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x86/gpu: Fix sign extension issue in Intel graphics stolen memory quirks

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Have the KB(),MB(),GB() macros produce unsigned longs to avoid
unintended sign extension issues with the gen2 memory size
detection.

What happens is first the uint8_t returned by
read_pci_config_byte() gets promoted to an int which gets
multiplied by another int from the MB() macro, and finally the
result gets sign extended to size_t.

Although this shouldn't be a problem in practice as all affected
gen2 platforms are 32bit AFAIK, so size_t will be 32 bits.

Reported-by: Bjorn Helgaas <bhelgaas@google.com>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1397382303-17525-1-git-send-email-ville.syrjala@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ville Syrjälä 2014-04-13 12:45:03 +03:00 committed by Ingo Molnar
parent f96364041c
commit 86e587623a
1 changed files with 1 additions and 1 deletions
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2
arch/x86/kernel/early-quirks.c
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@ -240,7 +240,7 @@ static u32 __init intel_stolen_base(int num, int slot, int func, size_t stolen_s
return base;
}
#define KB(x) ((x) * 1024)
#define KB(x) ((x) * 1024UL)
#define MB(x) (KB (KB (x)))
#define GB(x) (MB (KB (x)))