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spapr_drc: Fix potential undefined behaviour 

The DRC_INDEX_ID_MASK macro does a left shift on ~0, which is a signed
quantity, and therefore undefined behaviour according to the C spec.  In
particular this causes warnings from the clang sanitizer.

This fixes it by calculating the same mask without using ~0 (I think the
new method is a more common idiom for generating masks anyway).  For good
measure I also use 1ULL to force the expression's type to unsigned long
long, which should be good for assigning to anything we're going to want
to.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
This commit is contained in:
David Gibson 2015-09-03 10:08:23 +10:00
parent ad440b4ae0
commit 627c2ef789
1 changed files with 1 additions and 1 deletions
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2
hw/ppc/spapr_drc.c
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@ -32,7 +32,7 @@
#define DRC_CONTAINER_PATH "/dr-connector"
#define DRC_INDEX_TYPE_SHIFT 28
#define DRC_INDEX_ID_MASK (~(~0 << DRC_INDEX_TYPE_SHIFT))
#define DRC_INDEX_ID_MASK ((1ULL << DRC_INDEX_TYPE_SHIFT) - 1)
static sPAPRDRConnectorTypeShift get_type_shift(sPAPRDRConnectorType type)
{