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s390/bpf: Fix JMP_JGE_K (A >= K) and JMP_JGT_K (A > K)

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Currently the signed COMPARE HALFWORD IMMEDIATE (chi) and COMPARE (c)
instructions are used to compare "A" with "K". This is not correct
because "A" and "K" are both unsigned. To fix this remove the
chi instruction (no unsigned analogon available) and use the
unsigned COMPARE LOGICAL (cl) instruction instead of COMPARE (c).

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Michael Holzheu 2015-01-14 11:25:07 +01:00 committed by Martin Schwidefsky
parent f800c25b7a
commit 5a80244246
1 changed files with 3 additions and 6 deletions
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9
arch/s390/net/bpf_jit_comp.c
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@ -448,15 +448,12 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
mask = 0x800000; /* je */
kbranch: /* Emit compare if the branch targets are different */
if (filter->jt != filter->jf) {
if (K <= 16383)
/* chi %r5,<K> */
EMIT4_IMM(0xa75e0000, K);
else if (test_facility(21))
if (test_facility(21))
/* clfi %r5,<K> */
EMIT6_IMM(0xc25f0000, K);
else
/* c %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5950d000, EMIT_CONST(K));
/* cl %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5550d000, EMIT_CONST(K));
}
branch: if (filter->jt == filter->jf) {
if (filter->jt == 0)