[PATCH] ibmphp : read the length of ebda and map entire ebda region

[Chandru <chandru@in.ibm.com>]

ibmphp driver currently maps only 1KB of ebda memory area into kernel address 
space during driver initialization. This causes kernel oops when the driver is 
modprobe'd and it accesses memory area beyond 1KB within ebda segment. The first 
byte of ebda segment actually stores the length of the ebda region in 
Kilobytes. Hence make use of the length parameter and map the entire ebda 
region.


Signed-off-by: Chandru Siddalingappa <chandru@linux.vnet.ibm.com>
---

 drivers/pci/hotplug/ibmphp_ebda.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- linux-2.6.33-rc2/drivers/pci/hotplug/ibmphp_ebda.c.orig	2010-01-09 
15:23:54.000000000 +0530
+++ linux-2.6.33-rc2/drivers/pci/hotplug/ibmphp_ebda.c	2010-01-09 
17:01:06.000000000 +0530
@@ -245,7 +245,7 @@ static void __init print_ebda_hpc (void)
 
 int __init ibmphp_access_ebda (void)
 {
-	u8 format, num_ctlrs, rio_complete, hs_complete;
+	u8 format, num_ctlrs, rio_complete, hs_complete, ebda_sz;
 	u16 ebda_seg, num_entries, next_offset, offset, blk_id, sub_addr, re, rc_id, 
re_id, base;
 	int rc = 0;
 
@@ -260,7 +260,14 @@ int __init ibmphp_access_ebda (void)
 	iounmap (io_mem);
 	debug ("returned ebda segment: %x\n", ebda_seg);
 	
-	io_mem = ioremap(ebda_seg<<4, 1024);
+	io_mem = ioremap(ebda_seg<<4, 1);
+	ebda_sz = readb(io_mem);
+	iounmap(io_mem);
+	debug("ebda size: %d(KiB)\n", ebda_sz);
+	if (ebda_sz == 0)
+		return -ENOMEM;
+
+	io_mem = ioremap(ebda_seg<<4, (ebda_sz * 1024));
 	if (!io_mem )
 		return -ENOMEM;
 	next_offset = 0x180;