Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-07-13

The following pull-request contains BPF updates for your *net-next* tree.

We've added 36 non-merge commits during the last 7 day(s) which contain
a total of 62 files changed, 2242 insertions(+), 468 deletions(-).

The main changes are:

1) Avoid trace_printk warning banner by switching bpf_trace_printk to use
its own tracing event, from Alan.

2) Better libbpf support on older kernels, from Andrii.

3) Additional AF_XDP stats, from Ciara.

4) build time resolution of BTF IDs, from Jiri.

5) BPF_CGROUP_INET_SOCK_RELEASE hook, from Stanislav.
====================

Signed-off-by: David S. Miller <[e-mail]>

Documentation/bpf/btf.rst

···
 bpf_insn``. For ELF API, the ``insn_off`` is the byte offset from the
 beginning of section (``btf_ext_info_sec->sec_name_off``).
 
+4.2 .BTF_ids section
+====================
+
+The .BTF_ids section encodes BTF ID values that are used within the kernel.
+
+This section is created during the kernel compilation with the help of
+macros defined in ``include/linux/btf_ids.h`` header file. Kernel code can
+use them to create lists and sets (sorted lists) of BTF ID values.
+
+The ``BTF_ID_LIST`` and ``BTF_ID`` macros define unsorted list of BTF ID values,
+with following syntax::
+
+  BTF_ID_LIST(list)
+  BTF_ID(type1, name1)
+  BTF_ID(type2, name2)
+
+resulting in following layout in .BTF_ids section::
+
+  __BTF_ID__type1__name1__1:
+  .zero 4
+  __BTF_ID__type2__name2__2:
+  .zero 4
+
+The ``u32 list[];`` variable is defined to access the list.
+
+The ``BTF_ID_UNUSED`` macro defines 4 zero bytes. It's used when we
+want to define unused entry in BTF_ID_LIST, like::
+
+      BTF_ID_LIST(bpf_skb_output_btf_ids)
+      BTF_ID(struct, sk_buff)
+      BTF_ID_UNUSED
+      BTF_ID(struct, task_struct)
+
+All the BTF ID lists and sets are compiled in the .BTF_ids section and
+resolved during the linking phase of kernel build by ``resolve_btfids`` tool.
+
 5. Using BTF
 ************
 

Makefile

···
 STRIP		= $(CROSS_COMPILE)strip
 endif
 PAHOLE		= pahole
+RESOLVE_BTFIDS	= $(objtree)/tools/bpf/resolve_btfids/resolve_btfids
 LEX		= flex
 YACC		= bison
 AWK		= awk
···
 CLANG_FLAGS :=
 
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
-export CPP AR NM STRIP OBJCOPY OBJDUMP OBJSIZE READELF PAHOLE LEX YACC AWK INSTALLKERNEL
+export CPP AR NM STRIP OBJCOPY OBJDUMP OBJSIZE READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
···
 
 HOST_LIBELF_LIBS = $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)
 
+has_libelf = $(call try-run,\
+               echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
+
 ifdef CONFIG_STACK_VALIDATION
-  has_libelf := $(call try-run,\
-		echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
   ifeq ($(has_libelf),1)
     objtool_target := tools/objtool FORCE
   else
     SKIP_STACK_VALIDATION := 1
     export SKIP_STACK_VALIDATION
+  endif
+endif
+
+ifdef CONFIG_DEBUG_INFO_BTF
+  ifeq ($(has_libelf),1)
+    resolve_btfids_target := tools/bpf/resolve_btfids FORCE
+  else
+    ERROR_RESOLVE_BTFIDS := 1
   endif
 endif
 
···
 	$(Q)$(MAKE) $(build)=.
 
 # All the preparing..
-prepare: prepare0 prepare-objtool
+prepare: prepare0 prepare-objtool prepare-resolve_btfids
 
 # Support for using generic headers in asm-generic
 asm-generic := -f $(srctree)/scripts/Makefile.asm-generic obj
···
 	$(Q)$(MAKE) $(asm-generic)=arch/$(SRCARCH)/include/generated/uapi/asm \
 	generic=include/uapi/asm-generic
 
-PHONY += prepare-objtool
+PHONY += prepare-objtool prepare-resolve_btfids
 prepare-objtool: $(objtool_target)
 ifeq ($(SKIP_STACK_VALIDATION),1)
 ifdef CONFIG_UNWINDER_ORC
···
 endif
 endif
 
+prepare-resolve_btfids: $(resolve_btfids_target)
+ifeq ($(ERROR_RESOLVE_BTFIDS),1)
+	@echo "error: Cannot resolve BTF IDs for CONFIG_DEBUG_INFO_BTF, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
+	@false
+endif
 # Generate some files
 # ---------------------------------------------------------------------------
 

include/asm-generic/vmlinux.lds.h

···
 		__start_BTF = .;					\
 		*(.BTF)							\
 		__stop_BTF = .;						\
+	}								\
+	. = ALIGN(4);							\
+	.BTF_ids : AT(ADDR(.BTF_ids) - LOAD_OFFSET) {			\
+		*(.BTF_ids)						\
 	}
 #else
 #define BTF

include/linux/bpf-cgroup.h

···
 #define BPF_CGROUP_RUN_PROG_INET_SOCK(sk)				       \
 	BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET_SOCK_CREATE)
 
+#define BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk)			       \
+	BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET_SOCK_RELEASE)
+
 #define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk)				       \
 	BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET4_POST_BIND)
 
···
 #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk,skb) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) ({ 0; })
+#define BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk) ({ 0; })

include/linux/btf_ids.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_BTF_IDS_H
+#define _LINUX_BTF_IDS_H
+
+#include <linux/compiler.h> /* for __PASTE */
+
+/*
+ * Following macros help to define lists of BTF IDs placed
+ * in .BTF_ids section. They are initially filled with zeros
+ * (during compilation) and resolved later during the
+ * linking phase by resolve_btfids tool.
+ *
+ * Any change in list layout must be reflected in resolve_btfids
+ * tool logic.
+ */
+
+#define BTF_IDS_SECTION ".BTF_ids"
+
+#define ____BTF_ID(symbol)				\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
+".local " #symbol " ;                          \n"	\
+".type  " #symbol ", @object;                  \n"	\
+".size  " #symbol ", 4;                        \n"	\
+#symbol ":                                     \n"	\
+".zero 4                                       \n"	\
+".popsection;                                  \n");
+
+#define __BTF_ID(symbol) \
+	____BTF_ID(symbol)
+
+#define __ID(prefix) \
+	__PASTE(prefix, __COUNTER__)
+
+/*
+ * The BTF_ID defines unique symbol for each ID pointing
+ * to 4 zero bytes.
+ */
+#define BTF_ID(prefix, name) \
+	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__))
+
+/*
+ * The BTF_ID_LIST macro defines pure (unsorted) list
+ * of BTF IDs, with following layout:
+ *
+ * BTF_ID_LIST(list1)
+ * BTF_ID(type1, name1)
+ * BTF_ID(type2, name2)
+ *
+ * list1:
+ * __BTF_ID__type1__name1__1:
+ * .zero 4
+ * __BTF_ID__type2__name2__2:
+ * .zero 4
+ *
+ */
+#define __BTF_ID_LIST(name)				\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
+".local " #name ";                             \n"	\
+#name ":;                                      \n"	\
+".popsection;                                  \n");	\
+
+#define BTF_ID_LIST(name)				\
+__BTF_ID_LIST(name)					\
+extern u32 name[];
+
+/*
+ * The BTF_ID_UNUSED macro defines 4 zero bytes.
+ * It's used when we want to define 'unused' entry
+ * in BTF_ID_LIST, like:
+ *
+ *   BTF_ID_LIST(bpf_skb_output_btf_ids)
+ *   BTF_ID(struct, sk_buff)
+ *   BTF_ID_UNUSED
+ *   BTF_ID(struct, task_struct)
+ */
+
+#define BTF_ID_UNUSED					\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
+".zero 4                                       \n"	\
+".popsection;                                  \n");
+
+
+#endif

include/net/xdp_sock.h

···
 	spinlock_t tx_completion_lock;
 	/* Protects generic receive. */
 	spinlock_t rx_lock;
+
+	/* Statistics */
 	u64 rx_dropped;
+	u64 rx_queue_full;
+
 	struct list_head map_list;
 	/* Protects map_list */
 	spinlock_t map_list_lock;

include/uapi/linux/bpf.h

···
 	BPF_CGROUP_INET4_GETSOCKNAME,
 	BPF_CGROUP_INET6_GETSOCKNAME,
 	BPF_XDP_DEVMAP,
+	BPF_CGROUP_INET_SOCK_RELEASE,
 	__MAX_BPF_ATTACH_TYPE
 };
 

include/uapi/linux/if_xdp.h

···
 };
 
 struct xdp_statistics {
-	__u64 rx_dropped; /* Dropped for reasons other than invalid desc */
+	__u64 rx_dropped; /* Dropped for other reasons */
 	__u64 rx_invalid_descs; /* Dropped due to invalid descriptor */
 	__u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
+	__u64 rx_ring_full; /* Dropped due to rx ring being full */
+	__u64 rx_fill_ring_empty_descs; /* Failed to retrieve item from fill ring */
+	__u64 tx_ring_empty_descs; /* Failed to retrieve item from tx ring */
 };
 
 struct xdp_options {

include/uapi/linux/xdp_diag.h

···
 #define XDP_SHOW_RING_CFG	(1 << 1)
 #define XDP_SHOW_UMEM		(1 << 2)
 #define XDP_SHOW_MEMINFO	(1 << 3)
+#define XDP_SHOW_STATS		(1 << 4)
 
 enum {
 	XDP_DIAG_NONE,
···
 	XDP_DIAG_UMEM_FILL_RING,
 	XDP_DIAG_UMEM_COMPLETION_RING,
 	XDP_DIAG_MEMINFO,
+	XDP_DIAG_STATS,
 	__XDP_DIAG_MAX,
 };
 
···
 	__u32	queue_id;
 	__u32	flags;
 	__u32	refs;
+};
+
+struct xdp_diag_stats {
+	__u64	n_rx_dropped;
+	__u64	n_rx_invalid;
+	__u64	n_rx_full;
+	__u64	n_fill_ring_empty;
+	__u64	n_tx_invalid;
+	__u64	n_tx_ring_empty;
 };
 
 #endif /* _LINUX_XDP_DIAG_H */

kernel/bpf/btf.c

···
 #include <linux/sort.h>
 #include <linux/bpf_verifier.h>
 #include <linux/btf.h>
+#include <linux/btf_ids.h>
 #include <linux/skmsg.h>
 #include <linux/perf_event.h>
 #include <net/sock.h>
···
 	return kern_ctx_type->type;
 }
 
