From 9db7f2b818809ef2c40fbd64cfcf5ccb0107d7e8 Mon Sep 17 00:00:00 2001 From: Michael Holzheu Date: Wed, 29 Jul 2015 21:15:18 +0200 Subject: s390/bpf: recache skb->data/hlen for skb_vlan_push/pop 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 Signed-off-by: David S. Miller --- arch/s390/net/bpf_jit.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/s390/net/bpf_jit.h') diff --git a/arch/s390/net/bpf_jit.h b/arch/s390/net/bpf_jit.h index f6498eec9ee1..f010c93a88b1 100644 --- a/arch/s390/net/bpf_jit.h +++ b/arch/s390/net/bpf_jit.h @@ -36,6 +36,8 @@ extern u8 sk_load_word[], sk_load_half[], sk_load_byte[]; * | BPF stack | | * | | | * +---------------+ | + * | 8 byte skbp | | + * R15+170 -> +---------------+ | * | 8 byte hlen | | * R15+168 -> +---------------+ | * | 4 byte align | | @@ -51,11 +53,12 @@ extern u8 sk_load_word[], sk_load_half[], sk_load_byte[]; * We get 160 bytes stack space from calling function, but only use * 12 * 8 byte for old backchain, r15..r6, and tail_call_cnt. */ -#define STK_SPACE (MAX_BPF_STACK + 8 + 4 + 4 + 160) +#define STK_SPACE (MAX_BPF_STACK + 8 + 8 + 4 + 4 + 160) #define STK_160_UNUSED (160 - 12 * 8) #define STK_OFF (STK_SPACE - STK_160_UNUSED) #define STK_OFF_TMP 160 /* Offset of tmp buffer on stack */ #define STK_OFF_HLEN 168 /* Offset of SKB header length on stack */ +#define STK_OFF_SKBP 170 /* Offset of SKB pointer on stack */ #define STK_OFF_R6 (160 - 11 * 8) /* Offset of r6 on stack */ #define STK_OFF_TCCNT (160 - 12 * 8) /* Offset of tail_call_cnt on stack */ -- cgit