sizeof(dump_avail) / sizeof(dump_avail[0]));
 	pmap_bootstrap(freemempos, &kernel_l1pt);
 	msgbufp = (void *)msgbufpv.pv_va;
 	msgbufinit(msgbufp, msgbufsize);
 	mutex_init();
 
 	/*
-	 * Prepare map of physical memory regions available to vm subsystem.
+	 * Exclude the kernel (and all the things we allocated which immediately
+	 * follow the kernel) from the VM allocation pool but not from crash
+	 * dumps.  virtual_avail is a global variable which tracks the kva we've
+	 * "allocated" while setting up pmaps.
+	 *
+	 * Prepare the list of physical memory available to the vm subsystem.
 	 */
-	physmap_init(availmem_regions, availmem_regions_sz, abp->abp_physaddr);
+	arm_physmem_exclude_region(abp->abp_physaddr, 
+	    (virtual_avail - KERNVIRTADDR), EXFLAG_NOALLOC);
+	arm_physmem_init_kernel_globals();
 
 	init_param2(physmem);
 	kdb_init();
diff --git a/sys/arm/arm/physmem.c b/sys/arm/arm/physmem.c
new file mode 100644
index 0000000..db322fa
--- /dev/null
+++ b/sys/arm/arm/physmem.c
@@ -0,0 +1,314 @@
+/*-
+ * Copyright (c) 2014 Ian Lepore <ian@freebsd.org>
+ * All rights excluded.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_ddb.h"
+
+/*
+ * Routines for describing and initializing anything related to physical memory.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <vm/vm.h>
+#include <machine/physmem.h>
+
+/*
+ * These structures are used internally to keep track of regions of physical
+ * ram, and regions within the physical ram that need to be excluded.  An
+ * exclusion region can be excluded from crash dumps, from the vm pool of pages
+ * that can be allocated, or both, depending on the exclusion flags associated
+ * with the region.
+ */
+#define	MAX_HWCNT	10
+#define	MAX_EXCNT	10
+
+struct region {
+	vm_offset_t	addr;
+	vm_size_t	size;
+	uint32_t	flags;
+};
+
+static struct region hwregions[MAX_HWCNT];
+static struct region exregions[MAX_EXCNT];
+
+static size_t hwcnt;
+static size_t excnt;
+
+/*
+ * These "avail lists" are globals used to communicate physical memory layout to 
+ * other parts of the kernel.  Within the arrays, each value is the starting
+ * address of a contiguous area of physical address space.  The values at even
+ * indexes are areas that contain usable memory and the values at odd indexes
+ * are areas that aren't usable.  Each list is terminated by a pair of zero
+ * entries.
+ *
+ * dump_avail tells the dump code what regions to include in a crash dump, and
+ * phys_avail is the way we hand all the remaining physical ram we haven't used
+ * in early kernel init over to the vm system for allocation management.
+ *
+ * We size these arrays to hold twice as many available regions as we allow for
+ * hardware memory regions, to allow for the fact that exclusions can split a
+ * hardware region into two or more available regions.  In the real world there
+ * will typically be one or two hardware regions and two or three exclusions.
+ *
+ * Each available region in this list occupies two array slots (the start of the
+ * available region and the start of the unavailable region that follows it).
+ */
+#define	MAX_AVAIL_REGIONS	(MAX_HWCNT * 2)
+#define	MAX_AVAIL_ENTRIES	(MAX_AVAIL_REGIONS * 2)
+