+BTF_ID_LIST(bpf_ctx_convert_btf_id)
+BTF_ID(struct, bpf_ctx_convert)
+
 struct btf *btf_parse_vmlinux(void)
 {
 	struct btf_verifier_env *env = NULL;
 	struct bpf_verifier_log *log;
 	struct btf *btf = NULL;
-	int err, btf_id;
+	int err;
 
 	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
 	if (!env)
···
 	if (err)
 		goto errout;
 
-	/* find struct bpf_ctx_convert for type checking later */
-	btf_id = btf_find_by_name_kind(btf, "bpf_ctx_convert", BTF_KIND_STRUCT);
-	if (btf_id < 0) {
-		err = btf_id;
-		goto errout;
-	}
 	/* btf_parse_vmlinux() runs under bpf_verifier_lock */
-	bpf_ctx_convert.t = btf_type_by_id(btf, btf_id);
+	bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
 
 	/* find bpf map structs for map_ptr access checking */
 	err = btf_vmlinux_map_ids_init(btf, log);
···
 	return -EINVAL;
 }
 
-static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn,
-				   int arg)
-{
-	char fnname[KSYM_SYMBOL_LEN + 4] = "btf_";
-	const struct btf_param *args;
-	const struct btf_type *t;
-	const char *tname, *sym;
-	u32 btf_id, i;
-
-	if (IS_ERR(btf_vmlinux)) {
-		bpf_log(log, "btf_vmlinux is malformed\n");
-		return -EINVAL;
-	}
-
-	sym = kallsyms_lookup((long)fn, NULL, NULL, NULL, fnname + 4);
-	if (!sym) {
-		bpf_log(log, "kernel doesn't have kallsyms\n");
-		return -EFAULT;
-	}
-
-	for (i = 1; i <= btf_vmlinux->nr_types; i++) {
-		t = btf_type_by_id(btf_vmlinux, i);
-		if (BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF)
-			continue;
-		tname = __btf_name_by_offset(btf_vmlinux, t->name_off);
-		if (!strcmp(tname, fnname))
-			break;
-	}
-	if (i > btf_vmlinux->nr_types) {
-		bpf_log(log, "helper %s type is not found\n", fnname);
-		return -ENOENT;
-	}
-
-	t = btf_type_by_id(btf_vmlinux, t->type);
-	if (!btf_type_is_ptr(t))
-		return -EFAULT;
-	t = btf_type_by_id(btf_vmlinux, t->type);
-	if (!btf_type_is_func_proto(t))
-		return -EFAULT;
-
-	args = (const struct btf_param *)(t + 1);
-	if (arg >= btf_type_vlen(t)) {
-		bpf_log(log, "bpf helper %s doesn't have %d-th argument\n",
-			fnname, arg);
-		return -EINVAL;
-	}
-
-	t = btf_type_by_id(btf_vmlinux, args[arg].type);
-	if (!btf_type_is_ptr(t) || !t->type) {
-		/* anything but the pointer to struct is a helper config bug */
-		bpf_log(log, "ARG_PTR_TO_BTF is misconfigured\n");
-		return -EFAULT;
-	}
-	btf_id = t->type;
-	t = btf_type_by_id(btf_vmlinux, t->type);
-	/* skip modifiers */
-	while (btf_type_is_modifier(t)) {
-		btf_id = t->type;
-		t = btf_type_by_id(btf_vmlinux, t->type);
-	}
-	if (!btf_type_is_struct(t)) {
-		bpf_log(log, "ARG_PTR_TO_BTF is not a struct\n");
-		return -EFAULT;
-	}
-	bpf_log(log, "helper %s arg%d has btf_id %d struct %s\n", fnname + 4,
-		arg, btf_id, __btf_name_by_offset(btf_vmlinux, t->name_off));
-	return btf_id;
-}
-
 int btf_resolve_helper_id(struct bpf_verifier_log *log,
 			  const struct bpf_func_proto *fn, int arg)
 {
-	int *btf_id = &fn->btf_id[arg];
-	int ret;
+	int id;
 
 	if (fn->arg_type[arg] != ARG_PTR_TO_BTF_ID)
 		return -EINVAL;
-
-	ret = READ_ONCE(*btf_id);
-	if (ret)
-		return ret;
-	/* ok to race the search. The result is the same */
-	ret = __btf_resolve_helper_id(log, fn->func, arg);
-	if (!ret) {
-		/* Function argument cannot be type 'void' */
-		bpf_log(log, "BTF resolution bug\n");
-		return -EFAULT;
-	}
-	WRITE_ONCE(*btf_id, ret);
-	return ret;
+	id = fn->btf_id[arg];
+	if (!id || id > btf_vmlinux->nr_types)
+		return -EINVAL;
+	return id;
 }
 
 static int __get_type_size(struct btf *btf, u32 btf_id,

kernel/bpf/stackmap.c

···
 #include <linux/elf.h>
 #include <linux/pagemap.h>
 #include <linux/irq_work.h>
+#include <linux/btf_ids.h>
 #include "percpu_freelist.h"
 
 #define STACK_CREATE_FLAG_MASK					\
···
 	return __bpf_get_stack(regs, task, buf, size, flags);
 }
 
-static int bpf_get_task_stack_btf_ids[5];
+BTF_ID_LIST(bpf_get_task_stack_btf_ids)
+BTF_ID(struct, task_struct)
+
 const struct bpf_func_proto bpf_get_task_stack_proto = {
 	.func		= bpf_get_task_stack,
 	.gpl_only	= false,

kernel/bpf/syscall.c

···
 	case BPF_PROG_TYPE_CGROUP_SOCK:
 		switch (expected_attach_type) {
 		case BPF_CGROUP_INET_SOCK_CREATE:
+		case BPF_CGROUP_INET_SOCK_RELEASE:
 		case BPF_CGROUP_INET4_POST_BIND:
 		case BPF_CGROUP_INET6_POST_BIND:
 			return 0;
···
 		return BPF_PROG_TYPE_CGROUP_SKB;
 		break;
 	case BPF_CGROUP_INET_SOCK_CREATE:
+	case BPF_CGROUP_INET_SOCK_RELEASE:
 	case BPF_CGROUP_INET4_POST_BIND:
 	case BPF_CGROUP_INET6_POST_BIND:
 		return BPF_PROG_TYPE_CGROUP_SOCK;
···
 	case BPF_CGROUP_INET_INGRESS:
 	case BPF_CGROUP_INET_EGRESS:
 	case BPF_CGROUP_INET_SOCK_CREATE:
+	case BPF_CGROUP_INET_SOCK_RELEASE:
 	case BPF_CGROUP_INET4_BIND:
 	case BPF_CGROUP_INET6_BIND:
 	case BPF_CGROUP_INET4_POST_BIND:

kernel/trace/Makefile

···
 GCOV_PROFILE := y
 endif
 
+CFLAGS_bpf_trace.o := -I$(src)
+
 CFLAGS_trace_benchmark.o := -I$(src)
 CFLAGS_trace_events_filter.o := -I$(src)
 

kernel/trace/bpf_trace.c

···
 #include <linux/uaccess.h>
 #include <linux/ctype.h>
 #include <linux/kprobes.h>
+#include <linux/spinlock.h>
 #include <linux/syscalls.h>
 #include <linux/error-injection.h>
+#include <linux/btf_ids.h>
 
 #include <asm/tlb.h>
 
 #include "trace_probe.h"
 #include "trace.h"
+
+#define CREATE_TRACE_POINTS
+#include "bpf_trace.h"
 
 #define bpf_event_rcu_dereference(p)					\
 	rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex))
···
 	}
 }
 
+static DEFINE_RAW_SPINLOCK(trace_printk_lock);
+
+#define BPF_TRACE_PRINTK_SIZE   1024
+
+static inline __printf(1, 0) int bpf_do_trace_printk(const char *fmt, ...)
+{
+	static char buf[BPF_TRACE_PRINTK_SIZE];
+	unsigned long flags;
+	va_list ap;
+	int ret;
+
+	raw_spin_lock_irqsave(&trace_printk_lock, flags);
+	va_start(ap, fmt);
+	ret = vsnprintf(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+	/* vsnprintf() will not append null for zero-length strings */
+	if (ret == 0)
+		buf[0] = '\0';
+	trace_bpf_trace_printk(buf);
+	raw_spin_unlock_irqrestore(&trace_printk_lock, flags);
+
+	return ret;
+}
+
 /*
  * Only limited trace_printk() conversion specifiers allowed:
  * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pB %pks %pus %s
···
  */
 #define __BPF_TP_EMIT()	__BPF_ARG3_TP()
 #define __BPF_TP(...)							\
-	__trace_printk(0 /* Fake ip */,					\
-		       fmt, ##__VA_ARGS__)
+	bpf_do_trace_printk(fmt, ##__VA_ARGS__)
 
 #define __BPF_ARG1_TP(...)						\
 	((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64))	\
···
 const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
 {
 	/*
-	 * this program might be calling bpf_trace_printk,
-	 * so allocate per-cpu printk buffers
+	 * This program might be calling bpf_trace_printk,
+	 * so enable the associated bpf_trace/bpf_trace_printk event.
+	 * Repeat this each time as it is possible a user has
+	 * disabled bpf_trace_printk events.  By loading a program
+	 * calling bpf_trace_printk() however the user has expressed
+	 * the intent to see such events.
 	 */
-	trace_printk_init_buffers();
+	if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1))
+		pr_warn_ratelimited("could not enable bpf_trace_printk events");
 
 	return &bpf_trace_printk_proto;
 }
···
 	return err;
 }
 
-static int bpf_seq_printf_btf_ids[5];
+BTF_ID_LIST(bpf_seq_printf_btf_ids)
+BTF_ID(struct, seq_file)
+
 static const struct bpf_func_proto bpf_seq_printf_proto = {
 	.func		= bpf_seq_printf,
 	.gpl_only	= true,
···
 	return seq_write(m, data, len) ? -EOVERFLOW : 0;
 }
 
