From: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
Commit bffac3c593eba1f9da3efd0199e49ea6558a40ce ("PCI MSI: Fix undefined
shift by 32") does:
- temp = (1 << multi_msi_capable(control));
- temp = ((temp - 1) & ~temp);
+ temp = msi_mask((control & PCI_MSI_FLAGS_QMASK) >> 1);
and provides msi_mask() to avoid undefined shift by 32.
According to PCI Local Bus Spec 3.0 "6.8.1.3 Message Control for MSI",
relations between the encoded bits in control register, the number of
vectors and the proper maskbits should be as following table:
control[3::1] | vectors | maskbits
--------------+----------+-----------
000b | 1 | 0x1
001b | 2 | 0x3
010b | 4 | 0xf
011b | 8 | 0xff
100b | 16 | 0xffff
101b | 32 | 0xffffffff
110b | Reserved | n/a
111b | Reserved | n/a
This patch fixes the wrong array in the msi_mask().
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
Cc: Matthew Wilcox <matthew@xxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/pci/msi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN drivers/pci/msi.c~pci-msi-fix-msi_mask drivers/pci/msi.c
--- a/drivers/pci/msi.c~pci-msi-fix-msi_mask
+++ a/drivers/pci/msi.c
@@ -109,7 +109,7 @@ static void msix_set_enable(struct pci_d
*/
static inline __attribute_const__ u32 msi_mask(unsigned x)
{
- static const u32 mask[] = { 1, 2, 4, 0xf, 0xff, 0xffff, 0xffffffff };
+ static const u32 mask[] = { 1, 3, 0xf, 0xff, 0xffff, 0xffffffff };
return mask[x];
}
_
--
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