[PATCH bpf-next v4 0/5] Attach a cookie to a tracing program.

[PATCH bpf-next v4 0/5] Attach a cookie to a tracing program.

[Kui-Feng Lee]

Allow users to attach a 64-bits cookie to a bpf_link of fentry, fexit,
or fmod_ret.

This patchset includes several major changes.

 - Define struct bpf_tramp_links to replace bpf_tramp_prog.
   struct bpf_tramp_links collects bpf_links of a trampoline

 - Generate a trampoline to call bpf_progs of given bpf_links.

 - Trampolines always set/reset bpf_run_ctx before/after
   calling/leaving a tracing program.

 - Attach a cookie to a bpf_link of fentry/fexit/fmod_ret.  The value
   will be available when running the associated bpf_prog.

The major differences from v3:

 - rebase v3 to latest tip.

The major differences from v2:

 - Move the allocations of run_ctx (struct bpf_tramp_run_ctx) out of
   invoke_bpf_prog().

 - Move hlist_node out of bpf_link and introduce struct bpf_tramp_link
   to own hlist_node.

 - Store cookies at struct bpf_tracing_link.

 - Use SIB byte to reduce the number of instructions to set cookie
   values. (Use RSP directly)

v1: https://lore.kernel.org/all/20220126214809.3868787-1-kuifeng@fb.com/
v2: https://lore.kernel.org/bpf/20220316004231.1103318-1-kuifeng@fb.com/
v3: https://lore.kernel.org/bpf/20220407192552.2343076-1-kuifeng@fb.com/

Kui-Feng Lee (5):
  bpf, x86: Generate trampolines from bpf_tramp_links
  bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack
  bpf, x86: Attach a cookie to fentry/fexit/fmod_ret.
  lib/bpf: Assign cookies to links in libbpf.
  selftest/bpf: The test cses of BPF cookie for fentry/fexit/fmod_ret.

 arch/x86/net/bpf_jit_comp.c                   | 98 +++++++++++++++----
 include/linux/bpf.h                           | 56 ++++++++---
 include/linux/bpf_types.h                     |  1 +
 include/uapi/linux/bpf.h                      |  9 ++
 kernel/bpf/bpf_struct_ops.c                   | 69 ++++++++-----
 kernel/bpf/syscall.c                          | 54 ++++++----
 kernel/bpf/trampoline.c                       | 96 +++++++++++-------
 kernel/trace/bpf_trace.c                      | 17 ++++
 net/bpf/bpf_dummy_struct_ops.c                | 35 ++++++-
 tools/bpf/bpftool/link.c                      |  1 +
 tools/include/uapi/linux/bpf.h                |  8 ++
 tools/lib/bpf/bpf.c                           |  7 ++
 tools/lib/bpf/bpf.h                           |  3 +
 tools/lib/bpf/libbpf.c                        | 33 +++++++
 tools/lib/bpf/libbpf.h                        | 12 +++
 tools/lib/bpf/libbpf.map                      |  1 +
 .../selftests/bpf/prog_tests/bpf_cookie.c     | 52 ++++++++++
 .../selftests/bpf/progs/test_bpf_cookie.c     | 24 +++++
 18 files changed, 459 insertions(+), 117 deletions(-)

-- 
2.30.2

[PATCH bpf-next v4 1/5] bpf, x86: Generate trampolines from bpf_tramp_links

[Kui-Feng Lee]