-static int bpf_seq_write_btf_ids[5];
+BTF_ID_LIST(bpf_seq_write_btf_ids)
+BTF_ID(struct, seq_file)
+
 static const struct bpf_func_proto bpf_seq_write_proto = {
 	.func		= bpf_seq_write,
 	.gpl_only	= true,

kernel/trace/bpf_trace.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bpf_trace
+
+#if !defined(_TRACE_BPF_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+
+#define _TRACE_BPF_TRACE_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(bpf_trace_printk,
+
+	TP_PROTO(const char *bpf_string),
+
+	TP_ARGS(bpf_string),
+
+	TP_STRUCT__entry(
+		__string(bpf_string, bpf_string)
+	),
+
+	TP_fast_assign(
+		__assign_str(bpf_string, bpf_string);
+	),
+
+	TP_printk("%s", __get_str(bpf_string))
+);
+
+#endif /* _TRACE_BPF_TRACE_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE bpf_trace
+
+#include <trace/define_trace.h>

net/core/filter.c

···
 #include <net/ipv6_stubs.h>
 #include <net/bpf_sk_storage.h>
 #include <net/transp_v6.h>
+#include <linux/btf_ids.h>
 
 /**
  *	sk_filter_trim_cap - run a packet through a socket filter
···
 	.arg5_type	= ARG_CONST_SIZE_OR_ZERO,
 };
 
-static int bpf_skb_output_btf_ids[5];
+BTF_ID_LIST(bpf_skb_output_btf_ids)
+BTF_ID(struct, sk_buff)
+
 const struct bpf_func_proto bpf_skb_output_proto = {
 	.func		= bpf_skb_event_output,
 	.gpl_only	= true,
···
 	.arg5_type	= ARG_CONST_SIZE_OR_ZERO,
 };
 
-static int bpf_xdp_output_btf_ids[5];
+BTF_ID_LIST(bpf_xdp_output_btf_ids)
+BTF_ID(struct, xdp_buff)
+
 const struct bpf_func_proto bpf_xdp_output_proto = {
 	.func		= bpf_xdp_event_output,
 	.gpl_only	= true,
···
 	case offsetof(struct bpf_sock, priority):
 		switch (attach_type) {
 		case BPF_CGROUP_INET_SOCK_CREATE:
+		case BPF_CGROUP_INET_SOCK_RELEASE:
 			goto full_access;
 		default:
 			return false;

net/ipv4/af_inet.c

···
 	if (sk) {
 		long timeout;
 
+		if (!sk->sk_kern_sock)
+			BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk);
+
 		/* Applications forget to leave groups before exiting */
 		ip_mc_drop_socket(sk);
 

net/xdp/xsk.c

···
 	addr = xp_get_handle(xskb);
 	err = xskq_prod_reserve_desc(xs->rx, addr, len);
 	if (err) {
-		xs->rx_dropped++;
+		xs->rx_queue_full++;
 		return err;
 	}
 
···
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(xs, &umem->xsk_tx_list, list) {
-		if (!xskq_cons_peek_desc(xs->tx, desc, umem))
+		if (!xskq_cons_peek_desc(xs->tx, desc, umem)) {
+			xs->tx->queue_empty_descs++;
 			continue;
+		}
 
 		/* This is the backpressure mechanism for the Tx path.
 		 * Reserve space in the completion queue and only proceed
···
 
 		sent_frame = true;
 	}
+
+	xs->tx->queue_empty_descs++;
 
 out:
 	if (sent_frame)
···
 	ring->desc = offsetof(struct xdp_umem_ring, desc);
 }
 
+struct xdp_statistics_v1 {
+	__u64 rx_dropped;
+	__u64 rx_invalid_descs;
+	__u64 tx_invalid_descs;
+};
+
 static int xsk_getsockopt(struct socket *sock, int level, int optname,
 			  char __user *optval, int __user *optlen)
 {
···
 	case XDP_STATISTICS:
 	{
 		struct xdp_statistics stats;
+		bool extra_stats = true;
+		size_t stats_size;
 
-		if (len < sizeof(stats))
+		if (len < sizeof(struct xdp_statistics_v1)) {
 			return -EINVAL;
+		} else if (len < sizeof(stats)) {
+			extra_stats = false;
+			stats_size = sizeof(struct xdp_statistics_v1);
+		} else {
+			stats_size = sizeof(stats);
+		}
 
 		mutex_lock(&xs->mutex);
 		stats.rx_dropped = xs->rx_dropped;
+		if (extra_stats) {
+			stats.rx_ring_full = xs->rx_queue_full;
+			stats.rx_fill_ring_empty_descs =
+				xs->umem ? xskq_nb_queue_empty_descs(xs->umem->fq) : 0;
+			stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx);
+		} else {
+			stats.rx_dropped += xs->rx_queue_full;
+		}
 		stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
 		stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
 		mutex_unlock(&xs->mutex);
 
-		if (copy_to_user(optval, &stats, sizeof(stats)))
+		if (copy_to_user(optval, &stats, stats_size))
 			return -EFAULT;
-		if (put_user(sizeof(stats), optlen))
+		if (put_user(stats_size, optlen))
 			return -EFAULT;
 
 		return 0;

net/xdp/xsk_buff_pool.c

···
 
 	for (;;) {
 		if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
+			pool->fq->queue_empty_descs++;
 			xp_release(xskb);
 			return NULL;
 		}

net/xdp/xsk_diag.c

···
 	return err;
 }
 
+static int xsk_diag_put_stats(const struct xdp_sock *xs, struct sk_buff *nlskb)
+{
+	struct xdp_diag_stats du = {};
+
+	du.n_rx_dropped = xs->rx_dropped;
+	du.n_rx_invalid = xskq_nb_invalid_descs(xs->rx);
+	du.n_rx_full = xs->rx_queue_full;
+	du.n_fill_ring_empty = xs->umem ? xskq_nb_queue_empty_descs(xs->umem->fq) : 0;
+	du.n_tx_invalid = xskq_nb_invalid_descs(xs->tx);
+	du.n_tx_ring_empty = xskq_nb_queue_empty_descs(xs->tx);
+	return nla_put(nlskb, XDP_DIAG_STATS, sizeof(du), &du);
+}
+
 static int xsk_diag_fill(struct sock *sk, struct sk_buff *nlskb,
 			 struct xdp_diag_req *req,
 			 struct user_namespace *user_ns,
···
 
 	if ((req->xdiag_show & XDP_SHOW_MEMINFO) &&
 	    sock_diag_put_meminfo(sk, nlskb, XDP_DIAG_MEMINFO))
+		goto out_nlmsg_trim;
+
+	if ((req->xdiag_show & XDP_SHOW_STATS) &&
+	    xsk_diag_put_stats(xs, nlskb))
 		goto out_nlmsg_trim;
 
 	mutex_unlock(&xs->mutex);

net/xdp/xsk_queue.h

···
 	u32 cached_cons;
 	struct xdp_ring *ring;
 	u64 invalid_descs;
+	u64 queue_empty_descs;
 };
 
 /* The structure of the shared state of the rings are the same as the
···
 static inline u64 xskq_nb_invalid_descs(struct xsk_queue *q)
 {
 	return q ? q->invalid_descs : 0;
+}
+
+static inline u64 xskq_nb_queue_empty_descs(struct xsk_queue *q)
+{
+	return q ? q->queue_empty_descs : 0;
 }
 
 struct xsk_queue *xskq_create(u32 nentries, bool umem_queue);

samples/bpf/Makefile

···
 tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
 lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
 xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
-test_map_in_map-objs := bpf_load.o test_map_in_map_user.o
+test_map_in_map-objs := test_map_in_map_user.o
 per_socket_stats_example-objs := cookie_uid_helper_example.o
 xdp_redirect-objs := xdp_redirect_user.o
 xdp_redirect_map-objs := xdp_redirect_map_user.o

samples/bpf/fds_example.c

···
 #define BPF_M_MAP	1
 #define BPF_M_PROG	2
 
+char bpf_log_buf[BPF_LOG_BUF_SIZE];
+
 static void usage(void)
 {
 	printf("Usage: fds_example [...]\n");
···
 		BPF_EXIT_INSN(),
 	};
 	size_t insns_cnt = sizeof(insns) / sizeof(struct bpf_insn);
-	char bpf_log_buf[BPF_LOG_BUF_SIZE];
 	struct bpf_object *obj;
 	int prog_fd;
 

samples/bpf/map_perf_test_kern.c

···
 #include <linux/version.h>
 #include <uapi/linux/bpf.h>
 #include <bpf/bpf_helpers.h>
-#include "bpf_legacy.h"
 #include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+#include "trace_common.h"
 
 #define MAX_ENTRIES 1000
 #define MAX_NR_CPUS 1024
 
-struct bpf_map_def_legacy SEC("maps") hash_map = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = MAX_ENTRIES,
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, u32);
+	__type(value, long);
+	__uint(max_entries, MAX_ENTRIES);
+} hash_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_LRU_HASH);
+	__type(key, u32);
+	__type(value, long);
+	__uint(max_entries, 10000);
+} lru_hash_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_LRU_HASH);
+	__type(key, u32);
+	__type(value, long);
+	__uint(max_entries, 10000);
+	__uint(map_flags, BPF_F_NO_COMMON_LRU);
+} nocommon_lru_hash_map SEC(".maps");
+
+struct inner_lru {
+	__uint(type, BPF_MAP_TYPE_LRU_HASH);
+	__type(key, u32);
+	__type(value, long);
+	__uint(max_entries, MAX_ENTRIES);
+	__uint(map_flags, BPF_F_NUMA_NODE);
+	__uint(numa_node, 0);
+} inner_lru_hash_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
+	__uint(max_entries, MAX_NR_CPUS);
+	__uint(key_size, sizeof(u32));
+	__array(values, struct inner_lru); /* use inner_lru as inner map */
+} array_of_lru_hashs SEC(".maps") = {
+	/* statically initialize the first element */
+	.values = { &inner_lru_hash_map },
 };
 
-struct bpf_map_def_legacy SEC("maps") lru_hash_map = {
-	.type = BPF_MAP_TYPE_LRU_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = 10000,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+	__uint(key_size, sizeof(u32));
+	__uint(value_size, sizeof(long));
+	__uint(max_entries, MAX_ENTRIES);
+} percpu_hash_map SEC(".maps");
 
-struct bpf_map_def_legacy SEC("maps") nocommon_lru_hash_map = {
-	.type = BPF_MAP_TYPE_LRU_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = 10000,
-	.map_flags = BPF_F_NO_COMMON_LRU,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, u32);
+	__type(value, long);
+	__uint(max_entries, MAX_ENTRIES);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+} hash_map_alloc SEC(".maps");
 
-struct bpf_map_def_legacy SEC("maps") inner_lru_hash_map = {
-	.type = BPF_MAP_TYPE_LRU_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = MAX_ENTRIES,
-	.map_flags = BPF_F_NUMA_NODE,
-	.numa_node = 0,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+	__uint(key_size, sizeof(u32));
+	__uint(value_size, sizeof(long));
+	__uint(max_entries, MAX_ENTRIES);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+} percpu_hash_map_alloc SEC(".maps");
 
