The "linux,tce-size" property is only 32 bits (see
prom_initialize_tce_table() in arch/powerpc/kernel/prom_init.c).
Treating it as an unsigned long in iommu_table_setparms() leads to
access beyond the end of the property's buffer, so we pass garbage to
the memset() in that function.

[boot]0020 XICS Init
i8259 legacy interrupt controller initialized
[boot]0021 XICS Done
PID hash table entries: 4096 (order: 12, 32768 bytes)
cpu 0x0: Vector: 300 (Data Access) at [c0000000fe783850]
    pc: c000000000035e90: .memset+0x60/0xfc
    lr: c000000000044fa4: .iommu_table_setparms+0xb0/0x158
    sp: c0000000fe783ad0
   msr: 9000000000009032
   dar: c000000100000000
 dsisr: 42010000
  current = 0xc00000000450e810
  paca    = 0xc000000000411580
    pid   = 1, comm = swapper
enter ? for help
[link register   ] c000000000044fa4 .iommu_table_setparms+0xb0/0x158
[c0000000fe783ad0] c000000000044f4c .iommu_table_setparms+0x58/0x158
(unreliable)
[c0000000fe783b70] c00000000004529c
.iommu_bus_setup_pSeries+0x1c4/0x254
[c0000000fe783c00] c00000000002b8ac .do_bus_setup+0x3c/0xe4
[c0000000fe783c80] c00000000002c924 .pcibios_fixup_bus+0x64/0xd8
[c0000000fe783d00] c0000000001a2d5c .pci_scan_child_bus+0x6c/0x10c
[c0000000fe783da0] c00000000002be28 .scan_phb+0x17c/0x1b4
[c0000000fe783e40] c0000000003cfa00 .pcibios_init+0x58/0x19c
[c0000000fe783ec0] c0000000000094b4 .init+0x1e8/0x3d8
[c0000000fe783f90] c000000000026e54 .kernel_thread+0x4c/0x68

Signed-off-by: Nathan Lynch <ntl@pobox.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>