+vm_paddr_t phys_avail[MAX_AVAIL_ENTRIES + 2]; /* +2 to allow for a pair  */
+vm_paddr_t dump_avail[MAX_AVAIL_ENTRIES + 2]; /* of zeroes to terminate. */
+
+/* This is the total number of hardware pages, excluded or not. */
+long realmem;
+
+/*
+ * Print the contents of the physical and excluded region tables using the
+ * provided printf-like output function (which will be either printf or
+ * db_printf).
+ */
+static void
+physmem_dump_tables(int (*prfunc)(const char *, ...))
+{
+	int flags, i;
+	uintmax_t addr, size;
+	const unsigned int mbyte = 1024 * 1024;
+
+	prfunc("Physical memory chunk(s):\n");
+	for (i = 0; i < hwcnt; ++i) {
+		addr = hwregions[i].addr;
+		size = hwregions[i].size;
+		prfunc("  0x%08jx - 0x%08jx, %5ju MB (%7ju pages)\n", addr,
+		    addr + size - 1, size / mbyte, size / PAGE_SIZE);
+	}
+
+	prfunc("Excluded memory regions:\n");
+	for (i = 0; i < excnt; ++i) {
+		addr  = exregions[i].addr;
+		size  = exregions[i].size;
+		flags = exregions[i].flags;
+		prfunc("  0x%08jx - 0x%08jx, %5ju MB (%7ju pages) %s %s\n",
+		    addr, addr + size - 1, size / mbyte, size / PAGE_SIZE,
+		    (flags & EXFLAG_NOALLOC) ? "NoAlloc" : "",
+		    (flags & EXFLAG_NODUMP)  ? "NoDump" : "");
+	}
+}
+
+/*
+ * Print the contents of the static mapping table.  Used for bootverbose.
+ */
+void
+arm_physmem_print_tables()
+{
+
+	physmem_dump_tables(printf);
+}
+
+/*
+ * Walk the list of hardware regions, processing it against the list of
+ * exclusions that contain the given exflags, and generating an "avail list".
+ *
+ * Updates the kernel global 'realmem' with the sum of all pages in hw regions.
+ *
+ * Returns the number of pages of non-excluded memory added to the avail list.
+ */
+static long
+regions_to_avail(vm_paddr_t *avail, uint32_t exflags)
+{
+	size_t acnt, exi, hwi;
+	vm_paddr_t end, start, xend, xstart;
+	long availmem;
+	const struct region *exp, *hwp;
+
+	realmem = 0;
+	availmem = 0;
+	acnt = 0;
+	for (hwi = 0, hwp = hwregions; hwi < hwcnt; ++hwi, ++hwp) {
+		start = hwp->addr;
+		end   = hwp->size + start;
+		realmem += arm32_btop(end - start);
+		for (exi = 0, exp = exregions; exi < excnt; ++exi, ++exp) {
+			xstart = exp->addr;
+			xend   = exp->size + xstart;
+			/*
+			 * If the excluded region ends before this hw region,
+			 * continue checking with the next excluded region.
+			 */
+			if (xend <= start)
+				continue;
+			/*
+			 * If the excluded region begins after this hw region
+			 * we're done because both lists are sorted.
+			 */
+			if (xstart >= end)
+				break;
+			/*
+			 * If the excluded region completely covers this hw
+			 * region, shrink this hw region to zero size.
+			 */
+			if ((start >= xstart) && (end <= xend)) {
+				start = xend;
+				end = xend;
+				break;
+			}
+			/*
+			 * If the excluded region falls wholly within this hw
+			 * region without abutting or overlapping the beginning
+			 * or end, create an available entry from the leading
+			 * fragment, then adjust the start of this hw region to
+			 * the end of the excluded region, and continue checking
+			 * the next excluded region because another exclusion
+			 * could affect the remainder of this hw region.
+			 */
