From 0dcac272540613d41c05e89679e4ddb978b612f1 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 16 Mar 2022 13:24:09 +0100 Subject: bpf: Add multi kprobe link Adding new link type BPF_LINK_TYPE_KPROBE_MULTI that attaches kprobe program through fprobe API. The fprobe API allows to attach probe on multiple functions at once very fast, because it works on top of ftrace. On the other hand this limits the probe point to the function entry or return. The kprobe program gets the same pt_regs input ctx as when it's attached through the perf API. Adding new attach type BPF_TRACE_KPROBE_MULTI that allows attachment kprobe to multiple function with new link. User provides array of addresses or symbols with count to attach the kprobe program to. The new link_create uapi interface looks like: struct { __u32 flags; __u32 cnt; __aligned_u64 syms; __aligned_u64 addrs; } kprobe_multi; The flags field allows single BPF_TRACE_KPROBE_MULTI bit to create return multi kprobe. Signed-off-by: Masami Hiramatsu Signed-off-by: Jiri Olsa Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220316122419.933957-4-jolsa@kernel.org --- include/linux/bpf_types.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/bpf_types.h') diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 48a91c51c015..3e24ad0c4b3c 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -140,3 +140,4 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_XDP, xdp) #ifdef CONFIG_PERF_EVENTS BPF_LINK_TYPE(BPF_LINK_TYPE_PERF_EVENT, perf) #endif +BPF_LINK_TYPE(BPF_LINK_TYPE_KPROBE_MULTI, kprobe_multi) -- cgit v1.3-8-gc7d7 From f7e0beaf39d3868dc700d4954b26cf8443c5d423 Mon Sep 17 00:00:00 2001 From: Kui-Feng Lee Date: Tue, 10 May 2022 13:59:19 -0700 Subject: bpf, x86: Generate trampolines from bpf_tramp_links Replace struct bpf_tramp_progs with struct bpf_tramp_links to collect struct bpf_tramp_link(s) for a trampoline. struct bpf_tramp_link extends bpf_link to act as a linked list node. arch_prepare_bpf_trampoline() accepts a struct bpf_tramp_links to collects all bpf_tramp_link(s) that a trampoline should call. Change BPF trampoline and bpf_struct_ops to pass bpf_tramp_links instead of bpf_tramp_progs. Signed-off-by: Kui-Feng Lee Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220510205923.3206889-2-kuifeng@fb.com --- arch/x86/net/bpf_jit_comp.c | 36 +++++++++++---------- include/linux/bpf.h | 36 ++++++++++++++------- include/linux/bpf_types.h | 1 + include/uapi/linux/bpf.h | 1 + kernel/bpf/bpf_struct_ops.c | 71 +++++++++++++++++++++++++++------------- kernel/bpf/syscall.c | 23 +++++-------- kernel/bpf/trampoline.c | 73 ++++++++++++++++++++++++------------------ net/bpf/bpf_dummy_struct_ops.c | 24 +++++++++++--- tools/bpf/bpftool/link.c | 1 + tools/include/uapi/linux/bpf.h | 1 + 10 files changed, 164 insertions(+), 103 deletions(-) (limited to 'include/linux/bpf_types.h') diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 16b6efacf7c6..38eb43159230 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1762,10 +1762,12 @@ static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_args, } static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog, - struct bpf_prog *p, int stack_size, bool save_ret) + struct bpf_tramp_link *l, int stack_size, + bool save_ret) { u8 *prog = *pprog; u8 *jmp_insn; + struct bpf_prog *p = l->link.prog; /* arg1: mov rdi, progs[i] */ emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p); @@ -1850,14 +1852,14 @@ static int emit_cond_near_jump(u8 **pprog, void *func, void *ip, u8 jmp_cond) } static int invoke_bpf(const struct btf_func_model *m, u8 **pprog, - struct bpf_tramp_progs *tp, int stack_size, + struct bpf_tramp_links *tl, int stack_size, bool