diff options
| author | Matthew Wilcox <willy@wil.cx> | 2009-01-21 19:19:19 -0500 |
|---|---|---|
| committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2009-01-27 09:53:25 -0800 |
| commit | bffac3c593eba1f9da3efd0199e49ea6558a40ce (patch) | |
| tree | f2f91533d36172cef57cca43c8050ec265b978d8 /drivers/pci/msi.c | |
| parent | 476e7faefc43f106a90b5c96166c59b75de19d30 (diff) | |
| download | lwn-bffac3c593eba1f9da3efd0199e49ea6558a40ce.tar.gz lwn-bffac3c593eba1f9da3efd0199e49ea6558a40ce.zip | |
PCI MSI: Fix undefined shift by 32
Add an msi_mask() function which returns the correct bitmask for the
number of MSI interrupts you have. This fixes an undefined bug in
msi_capability_init().
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci/msi.c')
| -rw-r--r-- | drivers/pci/msi.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 896a15d70f5b..44f15ff70c1d 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -103,6 +103,16 @@ static void msix_set_enable(struct pci_dev *dev, int enable) } } +/* + * Essentially, this is ((1 << (1 << x)) - 1), but without the + * undefinedness of a << 32. + */ +static inline __attribute_const__ u32 msi_mask(unsigned x) +{ + static const u32 mask[] = { 1, 2, 4, 0xf, 0xff, 0xffff, 0xffffffff }; + return mask[x]; +} + static void msix_flush_writes(struct irq_desc *desc) { struct msi_desc *entry; @@ -407,8 +417,7 @@ static int msi_capability_init(struct pci_dev *dev) /* All MSIs are unmasked by default, Mask them all */ pci_read_config_dword(dev, base, &maskbits); - temp = (1 << multi_msi_capable(control)); - temp = ((temp - 1) & ~temp); + temp = msi_mask((control & PCI_MSI_FLAGS_QMASK) >> 1); maskbits |= temp; pci_write_config_dword(dev, base, maskbits); entry->msi_attrib.maskbits_mask = temp; |