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Revision 3af57f78c38131b7a66e2b01e06fdacae01992a3 authored by Heiko Carstens on 17 January 2014, 08:37:15 UTC, committed by David S. Miller on 18 January 2014, 02:54:49 UTC 
s390/bpf,jit: fix 32 bit divisions, use unsigned divide instructions
 
The s390 bpf jit compiler emits the signed divide instructions "dr" and "d"
for unsigned divisions.
This can cause problems: the dividend will be zero extended to a 64 bit value
and the divisor is the 32 bit signed value as specified A or X accumulator,
even though A and X are supposed to be treated as unsigned values.

The divide instrunctions will generate an exception if the result cannot be
expressed with a 32 bit signed value.
This is the case if e.g. the dividend is 0xffffffff and the divisor either 1
or also 0xffffffff (signed: -1).

To avoid all these issues simply use unsigned divide instructions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 75b99db
History
Tip revision: 64222515138e43da1fcf288f0289ef1020427b87 authored by Linus Torvalds on 22 October 2021, 05:06:08 UTC
Merge tag 'drm-fixes-2021-10-22' of git://anongit.freedesktop.org/drm/drm
Tip revision: 6422251
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