Re: [PATCH] of: of_mdio: Fix some endianness problems.

From: Sergei Shtylyov
Date: Mon Nov 01 2010 - 07:45:53 EST


Hello.

On 31-10-2010 5:54, Grant Likely wrote:

In of_mdiobus_register(), the __be32 *addr variable is dereferenced.
This will not work on little-endian targets. Also since it is
unsigned, checking for less than zero is redundant.

Fix these two issues.

Signed-off-by: David Daney<ddaney@xxxxxxxxxxxxxxxxxx>
Cc: Grant Likely<grant.likely@xxxxxxxxxxxx>
Cc: Jeremy Kerr<jeremy.kerr@xxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt<benh@xxxxxxxxxxxxxxxxxxx>
Cc: Dan Carpenter<error27@xxxxxxxxx>
Cc: Greg Kroah-Hartman<gregkh@xxxxxxx>
---
drivers/of/of_mdio.c | 23 ++++++++++++++---------
1 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index 1fce00e..b370306 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -52,27 +52,32 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)

/* Loop over the child nodes and register a phy_device for each one */
for_each_child_of_node(np, child) {
- const __be32 *addr;
+ const __be32 *paddr;
+ u32 addr;
int len;

/* A PHY must have a reg property in the range [0-31] */
- addr = of_get_property(child, "reg",&len);
- if (!addr || len< sizeof(*addr) || *addr>= 32 || *addr< 0) {
+ paddr = of_get_property(child, "reg",&len);
+ if (!paddr || len< sizeof(*paddr)) {
+addr_err:
dev_err(&mdio->dev, "%s has invalid PHY address\n",
child->full_name);
continue;
}
+ addr = be32_to_cpup(paddr);
+ if (addr>= 32)
+ goto addr_err;

goto's are fine for jumping to the end of a function to unwind
allocations, but please don't use it in this manner. The original
structure will actually work just fine if you do it thusly:

if (!paddr || len< sizeof(*paddr) ||
*(addr = be32_to_cpup(paddr))>= 32) {
dev_err(&mdio->dev, "%s has invalid PHY address\n",
child->full_name);
continue;
}

Otherwise this patch looks good. After you've reworked and retested
I'll pick it up for 2.6.37 (or dave will).

Actually, I mistyped this. I think it should be:

if (!paddr || len< sizeof(*paddr) ||
(addr = be32_to_cpup(paddr))>= 32) {

This assignment would probably cause checkpatch.pl to complain...

WBR, Sergei
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