+			if ((xstart > start) && (xend < end)) {
+				avail[acnt++] = start;
+				avail[acnt++] = xstart;
+				availmem += arm32_btop(xstart - start);
+				start = xend;
+				continue;
+			}
+			/*
+			 * If excluded region partially overlaps this region,
+			 * trim the excluded portion off the appropriate end.
+			 */
+			if ((xstart >= start) && (xstart <= end)) {
+				end = xstart;
+			} else if ((xend >= start) && (xend <= end)) {
+				start = xend;
+			}
+		}
+		/*
+		 * If the trimming actions above left a non-zero size, create an
+		 * available entry for it.
+		 */
+		if (end > start) {
+			avail[acnt++] = start;
+			avail[acnt++] = end;
+			availmem += arm32_btop(end - start);
+		}
+		if (acnt >= MAX_AVAIL_ENTRIES)
+			panic("Not enough space in the dump/phys_avail arrays");
+	}
+
+	return (availmem);
+}
+
+/*
+ * Insertion-sort a new entry into a regions list; sorted by start address.
+ */
+static void
+insert_region(struct region *regions, size_t rcnt, vm_offset_t addr,
+    vm_size_t size, uint32_t flags)
+{
+	size_t i;
+	struct region *ep, *rp;
+
+	ep = regions + rcnt;
+	for (i = 0, rp = regions; i < rcnt; ++i, ++rp) {
+		if (addr < rp->addr) {
+			bcopy(rp, rp + 1, (ep - rp) * sizeof(*rp));
+			break;
+		}
+	}
+	rp->addr  = addr;
+	rp->size  = size;
+	rp->flags = flags;
+}
+
+/*
+ * Add a hardware memory region.
+ */
+void
+arm_physmem_hardware_region(vm_offset_t pa, vm_size_t sz)
+{
+	vm_offset_t adj;
+
+	/*
+	 * Filter out the page at PA 0x00000000.  The VM can't handle it, as
+	 * pmap_extract() == 0 means failure.
+	 */
+	if (pa == 0) {
+		pa  = PAGE_SIZE;
+		sz -= PAGE_SIZE;
+	}
+
+	/*
+	 * Round the starting address up to a page boundary, and truncate the
+	 * ending page down to a page boundary.
+	 */
+	adj = round_page(pa) - pa;
+	pa  = round_page(pa);
+	sz  = trunc_page(sz - adj);
+
+	if (hwcnt < nitems(hwregions))
+		insert_region(hwregions, hwcnt++, pa, sz, 0);
+}
+
+/*
+ * Add an exclusion region.
+ */
+void arm_physmem_exclude_region(vm_offset_t pa, vm_size_t sz, uint32_t exflags)
+{
+	vm_offset_t adj;
+
+	/*
+	 * Truncate the starting address down to a page boundary, and round the
+	 * ending page up to a page boundary.
+	 */
+	adj = pa - trunc_page(pa);
+	pa  = trunc_page(pa);
+	sz  = round_page(sz + adj);
+
+	if (excnt < nitems(exregions))
+		insert_region(exregions, excnt++, pa, sz, exflags);
+}
+
+/*
+ * Process all the regions added earlier into the global avail lists.
+ */
+void
+arm_physmem_init_kernel_globals(void)
+{
+
+	regions_to_avail(dump_avail, EXFLAG_NODUMP);
+	physmem = regions_to_avail(phys_avail, EXFLAG_NOALLOC);
+}
+
+#ifdef DDB
+#include <ddb/ddb.h>
+
+DB_SHOW_COMMAND(physmem, db_show_physmem)
+{
+
+	physmem_dump_tables(db_printf);
+}
+
+#endif /* DDB */
+
diff --git a/sys/arm/at91/at91_machdep.c b/sys/arm/at91/at91_machdep.c
index 9e73d0c..d9d26d8 100644
--- a/sys/arm/at91/at91_machdep.c
+++ b/sys/arm/at91/at91_machdep.c
@@ -68,6 +68,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/exec.h>
 #include <sys/kdb.h>
 #include <sys/msgbuf.h>
+#include <machine/physmem.h>
 #include <machine/reg.h>
 #include <machine/cpu.h>
 #include <machine/board.h>
@@ -199,9 +200,6 @@ const struct arm_devmap_entry at91_devmap[] = {
 
