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s390/bpf: clear correct BPF accumulator register 

Currently we assumed the following BPF to eBPF register mapping:

 - BPF_REG_A -> BPF_REG_7
 - BPF_REG_X -> BPF_REG_8

Unfortunately this mapping is wrong. The correct mapping is:

 - BPF_REG_A -> BPF_REG_0
 - BPF_REG_X -> BPF_REG_7

So clear the correct registers and use the BPF_REG_A and BPF_REG_X
macros instead of BPF_REG_0/7.

Fixes: 0546231057 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Cc: stable@vger.kernel.org # 4.0+
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 2015-07-23 19:26:15 +02:00 committed by Martin Schwidefsky
parent cbfe8fa6cd
commit 30342fe65e
1 changed files with 7 additions and 7 deletions
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14
arch/s390/net/bpf_jit_comp.c
View File

@ -448,13 +448,13 @@ static void bpf_jit_prologue(struct bpf_jit *jit)
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0,
BPF_REG_1, offsetof(struct sk_buff, data));
}
/* BPF compatibility: clear A (%b7) and X (%b8) registers */
if (REG_SEEN(BPF_REG_7))
/* lghi %b7,0 */
EMIT4_IMM(0xa7090000, BPF_REG_7, 0);
if (REG_SEEN(BPF_REG_8))
/* lghi %b8,0 */
EMIT4_IMM(0xa7090000, BPF_REG_8, 0);
/* BPF compatibility: clear A (%b0) and X (%b7) registers */
if (REG_SEEN(BPF_REG_A))
/* lghi %ba,0 */
EMIT4_IMM(0xa7090000, BPF_REG_A, 0);
if (REG_SEEN(BPF_REG_X))
/* lghi %bx,0 */
EMIT4_IMM(0xa7090000, BPF_REG_X, 0);
}
/*