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Commit 209261c0 authored by Grant Grundler's avatar Grant Grundler Committed by Jeff Garzik
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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: default avatarGrant Grundler <grundler@parisc-linux.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 3480c63b

drivers/net/tulip/eeprom.c

+6 −0
Original line number Diff line number Diff line
@@ -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);

drivers/net/tulip/tulip_core.c

+6 −1
Original line number Diff line number Diff line
@@ -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;