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 <kuifeng@fb.com>
---
 arch/x86/net/bpf_jit_comp.c    | 36 +++++++++--------
 include/linux/bpf.h            | 38 ++++++++++++------
 include/linux/bpf_types.h      |  1 +
 include/uapi/linux/bpf.h       |  1 +
 kernel/bpf/bpf_struct_ops.c    | 69 ++++++++++++++++++++++----------
 kernel/bpf/syscall.c           | 23 ++++-------
 kernel/bpf/trampoline.c        | 73 +++++++++++++++++++---------------
 net/bpf/bpf_dummy_struct_ops.c | 35 +++++++++++++---
 tools/bpf/bpftool/link.c       |  1 +
 tools/include/uapi/linux/bpf.h |  1 +
 10 files changed, 175 insertions(+), 103 deletions(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 8fe35ed11fd6..4dcc0b1ac770 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1761,10 +1761,12 @@ 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);
@@ -1849,14 +1851,14 @@ 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;
 	}
@@ -1865,7 +1867,7 @@ 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;
@@ -1876,8 +1878,8 @@ 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:
@@ -1979,14 +1981,14 @@ 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;
@@ -2077,13 +2079,13 @@ 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;
@@ -2110,7 +2112,7 @@ 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
@@ -2120,12 +2122,12 @@ 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 bdb5298735ce..a1a3722d11b0 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -674,11 +674,11 @@ 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:
@@ -704,7 +704,7 @@ 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);
@@ -803,9 +803,12 @@ static __always_inline __nocfi unsigned int bpf_dispatcher_nop_func(
 {
 	return bpf_func(ctx, insnsi);
 }
+
+struct bpf_link;
+
 #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);
@@ -856,12 +859,12 @@ 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_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_link *link,
 					     struct bpf_trampoline *tr)
 {
 	return -ENOTSUPP;
@@ -960,7 +963,6 @@ 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 */
@@ -1047,6 +1049,18 @@ 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;
@@ -1084,8 +1098,8 @@ 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 d14b10b85e51..a4f557338af7 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 21069dbe9138..6aaaec69ec54 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -32,15 +32,15 @@ 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
@@ -282,9 +282,9 @@ 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;
 		}
 	}
 }
@@ -315,18 +315,32 @@ 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)
+{
+	kfree(link);
+}
+
+static 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,
@@ -337,7 +351,7 @@ 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;
@@ -361,8 +375,8 @@ 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;
@@ -385,6 +399,7 @@ 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;
@@ -438,16 +453,26 @@ 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)
@@ -490,7 +515,7 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
 	memset(uvalue, 0, map->value_size);
 	memset(kvalue, 0, map->value_size);
 unlock:
-	kfree(tprogs);
+	kfree(tlinks);
 	mutex_unlock(&st_map->lock);
 	return err;
 }
@@ -545,9 +570,9 @@ 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);
@@ -596,11 +621,11 @@ 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 cdaa1152436a..3078c0c9317f 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2640,19 +2640,12 @@ 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);
@@ -2665,7 +2658,7 @@ 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);
 }
@@ -2674,7 +2667,7 @@ 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",
@@ -2685,7 +2678,7 @@ 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,
@@ -2766,7 +2759,7 @@ 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;
 
@@ -2836,11 +2829,11 @@ 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 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
 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 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
 }
 
 /* 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..b3717f3ab44b 100644
--- a/net/bpf/bpf_dummy_struct_ops.c
+++ b/net/bpf/bpf_dummy_struct_ops.c
@@ -72,13 +72,28 @@ static int dummy_ops_call_op(void *image, struct bpf_dummy_ops_test_args *args)
 		    args->args[3], args->args[4]);
 }
 
+static void bpf_struct_ops_link_release(struct bpf_link *link)
+{
+}
+
+static void bpf_struct_ops_link_dealloc(struct bpf_link *link)
+{
+	kfree(link);
+}
+
+static 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_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 +107,8 @@ 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;
 	}
@@ -105,10 +120,18 @@ 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;
+	}
+	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)
 		goto out;
 
@@ -124,7 +147,9 @@ 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 d14b10b85e51..a4f557338af7 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,
 };
-- 
2.30.2

Re: [PATCH bpf-next v4 1/5] bpf, x86: Generate trampolines from bpf_tramp_links

[kernel test robot]

Hi Kui-Feng,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Kui-Feng-Lee/Attach-a-cookie-to-a-tracing-program/20220412-013832
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: hexagon-randconfig-r041-20220411 (https://download.01.org/0day-ci/archive/20220412/202204120650.7IbxkPWZ-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project c6e83f560f06cdfe8aa47b248d8bdc58f947274b)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/2f80aef15065fec24c46badf374a2e72d989fa16
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Kui-Feng-Lee/Attach-a-cookie-to-a-tracing-program/20220412-013832
        git checkout 2f80aef15065fec24c46badf374a2e72d989fa16
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash kernel/bpf/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> kernel/bpf/syscall.c:2648:42: error: incompatible pointer types passing 'struct bpf_tramp_link *' to parameter of type 'struct bpf_link *' [-Werror,-Wincompatible-pointer-types]
           WARN_ON_ONCE(bpf_trampoline_unlink_prog(&tr_link->link,
                                                   ^~~~~~~~~~~~~~
   include/asm-generic/bug.h:179:41: note: expanded from macro 'WARN_ON_ONCE'
   #define WARN_ON_ONCE(condition) WARN_ON(condition)
                                           ^~~~~~~~~
   include/asm-generic/bug.h:166:25: note: expanded from macro 'WARN_ON'
           int __ret_warn_on = !!(condition);                              \
                                  ^~~~~~~~~
   include/linux/bpf.h:867:63: note: passing argument to parameter 'link' here
   static inline int bpf_trampoline_unlink_prog(struct bpf_link *link,
                                                                 ^
   kernel/bpf/syscall.c:2836:33: error: incompatible pointer types passing 'struct bpf_tramp_link *' to parameter of type 'struct bpf_link *' [-Werror,-Wincompatible-pointer-types]
           err = bpf_trampoline_link_prog(&link->link, tr);
                                          ^~~~~~~~~~~
   include/linux/bpf.h:862:61: note: passing argument to parameter 'link' here
   static inline int bpf_trampoline_link_prog(struct bpf_link *link,
                                                               ^
   2 errors generated.