-struct bpf_map_def_legacy SEC("maps") array_of_lru_hashs = {
-	.type = BPF_MAP_TYPE_ARRAY_OF_MAPS,
-	.key_size = sizeof(u32),
-	.max_entries = MAX_NR_CPUS,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_LPM_TRIE);
+	__uint(key_size, 8);
+	__uint(value_size, sizeof(long));
+	__uint(max_entries, 10000);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+} lpm_trie_map_alloc SEC(".maps");
 
-struct bpf_map_def_legacy SEC("maps") percpu_hash_map = {
-	.type = BPF_MAP_TYPE_PERCPU_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = MAX_ENTRIES,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, long);
+	__uint(max_entries, MAX_ENTRIES);
+} array_map SEC(".maps");
 
-struct bpf_map_def_legacy SEC("maps") hash_map_alloc = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = MAX_ENTRIES,
-	.map_flags = BPF_F_NO_PREALLOC,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_LRU_HASH);
+	__type(key, u32);
+	__type(value, long);
+	__uint(max_entries, MAX_ENTRIES);
+} lru_hash_lookup_map SEC(".maps");
 
-struct bpf_map_def_legacy SEC("maps") percpu_hash_map_alloc = {
-	.type = BPF_MAP_TYPE_PERCPU_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = MAX_ENTRIES,
-	.map_flags = BPF_F_NO_PREALLOC,
-};
-
-struct bpf_map_def_legacy SEC("maps") lpm_trie_map_alloc = {
-	.type = BPF_MAP_TYPE_LPM_TRIE,
-	.key_size = 8,
-	.value_size = sizeof(long),
-	.max_entries = 10000,
-	.map_flags = BPF_F_NO_PREALLOC,
-};
-
-struct bpf_map_def_legacy SEC("maps") array_map = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = MAX_ENTRIES,
-};
-
-struct bpf_map_def_legacy SEC("maps") lru_hash_lookup_map = {
-	.type = BPF_MAP_TYPE_LRU_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(long),
-	.max_entries = MAX_ENTRIES,
-};
-
-SEC("kprobe/sys_getuid")
+SEC("kprobe/" SYSCALL(sys_getuid))
 int stress_hmap(struct pt_regs *ctx)
 {
 	u32 key = bpf_get_current_pid_tgid();
···
 	return 0;
 }
 
-SEC("kprobe/sys_geteuid")
+SEC("kprobe/" SYSCALL(sys_geteuid))
 int stress_percpu_hmap(struct pt_regs *ctx)
 {
 	u32 key = bpf_get_current_pid_tgid();
···
 	return 0;
 }
 
-SEC("kprobe/sys_getgid")
+SEC("kprobe/" SYSCALL(sys_getgid))
 int stress_hmap_alloc(struct pt_regs *ctx)
 {
 	u32 key = bpf_get_current_pid_tgid();
···
 	return 0;
 }
 
-SEC("kprobe/sys_getegid")
+SEC("kprobe/" SYSCALL(sys_getegid))
 int stress_percpu_hmap_alloc(struct pt_regs *ctx)
 {
 	u32 key = bpf_get_current_pid_tgid();
···
 	return 0;
 }
 
-SEC("kprobe/sys_connect")
+SEC("kprobe/" SYSCALL(sys_connect))
 int stress_lru_hmap_alloc(struct pt_regs *ctx)
 {
+	struct pt_regs *real_regs = (struct pt_regs *)PT_REGS_PARM1_CORE(ctx);
 	char fmt[] = "Failed at stress_lru_hmap_alloc. ret:%dn";
 	union {
 		u16 dst6[8];
···
 	long val = 1;
 	u32 key = 0;
 
-	in6 = (struct sockaddr_in6 *)PT_REGS_PARM2(ctx);
-	addrlen = (int)PT_REGS_PARM3(ctx);
+	in6 = (struct sockaddr_in6 *)PT_REGS_PARM2_CORE(real_regs);
+	addrlen = (int)PT_REGS_PARM3_CORE(real_regs);
 
 	if (addrlen != sizeof(*in6))
 		return 0;
···
 	return 0;
 }
 
-SEC("kprobe/sys_gettid")
+SEC("kprobe/" SYSCALL(sys_gettid))
 int stress_lpm_trie_map_alloc(struct pt_regs *ctx)
 {
 	union {
···
 	return 0;
 }
 
-SEC("kprobe/sys_getpgid")
+SEC("kprobe/" SYSCALL(sys_getpgid))
 int stress_hash_map_lookup(struct pt_regs *ctx)
 {
 	u32 key = 1, i;
···
 	return 0;
 }
 
-SEC("kprobe/sys_getppid")
+SEC("kprobe/" SYSCALL(sys_getppid))
 int stress_array_map_lookup(struct pt_regs *ctx)
 {
 	u32 key = 1, i;

samples/bpf/map_perf_test_user.c

···
 #include <sys/wait.h>
 #include <stdlib.h>
 #include <signal.h>
-#include <linux/bpf.h>
 #include <string.h>
 #include <time.h>
 #include <sys/resource.h>
···
 #include <errno.h>
 
 #include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
 
 #define TEST_BIT(t) (1U << (t))
 #define MAX_NR_CPUS 1024
···
 	[LRU_HASH_LOOKUP] = "lru_hash_lookup_map",
 };
 
+enum map_idx {
+	array_of_lru_hashs_idx,
+	hash_map_alloc_idx,
+	lru_hash_lookup_idx,
+	NR_IDXES,
+};
+
+static int map_fd[NR_IDXES];
+
 static int test_flags = ~0;
 static uint32_t num_map_entries;
 static uint32_t inner_lru_hash_size;
-static int inner_lru_hash_idx = -1;
-static int array_of_lru_hashs_idx = -1;
-static int lru_hash_lookup_idx = -1;
 static int lru_hash_lookup_test_entries = 32;
 static uint32_t max_cnt = 1000000;
 
···
 	__u64 start_time;
 	int i, ret;
 
-	if (test == INNER_LRU_HASH_PREALLOC) {
+	if (test == INNER_LRU_HASH_PREALLOC && cpu) {
+		/* If CPU is not 0, create inner_lru hash map and insert the fd
+		 * value into the array_of_lru_hash map. In case of CPU 0,
+		 * 'inner_lru_hash_map' was statically inserted on the map init
+		 */
 		int outer_fd = map_fd[array_of_lru_hashs_idx];
 		unsigned int mycpu, mynode;
 
 		assert(cpu < MAX_NR_CPUS);
 
-		if (cpu) {
-			ret = syscall(__NR_getcpu, &mycpu, &mynode, NULL);
-			assert(!ret);
+		ret = syscall(__NR_getcpu, &mycpu, &mynode, NULL);
+		assert(!ret);
 
-			inner_lru_map_fds[cpu] =
-				bpf_create_map_node(BPF_MAP_TYPE_LRU_HASH,
-						    test_map_names[INNER_LRU_HASH_PREALLOC],
-						    sizeof(uint32_t),
-						    sizeof(long),
-						    inner_lru_hash_size, 0,
-						    mynode);
-			if (inner_lru_map_fds[cpu] == -1) {
-				printf("cannot create BPF_MAP_TYPE_LRU_HASH %s(%d)\n",
-				       strerror(errno), errno);
-				exit(1);
-			}
-		} else {
-			inner_lru_map_fds[cpu] = map_fd[inner_lru_hash_idx];
+		inner_lru_map_fds[cpu] =
+			bpf_create_map_node(BPF_MAP_TYPE_LRU_HASH,
+					    test_map_names[INNER_LRU_HASH_PREALLOC],
+					    sizeof(uint32_t),
+					    sizeof(long),
+					    inner_lru_hash_size, 0,
+					    mynode);
+		if (inner_lru_map_fds[cpu] == -1) {
+			printf("cannot create BPF_MAP_TYPE_LRU_HASH %s(%d)\n",
+			       strerror(errno), errno);
+			exit(1);
 		}
 
 		ret = bpf_map_update_elem(outer_fd, &cpu,
···
 		key->data[1] = rand() & 0xff;
 		key->data[2] = rand() & 0xff;
 		key->data[3] = rand() & 0xff;
-		r = bpf_map_update_elem(map_fd[6], key, &value, 0);
+		r = bpf_map_update_elem(map_fd[hash_map_alloc_idx],
+					key, &value, 0);
 		assert(!r);
 	}
 
···
 	key->data[3] = 1;
 	value = 128;
 
-	r = bpf_map_update_elem(map_fd[6], key, &value, 0);
+	r = bpf_map_update_elem(map_fd[hash_map_alloc_idx], key, &value, 0);
 	assert(!r);
 }
 
-static void fixup_map(struct bpf_map_data *map, int idx)
+static void fixup_map(struct bpf_object *obj)
 {
+	struct bpf_map *map;
 	int i;
 
-	if (!strcmp("inner_lru_hash_map", map->name)) {
-		inner_lru_hash_idx = idx;
-		inner_lru_hash_size = map->def.max_entries;
-	}
+	bpf_object__for_each_map(map, obj) {
+		const char *name = bpf_map__name(map);
 
-	if (!strcmp("array_of_lru_hashs", map->name)) {
-		if (inner_lru_hash_idx == -1) {
-			printf("inner_lru_hash_map must be defined before array_of_lru_hashs\n");
-			exit(1);
+		/* Only change the max_entries for the enabled test(s) */
+		for (i = 0; i < NR_TESTS; i++) {
+			if (!strcmp(test_map_names[i], name) &&
+			    (check_test_flags(i))) {
+				bpf_map__resize(map, num_map_entries);
+				continue;
+			}
 		}
-		map->def.inner_map_idx = inner_lru_hash_idx;
-		array_of_lru_hashs_idx = idx;
 	}
-
-	if (!strcmp("lru_hash_lookup_map", map->name))
-		lru_hash_lookup_idx = idx;
-
-	if (num_map_entries <= 0)
-		return;
 
 	inner_lru_hash_size = num_map_entries;
-
-	/* Only change the max_entries for the enabled test(s) */
-	for (i = 0; i < NR_TESTS; i++) {
-		if (!strcmp(test_map_names[i], map->name) &&
-		    (check_test_flags(i))) {
-			map->def.max_entries = num_map_entries;
-		}
-	}
 }
 
 int main(int argc, char **argv)
 {
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+	struct bpf_link *links[8];
+	struct bpf_program *prog;
+	struct bpf_object *obj;
+	struct bpf_map *map;
 	char filename[256];
-	int num_cpu = 8;
+	int i = 0;
 
