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authorGrant Grundler <grundler@parisc-linux.org>2008-03-23 23:23:10 -0600
committerJeff Garzik <jeff@garzik.org>2008-03-28 21:52:14 -0400
commit209261c019f56d77f6a0cc38048e9a6f25867589 (patch)
tree36824a55e62c33e4ae4c24ce824d2948a83924de /drivers/net/tulip/eeprom.c
parent3480c63bdf008e9289aab94418f43b9592978fff (diff)
[netdrvr] tulip_read_eeprom fixes for BUG 4420
If "location" is > "addr_len" bits, the high bits of location would interfere with the READ_CMD sent to the eeprom controller. A patch was submitted to bug: http://bugzilla.kernel.org/show_bug.cgi?id=4420 which simply truncated the "location", read whatever was in "location modulo addr_len", and returned that value. That avoids confusing the eeprom but seems like the wrong solution to me. Correct would be to not read beyond "1 << addr_len" address of the eeprom. I am submitting two changes to implement this: 1) tulip_read_eeprom will return zero (since we can't return -EINVAL) if this is attempted (defensive programming). 2) In tulip_core.c, fix the tulip_read_eeprom caller so they don't iterate past addr_len bits and make sure the entire tp->eeprom[] array is cleared. I konw we don't strictly need both. I would prefer both in the tree since it documents the issue and provides a second "defense" from the bug from creeping back in. Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'drivers/net/tulip/eeprom.c')
-rw-r--r--drivers/net/tulip/eeprom.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/net/tulip/eeprom.c b/drivers/net/tulip/eeprom.c
index 206918bad53..da2206f6021 100644
--- a/drivers/net/tulip/eeprom.c
+++ b/drivers/net/tulip/eeprom.c
@@ -343,6 +343,12 @@ int __devinit tulip_read_eeprom(struct net_device *dev, int location, int addr_l
void __iomem *ee_addr = tp->base_addr + CSR9;
int read_cmd = location | (EE_READ_CMD << addr_len);
+ /* If location is past the end of what we can address, don't
+ * read some other location (ie truncate). Just return zero.
+ */
+ if (location > (1 << addr_len) - 1)
+ return 0;
+
iowrite32(EE_ENB & ~EE_CS, ee_addr);
iowrite32(EE_ENB, ee_addr);