vim +2648 kernel/bpf/syscall.c

  2642	
  2643	static void bpf_tracing_link_release(struct bpf_link *link)
  2644	{
  2645		struct bpf_tracing_link *tr_link =
  2646			container_of(link, struct bpf_tracing_link, link.link);
  2647	
> 2648		WARN_ON_ONCE(bpf_trampoline_unlink_prog(&tr_link->link,
  2649							tr_link->trampoline));
  2650	
  2651		bpf_trampoline_put(tr_link->trampoline);
  2652	
  2653		/* tgt_prog is NULL if target is a kernel function */
  2654		if (tr_link->tgt_prog)
  2655			bpf_prog_put(tr_link->tgt_prog);
  2656	}
  2657	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

[PATCH bpf-next v4 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack

[Kui-Feng Lee]

BPF trampolines will create a bpf_tramp_run_ctx, a bpf_run_ctx, on
stacks and set/reset the current bpf_run_ctx before/after calling a
bpf_prog.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
 arch/x86/net/bpf_jit_comp.c | 55 +++++++++++++++++++++++++++++++++++++
 include/linux/bpf.h         | 17 +++++++++---
 kernel/bpf/syscall.c        |  4 +--
 kernel/bpf/trampoline.c     | 23 +++++++++++++---
 4 files changed, 89 insertions(+), 10 deletions(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 4dcc0b1ac770..0f521be68f7b 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1766,10 +1766,26 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
 {
 	u8 *prog = *pprog;
 	u8 *jmp_insn;
+	int ctx_cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
 	struct bpf_prog *p = l->link.prog;
 
+	/* mov rdi, 0 */
+	emit_mov_imm64(&prog, BPF_REG_1, 0, 0);
+
+	/* Prepare struct bpf_tramp_run_ctx.
+	 *
+	 * bpf_tramp_run_ctx is already preserved by
+	 * arch_prepare_bpf_trampoline().
+	 *
+	 * mov QWORD PTR [rsp + ctx_cookie_off], rdi
+	 */
+	EMIT4(0x48, 0x89, 0x7C, 0x24); EMIT1(ctx_cookie_off);
+
 	/* arg1: mov rdi, progs[i] */
 	emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
+	/* arg2: mov rsi, rsp (struct bpf_run_ctx *) */
+	EMIT3(0x48, 0x89, 0xE6);
+
 	if (emit_call(&prog,
 		      p->aux->sleepable ? __bpf_prog_enter_sleepable :
 		      __bpf_prog_enter, prog))
@@ -1815,6 +1831,8 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
 	emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
 	/* arg2: mov rsi, rbx <- start time in nsec */
 	emit_mov_reg(&prog, true, BPF_REG_2, BPF_REG_6);
+	/* arg3: mov rdx, rsp (struct bpf_run_ctx *) */
+	EMIT3(0x48, 0x89, 0xE2);
 	if (emit_call(&prog,
 		      p->aux->sleepable ? __bpf_prog_exit_sleepable :
 		      __bpf_prog_exit, prog))
@@ -2079,6 +2097,16 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 		}
 	}
 
+	if (nr_args < 3 && (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links))
+		EMIT1(0x52);	/* push rdx */
+
+	if (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links) {
+		/* Prepare struct bpf_tramp_run_ctx.
+		 * sub rsp, sizeof(struct bpf_tramp_run_ctx)
+		 */
+		EMIT4(0x48, 0x83, 0xEC, sizeof(struct bpf_tramp_run_ctx));
+	}
+
 	if (fentry->nr_links)
 		if (invoke_bpf(m, &prog, fentry, regs_off,
 			       flags & BPF_TRAMP_F_RET_FENTRY_RET))
@@ -2098,6 +2126,15 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	}
 
 	if (flags & BPF_TRAMP_F_CALL_ORIG) {
+		/* pop struct bpf_tramp_run_ctx
+		 * add rsp, sizeof(struct bpf_tramp_run_ctx)
+		 */
+		if (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links)
+			EMIT4(0x48, 0x83, 0xC4, sizeof(struct bpf_tramp_run_ctx));
+
+		if (nr_args < 3 && (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links))
+			EMIT1(0x5A); /* pop rdx */
+
 		restore_regs(m, &prog, nr_args, regs_off);
 