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
-
 struct pv_addr systempage;
 struct pv_addr msgbufpv;
 struct pv_addr irqstack;
@@ -630,8 +628,6 @@ initarm(struct arm_boot_params *abp)
 	arm_vector_init(ARM_VECTORS_HIGH, ARM_VEC_ALL);
 
 	pmap_curmaxkvaddr = afterkern + L1_S_SIZE * (KERNEL_PT_KERN_NUM - 1);
-	arm_dump_avail_init(abp->abp_physaddr, memsize,
-	    sizeof(dump_avail)/sizeof(dump_avail[0]));
 	/* Always use the 256MB of KVA we have available between the kernel and devices */
 	vm_max_kernel_address = KERNVIRTADDR + (256 << 20);
 	pmap_bootstrap(freemempos, &kernel_l1pt);
@@ -639,15 +635,21 @@ initarm(struct arm_boot_params *abp)
 	msgbufinit(msgbufp, msgbufsize);
 	mutex_init();
 
-	i = 0;
-#if PHYSADDR != KERNPHYSADDR
-	phys_avail[i++] = PHYSADDR;
-	phys_avail[i++] = KERNPHYSADDR;
-#endif
-	phys_avail[i++] = virtual_avail - KERNVIRTADDR + KERNPHYSADDR;
-	phys_avail[i++] = PHYSADDR + memsize;
-	phys_avail[i++] = 0;
-	phys_avail[i++] = 0;
+	/*
+	 * Add the physical ram we have available.
+	 *
+	 * Exclude the kernel, and all the things we allocated which immediately
+	 * follow the kernel, from the VM allocation pool but not from crash
+	 * dumps.  virtual_avail is a global variable which tracks the kva we've
+	 * "allocated" while setting up pmaps.
+	 *
+	 * Prepare the list of physical memory available to the vm subsystem.
+	 */
+	arm_physmem_hardware_region(PHYSADDR, memsize);
+	arm_physmem_exclude_region(abp->abp_physaddr, 
+	    virtual_avail - KERNVIRTADDR, EXFLAG_NOALLOC);
+	arm_physmem_init_kernel_globals();
+
 	init_param2(physmem);
 	kdb_init();
 	return ((void *)(kernelstack.pv_va + USPACE_SVC_STACK_TOP -
diff --git a/sys/arm/econa/econa_machdep.c b/sys/arm/econa/econa_machdep.c
index 8f41494..d2b97b6 100644
--- a/sys/arm/econa/econa_machdep.c
+++ b/sys/arm/econa/econa_machdep.c
@@ -60,6 +60,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/exec.h>
 #include <sys/kdb.h>
 #include <sys/msgbuf.h>
+#include <machine/physmem.h>
 #include <machine/reg.h>
 #include <machine/cpu.h>
 
@@ -98,9 +99,6 @@ struct pv_addr kernel_pt_table[NUM_KERNEL_PTS];
 
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
-
 struct pv_addr systempage;
 struct pv_addr msgbufpv;
 struct pv_addr irqstack;
@@ -284,7 +282,6 @@ initarm(struct arm_boot_params *abp)
 	cninit();
 	mem_info = ((*ddr) >> 4) & 0x3;
 	memsize = (8<<mem_info)*1024*1024;
-	physmem = memsize / PAGE_SIZE;
 
 	/*
 	 * Pages were allocated during the secondary bootstrap for the
@@ -322,8 +319,6 @@ initarm(struct arm_boot_params *abp)
 	arm_vector_init(ARM_VECTORS_HIGH, ARM_VEC_ALL);
 
 	pmap_curmaxkvaddr = afterkern + L1_S_SIZE * (KERNEL_PT_KERN_NUM - 1);
-	arm_dump_avail_init(abp->abp_physaddr, memsize,
-	    sizeof(dump_avail) / sizeof(dump_avail[0]));
 	vm_max_kernel_address = KERNVIRTADDR + 3 * memsize;
 	pmap_bootstrap(freemempos, &kernel_l1pt);
 
@@ -332,16 +327,21 @@ initarm(struct arm_boot_params *abp)
 
 	mutex_init();
 
-	i = 0;
-#if PHYSADDR != KERNPHYSADDR
-	phys_avail[i++] = PHYSADDR;
-	phys_avail[i++] = KERNPHYSADDR;
-#endif
-	phys_avail[i++] = virtual_avail - KERNVIRTADDR + KERNPHYSADDR;
+	/*
+	 * Add the physical ram we have available.
+	 *
+	 * Exclude the kernel, and all the things we allocated which immediately
+	 * follow the kernel, from the VM allocation pool but not from crash
+	 * dumps.  virtual_avail is a global variable which tracks the kva we've
+	 * "allocated" while setting up pmaps.
+	 *
+	 * Prepare the list of physical memory available to the vm subsystem.
+	 */
+	arm_physmem_hardware_region(PHYSADDR, memsize);
+	arm_physmem_exclude_region(abp->abp_physaddr, 
+	    virtual_avail - KERNVIRTADDR, EXFLAG_NOALLOC);
+	arm_physmem_init_kernel_globals();
 