-	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
-	setrlimit(RLIMIT_MEMLOCK, &r);
+	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+		perror("setrlimit(RLIMIT_MEMLOCK)");
+		return 1;
+	}
 
 	if (argc > 1)
 		test_flags = atoi(argv[1]) ? : test_flags;
 
 	if (argc > 2)
-		num_cpu = atoi(argv[2]) ? : num_cpu;
+		nr_cpus = atoi(argv[2]) ? : nr_cpus;
 
 	if (argc > 3)
 		num_map_entries = atoi(argv[3]);
···
 	if (argc > 4)
 		max_cnt = atoi(argv[4]);
 
-	if (load_bpf_file_fixup_map(filename, fixup_map)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return 0;
+	}
+
+	map = bpf_object__find_map_by_name(obj, "inner_lru_hash_map");
+	if (libbpf_get_error(map)) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	inner_lru_hash_size = bpf_map__max_entries(map);
+	if (!inner_lru_hash_size) {
+		fprintf(stderr, "ERROR: failed to get map attribute\n");
+		goto cleanup;
+	}
+
+	/* resize BPF map prior to loading */
+	if (num_map_entries > 0)
+		fixup_map(obj);
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "array_of_lru_hashs");
+	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "hash_map_alloc");
+	map_fd[2] = bpf_object__find_map_fd_by_name(obj, "lru_hash_lookup_map");
+	if (map_fd[0] < 0 || map_fd[1] < 0 || map_fd[2] < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		links[i] = bpf_program__attach(prog);
+		if (libbpf_get_error(links[i])) {
+			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+			links[i] = NULL;
+			goto cleanup;
+		}
+		i++;
 	}
 
 	fill_lpm_trie();
 
-	run_perf_test(num_cpu);
+	run_perf_test(nr_cpus);
 
+cleanup:
+	for (i--; i >= 0; i--)
+		bpf_link__destroy(links[i]);
+
+	bpf_object__close(obj);
 	return 0;
 }

samples/bpf/test_map_in_map_kern.c

···
 #include <uapi/linux/bpf.h>
 #include <uapi/linux/in6.h>
 #include <bpf/bpf_helpers.h>
-#include "bpf_legacy.h"
 #include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+#include "trace_common.h"
 
 #define MAX_NR_PORTS 65536
 
 /* map #0 */
-struct bpf_map_def_legacy SEC("maps") port_a = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(int),
-	.max_entries = MAX_NR_PORTS,
-};
+struct inner_a {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, int);
+	__uint(max_entries, MAX_NR_PORTS);
+} port_a SEC(".maps");
 
 /* map #1 */
-struct bpf_map_def_legacy SEC("maps") port_h = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(int),
-	.max_entries = 1,
-};
+struct inner_h {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, u32);
+	__type(value, int);
+	__uint(max_entries, 1);
+} port_h SEC(".maps");
 
 /* map #2 */
-struct bpf_map_def_legacy SEC("maps") reg_result_h = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(int),
-	.max_entries = 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, u32);
+	__type(value, int);
+	__uint(max_entries, 1);
+} reg_result_h SEC(".maps");
 
 /* map #3 */
-struct bpf_map_def_legacy SEC("maps") inline_result_h = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(int),
-	.max_entries = 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, u32);
+	__type(value, int);
+	__uint(max_entries, 1);
+} inline_result_h SEC(".maps");
 
 /* map #4 */ /* Test case #0 */
-struct bpf_map_def_legacy SEC("maps") a_of_port_a = {
-	.type = BPF_MAP_TYPE_ARRAY_OF_MAPS,
-	.key_size = sizeof(u32),
-	.inner_map_idx = 0, /* map_fd[0] is port_a */
-	.max_entries = MAX_NR_PORTS,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
+	__uint(max_entries, MAX_NR_PORTS);
+	__uint(key_size, sizeof(u32));
+	__array(values, struct inner_a); /* use inner_a as inner map */
+} a_of_port_a SEC(".maps");
 
 /* map #5 */ /* Test case #1 */
-struct bpf_map_def_legacy SEC("maps") h_of_port_a = {
-	.type = BPF_MAP_TYPE_HASH_OF_MAPS,
-	.key_size = sizeof(u32),
-	.inner_map_idx = 0, /* map_fd[0] is port_a */
-	.max_entries = 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
+	__uint(max_entries, 1);
+	__uint(key_size, sizeof(u32));
+	__array(values, struct inner_a); /* use inner_a as inner map */
+} h_of_port_a SEC(".maps");
 
 /* map #6 */ /* Test case #2 */
-struct bpf_map_def_legacy SEC("maps") h_of_port_h = {
-	.type = BPF_MAP_TYPE_HASH_OF_MAPS,
-	.key_size = sizeof(u32),
-	.inner_map_idx = 1, /* map_fd[1] is port_h */
-	.max_entries = 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
+	__uint(max_entries, 1);
+	__uint(key_size, sizeof(u32));
+	__array(values, struct inner_h); /* use inner_h as inner map */
+} h_of_port_h SEC(".maps");
 
 static __always_inline int do_reg_lookup(void *inner_map, u32 port)
 {
···
 	return result ? *result : -ENOENT;
 }
 
-SEC("kprobe/sys_connect")
+SEC("kprobe/" SYSCALL(sys_connect))
 int trace_sys_connect(struct pt_regs *ctx)
 {
+	struct pt_regs *real_regs = (struct pt_regs *)PT_REGS_PARM1_CORE(ctx);
 	struct sockaddr_in6 *in6;
 	u16 test_case, port, dst6[8];
 	int addrlen, ret, inline_ret, ret_key = 0;
···
 	void *outer_map, *inner_map;
 	bool inline_hash = false;
 
-	in6 = (struct sockaddr_in6 *)PT_REGS_PARM2(ctx);
-	addrlen = (int)PT_REGS_PARM3(ctx);
+	in6 = (struct sockaddr_in6 *)PT_REGS_PARM2_CORE(real_regs);
+	addrlen = (int)PT_REGS_PARM3_CORE(real_regs);
 
 	if (addrlen != sizeof(*in6))
 		return 0;

samples/bpf/test_map_in_map_user.c

···
 #include <stdlib.h>
 #include <stdio.h>
 #include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
+
+static int map_fd[7];
 
 #define PORT_A		(map_fd[0])
 #define PORT_H		(map_fd[1])
···
 int main(int argc, char **argv)
 {
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	struct bpf_link *link = NULL;
+	struct bpf_program *prog;
+	struct bpf_object *obj;
 	char filename[256];
 
-	assert(!setrlimit(RLIMIT_MEMLOCK, &r));
+	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+		perror("setrlimit(RLIMIT_MEMLOCK)");
+		return 1;
+	}
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return 0;
+	}
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	prog = bpf_object__find_program_by_name(obj, "trace_sys_connect");
+	if (!prog) {
+		printf("finding a prog in obj file failed\n");
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "port_a");
+	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "port_h");
+	map_fd[2] = bpf_object__find_map_fd_by_name(obj, "reg_result_h");
+	map_fd[3] = bpf_object__find_map_fd_by_name(obj, "inline_result_h");
+	map_fd[4] = bpf_object__find_map_fd_by_name(obj, "a_of_port_a");
+	map_fd[5] = bpf_object__find_map_fd_by_name(obj, "h_of_port_a");
+	map_fd[6] = bpf_object__find_map_fd_by_name(obj, "h_of_port_h");
+	if (map_fd[0] < 0 || map_fd[1] < 0 || map_fd[2] < 0 ||
+	    map_fd[3] < 0 || map_fd[4] < 0 || map_fd[5] < 0 || map_fd[6] < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	link = bpf_program__attach(prog);
+	if (libbpf_get_error(link)) {
+		fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+		link = NULL;
+		goto cleanup;
 	}
 
 	test_map_in_map();
 
+cleanup:
+	bpf_link__destroy(link);
+	bpf_object__close(obj);
 	return 0;
 }

samples/bpf/test_probe_write_user_kern.c

···
 #include <linux/version.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+#include "trace_common.h"
 
 struct bpf_map_def SEC("maps") dnat_map = {
 	.type = BPF_MAP_TYPE_HASH,
···
  * This example sits on a syscall, and the syscall ABI is relatively stable
  * of course, across platforms, and over time, the ABI may change.
  */
-SEC("kprobe/sys_connect")
+SEC("kprobe/" SYSCALL(sys_connect))
 int bpf_prog1(struct pt_regs *ctx)
 {
+	struct pt_regs *real_regs = (struct pt_regs *)PT_REGS_PARM1_CORE(ctx);
+	void *sockaddr_arg = (void *)PT_REGS_PARM2_CORE(real_regs);
+	int sockaddr_len = (int)PT_REGS_PARM3_CORE(real_regs);
 	struct sockaddr_in new_addr, orig_addr = {};
 	struct sockaddr_in *mapped_addr;
-	void *sockaddr_arg = (void *)PT_REGS_PARM2(ctx);
-	int sockaddr_len = (int)PT_REGS_PARM3(ctx);
 
 	if (sockaddr_len > sizeof(orig_addr))
 		return 0;

samples/bpf/xdpsock_user.c

···
 static int opt_pkt_count;
 static u16 opt_pkt_size = MIN_PKT_SIZE;
 static u32 opt_pkt_fill_pattern = 0x12345678;
+static bool opt_extra_stats;
 static int opt_poll;
 static int opt_interval = 1;
 static u32 opt_xdp_bind_flags = XDP_USE_NEED_WAKEUP;
···
 	struct xsk_socket *xsk;
 	unsigned long rx_npkts;
 	unsigned long tx_npkts;
+	unsigned long rx_dropped_npkts;
+	unsigned long rx_invalid_npkts;
+	unsigned long tx_invalid_npkts;
+	unsigned long rx_full_npkts;
+	unsigned long rx_fill_empty_npkts;
+	unsigned long tx_empty_npkts;
 	unsigned long prev_rx_npkts;
 	unsigned long prev_tx_npkts;
+	unsigned long prev_rx_dropped_npkts;
+	unsigned long prev_rx_invalid_npkts;
+	unsigned long prev_tx_invalid_npkts;
+	unsigned long prev_rx_full_npkts;
+	unsigned long prev_rx_fill_empty_npkts;
+	unsigned long prev_tx_empty_npkts;
 	u32 outstanding_tx;
 };
 