 		/* call original function */
@@ -2110,6 +2147,15 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 		im->ip_after_call = prog;
 		memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
 		prog += X86_PATCH_SIZE;
+
+		if (nr_args < 3 && (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links))
+			EMIT1(0x52);	/* push rdx */
+
+		/* Prepare struct bpf_tramp_run_ctx.
+		 * sub rsp, sizeof(struct bpf_tramp_run_ctx)
+		 */
+		if (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links)
+			EMIT4(0x48, 0x83, 0xEC, sizeof(struct bpf_tramp_run_ctx));
 	}
 
 	if (fmod_ret->nr_links) {
@@ -2133,6 +2179,15 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 			goto cleanup;
 		}
 
+	/* pop struct bpf_tramp_run_ctx
+	 * add rsp, sizeof(struct bpf_tramp_run_ctx)
+	 */
+	if (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links)
+		EMIT4(0x48, 0x83, 0xC4, sizeof(struct bpf_tramp_run_ctx));
+
+	if (nr_args < 3 && (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links))
+		EMIT1(0x5A); /* pop rdx */
+
 	if (flags & BPF_TRAMP_F_RESTORE_REGS)
 		restore_regs(m, &prog, nr_args, regs_off);
 
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a1a3722d11b0..a94891bfab7f 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -681,6 +681,8 @@ struct bpf_tramp_links {
 	int nr_links;
 };
 
+struct bpf_tramp_run_ctx;
+
 /* Different use cases for BPF trampoline:
  * 1. replace nop at the function entry (kprobe equivalent)
  *    flags = BPF_TRAMP_F_RESTORE_REGS
@@ -707,10 +709,11 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *i
 				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);
-void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start);
-u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog);
-void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start);
+u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx);
+void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start, struct bpf_tramp_run_ctx *run_ctx);
+u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx);
+void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start,
+				       struct bpf_tramp_run_ctx *run_ctx);
 void notrace __bpf_tramp_enter(struct bpf_tramp_image *tr);
 void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr);
 
@@ -1304,6 +1307,12 @@ struct bpf_trace_run_ctx {
 	u64 bpf_cookie;
 };
 
+struct bpf_tramp_run_ctx {
+	struct bpf_run_ctx run_ctx;
+	u64 bpf_cookie;
+	struct bpf_run_ctx *saved_run_ctx;
+};
+
 static inline struct bpf_run_ctx *bpf_set_run_ctx(struct bpf_run_ctx *new_ctx)
 {
 	struct bpf_run_ctx *old_ctx = NULL;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 3078c0c9317f..e8f06311a0b5 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4802,13 +4802,13 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
 			return -EINVAL;
 		}
 
-		if (!__bpf_prog_enter_sleepable(prog)) {
+		if (!__bpf_prog_enter_sleepable(prog, NULL)) {
 			/* recursion detected */
 			bpf_prog_put(prog);
 			return -EBUSY;
 		}
 		attr->test.retval = bpf_prog_run(prog, (void *) (long) attr->test.ctx_in);
-		__bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */);
+		__bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */, NULL);
 		bpf_prog_put(prog);
 		return 0;
 #endif
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index d5e6bc5517cb..0c32828c2698 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -568,11 +568,15 @@ static void notrace inc_misses_counter(struct bpf_prog *prog)
  * [2..MAX_U64] - execute bpf prog and record execution time.
  *     This is start time.
  */
-u64 notrace __bpf_prog_enter(struct bpf_prog *prog)
+u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
 	__acquires(RCU)
 {
 	rcu_read_lock();
 	migrate_disable();
+
+	if (run_ctx)
+		run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
 	if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) {
 		inc_misses_counter(prog);
 		return 0;
@@ -602,20 +606,27 @@ static void notrace update_prog_stats(struct bpf_prog *prog,
 	}
 }
 
