alistair23-linux/arch/s390/net
Heiko Carstens 3af57f78c3 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>
2014-01-17 18:54:49 -08:00
..
bpf_jit.S s390/bpf,jit: BPF Just In Time compiler for s390 2012-09-26 15:44:49 +02:00
bpf_jit_comp.c s390/bpf,jit: fix 32 bit divisions, use unsigned divide instructions 2014-01-17 18:54:49 -08:00
Makefile s390/bpf,jit: BPF Just In Time compiler for s390 2012-09-26 15:44:49 +02:00