···
 	}
 }
 
+static int xsk_get_xdp_stats(int fd, struct xsk_socket_info *xsk)
+{
+	struct xdp_statistics stats;
+	socklen_t optlen;
+	int err;
+
+	optlen = sizeof(stats);
+	err = getsockopt(fd, SOL_XDP, XDP_STATISTICS, &stats, &optlen);
+	if (err)
+		return err;
+
+	if (optlen == sizeof(struct xdp_statistics)) {
+		xsk->rx_dropped_npkts = stats.rx_dropped;
+		xsk->rx_invalid_npkts = stats.rx_invalid_descs;
+		xsk->tx_invalid_npkts = stats.tx_invalid_descs;
+		xsk->rx_full_npkts = stats.rx_ring_full;
+		xsk->rx_fill_empty_npkts = stats.rx_fill_ring_empty_descs;
+		xsk->tx_empty_npkts = stats.tx_ring_empty_descs;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
 static void dump_stats(void)
 {
 	unsigned long now = get_nsecs();
···
 
 	for (i = 0; i < num_socks && xsks[i]; i++) {
 		char *fmt = "%-15s %'-11.0f %'-11lu\n";
-		double rx_pps, tx_pps;
+		double rx_pps, tx_pps, dropped_pps, rx_invalid_pps, full_pps, fill_empty_pps,
+			tx_invalid_pps, tx_empty_pps;
 
 		rx_pps = (xsks[i]->rx_npkts - xsks[i]->prev_rx_npkts) *
 			 1000000000. / dt;
···
 
 		xsks[i]->prev_rx_npkts = xsks[i]->rx_npkts;
 		xsks[i]->prev_tx_npkts = xsks[i]->tx_npkts;
+
+		if (opt_extra_stats) {
+			if (!xsk_get_xdp_stats(xsk_socket__fd(xsks[i]->xsk), xsks[i])) {
+				dropped_pps = (xsks[i]->rx_dropped_npkts -
+						xsks[i]->prev_rx_dropped_npkts) * 1000000000. / dt;
+				rx_invalid_pps = (xsks[i]->rx_invalid_npkts -
+						xsks[i]->prev_rx_invalid_npkts) * 1000000000. / dt;
+				tx_invalid_pps = (xsks[i]->tx_invalid_npkts -
+						xsks[i]->prev_tx_invalid_npkts) * 1000000000. / dt;
+				full_pps = (xsks[i]->rx_full_npkts -
+						xsks[i]->prev_rx_full_npkts) * 1000000000. / dt;
+				fill_empty_pps = (xsks[i]->rx_fill_empty_npkts -
+						xsks[i]->prev_rx_fill_empty_npkts)
+						* 1000000000. / dt;
+				tx_empty_pps = (xsks[i]->tx_empty_npkts -
+						xsks[i]->prev_tx_empty_npkts) * 1000000000. / dt;
+
+				printf(fmt, "rx dropped", dropped_pps,
+				       xsks[i]->rx_dropped_npkts);
+				printf(fmt, "rx invalid", rx_invalid_pps,
+				       xsks[i]->rx_invalid_npkts);
+				printf(fmt, "tx invalid", tx_invalid_pps,
+				       xsks[i]->tx_invalid_npkts);
+				printf(fmt, "rx queue full", full_pps,
+				       xsks[i]->rx_full_npkts);
+				printf(fmt, "fill ring empty", fill_empty_pps,
+				       xsks[i]->rx_fill_empty_npkts);
+				printf(fmt, "tx ring empty", tx_empty_pps,
+				       xsks[i]->tx_empty_npkts);
+
+				xsks[i]->prev_rx_dropped_npkts = xsks[i]->rx_dropped_npkts;
+				xsks[i]->prev_rx_invalid_npkts = xsks[i]->rx_invalid_npkts;
+				xsks[i]->prev_tx_invalid_npkts = xsks[i]->tx_invalid_npkts;
+				xsks[i]->prev_rx_full_npkts = xsks[i]->rx_full_npkts;
+				xsks[i]->prev_rx_fill_empty_npkts = xsks[i]->rx_fill_empty_npkts;
+				xsks[i]->prev_tx_empty_npkts = xsks[i]->tx_empty_npkts;
+			} else {
+				printf("%-15s\n", "Error retrieving extra stats");
+			}
+		}
 	}
 }
 
···
 	{"tx-pkt-count", required_argument, 0, 'C'},
 	{"tx-pkt-size", required_argument, 0, 's'},
 	{"tx-pkt-pattern", required_argument, 0, 'P'},
+	{"extra-stats", no_argument, 0, 'x'},
 	{0, 0, 0, 0}
 };
 
···
 		"			(Default: %d bytes)\n"
 		"			Min size: %d, Max size %d.\n"
 		"  -P, --tx-pkt-pattern=nPacket fill pattern. Default: 0x%x\n"
+		"  -x, --extra-stats	Display extra statistics.\n"
 		"\n";
 	fprintf(stderr, str, prog, XSK_UMEM__DEFAULT_FRAME_SIZE,
 		opt_batch_size, MIN_PKT_SIZE, MIN_PKT_SIZE,
···
 	opterr = 0;
 
 	for (;;) {
-		c = getopt_long(argc, argv, "Frtli:q:pSNn:czf:muMd:b:C:s:P:",
+		c = getopt_long(argc, argv, "Frtli:q:pSNn:czf:muMd:b:C:s:P:x",
 				long_options, &option_index);
 		if (c == -1)
 			break;
···
 			break;
 		case 'P':
 			opt_pkt_fill_pattern = strtol(optarg, NULL, 16);
+			break;
+		case 'x':
+			opt_extra_stats = 1;
 			break;
 		default:
 			usage(basename(argv[0]));

scripts/link-vmlinux.sh

···
 
 vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
 
+# fill in BTF IDs
+if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
+info BTFIDS vmlinux
+${RESOLVE_BTFIDS} vmlinux
+fi
+
 if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
 	info SORTTAB vmlinux
 	if ! sorttable vmlinux; then

tools/Makefile

···
 cgroup firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging: FORCE
 	$(call descend,$@)
 
+bpf/%: FORCE
+	$(call descend,$@)
+
 liblockdep: FORCE
 	$(call descend,lib/lockdep)
 

tools/bpf/Makefile

···
 runqslower_clean:
 	$(call descend,runqslower,clean)
 
+resolve_btfids:
+	$(call descend,resolve_btfids)
+
+resolve_btfids_clean:
+	$(call descend,resolve_btfids,clean)
+
 .PHONY: all install clean bpftool bpftool_install bpftool_clean \
-	runqslower runqslower_install runqslower_clean
+	runqslower runqslower_install runqslower_clean \
+	resolve_btfids resolve_btfids_clean

tools/bpf/bpftool/common.c

···
 	[BPF_CGROUP_INET_INGRESS]	= "ingress",
 	[BPF_CGROUP_INET_EGRESS]	= "egress",
 	[BPF_CGROUP_INET_SOCK_CREATE]	= "sock_create",
+	[BPF_CGROUP_INET_SOCK_RELEASE]	= "sock_release",
 	[BPF_CGROUP_SOCK_OPS]		= "sock_ops",
 	[BPF_CGROUP_DEVICE]		= "device",
 	[BPF_CGROUP_INET4_BIND]		= "bind4",

tools/bpf/bpftool/gen.c

···
 		return NULL;
 }
 
-static void codegen_btf_dump_printf(void *ct, const char *fmt, va_list args)
+static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args)
 {
 	vprintf(fmt, args);
 }
···
 	int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec);
 	const char *sec_ident;
 	char var_ident[256];
+	bool strip_mods = false;
 
-	if (strcmp(sec_name, ".data") == 0)
+	if (strcmp(sec_name, ".data") == 0) {
 		sec_ident = "data";
-	else if (strcmp(sec_name, ".bss") == 0)
+	} else if (strcmp(sec_name, ".bss") == 0) {
 		sec_ident = "bss";
-	else if (strcmp(sec_name, ".rodata") == 0)
+	} else if (strcmp(sec_name, ".rodata") == 0) {
 		sec_ident = "rodata";
-	else if (strcmp(sec_name, ".kconfig") == 0)
+		strip_mods = true;
+	} else if (strcmp(sec_name, ".kconfig") == 0) {
 		sec_ident = "kconfig";
-	else
+	} else {
 		return 0;
+	}
 
 	printf("	struct %s__%s {\n", obj_name, sec_ident);
 	for (i = 0; i < vlen; i++, sec_var++) {
···
 		DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
 			.field_name = var_ident,
 			.indent_level = 2,
+			.strip_mods = strip_mods,
 		);
 		int need_off = sec_var->offset, align_off, align;
 		__u32 var_type_id = var->type;
-		const struct btf_type *t;
-
-		t = btf__type_by_id(btf, var_type_id);
-		while (btf_is_mod(t)) {
-			var_type_id = t->type;
-			t = btf__type_by_id(btf, var_type_id);
-		}
 
 		if (off > need_off) {
 			p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n",

tools/bpf/bpftool/pids.c

···
 
 int build_obj_refs_table(struct obj_refs_table *table, enum bpf_obj_type type)
 {
-	p_err("bpftool built without PID iterator support");
 	return -ENOTSUP;
 }
 void delete_obj_refs_table(struct obj_refs_table *table) {}
 void emit_obj_refs_plain(struct obj_refs_table *table, __u32 id, const char *prefix) {}
+void emit_obj_refs_json(struct obj_refs_table *table, __u32 id, json_writer_t *json_writer) {}
 
