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[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>
This commit is contained in:
Grant Grundler 2008-03-23 23:23:10 -06:00 committed by Jeff Garzik
parent 3480c63bdf
commit 209261c019
2 changed files with 12 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/net/tulip/eeprom.c
View File

@ -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);

7
drivers/net/tulip/tulip_core.c
View File

@ -1437,6 +1437,7 @@ static int __devinit tulip_init_one (struct pci_dev *pdev,
EEPROM.
*/
ee_data = tp->eeprom;
memset(ee_data, 0, sizeof(tp->eeprom));
sum = 0;
if (chip_idx == LC82C168) {
for (i = 0; i < 3; i++) {
@ -1458,8 +1459,12 @@ static int __devinit tulip_init_one (struct pci_dev *pdev,
/* A serial EEPROM interface, we read now and sort it out later. */
int sa_offset = 0;
int ee_addr_size = tulip_read_eeprom(dev, 0xff, 8) & 0x40000 ? 8 : 6;
int ee_max_addr = ((1 << ee_addr_size) - 1) * sizeof(u16);
for (i = 0; i < sizeof(tp->eeprom); i+=2) {
if (ee_max_addr > sizeof(tp->eeprom))
ee_max_addr = sizeof(tp->eeprom);
for (i = 0; i < ee_max_addr ; i += sizeof(u16)) {
u16 data = tulip_read_eeprom(dev, i/2, ee_addr_size);
ee_data[i] = data & 0xff;
ee_data[i + 1] = data >> 8;