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authorMatthew Wilcox <willy@wil.cx>2009-01-21 19:19:19 -0500
committerJesse Barnes <jbarnes@virtuousgeek.org>2009-01-27 09:53:25 -0800
commitbffac3c593eba1f9da3efd0199e49ea6558a40ce (patch)
treef2f91533d36172cef57cca43c8050ec265b978d8 /drivers/pci/msi.c
parent476e7faefc43f106a90b5c96166c59b75de19d30 (diff)
downloadlinux-bffac3c593eba1f9da3efd0199e49ea6558a40ce.tar.bz2
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.c13
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;