Add __attribute__((preserve_static_offset)) for the following BPF related structures: - __sk_buff - bpf_cgroup_dev_ctx - bpf_perf_event_data - bpf_sk_lookup - bpf_sock - bpf_sock_addr - bpf_sock_ops - bpf_sockopt - bpf_sysctl - sk_msg_md - sk_reuseport_md - xdp_md Access to these structures is rewritten by BPF verifier. (See verifier.c:convert_ctx_access). The rewrite requires that offsets used in access to fields of these structures are constant values. __attribute__((preserve_static_offset)) is a hint to clang that ensures that constant offsets are used. (See https://reviews.llvm.org/D133361 for details). Signed-off-by: Eduard Zingerman <eddyz87@xxxxxxxxx> --- include/uapi/linux/bpf.h | 28 ++++++++++++++--------- include/uapi/linux/bpf_perf_event.h | 8 ++++++- tools/include/uapi/linux/bpf.h | 28 ++++++++++++++--------- tools/include/uapi/linux/bpf_perf_event.h | 8 ++++++- 4 files changed, 48 insertions(+), 24 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index e0545201b55f..75eee56ed732 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -69,6 +69,12 @@ enum { /* BPF has 10 general purpose 64-bit registers and stack frame. */ #define MAX_BPF_REG __MAX_BPF_REG +#if __has_attribute(preserve_static_offset) && defined(__bpf__) +#define __bpf_ctx __attribute__((preserve_static_offset)) +#else +#define __bpf_ctx +#endif + struct bpf_insn { __u8 code; /* opcode */ __u8 dst_reg:4; /* dest register */ @@ -6190,7 +6196,7 @@ struct __sk_buff { __u8 tstamp_type; __u32 :24; /* Padding, future use. */ __u64 hwtstamp; -}; +} __bpf_ctx; struct bpf_tunnel_key { __u32 tunnel_id; @@ -6271,7 +6277,7 @@ struct bpf_sock { __u32 dst_ip6[4]; __u32 state; __s32 rx_queue_mapping; -}; +} __bpf_ctx; struct bpf_tcp_sock { __u32 snd_cwnd; /* Sending congestion window */ @@ -6379,7 +6385,7 @@ struct xdp_md { __u32 rx_queue_index; /* rxq->queue_index */ __u32 egress_ifindex; /* txq->dev->ifindex */ -}; +} __bpf_ctx; /* DEVMAP map-value layout * @@ -6429,7 +6435,7 @@ struct sk_msg_md { __u32 size; /* Total size of sk_msg */ __bpf_md_ptr(struct bpf_sock *, sk); /* current socket */ -}; +} __bpf_ctx; struct sk_reuseport_md { /* @@ -6468,7 +6474,7 @@ struct sk_reuseport_md { */ __bpf_md_ptr(struct bpf_sock *, sk); __bpf_md_ptr(struct bpf_sock *, migrating_sk); -}; +} __bpf_ctx; #define BPF_TAG_SIZE 8 @@ -6678,7 +6684,7 @@ struct bpf_sock_addr { * Stored in network byte order. */ __bpf_md_ptr(struct bpf_sock *, sk); -}; +} __bpf_ctx; /* User bpf_sock_ops struct to access socket values and specify request ops * and their replies. @@ -6761,7 +6767,7 @@ struct bpf_sock_ops { * been written yet. */ __u64 skb_hwtstamp; -}; +} __bpf_ctx; /* Definitions for bpf_sock_ops_cb_flags */ enum { @@ -7034,7 +7040,7 @@ struct bpf_cgroup_dev_ctx { __u32 access_type; __u32 major; __u32 minor; -}; +} __bpf_ctx; struct bpf_raw_tracepoint_args { __u64 args[0]; @@ -7245,7 +7251,7 @@ struct bpf_sysctl { __u32 file_pos; /* Sysctl file position to read from, write to. * Allows 1,2,4-byte read an 4-byte write. */ -}; +} __bpf_ctx; struct bpf_sockopt { __bpf_md_ptr(struct bpf_sock *, sk); @@ -7256,7 +7262,7 @@ struct bpf_sockopt { __s32 optname; __s32 optlen; __s32 retval; -}; +} __bpf_ctx; struct bpf_pidns_info { __u32 pid; @@ -7280,7 +7286,7 @@ struct bpf_sk_lookup { __u32 local_ip6[4]; /* Network byte order */ __u32 local_port; /* Host byte order */ __u32 ingress_ifindex; /* The arriving interface. Determined by inet_iif. */ -}; +} __bpf_ctx; /* * struct btf_ptr is used for typed pointer representation; the diff --git a/include/uapi/linux/bpf_perf_event.h b/include/uapi/linux/bpf_perf_event.h index eb1b9d21250c..cf614ddf0381 100644 --- a/include/uapi/linux/bpf_perf_event.h +++ b/include/uapi/linux/bpf_perf_event.h @@ -10,10 +10,16 @@ #include <asm/bpf_perf_event.h> +#if __has_attribute(preserve_static_offset) && defined(__bpf__) +#define __bpf_ctx __attribute__((preserve_static_offset)) +#else +#define __bpf_ctx +#endif + struct bpf_perf_event_data { bpf_user_pt_regs_t regs; __u64 sample_period; __u64 addr; -}; +} __bpf_ctx; #endif /* _UAPI__LINUX_BPF_PERF_EVENT_H__ */ diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index e0545201b55f..75eee56ed732 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -69,6 +69,12 @@ enum { /* BPF has 10 general purpose 64-bit registers and stack frame. */ #define MAX_BPF_REG __MAX_BPF_REG +#if __has_attribute(preserve_static_offset) && defined(__bpf__) +#define __bpf_ctx __attribute__((preserve_static_offset)) +#else +#define __bpf_ctx +#endif + struct bpf_insn { __u8 code; /* opcode */ __u8 dst_reg:4; /* dest register */ @@ -6190,7 +6196,7 @@ struct __sk_buff { __u8 tstamp_type; __u32 :24; /* Padding, future use. */ __u64 hwtstamp; -}; +} __bpf_ctx; struct bpf_tunnel_key { __u32 tunnel_id; @@ -6271,7 +6277,7 @@ struct bpf_sock { __u32 dst_ip6[4]; __u32 state; __s32 rx_queue_mapping; -}; +} __bpf_ctx; struct bpf_tcp_sock { __u32 snd_cwnd; /* Sending congestion window */ @@ -6379,7 +6385,7 @@ struct xdp_md { __u32 rx_queue_index; /* rxq->queue_index */ __u32 egress_ifindex; /* txq->dev->ifindex */ -}; +} __bpf_ctx; /* DEVMAP map-value layout * @@ -6429,7 +6435,7 @@ struct sk_msg_md { __u32 size; /* Total size of sk_msg */ __bpf_md_ptr(struct bpf_sock *, sk); /* current socket */ -}; +} __bpf_ctx; struct sk_reuseport_md { /* @@ -6468,7 +6474,7 @@ struct sk_reuseport_md { */ __bpf_md_ptr(struct bpf_sock *, sk); __bpf_md_ptr(struct bpf_sock *, migrating_sk); -}; +} __bpf_ctx; #define BPF_TAG_SIZE 8 @@ -6678,7 +6684,7 @@ struct bpf_sock_addr { * Stored in network byte order. */ __bpf_md_ptr(struct bpf_sock *, sk); -}; +} __bpf_ctx; /* User bpf_sock_ops struct to access socket values and specify request ops * and their replies. @@ -6761,7 +6767,7 @@ struct bpf_sock_ops { * been written yet. */ __u64 skb_hwtstamp; -}; +} __bpf_ctx; /* Definitions for bpf_sock_ops_cb_flags */ enum { @@ -7034,7 +7040,7 @@ struct bpf_cgroup_dev_ctx { __u32 access_type; __u32 major; __u32 minor; -}; +} __bpf_ctx; struct bpf_raw_tracepoint_args { __u64 args[0]; @@ -7245,7 +7251,7 @@ struct bpf_sysctl { __u32 file_pos; /* Sysctl file position to read from, write to. * Allows 1,2,4-byte read an 4-byte write. */ -}; +} __bpf_ctx; struct bpf_sockopt { __bpf_md_ptr(struct bpf_sock *, sk); @@ -7256,7 +7262,7 @@ struct bpf_sockopt { __s32 optname; __s32 optlen; __s32 retval; -}; +} __bpf_ctx; struct bpf_pidns_info { __u32 pid; @@ -7280,7 +7286,7 @@ struct bpf_sk_lookup { __u32 local_ip6[4]; /* Network byte order */ __u32 local_port; /* Host byte order */ __u32 ingress_ifindex; /* The arriving interface. Determined by inet_iif. */ -}; +} __bpf_ctx; /* * struct btf_ptr is used for typed pointer representation; the diff --git a/tools/include/uapi/linux/bpf_perf_event.h b/tools/include/uapi/linux/bpf_perf_event.h index eb1b9d21250c..cf614ddf0381 100644 --- a/tools/include/uapi/linux/bpf_perf_event.h +++ b/tools/include/uapi/linux/bpf_perf_event.h @@ -10,10 +10,16 @@ #include <asm/bpf_perf_event.h> +#if __has_attribute(preserve_static_offset) && defined(__bpf__) +#define __bpf_ctx __attribute__((preserve_static_offset)) +#else +#define __bpf_ctx +#endif + struct bpf_perf_event_data { bpf_user_pt_regs_t regs; __u64 sample_period; __u64 addr; -}; +} __bpf_ctx; #endif /* _UAPI__LINUX_BPF_PERF_EVENT_H__ */ -- 2.42.1
