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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>
70 lines
2.0 KiB
C
70 lines
2.0 KiB
C
/*
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* BPF Jit compiler defines
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*
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* Copyright IBM Corp. 2012,2015
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*
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
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* Michael Holzheu <holzheu@linux.vnet.ibm.com>
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*/
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#ifndef __ARCH_S390_NET_BPF_JIT_H
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#define __ARCH_S390_NET_BPF_JIT_H
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#ifndef __ASSEMBLY__
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#include <linux/filter.h>
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#include <linux/types.h>
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extern u8 sk_load_word_pos[], sk_load_half_pos[], sk_load_byte_pos[];
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extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
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#endif /* __ASSEMBLY__ */
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/*
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* Stackframe layout (packed stack):
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*
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* ^ high
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* +---------------+ |
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* | old backchain | |
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* +---------------+ |
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* | r15 - r6 | |
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* +---------------+ |
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* | 4 byte align | |
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* | tail_call_cnt | |
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* BFP -> +===============+ |
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* | | |
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* | BPF stack | |
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* | | |
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* +---------------+ |
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* | 8 byte skbp | |
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* R15+170 -> +---------------+ |
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* | 8 byte hlen | |
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* R15+168 -> +---------------+ |
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* | 4 byte align | |
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* +---------------+ |
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* | 4 byte temp | |
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* | for bpf_jit.S | |
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* R15+160 -> +---------------+ |
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* | new backchain | |
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* R15+152 -> +---------------+ |
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* | + 152 byte SA | |
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* R15 -> +---------------+ + low
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*
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* We get 160 bytes stack space from calling function, but only use
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* 12 * 8 byte for old backchain, r15..r6, and tail_call_cnt.
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*/
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#define STK_SPACE (MAX_BPF_STACK + 8 + 8 + 4 + 4 + 160)
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#define STK_160_UNUSED (160 - 12 * 8)
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#define STK_OFF (STK_SPACE - STK_160_UNUSED)
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#define STK_OFF_TMP 160 /* Offset of tmp buffer on stack */
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#define STK_OFF_HLEN 168 /* Offset of SKB header length on stack */
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#define STK_OFF_SKBP 170 /* Offset of SKB pointer on stack */
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#define STK_OFF_R6 (160 - 11 * 8) /* Offset of r6 on stack */
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#define STK_OFF_TCCNT (160 - 12 * 8) /* Offset of tail_call_cnt on stack */
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/* Offset to skip condition code check */
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#define OFF_OK 4
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#endif /* __ARCH_S390_NET_BPF_JIT_H */
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