 #else /* BPFTOOL_WITHOUT_SKELETONS */
 

tools/bpf/resolve_btfids/Build

···
+resolve_btfids-y += main.o
+resolve_btfids-y += rbtree.o
+resolve_btfids-y += zalloc.o
+resolve_btfids-y += string.o
+resolve_btfids-y += ctype.o
+resolve_btfids-y += str_error_r.o
+
+$(OUTPUT)%.o: ../../lib/%.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)

tools/bpf/resolve_btfids/Makefile

···
+# SPDX-License-Identifier: GPL-2.0-only
+include ../../scripts/Makefile.include
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+ifeq ($(V),1)
+  Q =
+  msg =
+else
+  Q = @
+  msg = @printf '  %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))";
+  MAKEFLAGS=--no-print-directory
+endif
+
+OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/
+
+LIBBPF_SRC := $(srctree)/tools/lib/bpf/
+SUBCMD_SRC := $(srctree)/tools/lib/subcmd/
+
+BPFOBJ     := $(OUTPUT)/libbpf.a
+SUBCMDOBJ  := $(OUTPUT)/libsubcmd.a
+
+BINARY     := $(OUTPUT)/resolve_btfids
+BINARY_IN  := $(BINARY)-in.o
+
+all: $(BINARY)
+
+$(OUTPUT):
+	$(call msg,MKDIR,,$@)
+	$(Q)mkdir -p $(OUTPUT)
+
+$(SUBCMDOBJ): fixdep FORCE
+	$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(OUTPUT)
+
+$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)
+	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)  OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
+
+CFLAGS := -g \
+          -I$(srctree)/tools/include \
+          -I$(srctree)/tools/include/uapi \
+          -I$(LIBBPF_SRC) \
+          -I$(SUBCMD_SRC)
+
+LIBS = -lelf -lz
+
+export srctree OUTPUT CFLAGS Q
+include $(srctree)/tools/build/Makefile.include
+
+$(BINARY_IN): fixdep FORCE
+	$(Q)$(MAKE) $(build)=resolve_btfids
+
+$(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
+	$(call msg,LINK,$@)
+	$(Q)$(CC) $(BINARY_IN) $(LDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
+
+libsubcmd-clean:
+	$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(OUTPUT) clean
+
+libbpf-clean:
+	$(Q)$(MAKE) -C $(LIBBPF_SRC) OUTPUT=$(OUTPUT) clean
+
+clean: libsubcmd-clean libbpf-clean fixdep-clean
+	$(call msg,CLEAN,$(BINARY))
+	$(Q)$(RM) -f $(BINARY); \
+	find $(if $(OUTPUT),$(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
+
+tags:
+	$(call msg,GEN,,tags)
+	$(Q)ctags -R . $(LIBBPF_SRC) $(SUBCMD_SRC)
+
+FORCE:
+
+.PHONY: all FORCE clean tags