-	phys_avail[i++] = PHYSADDR + memsize;
-	phys_avail[i++] = 0;
-	phys_avail[i++] = 0;
 	init_param2(physmem);
 	kdb_init();
 
diff --git a/sys/arm/include/machdep.h b/sys/arm/include/machdep.h
index 0a55849..c37f386 100644
--- a/sys/arm/include/machdep.h
+++ b/sys/arm/include/machdep.h
@@ -71,7 +71,4 @@ void initarm_late_init(void);
 void board_set_serial(uint64_t);
 void board_set_revision(uint32_t);
 
-/* Setup standard arrays */
-void arm_dump_avail_init(vm_paddr_t, vm_offset_t, size_t);
-
 #endif /* !_MACHINE_MACHDEP_H_ */
diff --git a/sys/arm/include/physmem.h b/sys/arm/include/physmem.h
new file mode 100644
index 0000000..1779d28
--- /dev/null
+++ b/sys/arm/include/physmem.h
@@ -0,0 +1,86 @@
+/*-
+ * Copyright (c) 2014 Ian Lepore <ian@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef	_MACHINE_PHYSMEM_H_
+#define	_MACHINE_PHYSMEM_H_
+
+/*
+ * Routines to help configure physical ram.
+ *
+ * Multiple regions of contiguous physical ram can be added (in any order).
+ *
+ * Multiple regions of physical ram that should be excluded from crash dumps, or
+ * memory allocation, or both, can be added (in any order).
+ *
+ * After all early kernel init is done and it's time to configure all
+ * remainining non-excluded physical ram for use by other parts of the kernel,
+ * arm_physmem_init_kernel_globals() processes the hardware regions and
+ * exclusion regions to generate the global dump_avail and phys_avail arrays
+ * that communicate physical ram configuration to other parts of the kernel.
+ */
+
+#define	EXFLAG_NODUMP	0x01
+#define	EXFLAG_NOALLOC	0x02
+
+void arm_physmem_hardware_region(vm_offset_t pa, vm_size_t sz);
+void arm_physmem_exclude_region(vm_offset_t pa, vm_size_t sz, uint32_t flags);
+void arm_physmem_init_kernel_globals(void);
+void arm_physmem_print_tables(void);
+
+/*
+ * Convenience routines for FDT.
+ */
+
+#ifdef FDT
+
+#include <machine/ofw_machdep.h>
+
+inline void 
+arm_physmem_hardware_regions(struct mem_region * mrptr, int mrcount)
+{
+	while (mrcount--) {
+		arm_physmem_hardware_region(mrptr->mr_start, mrptr->mr_size);
+		++mrptr;
+	}
+}
+
+inline void
+arm_physmem_exclude_regions(struct mem_region * mrptr, int mrcount, 
+    uint32_t exflags)
+{
+	while (mrcount--) {
+		arm_physmem_exclude_region(mrptr->mr_start, mrptr->mr_size, 
+		    exflags);
+		++mrptr;
+	}
+}
+
+#endif /* FDT */
+
+#endif
+
diff --git a/sys/arm/s3c2xx0/s3c24x0_machdep.c b/sys/arm/s3c2xx0/s3c24x0_machdep.c
index 84776e8..b306355 100644
--- a/sys/arm/s3c2xx0/s3c24x0_machdep.c
+++ b/sys/arm/s3c2xx0/s3c24x0_machdep.c
@@ -70,6 +70,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/exec.h>
 #include <sys/kdb.h>
 #include <sys/msgbuf.h>
+#include <machine/physmem.h>
 #include <machine/reg.h>
 #include <machine/cpu.h>
 
@@ -113,9 +114,6 @@ struct pv_addr kernel_pt_table[NUM_KERNEL_PTS];
 
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
-
 struct pv_addr systempage;
 struct pv_addr msgbufpv;
 struct pv_addr irqstack;
@@ -384,20 +382,26 @@ initarm(struct arm_boot_params *abp)
 	arm_vector_init(ARM_VECTORS_HIGH, ARM_VEC_ALL);
 
 	pmap_curmaxkvaddr = afterkern + 0x100000 * (KERNEL_PT_KERN_NUM - 1);
-	arm_dump_avail_init(abp->abp_physaddr, memsize,
-	    sizeof(dump_avail) / sizeof(dump_avail[0]));
 	vm_max_kernel_address = KERNVIRTADDR + 3 * memsize;
 	pmap_bootstrap(freemempos, &kernel_l1pt);
 	msgbufp = (void*)msgbufpv.pv_va;
 	msgbufinit(msgbufp, msgbufsize);
 	mutex_init();
 
