From: Michael Holzheu Date: Thu, 23 Jul 2015 17:26:15 +0000 (+0200) Subject: s390/bpf: clear correct BPF accumulator register X-Git-Tag: firefly_0821_release~176^2~1346^2~1 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=30342fe65e511007672437741158d493472f427f;p=firefly-linux-kernel-4.4.55.git 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: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Cc: stable@vger.kernel.org # 4.0+ Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky --- diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index fee782acc2ee..8d2e5165865f 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -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); } /*