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SubjectRe: PCI: check szhi when sz is 0 when 64 bit iomem bigger than 4G
On Fri, 24 Nov 2006 10:46:00 -0800
"Yinghai Lu" <yinghai.lu@amd.com> wrote:

> On 11/23/06, Greg KH <greg@kroah.com> wrote:
> > On Mon, Nov 06, 2006 at 07:29:24PM -0800, Lu, Yinghai wrote:
> > > [PATCH] PCI: check szhi when sz is 0 when 64 bit iomem bigger than 4G
> > I'm dropping this patch, as the compiler warnings show that something is
> > still wrong here.
>
> Andrew,
>
> Can you send out that revised patch out to the list?
>

This is Greg's
gregkh-pci-pci-check-szhi-when-sz-is-0-when-64-bit-iomem-bigger-than-4g.patch
plus three fixes from myself as logged below:




From: Andrew Morton <akpm@osdl.org>

- Abstract masking code out to a separate function

- Various coding style cleanups

- Clean up comment

From: Andrew Morton <akpm@osdl.org>

drivers/pci/probe.c:222: warning: left shift count >= width of type
drivers/pci/probe.c:223: warning: left shift count >= width of type

From: Andrew Morton <akpm@osdl.org>

drivers/pci/probe.c:180: warning: 'sz64' may be used uninitialized in this function



Greg's
gregkh-pci-pci-check-szhi-when-sz-is-0-when-64-bit-iomem-bigger-than-4g.patch
can be replaced by this diff. But we still don't have a *complete*
description of what it all does.



drivers/pci/probe.c | 69 ++++++++++++++++++++++++++++++++++--------
1 file changed, 56 insertions(+), 13 deletions(-)
diff -puN drivers/pci/probe.c~gregkh-pci-pci-check-szhi-when-sz-is-0-when-64-bit-iomem-bigger-than-4g drivers/pci/probe.c
--- a/drivers/pci/probe.c~gregkh-pci-pci-check-szhi-when-sz-is-0-when-64-bit-iomem-bigger-than-4g
+++ a/drivers/pci/probe.c
@@ -144,6 +144,32 @@ 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 inline int is_64bit_memory(u32 mask)
+{
+ if ((mask & (PCI_BASE_ADDRESS_SPACE|PCI_BASE_ADDRESS_MEM_TYPE_MASK)) ==
+ (PCI_BASE_ADDRESS_SPACE_MEMORY|PCI_BASE_ADDRESS_MEM_TYPE_64))
+ return 1;
+ return 0;
+}
+
static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
{
unsigned int pos, reg, next;
@@ -151,6 +177,10 @@ static void pci_read_bases(struct pci_de
struct resource *res;

for(pos=0; pos<howmany; pos = next) {
+ u64 l64;
+ u64 sz64;
+ u32 raw_sz;
+
next = pos+1;
res = &dev->resource[pos];
res->name = pci_name(dev);
@@ -163,9 +193,16 @@ static void pci_read_bases(struct pci_de
continue;
if (l == 0xffffffff)
l = 0;
- if ((l & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_MEMORY) {
+ raw_sz = sz;
+ if ((l & PCI_BASE_ADDRESS_SPACE) ==
+ PCI_BASE_ADDRESS_SPACE_MEMORY) {
sz = pci_size(l, sz, (u32)PCI_BASE_ADDRESS_MEM_MASK);
- if (!sz)
+ /*
+ * For 64bit prefetchable memory sz could be 0, if the
+ * real size is bigger than 4G, so we need to check
+ * szhi for that.
+ */
+ if (!is_64bit_memory(l) && !sz)
continue;
res->start = l & PCI_BASE_ADDRESS_MEM_MASK;
res->flags |= l & ~PCI_BASE_ADDRESS_MEM_MASK;
@@ -178,30 +215,36 @@ static void pci_read_bases(struct pci_de
}
res->end = res->start + (unsigned long) sz;
res->flags |= pci_calc_resource_flags(l);
- if ((l & (PCI_BASE_ADDRESS_SPACE | PCI_BASE_ADDRESS_MEM_TYPE_MASK))
- == (PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_64)) {
+ if (is_64bit_memory(l)) {
u32 szhi, lhi;
+
pci_read_config_dword(dev, reg+4, &lhi);
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 = ((u64)szhi << 32) | raw_sz;
+ l64 = ((u64)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) {
- printk(KERN_ERR "PCI: Unable to handle 64-bit BAR for device %s\n", pci_name(dev));
+ 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;
} else if (lhi) {
/* 64-bit wide address, treat as disabled */
- pci_write_config_dword(dev, reg, l & ~(u32)PCI_BASE_ADDRESS_MEM_MASK);
+ pci_write_config_dword(dev, reg,
+ l & ~(u32)PCI_BASE_ADDRESS_MEM_MASK);
pci_write_config_dword(dev, reg+4, 0);
res->start = 0;
res->end = sz;
_
-
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