-void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start)
+void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start, struct bpf_tramp_run_ctx *run_ctx)
 	__releases(RCU)
 {
+	if (run_ctx)
+		bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
 	update_prog_stats(prog, start);
 	__this_cpu_dec(*(prog->active));
 	migrate_enable();
 	rcu_read_unlock();
 }
 
-u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog)
+u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
 {
 	rcu_read_lock_trace();
 	migrate_disable();
 	might_fault();
+
+	if (run_ctx)
+		run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
 	if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) {
 		inc_misses_counter(prog);
 		return 0;
@@ -623,8 +634,12 @@ u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog)
 	return bpf_prog_start_time();
 }
 
-void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start)
+void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start,
+				       struct bpf_tramp_run_ctx *run_ctx)
 {
+	if (run_ctx)
+		bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
 	update_prog_stats(prog, start);
 	__this_cpu_dec(*(prog->active));
 	migrate_enable();
-- 
2.30.2

Re: [PATCH bpf-next v4 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack

[Alexei Starovoitov]

On Mon, Apr 11, 2022 at 5:35 PM Kui-Feng Lee <kuifeng@fb.com> wrote:
> -u64 notrace __bpf_prog_enter(struct bpf_prog *prog)
> +u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
>         __acquires(RCU)
>  {
>         rcu_read_lock();
>         migrate_disable();
> +
> +       if (run_ctx)
> +               run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);

3rd time the same comment.
Looks like you're missing my emails.
Please fix your email filters.

Re: [PATCH bpf-next v4 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack

[Kui-Feng Lee]

On Mon, 2022-04-11 at 21:25 +0000, Alexei Starovoitov wrote:
> On Mon, Apr 11, 2022 at 5:35 PM Kui-Feng Lee <kuifeng@fb.com> wrote:
> > -u64 notrace __bpf_prog_enter(struct bpf_prog *prog)
> > +u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct
> > bpf_tramp_run_ctx *run_ctx)
> >         __acquires(RCU)
> >  {
> >         rcu_read_lock();
> >         migrate_disable();
> > +
> > +       if (run_ctx)
> > +               run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx-
> > >run_ctx);
> 
> 3rd time the same comment.
> Looks like you're missing my emails.
> Please fix your email filters.
Got it! Sorry for that!

[PATCH bpf-next v4 3/5] bpf, x86: Attach a cookie to fentry/fexit/fmod_ret.

[Kui-Feng Lee]

Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie
to a link of a trace hook.  A cookie of a bpf_tracing_link is
available by calling bpf_get_attach_cookie when running the BPF
program of the attached link.

The value of a cookie will be set at bpf_tramp_run_ctx by the
trampoline of the link.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
 arch/x86/net/bpf_jit_comp.c    | 11 +++++++++--
 include/linux/bpf.h            |  1 +
 include/uapi/linux/bpf.h       |  8 ++++++++
 kernel/bpf/syscall.c           | 27 +++++++++++++++++++++++----
 kernel/trace/bpf_trace.c       | 17 +++++++++++++++++
 tools/include/uapi/linux/bpf.h |  7 +++++++
 6 files changed, 65 insertions(+), 6 deletions(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 0f521be68f7b..18d02dcd810a 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1764,13 +1764,20 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
 			   struct bpf_tramp_link *l, int stack_size,
 			   bool save_ret)
 {
+	u64 cookie = 0;
 	u8 *prog = *pprog;
 	u8 *jmp_insn;
 	int ctx_cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
 	struct bpf_prog *p = l->link.prog;
 
-	/* mov rdi, 0 */
-	emit_mov_imm64(&prog, BPF_REG_1, 0, 0);
+	if (l->link.type == BPF_LINK_TYPE_TRACING) {
+		struct bpf_tracing_link *tr_link =
+			container_of(l, struct bpf_tracing_link, link);
+		cookie = tr_link->cookie;
+	}
+
+	/* mov rdi, cookie */
+	emit_mov_imm64(&prog, BPF_REG_1, (long) cookie >> 32, (u32) (long) cookie);
 
 	/* Prepare struct bpf_tramp_run_ctx.
 	 *
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a94891bfab7f..2a6f70ebd84a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1062,6 +1062,7 @@ struct bpf_tracing_link {
 	enum bpf_attach_type attach_type;
 	struct bpf_trampoline *trampoline;
 	struct bpf_prog *tgt_prog;
+	u64 cookie;
 };
 
 struct bpf_link_primer {
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a4f557338af7..5e901e6d17ea 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1436,6 +1436,7 @@ union bpf_attr {
 	struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
 		__u64 name;
 		__u32 prog_fd;
+		__u64 bpf_cookie;
 	} raw_tracepoint;
 
 	struct { /* anonymous struct for BPF_BTF_LOAD */
@@ -1490,6 +1491,13 @@ union bpf_attr {
 				__aligned_u64	addrs;
 				__aligned_u64	cookies;
 			} kprobe_multi;
+			struct {
+				/* black box user-provided value passed through
+				 * to BPF program at the execution time and
+				 * accessible through bpf_get_attach_cookie() BPF helper
+				 */
+				__u64		bpf_cookie;
+			} tracing;
 		};
 	} link_create;
 