-	physmem = memsize / PAGE_SIZE;
-
-	phys_avail[0] = virtual_avail - KERNVIRTADDR + KERNPHYSADDR;
-	phys_avail[1] = PHYSADDR + memsize;
-	phys_avail[2] = 0;
-	phys_avail[3] = 0;
+	/*
+	 * Add the physical ram we have available.
+	 *
+	 * Exclude the kernel, and all the things we allocated which immediately
+	 * follow the kernel, from the VM allocation pool but not from crash
+	 * dumps.  virtual_avail is a global variable which tracks the kva we've
+	 * "allocated" while setting up pmaps.
+	 *
+	 * Prepare the list of physical memory available to the vm subsystem.
+	 */
+	arm_physmem_hardware_region(PHYSADDR, memsize);
+	arm_physmem_exclude_region(abp->abp_physaddr, 
+	    virtual_avail - KERNVIRTADDR, EXFLAG_NOALLOC);
+	arm_physmem_init_kernel_globals();
 
 	init_param2(physmem);
 	kdb_init();
diff --git a/sys/arm/sa11x0/assabet_machdep.c b/sys/arm/sa11x0/assabet_machdep.c
index 56b0f30..220db17 100644
--- a/sys/arm/sa11x0/assabet_machdep.c
+++ b/sys/arm/sa11x0/assabet_machdep.c
@@ -122,8 +122,6 @@ extern vm_offset_t sa1_cache_clean_addr;
 #endif
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
 vm_paddr_t physical_start;
 vm_paddr_t physical_end;
 vm_paddr_t physical_freestart;
diff --git a/sys/arm/xscale/i80321/ep80219_machdep.c b/sys/arm/xscale/i80321/ep80219_machdep.c
index 44610ea..cf2e35e 100644
--- a/sys/arm/xscale/i80321/ep80219_machdep.c
+++ b/sys/arm/xscale/i80321/ep80219_machdep.c
@@ -110,9 +110,6 @@ struct pv_addr kernel_pt_table[NUM_KERNEL_PTS];
 
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
-
 struct pv_addr systempage;
 struct pv_addr msgbufpv;
 struct pv_addr irqstack;
diff --git a/sys/arm/xscale/i80321/iq31244_machdep.c b/sys/arm/xscale/i80321/iq31244_machdep.c
index d6b1b93..8b1de79 100644
--- a/sys/arm/xscale/i80321/iq31244_machdep.c
+++ b/sys/arm/xscale/i80321/iq31244_machdep.c
@@ -110,9 +110,6 @@ struct pv_addr kernel_pt_table[NUM_KERNEL_PTS];
 
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
-
 struct pv_addr systempage;
 struct pv_addr msgbufpv;
 struct pv_addr irqstack;
diff --git a/sys/arm/xscale/i8134x/crb_machdep.c b/sys/arm/xscale/i8134x/crb_machdep.c
index 29258d0..b411635 100644
--- a/sys/arm/xscale/i8134x/crb_machdep.c
+++ b/sys/arm/xscale/i8134x/crb_machdep.c
@@ -113,9 +113,6 @@ struct pv_addr kernel_pt_table[NUM_KERNEL_PTS];
 
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
-
 struct pv_addr systempage;
 struct pv_addr msgbufpv;
 struct pv_addr irqstack;
diff --git a/sys/arm/xscale/ixp425/avila_machdep.c b/sys/arm/xscale/ixp425/avila_machdep.c
index f95480a..7b63f92 100644
--- a/sys/arm/xscale/ixp425/avila_machdep.c
+++ b/sys/arm/xscale/ixp425/avila_machdep.c
@@ -70,6 +70,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/exec.h>
 #include <sys/kdb.h>
 #include <sys/msgbuf.h>
+#include <machine/physmem.h>
 #include <machine/reg.h>
 #include <machine/cpu.h>
 
