John,
In case you cannot find it, here is a copy of David's patch.
Larry
From David Woodhouse.
It's very simple... if we use inw instead of readw for the faulting I/O
access, then the machine check gets trapped. We can do this because on
PPC, PCI I/O is actually memory-mapped. The CPU doesn't have a separate
I/O space and instructions. So we just compensate for the address at
which PCI I/O is mapped, and abuse inw().
Then we make bcm43xx_phy_read() print the register it tried to access
whenever it gets 0xFFFF, and stick a WARN_ON(1) in the machine check
handler when it detects a machine check caused by an I/O access...
--- ../linux-2.6.20.ppc64/./drivers/net/wireless/mac80211/bcm43xx/bcm43xx_phy.c 2007-04-14
21:51:02.000000000 +0100
+++ ./drivers/net/wireless/mac80211/bcm43xx/bcm43xx_phy.c 2007-04-16 01:39:44.000000000 +0100
@@ -269,10 +270,13 @@ static inline u16 adjust_phyreg_for_phyt
u16 bcm43xx_phy_read(struct bcm43xx_wldev *dev, u16 offset)
{
struct bcm43xx_phy *phy = &dev->phy;
-
+ uint16_t foo;
offset = adjust_phyreg_for_phytype(phy, offset);
bcm43xx_write16(dev, BCM43xx_MMIO_PHY_CONTROL, offset);
- return bcm43xx_read16(dev, BCM43xx_MMIO_PHY_DATA);
+ foo = bcm43xx_read16(dev, BCM43xx_MMIO_PHY_DATA);
+ if (foo == 0xffff)
+ printk(KERN_DEBUG "Read phy reg %x; got 0xFFFF.\n", offset);
+ return foo;
}
void bcm43xx_phy_write(struct bcm43xx_wldev *dev, u16 offset, u16 val)
--- ../linux-2.6.20.ppc64/./drivers/ssb/pci.c 2007-04-14 21:51:02.000000000 +0100
+++ ./drivers/ssb/pci.c 2007-04-15 23:44:27.000000000 +0100
@@ -475,6 +475,7 @@ static u16 ssb_pci_read16(struct ssb_dev
if (unlikely(ssb_pci_switch_core(bus, dev)))
return 0xFFFF;
}
+ return inw(bus->mmio + offset - isa_io_base);
return readw(bus->mmio + offset);
}
--- ../linux-2.6.20.ppc64/./arch/powerpc/kernel/traps.c 2007-04-14 21:50:40.000000000 +0100
+++ ./arch/powerpc/kernel/traps.c 2007-04-15 23:45:48.000000000 +0100
@@ -343,8 +343,10 @@ void machine_check_exception(struct pt_r
return;
}
- if (check_io_access(regs))
+ if (check_io_access(regs)) {
+ WARN_ON(1);
return;
+ }
#if defined(CONFIG_4xx) && !defined(CONFIG_440A)
if (reason & ESR_IMCP) {
--
dwmw2
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