diff options
Diffstat (limited to '')
| -rw-r--r-- | include/linux/bpf.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 8b90db25348a..0d4c5c224d79 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -14,6 +14,8 @@ #include <linux/numa.h> #include <linux/wait.h> #include <linux/u64_stats_sync.h> +#include <linux/refcount.h> +#include <linux/mutex.h> struct bpf_verifier_env; struct bpf_verifier_log; @@ -384,6 +386,100 @@ struct bpf_prog_stats { struct u64_stats_sync syncp; } __aligned(2 * sizeof(u64)); +struct btf_func_model { + u8 ret_size; + u8 nr_args; + u8 arg_size[MAX_BPF_FUNC_ARGS]; +}; + +/* Restore arguments before returning from trampoline to let original function + * continue executing. This flag is used for fentry progs when there are no + * fexit progs. + */ +#define BPF_TRAMP_F_RESTORE_REGS BIT(0) +/* Call original function after fentry progs, but before fexit progs. + * Makes sense for fentry/fexit, normal calls and indirect calls. + */ +#define BPF_TRAMP_F_CALL_ORIG BIT(1) +/* Skip current frame and return to parent. Makes sense for fentry/fexit + * programs only. Should not be used with normal calls and indirect calls. + */ +#define BPF_TRAMP_F_SKIP_FRAME BIT(2) + +/* Different use cases for BPF trampoline: + * 1. replace nop at the function entry (kprobe equivalent) + * flags = BPF_TRAMP_F_RESTORE_REGS + * fentry = a set of programs to run before returning from trampoline + * + * 2. replace nop at the function entry (kprobe + kretprobe equivalent) + * flags = BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME + * orig_call = fentry_ip + MCOUNT_INSN_SIZE + * fentry = a set of program to run before calling original function + * fexit = a set of program to run after original function + * + * 3. replace direct call instruction anywhere in the function body + * or assign a function pointer for indirect call (like tcp_congestion_ops->cong_avoid) + * With flags = 0 + * fentry = a set of programs to run before returning from trampoline + * With flags = BPF_TRAMP_F_CALL_ORIG + * orig_call = original callback addr or direct function addr + * fentry = a set of program to run before calling original function + * fexit = a set of program to run after original function + */ +int arch_prepare_bpf_trampoline(void *image, struct btf_func_model *m, u32 flags, + struct bpf_prog **fentry_progs, int fentry_cnt, + struct bpf_prog **fexit_progs, int fexit_cnt, + void *orig_call); +/* these two functions are called from generated trampoline */ +u64 notrace __bpf_prog_enter(void); +void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start); + +enum bpf_tramp_prog_type { + BPF_TRAMP_FENTRY, + BPF_TRAMP_FEXIT, + BPF_TRAMP_MAX +}; + +struct bpf_trampoline { + /* hlist for trampoline_table */ + struct hlist_node hlist; + /* serializes access to fields of this trampoline */ + struct mutex mutex; + refcount_t refcnt; + u64 key; + struct { + struct btf_func_model model; + void *addr; + } func; + /* list of BPF programs using this trampoline */ + struct hlist_head progs_hlist[BPF_TRAMP_MAX]; + /* Number of attached programs. A counter per kind. */ + int progs_cnt[BPF_TRAMP_MAX]; + /* Executable image of trampoline */ + void *image; + u64 selector; +}; +#ifdef CONFIG_BPF_JIT +struct bpf_trampoline *bpf_trampoline_lookup(u64 key); +int bpf_trampoline_link_prog(struct bpf_prog *prog); +int bpf_trampoline_unlink_prog(struct bpf_prog *prog); +void bpf_trampoline_put(struct bpf_trampoline *tr); +#else +static inline struct bpf_trampoline *bpf_trampoline_lookup(u64 key) +{ + return NULL; +} +static inline int bpf_trampoline_link_prog(struct bpf_prog *prog) +{ + return -ENOTSUPP; +} +static inline int bpf_trampoline_unlink_prog(struct bpf_prog *prog) +{ + return -ENOTSUPP; +} +static inline void bpf_trampoline_put(struct bpf_trampoline *tr) {} +#endif + struct bpf_prog_aux { atomic_t refcnt; u32 used_map_cnt; @@ -398,6 +494,9 @@ struct bpf_prog_aux { bool verifier_zext; /* Zero extensions has been inserted by verifier. */ bool offload_requested; bool attach_btf_trace; /* true if attaching to BTF-enabled raw tp */ + enum bpf_tramp_prog_type trampoline_prog_type; + struct bpf_trampoline *trampoline; + struct hlist_node tramp_hlist; /* BTF_KIND_FUNC_PROTO for valid attach_btf_id */ const struct btf_type *attach_func_proto; /* function name for valid attach_btf_id */ @@ -784,6 +883,12 @@ int btf_struct_access(struct bpf_verifier_log *log, u32 *next_btf_id); u32 btf_resolve_helper_id(struct bpf_verifier_log *log, void *, int); +int btf_distill_func_proto(struct bpf_verifier_log *log, + struct btf *btf, + const struct btf_type *func_proto, + const char *func_name, + struct btf_func_model *m); + #else /* !CONFIG_BPF_SYSCALL */ static inline struct bpf_prog *bpf_prog_get(u32 ufd) { |