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spapr_pci: Fix unsafe signed/unsigned comparisons 

spapr_pci.c contains a number of expressions of the form (uval == -1) or
(uval != -1), where 'uval' is an unsigned value.

This mostly works in practice, because as long as the width of uval is
greater or equal than that of (int), the -1 will be promoted to the
unsigned type, which is the expected outcome.

However, at least for the cases where uval is uint32_t, this would break
on platforms where sizeof(int) > 4 (and a few such do exist), because then
the uint32_t value would be promoted to the larger int type, and never be
equal to -1.

This patch fixes these errors.  The fixes for the (uint32_t) cases are
necessary as described above.  I've made similar fixes to (uint64_t) and
(hwaddr) cases.  Those are strictly theoretical, since I don't know of any
platforms where sizeof(int) > 8, but hey, it's not that hard so we might
as well be strictly C standard compliant.

Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
David Gibson 2015-03-19 15:14:18 +11:00 committed by Alexander Graf
parent 31ce0adb79
commit 421b1b27f6
1 changed files with 8 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
hw/ppc/spapr_pci.c
View File

@ -742,12 +742,12 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
PCIBus *bus;
uint64_t msi_window_size = 4096;
if (sphb->index != -1) {
if (sphb->index != (uint32_t)-1) {
hwaddr windows_base;
if ((sphb->buid != -1) || (sphb->dma_liobn != -1)
|| (sphb->mem_win_addr != -1)
|| (sphb->io_win_addr != -1)) {
if ((sphb->buid != (uint64_t)-1) || (sphb->dma_liobn != (uint32_t)-1)
|| (sphb->mem_win_addr != (hwaddr)-1)
|| (sphb->io_win_addr != (hwaddr)-1)) {
error_setg(errp, "Either \"index\" or other parameters must"
" be specified for PAPR PHB, not both");
return;
@ -768,22 +768,22 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
sphb->io_win_addr = windows_base + SPAPR_PCI_IO_WIN_OFF;
}
if (sphb->buid == -1) {
if (sphb->buid == (uint64_t)-1) {
error_setg(errp, "BUID not specified for PHB");
return;
}
if (sphb->dma_liobn == -1) {
if (sphb->dma_liobn == (uint32_t)-1) {
error_setg(errp, "LIOBN not specified for PHB");
return;
}
if (sphb->mem_win_addr == -1) {
if (sphb->mem_win_addr == (hwaddr)-1) {
error_setg(errp, "Memory window address not specified for PHB");
return;
}
if (sphb->io_win_addr == -1) {
if (sphb->io_win_addr == (hwaddr)-1) {
error_setg(errp, "IO window address not specified for PHB");
return;
}