save_ret) { int i; u8 *prog = *pprog; - for (i = 0; i < tp->nr_progs; i++) { - if (invoke_bpf_prog(m, &prog, tp->progs[i], stack_size, + for (i = 0; i < tl->nr_links; i++) { + if (invoke_bpf_prog(m, &prog, tl->links[i], stack_size, save_ret)) return -EINVAL; } @@ -1866,7 +1868,7 @@ static int invoke_bpf(const struct btf_func_model *m, u8 **pprog, } static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog, - struct bpf_tramp_progs *tp, int stack_size, + struct bpf_tramp_links *tl, int stack_size, u8 **branches) { u8 *prog = *pprog; @@ -1877,8 +1879,8 @@ static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog, */ emit_mov_imm32(&prog, false, BPF_REG_0, 0); emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8); - for (i = 0; i < tp->nr_progs; i++) { - if (invoke_bpf_prog(m, &prog, tp->progs[i], stack_size, true)) + for (i = 0; i < tl->nr_links; i++) { + if (invoke_bpf_prog(m, &prog, tl->links[i], stack_size, true)) return -EINVAL; /* mod_ret prog stored return value into [rbp - 8]. Emit: @@ -1980,14 +1982,14 @@ static bool is_valid_bpf_tramp_flags(unsigned int flags) */ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end, const struct btf_func_model *m, u32 flags, - struct bpf_tramp_progs *tprogs, + struct bpf_tramp_links *tlinks, void *orig_call) { int ret, i, nr_args = m->nr_args; int regs_off, ip_off, args_off, stack_size = nr_args * 8; - struct bpf_tramp_progs *fentry = &tprogs[BPF_TRAMP_FENTRY]; - struct bpf_tramp_progs *fexit = &tprogs[BPF_TRAMP_FEXIT]; - struct bpf_tramp_progs *fmod_ret = &tprogs[BPF_TRAMP_MODIFY_RETURN]; + struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY]; + struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT]; + struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN]; u8 **branches = NULL; u8 *prog; bool save_ret; @@ -2078,13 +2080,13 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i } } - if (fentry->nr_progs) + if (fentry->nr_links) if (invoke_bpf(m, &prog, fentry, regs_off, flags & BPF_TRAMP_F_RET_FENTRY_RET)) return -EINVAL; - if (fmod_ret->nr_progs) { - branches = kcalloc(fmod_ret->nr_progs, sizeof(u8 *), + if (fmod_ret->nr_links) { + branches = kcalloc(fmod_ret->nr_links, sizeof(u8 *), GFP_KERNEL); if (!branches) return -ENOMEM; @@ -2111,7 +2113,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i prog += X86_PATCH_SIZE; } - if (fmod_ret->nr_progs) { + if (fmod_ret->nr_links) { /* From Intel 64 and IA-32 Architectures Optimization * Reference Manual, 3.4.1.4 Code Alignment, Assembly/Compiler * Coding Rule 11: All branch targets should be 16-byte @@ -2121,12 +2123,12 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i /* Update the branches saved in invoke_bpf_mod_ret with the * aligned address of do_fexit. */ - for (i = 0; i < fmod_ret->nr_progs; i++) + for (i = 0; i < fmod_ret->nr_links; i++) emit_cond_near_jump(&branches[i], prog, branches[i], X86_JNE); } - if (fexit->nr_progs) + if (fexit->nr_links) if (invoke_bpf(m, &prog, fexit, regs_off, false)) { ret = -EINVAL; goto cleanup; diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 551b7198ae8a..75e0110a65e1 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -723,11 +723,11 @@ struct btf_func_model { /* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50 * bytes on x86. Pick a number to fit into BPF_IMAGE_SIZE / 2 */ -#define BPF_MAX_TRAMP_PROGS 38 +#define BPF_MAX_TRAMP_LINKS 38 -struct bpf_tramp_progs { - struct bpf_prog *progs[BPF_MAX_TRAMP_PROGS]; - int nr_progs; +struct bpf_tramp_links { + struct bpf_tramp_link *links[BPF_MAX_TRAMP_LINKS]; + int nr_links; }; /* Different use cases for BPF trampoline: @@ -753,7 +753,7 @@ struct bpf_tramp_progs { struct bpf_tramp_image; int arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *image_end, const struct btf_func_model *m, u32 flags, - struct bpf_tramp_progs *tprogs, + struct bpf_tramp_links *tlinks, void *orig_call); /* these two functions are called from generated trampoline */ u64 notrace __bpf_prog_enter(struct bpf_prog *prog); @@ -852,9 +852,10 @@ static __always_inline __nocfi unsigned int bpf_dispatcher_nop_func( { return bpf_func(ctx, insnsi); } + #ifdef CONFIG_BPF_JIT -int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr); -int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr); +int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr); +int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr); struct bpf_trampoline *bpf_trampoline_get(u64 key, struct bpf_attach_target_info *tgt_info); void bpf_trampoline_put(struct bpf_trampoline *tr); @@ -905,12 +906,12 @@ int bpf_jit_charge_modmem(u32 size); void bpf_jit_uncharge_modmem(u32 size); bool bpf_prog_has_trampoline(const struct bpf_prog *prog); #else -static inline int bpf_trampoline_link_prog(struct bpf_prog *prog, +static inline int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr) { return -ENOTSUPP; } -static inline int bpf_trampoline_unlink_prog(struct bpf_prog *prog, +static inline int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr) { return -ENOTSUPP; @@ -1009,7 +1010,6 @@ struct bpf_prog_aux { bool tail_call_reachable; bool xdp_has_frags; bool use_bpf_prog_pack; - 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 */ @@ -1096,6 +1096,18 @@ struct bpf_link_ops { struct bpf_link_info *info); }; +struct bpf_tramp_link { + struct bpf_link link; + struct hlist_node tramp_hlist; +}; + +struct bpf_tracing_link { + struct bpf_tramp_link link; + enum bpf_attach_type attach_type; + struct bpf_trampoline *trampoline; + struct bpf_prog *tgt_prog; +}; + struct bpf_link_primer { struct bpf_link *link; struct file *file; @@ -1133,8 +1145,8 @@ bool bpf_struct_ops_get(const void *kdata); void bpf_struct_ops_put(const void *kdata); int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key, void *value); -int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_progs *tprogs, - struct bpf_prog *prog, +int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks, + struct bpf_tramp_link *link, const struct btf_func_model *model, void *image, void *image_end); static inline bool bpf_try_module_get(const void *data, struct module *owner) diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 3e24ad0c4b3c..2b9112b80171 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -141,3 +141,4 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_XDP, xdp) BPF_LINK_TYPE(BPF_LINK_TYPE_PERF_EVENT, perf) #endif BPF_LINK_TYPE(BPF_LINK_TYPE_KPROBE_MULTI, kprobe_multi) +BPF_LINK_TYPE(BPF_LINK_TYPE_STRUCT_OPS, struct_ops) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 95a3d1ff6255..3d032ea1b6a3 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1013,6 +1013,7 @@ enum bpf_link_type { BPF_LINK_TYPE_XDP = 6, BPF_LINK_TYPE_PERF_EVENT = 7, BPF_LINK_TYPE_KPROBE_MULTI = 8, + BPF_LINK_TYPE_STRUCT_OPS = 9, MAX_BPF_LINK_TYPE, }; diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 3a0103ad97bc..d9a3c9207240 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -33,15 +33,15 @@ struct bpf_struct_ops_map { const struct bpf_struct_ops *st_ops; /* protect map_update */ struct mutex lock; - /* progs has all the bpf_prog that is populated + /* link has all the bpf_links that is populated * to the func ptr of the kernel's struct * (in kvalue.data). */ - struct bpf_prog **progs; + struct bpf_link **links; /* image is a page that has all the trampolines * that stores the func args before calling the