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index e8f06311a0b5..e0e0c58fe247 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2695,9 +2695,10 @@ static const struct bpf_link_ops bpf_tracing_link_lops = {
 	.fill_link_info = bpf_tracing_link_fill_link_info,
 };
 
-static int bpf_tracing_prog_attach(struct bpf_prog *prog,
-				   int tgt_prog_fd,
-				   u32 btf_id)
+static int bpf_tracing_prog_attach_cookie(struct bpf_prog *prog,
+					  int tgt_prog_fd,
+					  u32 btf_id,
+					  u64 bpf_cookie)
 {
 	struct bpf_link_primer link_primer;
 	struct bpf_prog *tgt_prog = NULL;
@@ -2762,6 +2763,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
 	bpf_link_init(&link->link.link, BPF_LINK_TYPE_TRACING,
 		      &bpf_tracing_link_lops, prog);
 	link->attach_type = prog->expected_attach_type;
+	link->cookie = bpf_cookie;
 
 	mutex_lock(&prog->aux->dst_mutex);
 
@@ -2871,6 +2873,13 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
 	return err;
 }
 
+static int bpf_tracing_prog_attach(struct bpf_prog *prog,
+				   int tgt_prog_fd,
+				   u32 btf_id)
+{
+	return bpf_tracing_prog_attach_cookie(prog, tgt_prog_fd, btf_id, 0);
+}
+
 struct bpf_raw_tp_link {
 	struct bpf_link link;
 	struct bpf_raw_event_map *btp;
@@ -3023,7 +3032,7 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro
 }
 #endif /* CONFIG_PERF_EVENTS */
 
-#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
+#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.bpf_cookie
 
 static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
 {
@@ -3187,6 +3196,10 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type)
 		return BPF_PROG_TYPE_SK_LOOKUP;
 	case BPF_XDP:
 		return BPF_PROG_TYPE_XDP;
+	case BPF_TRACE_FENTRY:
+	case BPF_TRACE_FEXIT:
+	case BPF_MODIFY_RETURN:
+		return BPF_PROG_TYPE_TRACING;
 	default:
 		return BPF_PROG_TYPE_UNSPEC;
 	}
@@ -4251,6 +4264,12 @@ static int tracing_bpf_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
 		return bpf_tracing_prog_attach(prog,
 					       attr->link_create.target_fd,
 					       attr->link_create.target_btf_id);
+	else if (prog->type == BPF_PROG_TYPE_TRACING)
+		return bpf_tracing_prog_attach_cookie(prog,
+						      0,
+						      0,
+						      attr->link_create.tracing.bpf_cookie);
+
 	return -EINVAL;
 }
 
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index b26f3da943de..c5713d5fba45 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1088,6 +1088,21 @@ static const struct bpf_func_proto bpf_get_attach_cookie_proto_pe = {
 	.arg1_type	= ARG_PTR_TO_CTX,
 };
 
+BPF_CALL_1(bpf_get_attach_cookie_tracing, void *, ctx)
+{
+	struct bpf_trace_run_ctx *run_ctx;
+
+	run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
+	return run_ctx->bpf_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_attach_cookie_proto_tracing = {
+	.func		= bpf_get_attach_cookie_tracing,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
 BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags)
 {
 #ifndef CONFIG_X86
@@ -1716,6 +1731,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return bpf_prog_has_trampoline(prog) ? &bpf_get_func_ret_proto : NULL;
 	case BPF_FUNC_get_func_arg_cnt:
 		return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_cnt_proto : NULL;
+	case BPF_FUNC_get_attach_cookie:
+		return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto_tracing : NULL;
 	default:
 		fn = raw_tp_prog_func_proto(func_id, prog);
 		if (!fn && prog->expected_attach_type == BPF_TRACE_ITER)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a4f557338af7..a5ee57f09e04 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1490,6 +1490,13 @@ union bpf_attr {
 				__aligned_u64	addrs;
 				__aligned_u64	cookies;
 			} kprobe_multi;
+			struct {
+				/* black box user-provided value passed through
+				 * to BPF program at the execution time and
+				 * accessible through bpf_get_attach_cookie() BPF helper
+				 */
+				__u64		bpf_cookie;
+			} tracing;
 		};
 	} link_create;
 
-- 
2.30.2

[PATCH bpf-next v4 4/5] lib/bpf: Assign cookies to links in libbpf.

