Re: [Patch] PCI: check szhi when sz is 0 for 64 bit pref mem

[Yinghai Lu]

please check version with pci_size64.
[PATCH] PCI: check szhi when sz is 0 when 64 bit iomem bigger than 4G

	If the PCI device is 64-bit memory and has a size of 0xnnnnnnnn00000000 then
	pci_read_bases() will incorrectly assume that it has a size of zero.

	Cc: Myles Watson <myles@xxxxxxxxxxxxxxxxxxxxx>
	Signed-off-by: Yinghai Lu <yinghai.lu@xxxxxxx>
	Cc: Greg KH <greg@xxxxxxxxx>
	Signed-off-by: Andrew Morton <akpm@xxxxxxxx>

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index e159d66..0e2b10c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -144,6 +144,24 @@ static u32 pci_size(u32 base, u32 maxbas
 	return size;
 }
 
+static u64 pci_size64(u64 base, u64 maxbase, u64 mask)
+{
+	u64 size = mask & maxbase;	/* Find the significant bits */
+	if (!size)
+		return 0;
+
+	/* Get the lowest of them to find the decode size, and
+	   from that the extent.  */
+	size = (size & ~(size-1)) - 1;
+
+	/* base == maxbase can be valid only if the BAR has
+	   already been programmed with all 1s.  */
+	if (base == maxbase && ((base | size) & mask) != mask)
+		return 0;
+
+	return size;
+}
+
 static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
 {
 	unsigned int pos, reg, next;
@@ -151,6 +169,7 @@ static void pci_read_bases(struct pci_de
 	struct resource *res;
 
 	for(pos=0; pos<howmany; pos = next) {
+		u64 l64, sz64;
 		next = pos+1;
 		res = &dev->resource[pos];
 		res->name = pci_name(dev);
@@ -164,9 +183,15 @@ static void pci_read_bases(struct pci_de
 		if (l == 0xffffffff)
 			l = 0;
 		if ((l & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_MEMORY) {
+			sz64 = sz;
 			sz = pci_size(l, sz, (u32)PCI_BASE_ADDRESS_MEM_MASK);
-			if (!sz)
-				continue;
+			/* for 64bit pref, sz could be 0, if the real size is bigger than 4G,
+				so need to check szhi for it
+			 */
+			if ((l & (PCI_BASE_ADDRESS_SPACE | PCI_BASE_ADDRESS_MEM_TYPE_MASK))
+			    != (PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_64)) 
+				if (!sz)
+					continue;
 			res->start = l & PCI_BASE_ADDRESS_MEM_MASK;
 			res->flags |= l & ~PCI_BASE_ADDRESS_MEM_MASK;
 		} else {
@@ -185,17 +210,21 @@ static void pci_read_bases(struct pci_de
 			pci_write_config_dword(dev, reg+4, ~0);
 			pci_read_config_dword(dev, reg+4, &szhi);
 			pci_write_config_dword(dev, reg+4, lhi);
-			szhi = pci_size(lhi, szhi, 0xffffffff);
+			sz64 |= ((unsigned long) szhi) << 32;
+			l64 = (((unsigned long) lhi) << 32) | l;
+			sz64 = pci_size64(l64, sz64, PCI_BASE_ADDRESS_MEM_MASK);
 			next++;
 #if BITS_PER_LONG == 64
-			res->start |= ((unsigned long) lhi) << 32;
-			res->end = res->start + sz;
-			if (szhi) {
-				/* This BAR needs > 4GB?  Wow. */
-				res->end |= (unsigned long)szhi<<32;
+			if (!sz64) {
+				res->start = 0;
+				res->end = 0;
+				res->flags = 0;
+				continue;
 			}
+			res->start = l64 & PCI_BASE_ADDRESS_MEM_MASK;
+			res->end = res->start + sz64;
 #else
-			if (szhi) {
+			if (sz64>0x100000000ULL) {
 				printk(KERN_ERR "PCI: Unable to handle 64-bit BAR for device %s\n", pci_name(dev));
 				res->start = 0;
 				res->flags = 0;