Unpopulated CRIME memory banks (or logically empty due to CRIME merging

contiguous 64MB DIMMs in a single 128MB one) are not reported as memory at
offset zero, but actually as duplicates of the first entry (which always
matches real memory).

If the DIMMs are set up in decreasing sizes, as recommanded by SGI, the
first entry will be configured at offset zero, so the existing code would
run fine.

If, however, you order your DIMMs in a different order, the first entry
might not be at offset zero, so the kernel will mess up its memory
information, which will cause random effects from simply misreported memory
sizes, to the inability to boot.

Fix this by strengthening the check for an empty bank.

Problem reported by Jason Bergstrom (bergie, bergie dot net), analysis
and fix by me.

1 files changed, 24 insertions, 12 deletions

diff --git a/sys/arch/sgi/sgi/ip32_machdep.c b/sys/arch/sgi/sgi/ip32_machdep.c
index 93a273b5645..e46587347d8 100644
--- a/sys/arch/sgi/sgi/ip32_machdep.c
+++ b/sys/arch/sgi/sgi/ip32_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip32_machdep.c,v 1.2 2008/04/24 12:29:34 jsing Exp $ */
+/*	$OpenBSD: ip32_machdep.c,v 1.3 2008/05/04 12:27:46 miod Exp $ */
 
 /*
  * Copyright (c) 2003-2004 Opsycon AB  (www.opsycon.se / www.opsycon.com)
@@ -59,26 +59,37 @@ crime_configure_memory(void)
 	volatile u_int64_t *bank_ctrl;
 	paddr_t addr;
 	psize_t size;
+	u_int64_t ctrl0, ctrl;
 	u_int32_t first_page, last_page;
 	int bank, i;
 
 	bank_ctrl = (void *)PHYS_TO_KSEG1(CRIMEBUS_BASE + CRIME_MEM_BANK0_CONTROL);
 	for (bank = 0; bank < CRIME_MAX_BANKS; bank++) {
-		addr = (bank_ctrl[bank] & CRIME_MEM_BANK_ADDR) << 25;
-		size = (bank_ctrl[bank] & CRIME_MEM_BANK_128MB) ? 128 : 32;
+		ctrl = bank_ctrl[bank];
+		addr = (ctrl & CRIME_MEM_BANK_ADDR) << 25;
+		size = (ctrl & CRIME_MEM_BANK_128MB) ? 128 : 32;
+
+		/*
+		 * Empty banks are reported as duplicates of bank #0.
+		 */
+		if (bank == 0)
+			ctrl0 = ctrl;
+		else if (ctrl == ctrl0)
+			continue;
+
 #ifdef DEBUG
-		bios_printf("crime: bank %d contains %ld MB at 0x%lx\n",
+		bios_printf("crime: bank %d contains %ld MB at %p\n",
 		    bank, size, addr);
 #endif
 
 		/*
-		 * Do not report memory regions below 256MB, since ARCBIOS will do.
-		 * Moreover, empty banks are reported at address zero.
+		 * Do not report memory regions below 256MB, since ARCBIOS
+		 * will do.
 		 */
 		if (addr < 256 * 1024 * 1024)
 			continue;
 
-		addr += 1024 * 1024 * 1024;
+		addr += CRIME_MEMORY_OFFSET;
 		size *= 1024 * 1024;
 		first_page = atop(addr);
 		last_page = atop(addr + size);
@@ -100,12 +111,13 @@ crime_configure_memory(void)
 				m->mem_last_page = last_page;
 			}
 		}
-		if (m != NULL && m->mem_last_page == 0) {
-			m->mem_first_page = first_page;
-			m->mem_last_page = last_page;
-		}
-		if (m != NULL)
+		if (m != NULL) {
+			if (m->mem_last_page == 0) {
+				m->mem_first_page = first_page;
+				m->mem_last_page = last_page;
+			}
 			physmem += atop(size);
+		}
 	}
 
 #ifdef DEBUG