[Kui-Feng Lee]

Add a cookie field to the attributes of bpf_link_create().
Add bpf_program__attach_trace_opts() to attach a cookie to a link.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
 tools/lib/bpf/bpf.c      |  7 +++++++
 tools/lib/bpf/bpf.h      |  3 +++
 tools/lib/bpf/libbpf.c   | 33 +++++++++++++++++++++++++++++++++
 tools/lib/bpf/libbpf.h   | 12 ++++++++++++
 tools/lib/bpf/libbpf.map |  1 +
 5 files changed, 56 insertions(+)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index cf27251adb92..c2454979c3c4 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -863,6 +863,13 @@ int bpf_link_create(int prog_fd, int target_fd,
 		if (!OPTS_ZEROED(opts, kprobe_multi))
 			return libbpf_err(-EINVAL);
 		break;
+	case BPF_TRACE_FENTRY:
+	case BPF_TRACE_FEXIT:
+	case BPF_MODIFY_RETURN:
+		attr.link_create.tracing.bpf_cookie = OPTS_GET(opts, tracing.bpf_cookie, 0);
+		if (!OPTS_ZEROED(opts, tracing))
+			return libbpf_err(-EINVAL);
+		break;
 	default:
 		if (!OPTS_ZEROED(opts, flags))
 			return libbpf_err(-EINVAL);
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index f4b4afb6d4ba..4cdbabcccefc 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -410,6 +410,9 @@ struct bpf_link_create_opts {
 	__u32 iter_info_len;
 	__u32 target_btf_id;
 	union {
+		struct {
+			__u64 bpf_cookie;
+		} tracing;
 		struct {
 			__u64 bpf_cookie;
 		} perf_event;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index bf4f7ac54ebf..8586e1efd780 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -11262,6 +11262,39 @@ struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog)
 	return bpf_program__attach_btf_id(prog);
 }
 
+struct bpf_link *bpf_program__attach_trace_opts(const struct bpf_program *prog,
+						const struct bpf_trace_opts *opts)
+{
+	char errmsg[STRERR_BUFSIZE];
+	struct bpf_link *link;
+	int prog_fd, pfd;
+
+	LIBBPF_OPTS(bpf_link_create_opts, link_opts);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-ENOMEM);
+	link->detach = &bpf_link__detach_fd;
+
+	link_opts.tracing.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
+	pfd = bpf_link_create(prog_fd, 0, prog->expected_attach_type, &link_opts);
+	if (pfd < 0) {
+		pfd = -errno;
+		free(link);
+		pr_warn("prog '%s': failed to attach: %s\n",
+			prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
+		return libbpf_err_ptr(pfd);
+	}
+	link->fd = pfd;
+	return (struct bpf_link *)link;
+}
+
 struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog)
 {
 	return bpf_program__attach_btf_id(prog);
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 63d66f1adf1a..e0dd3f9a5aca 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -563,8 +563,20 @@ bpf_program__attach_tracepoint_opts(const struct bpf_program *prog,
 LIBBPF_API struct bpf_link *
 bpf_program__attach_raw_tracepoint(const struct bpf_program *prog,
 				   const char *tp_name);
+
+struct bpf_trace_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
+	__u64 bpf_cookie;
+};
+#define bpf_trace_opts__last_field bpf_cookie
+
 LIBBPF_API struct bpf_link *
 bpf_program__attach_trace(const struct bpf_program *prog);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_trace_opts(const struct bpf_program *prog, const struct bpf_trace_opts *opts);
+
 LIBBPF_API struct bpf_link *
 bpf_program__attach_lsm(const struct bpf_program *prog);
 LIBBPF_API struct bpf_link *
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 82f6d62176dd..9235da802e31 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -424,6 +424,7 @@ LIBBPF_0.6.0 {
 LIBBPF_0.7.0 {
 	global:
 		bpf_btf_load;
+		bpf_program__attach_trace_opts;
 		bpf_program__expected_attach_type;
 		bpf_program__log_buf;
 		bpf_program__log_level;
-- 
2.30.2

[PATCH bpf-next v4 5/5] selftest/bpf: The test cses of BPF cookie for fentry/fexit/fmod_ret.