@@ -114,9 +115,6 @@ struct pv_addr kernel_pt_table[NUM_KERNEL_PTS];
 
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[10];
-vm_paddr_t dump_avail[4];
-
 struct pv_addr systempage;
 struct pv_addr msgbufpv;
 struct pv_addr irqstack;
@@ -391,7 +389,6 @@ initarm(struct arm_boot_params *abp)
 		memsize = ixp435_ddram_size();
 	else
 		memsize = ixp425_sdram_size();
-	physmem = memsize / PAGE_SIZE;
 
 	/* Set stack for exception handlers */
 
@@ -405,19 +402,26 @@ initarm(struct arm_boot_params *abp)
 	arm_vector_init(ARM_VECTORS_HIGH, ARM_VEC_ALL);
 
 	pmap_curmaxkvaddr = afterkern + PAGE_SIZE;
-	arm_dump_avail_init(abp->abp_physaddr, memsize,
-	    sizeof(dump_avail) / sizeof(dump_avail[0]));
 	vm_max_kernel_address = 0xe0000000;
 	pmap_bootstrap(pmap_curmaxkvaddr, &kernel_l1pt);
 	msgbufp = (void*)msgbufpv.pv_va;
 	msgbufinit(msgbufp, msgbufsize);
 	mutex_init();
 
-	i = 0;
-	phys_avail[i++] = round_page(virtual_avail - KERNBASE + PHYSADDR);
-	phys_avail[i++] = trunc_page(PHYSADDR + memsize - 1);
-	phys_avail[i++] = 0;
-	phys_avail[i] = 0;
+	/*
+	 * Add the physical ram we have available.
+	 *
+	 * Exclude the kernel, and all the things we allocated which immediately
+	 * follow the kernel, from the VM allocation pool but not from crash
+	 * dumps.  virtual_avail is a global variable which tracks the kva we've
+	 * "allocated" while setting up pmaps.
+	 *
+	 * Prepare the list of physical memory available to the vm subsystem.
+	 */
+	arm_physmem_hardware_region(PHYSADDR, memsize);
+	arm_physmem_exclude_region(abp->abp_physaddr, 
+	    virtual_avail - KERNVIRTADDR, EXFLAG_NOALLOC);
+	arm_physmem_init_kernel_globals();
 
 	init_param2(physmem);
 	kdb_init();
diff --git a/sys/arm/xscale/pxa/pxa_machdep.c b/sys/arm/xscale/pxa/pxa_machdep.c
index 860dd7e..dfaccef 100644
--- a/sys/arm/xscale/pxa/pxa_machdep.c
+++ b/sys/arm/xscale/pxa/pxa_machdep.c
@@ -110,9 +110,6 @@ struct pv_addr kernel_pt_table[NUM_KERNEL_PTS];
 
 /* Physical and virtual addresses for some global pages */
 
-vm_paddr_t phys_avail[PXA2X0_SDRAM_BANKS * 2 + 4];
-vm_paddr_t dump_avail[PXA2X0_SDRAM_BANKS * 2 + 4];
-
 struct pv_addr systempage;
 struct pv_addr msgbufpv;
 struct pv_addr irqstack;
diff --git a/sys/conf/files.arm b/sys/conf/files.arm
index f2d0244..71478e3 100644
--- a/sys/conf/files.arm
+++ b/sys/conf/files.arm
@@ -33,6 +33,7 @@ arm/arm/mem.c			optional	mem
 arm/arm/minidump_machdep.c	optional	mem
 arm/arm/mp_machdep.c		optional	smp
 arm/arm/nexus.c			standard
+arm/arm/physmem.c		standard
 arm/arm/pl190.c			optional	pl190
 arm/arm/pl310.c			optional	pl310
 arm/arm/pmap.c			optional	cpu_arm9 | cpu_arm9e | cpu_fa526 | cpu_sa1100 | cpu_sa1110 | cpu_xscale_80219 | cpu_xscale_80321 | cpu_xscale_81342 | cpu_xscale_ixp425 | cpu_xscale_ixp435 | cpu_xscale_pxa2x0