bpf_prog. * A PAGE_SIZE "image" is enough to store all trampoline for - * "progs[]". + * "links[]". */ void *image; /* uvalue->data stores the kernel struct @@ -283,9 +283,9 @@ static void bpf_struct_ops_map_put_progs(struct bpf_struct_ops_map *st_map) u32 i; for (i = 0; i < btf_type_vlen(t); i++) { - if (st_map->progs[i]) { - bpf_prog_put(st_map->progs[i]); - st_map->progs[i] = NULL; + if (st_map->links[i]) { + bpf_link_put(st_map->links[i]); + st_map->links[i] = NULL; } } } @@ -316,18 +316,34 @@ static int check_zero_holes(const struct btf_type *t, void *data) return 0; } -int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_progs *tprogs, - struct bpf_prog *prog, +static void bpf_struct_ops_link_release(struct bpf_link *link) +{ +} + +static void bpf_struct_ops_link_dealloc(struct bpf_link *link) +{ + struct bpf_tramp_link *tlink = container_of(link, struct bpf_tramp_link, link); + + kfree(tlink); +} + +const struct bpf_link_ops bpf_struct_ops_link_lops = { + .release = bpf_struct_ops_link_release, + .dealloc = bpf_struct_ops_link_dealloc, +}; + +int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks, + struct bpf_tramp_link *link, const struct btf_func_model *model, void *image, void *image_end) { u32 flags; - tprogs[BPF_TRAMP_FENTRY].progs[0] = prog; - tprogs[BPF_TRAMP_FENTRY].nr_progs = 1; + tlinks[BPF_TRAMP_FENTRY].links[0] = link; + tlinks[BPF_TRAMP_FENTRY].nr_links = 1; flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0; return arch_prepare_bpf_trampoline(NULL, image, image_end, - model, flags, tprogs, NULL); + model, flags, tlinks, NULL); } static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, @@ -338,7 +354,7 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, struct bpf_struct_ops_value *uvalue, *kvalue; const struct btf_member *member; const struct btf_type *t = st_ops->type; - struct bpf_tramp_progs *tprogs = NULL; + struct bpf_tramp_links *tlinks = NULL; void *udata, *kdata; int prog_fd, err = 0; void *image, *image_end; @@ -362,8 +378,8 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, if (uvalue->state || refcount_read(&uvalue->refcnt)) return -EINVAL; - tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL); - if (!tprogs) + tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL); + if (!tlinks) return -ENOMEM; uvalue = (struct bpf_struct_ops_value *)st_map->uvalue; @@ -386,6 +402,7 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, for_each_member(i, t, member) { const struct btf_type *mtype, *ptype; struct bpf_prog *prog; + struct bpf_tramp_link *link; u32 moff; moff = __btf_member_bit_offset(t, member) / 8; @@ -439,16 +456,26 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, err = PTR_ERR(prog); goto reset_unlock; } - st_map->progs[i] = prog; if (prog->type != BPF_PROG_TYPE_STRUCT_OPS || prog->aux->attach_btf_id != st_ops->type_id || prog->expected_attach_type != i) { + bpf_prog_put(prog); err = -EINVAL; goto reset_unlock; } - err = bpf_struct_ops_prepare_trampoline(tprogs, prog, + link = kzalloc(sizeof(*link), GFP_USER); + if (!link) { + bpf_prog_put(prog); + err = -ENOMEM; + goto reset_unlock; + } + bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, + &bpf_struct_ops_link_lops, prog); + st_map->links[i] = &link->link; + + err = bpf_struct_ops_prepare_trampoline(tlinks, link, &st_ops->func_models[i], image, image_end); if (err < 0) @@ -491,7 +518,7 @@ reset_unlock: memset(uvalue, 0, map->value_size); memset(kvalue, 0, map->value_size); unlock: - kfree(tprogs); + kfree(tlinks); mutex_unlock(&st_map->lock); return err; } @@ -546,9 +573,9 @@ static void bpf_struct_ops_map_free(struct bpf_map *map) { struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map; - if (st_map->progs) + if (st_map->links) bpf_struct_ops_map_put_progs(st_map); - bpf_map_area_free(st_map->progs); + bpf_map_area_free(st_map->links); bpf_jit_free_exec(st_map->image); bpf_map_area_free(st_map->uvalue); bpf_map_area_free(st_map); @@ -597,11 +624,11 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) map = &st_map->map; st_map->uvalue = bpf_map_area_alloc(vt->size, NUMA_NO_NODE); - st_map->progs = - bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_prog *), + st_map->links = + bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_links *), NUMA_NO_NODE); st_map->image = bpf_jit_alloc_exec(PAGE_SIZE); - if (!st_map->uvalue || !st_map->progs || !st_map->image) { + if (!st_map->uvalue || !st_map->links || !st_map->image) { bpf_struct_ops_map_free(map); return ERR_PTR(-ENOMEM); } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 50164d324eaf..2dc582773344 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2864,19 +2864,12 @@ struct bpf_link *bpf_link_get_from_fd(u32 ufd) } EXPORT_SYMBOL(bpf_link_get_from_fd); -struct bpf_tracing_link { - struct bpf_link link; - enum bpf_attach_type attach_type; - struct bpf_trampoline *trampoline; - struct bpf_prog *tgt_prog; -}; - static void bpf_tracing_link_release(struct bpf_link *link) { struct bpf_tracing_link *tr_link = - container_of(link, struct bpf_tracing_link, link); + container_of(link, struct bpf_tracing_link, link.link); - WARN_ON_ONCE(bpf_trampoline_unlink_prog(link->prog, + WARN_ON_ONCE(bpf_trampoline_unlink_prog(&tr_link->link, tr_link->trampoline)); bpf_trampoline_put(tr_link->trampoline); @@ -2889,7 +2882,7 @@ static void bpf_tracing_link_release(struct bpf_link *link) static void bpf_tracing_link_dealloc(struct bpf_link *link) { struct bpf_tracing_link *tr_link = - container_of(link, struct bpf_tracing_link, link); + container_of(link, struct bpf_tracing_link, link.link); kfree(tr_link); } @@ -2898,7 +2891,7 @@ static void bpf_tracing_link_show_fdinfo(const struct bpf_link *link, struct seq_file *seq) { struct bpf_tracing_link *tr_link = - container_of(link, struct bpf_tracing_link, link); + container_of(link, struct bpf_tracing_link, link.link); seq_printf(seq, "attach_type:\t%d\n", @@ -2909,7 +2902,7 @@ static int bpf_tracing_link_fill_link_info(const struct bpf_link *link, struct bpf_link_info *info) { struct bpf_tracing_link *tr_link = - container_of(link, struct bpf_tracing_link, link); + container_of(link, struct bpf_tracing_link, link.link); info->tracing.attach_type = tr_link->attach_type; bpf_trampoline_unpack_key(tr_link->trampoline->key, @@ -2990,7 +2983,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog, err = -ENOMEM; goto out_put_prog; } - bpf_link_init(&link->link, BPF_LINK_TYPE_TRACING, + bpf_link_init(&link->link.link, BPF_LINK_TYPE_TRACING, &bpf_tracing_link_lops, prog); link->attach_type = prog->expected_attach_type; @@ -3060,11 +3053,11 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog, tgt_prog = prog->aux->dst_prog; } - err = bpf_link_prime(&link->link, &link_primer); + err = bpf_link_prime(&link->link.link, &link_primer); if (err) goto out_unlock; - err = bpf_trampoline_link_prog(prog, tr); + err = bpf_trampoline_link_prog(&link->link, tr); if (err) { bpf_link_cleanup(&link_primer); link = NULL; diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index ada97751ae1b..d5e6bc5517cb 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -168,30 +168,30 @@ static int register_fentry(struct bpf_trampoline *tr, void *new_addr) return ret; } -static struct bpf_tramp_progs * +static struct bpf_tramp_links * bpf_trampoline_get_progs(const struct bpf_trampoline *tr, int *total, bool *ip_arg) { - const struct bpf_prog_aux *aux; - struct bpf_tramp_progs *tprogs; - struct bpf_prog **progs; + struct bpf_tramp_link *link; + struct bpf_tramp_links *tlinks; + struct bpf_tramp_link **links; int kind; *total = 0; - tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL); - if (!tprogs) + tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL); + if (!tlinks) return ERR_PTR(-ENOMEM); for (kind = 0; kind < BPF_TRAMP_MAX; kind++) { - tprogs[kind].nr_progs = tr->progs_cnt[kind]; + tlinks[kind].nr_links = tr->progs_cnt[kind]; *total += tr->progs_cnt[kind]; - progs = tprogs[kind].progs; + links = tlinks[kind].links; - hlist_for_each_entry(aux, &tr->progs_hlist[kind], tramp_hlist) { - *ip_arg |= aux->prog->call_get_func_ip; - *progs++ = aux->prog; + hlist_for_each_entry(link, &tr->progs_hlist[kind], tramp_hlist) { + *ip_arg |= link->link.prog->call_get_func_ip; + *links++ = link; } } - return tprogs; + return tlinks; } static void __bpf_tramp_image_put_deferred(struct work_struct *work) @@ -330,14 +330,14 @@ out: static int bpf_trampoline_update(struct bpf_trampoline *tr) { struct bpf_tramp_image *im; - struct bpf_tramp_progs *tprogs; + struct bpf_tramp_links *tlinks; u32 flags = BPF_TRAMP_F_RESTORE_REGS; bool ip_arg = false; int err, total; - tprogs = bpf_trampoline_get_progs(tr, &total, &ip_arg); - if (IS_ERR(tprogs)) - return PTR_ERR(tprogs); + tlinks = bpf_trampoline_get_progs(tr, &total, &ip_arg); + if (IS_ERR(tlinks)) + return PTR_ERR(tlinks); if (total == 0) { err = unregister_fentry(tr, tr->cur_image->image); @@ -353,15 +353,15 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr) goto out; } - if (tprogs[BPF_TRAMP_FEXIT].nr_progs || - tprogs[BPF_TRAMP_MODIFY_RETURN].nr_progs) + if (tlinks[BPF_TRAMP_FEXIT].nr_links || + tlinks[BPF_TRAMP_MODIFY_RETURN].nr_links) flags = BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME; if (ip_arg) flags |= BPF_TRAMP_F_IP_ARG; err = arch_prepare_bpf_trampoline(im, im->image, im->image + PAGE_SIZE, - &tr->func.model, flags, tprogs, + &tr->func.model, flags, tlinks, tr->func.addr); if (err < 0) goto out; @@ -381,7 +381,7 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr) tr->cur_image = im; tr->selector++; out: - kfree(tprogs); + kfree(tlinks); return err; } @@ -407,13 +407,14 @@ static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(struct bpf_prog *prog) } } -int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr) +int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr) { enum bpf_tramp_prog_type kind; + struct bpf_tramp_link *link_exiting; int err = 0; int cnt; - kind = bpf_attach_type_to_tramp(prog); + kind = bpf_attach_type_to_tramp(link->link.prog); mutex_lock(&tr->mutex); if (tr->extension_prog) { /* cannot attach fentry/fexit if extension prog is attached. @@ -429,25 +430,33 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr) err = -EBUSY; goto out; } - tr->extension_prog = prog; + tr->extension_prog = link->link.prog; err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL, - prog->bpf_func); + link->link.prog->bpf_func); goto out; } - if (cnt >= BPF_MAX_TRAMP_PROGS) { + if (cnt >= BPF_MAX_TRAMP_LINKS) { err = -E2BIG; goto out; } - if (!hlist_unhashed(&prog->aux->tramp_hlist)) { + if (!hlist_unhashed(&link->tramp_hlist)) { /* prog already linked */ err = -EBUSY; goto out; } - hlist_add_head(&prog->aux->tramp_hlist, &tr->progs_hlist[kind]); + hlist_for_each_entry(link_exiting, &tr->progs_hlist[kind], tramp_hlist) { + if (link_exiting->link.prog != link->link.prog) + continue; + /* prog already linked */ + err = -EBUSY; + goto out; + } + + hlist_add_head(&link->tramp_hlist, &tr->progs_hlist[kind]); tr->progs_cnt[kind]++; err = bpf_trampoline_update(tr); if (err) { - hlist_del_init(&prog->aux->tramp_hlist); + hlist_del_init(&link->tramp_hlist); tr->progs_cnt[kind]--; } out: @@ -456,12 +465,12 @@ out: } /* bpf_trampoline_unlink_prog() should never fail. */ -int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr) +int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr) { enum bpf_tramp_prog_type kind; int err; - kind = bpf_attach_type_to_tramp(prog); + kind = bpf_attach_type_to_tramp(link->link.prog); mutex_lock(&tr->mutex); if (kind == BPF_TRAMP_REPLACE) { WARN_ON_ONCE(!tr->extension_prog); @@ -470,7 +479,7 @@ int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr) tr->extension_prog = NULL; goto out; } - hlist_del_init(&prog->aux->tramp_hlist); + hlist_del_init(&link->tramp_hlist); tr->progs_cnt[kind]--; err = bpf_trampoline_update(tr); out: @@ -635,7 +644,7 @@ void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr) int __weak arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *image_end, const struct btf_func_model *m, u32 flags, - struct bpf_tramp_progs *tprogs, + struct bpf_tramp_links *tlinks, void *orig_call) { return -ENOTSUPP; diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c index d0e54e30658a..e78dadfc5829 100644 --- a/net/bpf/bpf_dummy_struct_ops.c +++ b/net/bpf/bpf_dummy_struct_ops.c @@ -72,13 +72,16 @@ static int dummy_ops_call_op(void *image, struct bpf_dummy_ops_test_args *args) args->args[3], args->args[4]); } +extern const struct bpf_link_ops bpf_struct_ops_link_lops; + int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, union bpf_attr __user *uattr) { const struct bpf_struct_ops *st_ops = &bpf_bpf_dummy_ops; const struct btf_type *func_proto; struct bpf_dummy_ops_test_args *args; - struct bpf_tramp_progs *tprogs; + struct bpf_tramp_links *tlinks; + struct bpf_tramp_link *link = NULL; void *image = NULL; unsigned int op_idx; int prog_ret; @@ -92,8 +95,8 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, if (IS_ERR(args)) return PTR_ERR(args); - tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL); - if (!tprogs) { + tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL); + if (!tlinks) { err = -ENOMEM; goto out; } @@ -105,8 +108,17 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, } set_vm_flush_reset_perms(image); + link = kzalloc(sizeof(*link), GFP_USER); + if (!link) { + err = -ENOMEM; + goto out; + } + /* prog doesn't take the ownership of the reference from caller */ + bpf_prog_inc(prog); + bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_link_lops, prog); + op_idx = prog->expected_attach_type; - err = bpf_struct_ops_prepare_trampoline(tprogs, prog, + err = bpf_struct_ops_prepare_trampoline(tlinks, link, &st_ops->func_models[op_idx], image, image + PAGE_SIZE); if (err < 0) @@ -124,7 +136,9 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, out: kfree(args); bpf_jit_free_exec(image); - kfree(tprogs); + if (link) + bpf_link_put(&link->link); + kfree(tlinks); return err; } diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index 8fb0116f9136..6353a789322b 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -23,6 +23,7 @@ static const char * const link_type_name[] = { [BPF_LINK_TYPE_XDP] = "xdp", [BPF_LINK_TYPE_PERF_EVENT] = "perf_event", [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", + [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", }; static struct hashmap *link_table; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 95a3d1ff6255..3d032ea1b6a3 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1013,6 +1013,7 @@ enum bpf_link_type { BPF_LINK_TYPE_XDP = 6, BPF_LINK_TYPE_PERF_EVENT = 7, BPF_LINK_TYPE_KPROBE_MULTI = 8, + BPF_LINK_TYPE_STRUCT_OPS = 9, MAX_BPF_LINK_TYPE, }; -- cgit v1.3-8-gc7d7