[Kui-Feng Lee]

Make sure BPF cookies are correct for fentry/fexit/fmod_ret.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
 .../selftests/bpf/prog_tests/bpf_cookie.c     | 52 +++++++++++++++++++
 .../selftests/bpf/progs/test_bpf_cookie.c     | 24 +++++++++
 2 files changed, 76 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
index 923a6139b2d8..7f05056c66d4 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
@@ -410,6 +410,56 @@ static void pe_subtest(struct test_bpf_cookie *skel)
 	bpf_link__destroy(link);
 }
 
+static void tracing_subtest(struct test_bpf_cookie *skel)
+{
+	__u64 cookie;
+	int prog_fd;
+	int fentry_fd = -1, fexit_fd = -1, fmod_ret_fd = -1;
+
+	LIBBPF_OPTS(bpf_test_run_opts, opts, .repeat = 1);
+	LIBBPF_OPTS(bpf_link_create_opts, link_opts);
+
+	skel->bss->fentry_res = 0;
+	skel->bss->fexit_res = 0;
+
+	cookie = 0x100000;
+	prog_fd = bpf_program__fd(skel->progs.fentry_test1);
+	link_opts.tracing.bpf_cookie = cookie;
+	fentry_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_FENTRY, &link_opts);
+
+	cookie = 0x200000;
+	prog_fd = bpf_program__fd(skel->progs.fexit_test1);
+	link_opts.tracing.bpf_cookie = cookie;
+	fexit_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_FEXIT, &link_opts);
+	if (!ASSERT_GE(fexit_fd, 0, "fexit.open"))
+		goto cleanup;
+
+	cookie = 0x300000;
+	prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
+	link_opts.tracing.bpf_cookie = cookie;
+	fmod_ret_fd = bpf_link_create(prog_fd, 0, BPF_MODIFY_RETURN, &link_opts);
+	if (!ASSERT_GE(fmod_ret_fd, 0, "fmod_ret.opoen"))
+		goto cleanup;
+
+	prog_fd = bpf_program__fd(skel->progs.fentry_test1);
+	bpf_prog_test_run_opts(prog_fd, &opts);
+
+	prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
+	bpf_prog_test_run_opts(prog_fd, &opts);
+
+	ASSERT_EQ(skel->bss->fentry_res, 0x100000, "fentry_res");
+	ASSERT_EQ(skel->bss->fexit_res, 0x200000, "fexit_res");
+	ASSERT_EQ(skel->bss->fmod_ret_res, 0x300000, "fmod_ret_res");
+
+cleanup:
+	if (fentry_fd >= 0)
+		close(fentry_fd);
+	if (fexit_fd >= 0)
+		close(fexit_fd);
+	if (fmod_ret_fd >= 0)
+		close(fmod_ret_fd);
+}
+
 void test_bpf_cookie(void)
 {
 	struct test_bpf_cookie *skel;
@@ -432,6 +482,8 @@ void test_bpf_cookie(void)
 		tp_subtest(skel);
 	if (test__start_subtest("perf_event"))
 		pe_subtest(skel);
+	if (test__start_subtest("trampoline"))
+		tracing_subtest(skel);
 
 	test_bpf_cookie__destroy(skel);
 }
diff --git a/tools/testing/selftests/bpf/progs/test_bpf_cookie.c b/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
index 0e2222968918..c37bc6ad0b70 100644
--- a/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
+++ b/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
@@ -14,6 +14,9 @@ int uprobe_res;
 int uretprobe_res;
 int tp_res;
 int pe_res;
+int fentry_res;
+int fexit_res;
+int fmod_ret_res;
 
 static void update(void *ctx, int *res)
 {
@@ -82,4 +85,25 @@ int handle_pe(struct pt_regs *ctx)
 	return 0;
 }
 
+SEC("fentry/bpf_fentry_test1")
+int BPF_PROG(fentry_test1, int a)
+{
+	update(ctx, &fentry_res);
+	return 0;
+}
+
+SEC("fexit/bpf_fentry_test1")
+int BPF_PROG(fexit_test1, int a, int ret)
+{
+	update(ctx, &fexit_res);
+	return 0;
+}
+
+SEC("fmod_ret/bpf_modify_return_test")
+int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
+{
+	update(ctx, &fmod_ret_res);
+	return 1234;
+}
+
 char _license[] SEC("license") = "GPL";
-- 
2.30.2