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path: root/arch/s390/net/bpf_jit.h
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2016-05-19s390/bpf: fix recache skb->data/hlen for skb_vlan_push/popMichael Holzheu
In case of usage of skb_vlan_push/pop, in the prologue we store the SKB pointer on the stack and restore it after BPF_JMP_CALL to skb_vlan_push/pop. Unfortunately currently there are two bugs in the code: 1) The wrong stack slot (offset 170 instead of 176) is used 2) The wrong register (W1 instead of B1) is saved So fix this and use correct stack slot and register. Fixes: 9db7f2b81880 ("s390/bpf: recache skb->data/hlen for skb_vlan_push/pop") Cc: stable@vger.kernel.org # 4.3+ Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-29s390/bpf: recache skb->data/hlen for skb_vlan_push/popMichael Holzheu
Allow eBPF programs attached to TC qdiscs call skb_vlan_push/pop via helper functions. These functions may change skb->data/hlen. This data is cached by s390 JIT to improve performance of ld_abs/ld_ind instructions. Therefore after a change we have to reload the data. In case of usage of skb_vlan_push/pop, in the prologue we store the SKB pointer on the stack and restore it after BPF_JMP_CALL to skb_vlan_push/pop. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-09s390/bpf: implement bpf_tail_call() helperMichael Holzheu
bpf_tail_call() arguments: - ctx......: Context pointer - jmp_table: One of BPF_MAP_TYPE_PROG_ARRAY maps used as the jump table - index....: Index in the jump table In this implementation s390x JIT does stack unwinding and jumps into the callee program prologue. Caller and callee use the same stack. With this patch a tail call generates the following code on s390x: if (index >= array->map.max_entries) goto out 000003ff8001c7e4: e31030100016 llgf %r1,16(%r3) 000003ff8001c7ea: ec41001fa065 clgrj %r4,%r1,10,3ff8001c828 if (tail_call_cnt++ > MAX_TAIL_CALL_CNT) goto out; 000003ff8001c7f0: a7080001 lhi %r0,1 000003ff8001c7f4: eb10f25000fa laal %r1,%r0,592(%r15) 000003ff8001c7fa: ec120017207f clij %r1,32,2,3ff8001c828 prog = array->prog[index]; if (prog == NULL) goto out; 000003ff8001c800: eb140003000d sllg %r1,%r4,3 000003ff8001c806: e31310800004 lg %r1,128(%r3,%r1) 000003ff8001c80c: ec18000e007d clgij %r1,0,8,3ff8001c828 Restore registers before calling function 000003ff8001c812: eb68f2980004 lmg %r6,%r8,664(%r15) 000003ff8001c818: ebbff2c00004 lmg %r11,%r15,704(%r15) goto *(prog->bpf_func + tail_call_start); 000003ff8001c81e: e31100200004 lg %r1,32(%r1,%r0) 000003ff8001c824: 47f01006 bc 15,6(%r1) Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-03s390/bpf: fix stack allocationMichael Holzheu
On s390x we have to provide 160 bytes stack space before we can call the next function. From the 160 bytes that we got from the previous function we only use 11 * 8 bytes and have 160 - 11 * 8 bytes left. Currently for BPF we allocate additional 160 - 11 * 8 bytes for the next function. This is wrong because then the next function only gets: (160 - 11 * 8) + (160 - 11 * 8) = 2 * 72 = 144 bytes Fix this and allocate enough memory for the next function. Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-04-15s390/bpf: Add s390x eBPF JIT compiler backendMichael Holzheu
Replace 32 bit BPF JIT backend with new 64 bit eBPF backend. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>