Fix boot dump on bigmem machines.

Allocate a bouncebuffer at boot time and bounce all pages over
0xffffffff through it.

``looks right but not tested'' miod@, ok krw (who watched me test it on
his monster laptop.

1 files changed, 64 insertions, 5 deletions

diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c
index 20c53cad618..6baafb47ed2 100644
--- a/sys/arch/amd64/amd64/machdep.c
+++ b/sys/arch/amd64/amd64/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.144 2011/06/26 22:39:59 deraadt Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.145 2011/07/03 20:22:07 oga Exp $	*/
 /*	$NetBSD: machdep.c,v 1.3 2003/05/07 22:58:18 fvdl Exp $	*/
 
 /*-
@@ -165,6 +165,11 @@ u_int64_t	dumpmem_high;
 extern int	boothowto;
 int	cpu_class;
 
+paddr_t	dumpmem_paddr;
+vaddr_t	dumpmem_vaddr;
+psize_t	dumpmem_sz;
+
+
 char	*ssym = NULL;
 vaddr_t kern_end;
 
@@ -790,6 +795,7 @@ cpu_dump(void)
 	kcore_seg_t *segp;
 	cpu_kcore_hdr_t *cpuhdrp;
 	phys_ram_seg_t *memsegp;
+	caddr_t va;
 	int i;
 
 	dump = bdevsw[major(dumpdev)].d_dump;
@@ -820,7 +826,17 @@ cpu_dump(void)
 		memsegp[i].size = mem_clusters[i].size & ~PAGE_MASK;
 	}
 
-	return (dump(dumpdev, dumplo, (caddr_t)buf, dbtob(1)));
+	/*
+	 * If we have dump memory then assume the kernel stack is in high
+	 * memory and bounce
+	 */
+	if (dumpmem_vaddr != 0) {
+		bcopy(buf, (char *)dumpmem_vaddr, sizeof(buf));
+		va = (caddr_t)dumpmem_vaddr;
+	} else {
+		va = (caddr_t)buf;
+	}
+	return (dump(dumpdev, dumplo, va, dbtob(1)));
 }
 
 /*
@@ -870,6 +886,7 @@ dumpsys(void)
 	u_long totalbytesleft, bytes, i, n, memseg;
 	u_long maddr;
 	daddr64_t blkno;
+	void *va;
 	int (*dump)(dev_t, daddr64_t, caddr_t, size_t);
 	int error;
 
@@ -925,9 +942,16 @@ dumpsys(void)
 			n = bytes - i;
 			if (n > BYTES_PER_DUMP)
 				n = BYTES_PER_DUMP;
+			if (maddr > 0xffffffff) {
+				va = (void *)dumpmem_vaddr;
+				if (n > dumpmem_sz)
+					n = dumpmem_sz;
+				bcopy((void *)PMAP_DIRECT_MAP(maddr), va, n);
+			} else {
+				va = (void *)PMAP_DIRECT_MAP(maddr);
+			}
 
-			error = (*dump)(dumpdev, blkno,
-			    (caddr_t)PMAP_DIRECT_MAP(maddr), n);
+			error = (*dump)(dumpdev, blkno, va, n);
 			if (error)
 				goto err;
 			maddr += n;
@@ -1414,6 +1438,42 @@ init_x86_64(paddr_t first_avail)
 	}
 
 	/*
+	 * Steal some memory for a dump bouncebuffer if we have memory over
+	 * the 32-bit barrier.
+	 */
+	if (avail_end > 0xffffffff) {
+		struct vm_physseg *vps = NULL;
+		psize_t sz = round_page(MAX(BYTES_PER_DUMP, dbtob(1)));
+
+		/* XXX assumes segments are ordered */
+		for (x = 0; x < vm_nphysseg; x++) {
+			vps = &vm_physmem[x];
+			/* Find something between 16meg and 4gig */
+			if (ptoa(vps->avail_end) <= 0xffffffff &&
+			    ptoa(vps->avail_start) >= 0xffffff)
+				break;
+		}
+		if (x == vm_nphysseg)
+			panic("init_x86_64: no memory between "
+			    "0xffffff-0xffffffff");
+
+		/* Shrink so it'll fit in the segment. */
+		if ((vps->avail_end - vps->avail_start) < atop(sz))
+			sz = ptoa(vps->avail_end - vps->avail_start);
+
+		vps->avail_end -= atop(sz);
+		vps->end -= atop(sz);
+		dumpmem_paddr = ptoa(vps->avail_end);
+		dumpmem_vaddr = PMAP_DIRECT_MAP(dumpmem_paddr);
+		dumpmem_sz = sz;
+
+		/* Remove the last segment if it now has no pages. */
+		if (vps->start == vps->end) {
+			for (vm_nphysseg--; x < vm_nphysseg; x++)
+				vm_physmem[x] = vm_physmem[x + 1];
+		}
+	}
+	/*
 	 * XXXfvdl todo: acpi wakeup code.
 	 */
 
@@ -1491,7 +1551,6 @@ init_x86_64(paddr_t first_avail)
 		kgdb_connect(1);
 	}
 #endif
-
 }
 
 #ifdef KGDB