tools/bpf/resolve_btfids/main.c

···
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * resolve_btfids scans Elf object for .BTF_ids section and resolves
+ * its symbols with BTF ID values.
+ *
+ * Each symbol points to 4 bytes data and is expected to have
+ * following name syntax:
+ *
+ * __BTF_ID__<type>__<symbol>[__<id>]
+ *
+ * type is:
+ *
+ *   func    - lookup BTF_KIND_FUNC symbol with <symbol> name
+ *             and store its ID into the data:
+ *
+ *             __BTF_ID__func__vfs_close__1:
+ *             .zero 4
+ *
+ *   struct  - lookup BTF_KIND_STRUCT symbol with <symbol> name
+ *             and store its ID into the data:
+ *
+ *             __BTF_ID__struct__sk_buff__1:
+ *             .zero 4
+ *
+ *   union   - lookup BTF_KIND_UNION symbol with <symbol> name
+ *             and store its ID into the data:
+ *
+ *             __BTF_ID__union__thread_union__1:
+ *             .zero 4
+ *
+ *   typedef - lookup BTF_KIND_TYPEDEF symbol with <symbol> name
+ *             and store its ID into the data:
+ *
+ *             __BTF_ID__typedef__pid_t__1:
+ *             .zero 4
+ *
+ *   set     - store symbol size into first 4 bytes and sort following
+ *             ID list
+ *
+ *             __BTF_ID__set__list:
+ *             .zero 4
+ *             list:
+ *             __BTF_ID__func__vfs_getattr__3:
+ *             .zero 4
+ *             __BTF_ID__func__vfs_fallocate__4:
+ *             .zero 4
+ */
+
+#define  _GNU_SOURCE
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <libelf.h>
+#include <gelf.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <linux/rbtree.h>
+#include <linux/zalloc.h>
+#include <linux/err.h>
+#include <btf.h>
+#include <libbpf.h>
+#include <parse-options.h>
+
+#define BTF_IDS_SECTION	".BTF_ids"
+#define BTF_ID		"__BTF_ID__"
+
+#define BTF_STRUCT	"struct"
+#define BTF_UNION	"union"
+#define BTF_TYPEDEF	"typedef"
+#define BTF_FUNC	"func"
+#define BTF_SET		"set"
+
+#define ADDR_CNT	100
+
+struct btf_id {
+	struct rb_node	 rb_node;
+	char		*name;
+	union {
+		int	 id;
+		int	 cnt;
+	};
+	int		 addr_cnt;
+	Elf64_Addr	 addr[ADDR_CNT];
+};
+
+struct object {
+	const char *path;
+	const char *btf;
+
+	struct {
+		int		 fd;
+		Elf		*elf;
+		Elf_Data	*symbols;
+		Elf_Data	*idlist;
+		int		 symbols_shndx;
+		int		 idlist_shndx;
+		size_t		 strtabidx;
+		unsigned long	 idlist_addr;
+	} efile;
+
+	struct rb_root	sets;
+	struct rb_root	structs;
+	struct rb_root	unions;
+	struct rb_root	typedefs;
+	struct rb_root	funcs;
+
+	int nr_funcs;
+	int nr_structs;
+	int nr_unions;
+	int nr_typedefs;
+};
+
+static int verbose;
+
+int eprintf(int level, int var, const char *fmt, ...)
+{
+	va_list args;
+	int ret;
+
+	if (var >= level) {
+		va_start(args, fmt);
+		ret = vfprintf(stderr, fmt, args);
+		va_end(args);
+	}
+	return ret;
+}
+
+#ifndef pr_fmt
+#define pr_fmt(fmt) fmt
+#endif
+
+#define pr_debug(fmt, ...) \
+	eprintf(1, verbose, pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_debugN(n, fmt, ...) \
+	eprintf(n, verbose, pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_err(fmt, ...) \
+	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
+
+static bool is_btf_id(const char *name)
+{
+	return name && !strncmp(name, BTF_ID, sizeof(BTF_ID) - 1);
+}
+
+static struct btf_id *btf_id__find(struct rb_root *root, const char *name)
+{
+	struct rb_node *p = root->rb_node;
+	struct btf_id *id;
+	int cmp;
+
+	while (p) {
+		id = rb_entry(p, struct btf_id, rb_node);
+		cmp = strcmp(id->name, name);
+		if (cmp < 0)
+			p = p->rb_left;
+		else if (cmp > 0)
+			p = p->rb_right;
+		else
+			return id;
+	}
+	return NULL;
+}
+
+static struct btf_id*
+btf_id__add(struct rb_root *root, char *name, bool unique)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
+	struct btf_id *id;
+	int cmp;
+
+	while (*p != NULL) {
+		parent = *p;
+		id = rb_entry(parent, struct btf_id, rb_node);
+		cmp = strcmp(id->name, name);
+		if (cmp < 0)
+			p = &(*p)->rb_left;
+		else if (cmp > 0)
+			p = &(*p)->rb_right;
+		else
+			return unique ? NULL : id;
+	}
+
+	id = zalloc(sizeof(*id));
+	if (id) {
+		pr_debug("adding symbol %s\n", name);
+		id->name = name;
+		rb_link_node(&id->rb_node, parent, p);
+		rb_insert_color(&id->rb_node, root);
+	}
+	return id;
+}
+
+static char *get_id(const char *prefix_end)
+{
+	/*
+	 * __BTF_ID__func__vfs_truncate__0
+	 * prefix_end =  ^
+	 */
+	char *p, *id = strdup(prefix_end + sizeof("__") - 1);
+
+	if (id) {
+		/*
+		 * __BTF_ID__func__vfs_truncate__0
+		 * id =            ^
+		 *
+		 * cut the unique id part
+		 */
+		p = strrchr(id, '_');
+		p--;
+		if (*p != '_') {
+			free(id);
+			return NULL;
+		}
+		*p = '\0';
+	}
+	return id;
+}
+
+static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
+{
+	char *id;
+
+	id = get_id(name + size);
+	if (!id) {
+		pr_err("FAILED to parse symbol name: %s\n", name);
+		return NULL;
+	}
+
+	return btf_id__add(root, id, false);
+}
+
+static int elf_collect(struct object *obj)
+{
+	Elf_Scn *scn = NULL;
+	size_t shdrstrndx;
+	int idx = 0;
+	Elf *elf;
+	int fd;
+
+	fd = open(obj->path, O_RDWR, 0666);
+	if (fd == -1) {
+		pr_err("FAILED cannot open %s: %s\n",
+			obj->path, strerror(errno));
+		return -1;
+	}
+
+	elf_version(EV_CURRENT);
+
+	elf = elf_begin(fd, ELF_C_RDWR_MMAP, NULL);
+	if (!elf) {
+		pr_err("FAILED cannot create ELF descriptor: %s\n",
+			elf_errmsg(-1));
+		return -1;
+	}
+
+	obj->efile.fd  = fd;
+	obj->efile.elf = elf;
+
+	elf_flagelf(elf, ELF_C_SET, ELF_F_LAYOUT);
+
+	if (elf_getshdrstrndx(elf, &shdrstrndx) != 0) {
+		pr_err("FAILED cannot get shdr str ndx\n");
+		return -1;
+	}
+
+	/*
+	 * Scan all the elf sections and look for save data
+	 * from .BTF_ids section and symbols.
+	 */
+	while ((scn = elf_nextscn(elf, scn)) != NULL) {
+		Elf_Data *data;
+		GElf_Shdr sh;
+		char *name;
+
+		idx++;
+		if (gelf_getshdr(scn, &sh) != &sh) {
+			pr_err("FAILED get section(%d) header\n", idx);
+			return -1;
+		}
+
+		name = elf_strptr(elf, shdrstrndx, sh.sh_name);
+		if (!name) {
+			pr_err("FAILED get section(%d) name\n", idx);
+			return -1;
+		}
+
+		data = elf_getdata(scn, 0);
+		if (!data) {
+			pr_err("FAILED to get section(%d) data from %s\n",
+				idx, name);
+			return -1;
+		}
+
+		pr_debug2("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
+			  idx, name, (unsigned long) data->d_size,
+			  (int) sh.sh_link, (unsigned long) sh.sh_flags,
+			  (int) sh.sh_type);
+
+		if (sh.sh_type == SHT_SYMTAB) {
+			obj->efile.symbols       = data;
+			obj->efile.symbols_shndx = idx;
+			obj->efile.strtabidx     = sh.sh_link;
+		} else if (!strcmp(name, BTF_IDS_SECTION)) {
+			obj->efile.idlist       = data;
+			obj->efile.idlist_shndx = idx;
+			obj->efile.idlist_addr  = sh.sh_addr;
+		}
+	}
+
+	return 0;
+}
+
+static int symbols_collect(struct object *obj)
+{
+	Elf_Scn *scn = NULL;
+	int n, i, err = 0;
+	GElf_Shdr sh;
+	char *name;
+
+	scn = elf_getscn(obj->efile.elf, obj->efile.symbols_shndx);
+	if (!scn)
+		return -1;
+
+	if (gelf_getshdr(scn, &sh) != &sh)
+		return -1;
+
+	n = sh.sh_size / sh.sh_entsize;
+
+	/*
+	 * Scan symbols and look for the ones starting with
+	 * __BTF_ID__* over .BTF_ids section.
+	 */
+	for (i = 0; !err && i < n; i++) {
+		char *tmp, *prefix;
+		struct btf_id *id;
+		GElf_Sym sym;
+		int err = -1;
+
+		if (!gelf_getsym(obj->efile.symbols, i, &sym))
+			return -1;
+
+		if (sym.st_shndx != obj->efile.idlist_shndx)
+			continue;
+
+		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
+				  sym.st_name);
+
+		if (!is_btf_id(name))
+			continue;
+
+		/*
+		 * __BTF_ID__TYPE__vfs_truncate__0
+		 * prefix =  ^
+		 */
+		prefix = name + sizeof(BTF_ID) - 1;
+
+		/* struct */
+		if (!strncmp(prefix, BTF_STRUCT, sizeof(BTF_STRUCT) - 1)) {
+			obj->nr_structs++;
+			id = add_symbol(&obj->structs, prefix, sizeof(BTF_STRUCT) - 1);
+		/* union  */
+		} else if (!strncmp(prefix, BTF_UNION, sizeof(BTF_UNION) - 1)) {
+			obj->nr_unions++;
+			id = add_symbol(&obj->unions, prefix, sizeof(BTF_UNION) - 1);
+		/* typedef */
+		} else if (!strncmp(prefix, BTF_TYPEDEF, sizeof(BTF_TYPEDEF) - 1)) {
+			obj->nr_typedefs++;
+			id = add_symbol(&obj->typedefs, prefix, sizeof(BTF_TYPEDEF) - 1);
+		/* func */
+		} else if (!strncmp(prefix, BTF_FUNC, sizeof(BTF_FUNC) - 1)) {
+			obj->nr_funcs++;
+			id = add_symbol(&obj->funcs, prefix, sizeof(BTF_FUNC) - 1);
+		/* set */
+		} else if (!strncmp(prefix, BTF_SET, sizeof(BTF_SET) - 1)) {
+			id = add_symbol(&obj->sets, prefix, sizeof(BTF_SET) - 1);
+			/*
+			 * SET objects store list's count, which is encoded
+			 * in symbol's size, together with 'cnt' field hence
+			 * that - 1.
+			 */
+			if (id)
+				id->cnt = sym.st_size / sizeof(int) - 1;
+		} else {
+			pr_err("FAILED unsupported prefix %s\n", prefix);
+			return -1;
+		}
+
+		if (!id)
+			return -ENOMEM;
+
+		if (id->addr_cnt >= ADDR_CNT) {
+			pr_err("FAILED symbol %s crossed the number of allowed lists",
+				id->name);
+			return -1;
+		}
+		id->addr[id->addr_cnt++] = sym.st_value;
+	}
+
+	return 0;
+}
+
+static struct btf *btf__parse_raw(const char *file)
+{
+	struct btf *btf;
+	struct stat st;
+	__u8 *buf;
+	FILE *f;
+
+	if (stat(file, &st))
+		return NULL;
+
+	f = fopen(file, "rb");
+	if (!f)
+		return NULL;
+
+	buf = malloc(st.st_size);
+	if (!buf) {
+		btf = ERR_PTR(-ENOMEM);
+		goto exit_close;
+	}
+
+	if ((size_t) st.st_size != fread(buf, 1, st.st_size, f)) {
+		btf = ERR_PTR(-EINVAL);
+		goto exit_free;
+	}
+
+	btf = btf__new(buf, st.st_size);
+
+exit_free:
+	free(buf);
+exit_close:
+	fclose(f);
+	return btf;
+}
+
+static bool is_btf_raw(const char *file)
+{
+	__u16 magic = 0;
+	int fd, nb_read;
+
+	fd = open(file, O_RDONLY);
+	if (fd < 0)
+		return false;
+
+	nb_read = read(fd, &magic, sizeof(magic));
+	close(fd);
+	return nb_read == sizeof(magic) && magic == BTF_MAGIC;
+}
+
+static struct btf *btf_open(const char *path)
+{
+	if (is_btf_raw(path))
+		return btf__parse_raw(path);
+	else
+		return btf__parse_elf(path, NULL);
+}
+
+static int symbols_resolve(struct object *obj)
+{
+	int nr_typedefs = obj->nr_typedefs;
+	int nr_structs  = obj->nr_structs;
+	int nr_unions   = obj->nr_unions;
+	int nr_funcs    = obj->nr_funcs;
+	int err, type_id;
+	struct btf *btf;
+	__u32 nr;
+
+	btf = btf_open(obj->btf ?: obj->path);
+	err = libbpf_get_error(btf);
+	if (err) {
+		pr_err("FAILED: load BTF from %s: %s",
+			obj->path, strerror(err));
+		return -1;
+	}
+
+	err = -1;
+	nr  = btf__get_nr_types(btf);
+
+	/*
+	 * Iterate all the BTF types and search for collected symbol IDs.
+	 */
+	for (type_id = 1; type_id <= nr; type_id++) {
+		const struct btf_type *type;
+		struct rb_root *root;
+		struct btf_id *id;
+		const char *str;
+		int *nr;
+
+		type = btf__type_by_id(btf, type_id);
+		if (!type) {
+			pr_err("FAILED: malformed BTF, can't resolve type for ID %d\n",
+				type_id);
+			goto out;
+		}
+
+		if (btf_is_func(type) && nr_funcs) {
+			nr   = &nr_funcs;
+			root = &obj->funcs;
+		} else if (btf_is_struct(type) && nr_structs) {
+			nr   = &nr_structs;
+			root = &obj->structs;
+		} else if (btf_is_union(type) && nr_unions) {
+			nr   = &nr_unions;
+			root = &obj->unions;
+		} else if (btf_is_typedef(type) && nr_typedefs) {
+			nr   = &nr_typedefs;
+			root = &obj->typedefs;
+		} else
+			continue;
+
+		str = btf__name_by_offset(btf, type->name_off);
+		if (!str) {
+			pr_err("FAILED: malformed BTF, can't resolve name for ID %d\n",
+				type_id);
+			goto out;
+		}
+
+		id = btf_id__find(root, str);
+		if (id) {
+			id->id = type_id;
+			(*nr)--;
+		}
+	}
+
+	err = 0;
+out:
+	btf__free(btf);
+	return err;
+}
+
+static int id_patch(struct object *obj, struct btf_id *id)
+{
+	Elf_Data *data = obj->efile.idlist;
+	int *ptr = data->d_buf;
+	int i;
+
+	if (!id->id) {
+		pr_err("FAILED unresolved symbol %s\n", id->name);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < id->addr_cnt; i++) {
+		unsigned long addr = id->addr[i];
+		unsigned long idx = addr - obj->efile.idlist_addr;
+
+		pr_debug("patching addr %5lu: ID %7d [%s]\n",
+			 idx, id->id, id->name);
+
+		if (idx >= data->d_size) {
+			pr_err("FAILED patching index %lu out of bounds %lu\n",
+				idx, data->d_size);
+			return -1;
+		}
+
+		idx = idx / sizeof(int);
+		ptr[idx] = id->id;
+	}
+
+	return 0;
+}
+
+static int __symbols_patch(struct object *obj, struct rb_root *root)
+{
+	struct rb_node *next;
+	struct btf_id *id;
+
+	next = rb_first(root);
+	while (next) {
+		id = rb_entry(next, struct btf_id, rb_node);
+
+		if (id_patch(obj, id))
+			return -1;
+
+		next = rb_next(next);
+	}
+	return 0;
+}
+
+static int cmp_id(const void *pa, const void *pb)
+{
+	const int *a = pa, *b = pb;
+
+	return *a - *b;
+}
+
+static int sets_patch(struct object *obj)
+{
+	Elf_Data *data = obj->efile.idlist;
+	int *ptr = data->d_buf;
+	struct rb_node *next;
+
+	next = rb_first(&obj->sets);
+	while (next) {
+		unsigned long addr, idx;
+		struct btf_id *id;
+		int *base;
+		int cnt;
+
+		id   = rb_entry(next, struct btf_id, rb_node);
+		addr = id->addr[0];
+		idx  = addr - obj->efile.idlist_addr;
+
+		/* sets are unique */
+		if (id->addr_cnt != 1) {
+			pr_err("FAILED malformed data for set '%s'\n",
+				id->name);
+			return -1;
+		}
+
+		idx = idx / sizeof(int);
+		base = &ptr[idx] + 1;
+		cnt = ptr[idx];
+
+		pr_debug("sorting  addr %5lu: cnt %6d [%s]\n",
+			 (idx + 1) * sizeof(int), cnt, id->name);
+
+		qsort(base, cnt, sizeof(int), cmp_id);
+
+		next = rb_next(next);
+	}
+}
+
+static int symbols_patch(struct object *obj)
+{
+	int err;
+
+	if (__symbols_patch(obj, &obj->structs)  ||
+	    __symbols_patch(obj, &obj->unions)   ||
+	    __symbols_patch(obj, &obj->typedefs) ||
+	    __symbols_patch(obj, &obj->funcs)    ||
+	    __symbols_patch(obj, &obj->sets))
+		return -1;
+
+	if (sets_patch(obj))
+		return -1;
+
+	elf_flagdata(obj->efile.idlist, ELF_C_SET, ELF_F_DIRTY);
+
+	err = elf_update(obj->efile.elf, ELF_C_WRITE);
+	if (err < 0) {
+		pr_err("FAILED elf_update(WRITE): %s\n",
+			elf_errmsg(-1));
+	}
+
+	pr_debug("update %s for %s\n",
+		 err >= 0 ? "ok" : "failed", obj->path);
+	return err < 0 ? -1 : 0;
+}
+
+static const char * const resolve_btfids_usage[] = {
+	"resolve_btfids [<options>] <ELF object>",
+	NULL
+};
+
+int main(int argc, const char **argv)
+{
+	bool no_fail = false;
+	struct object obj = {
+		.efile = {
+			.idlist_shndx  = -1,
+			.symbols_shndx = -1,
+		},
+		.structs  = RB_ROOT,
+		.unions   = RB_ROOT,
+		.typedefs = RB_ROOT,
+		.funcs    = RB_ROOT,
+		.sets     = RB_ROOT,
+	};
+	struct option btfid_options[] = {
+		OPT_INCR('v', "verbose", &verbose,
+			 "be more verbose (show errors, etc)"),
+		OPT_STRING(0, "btf", &obj.btf, "BTF data",
+			   "BTF data"),
+		OPT_BOOLEAN(0, "no-fail", &no_fail,
+			   "do not fail if " BTF_IDS_SECTION " section is not found"),
+		OPT_END()
+	};
+	int err = -1;
+
+	argc = parse_options(argc, argv, btfid_options, resolve_btfids_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+	if (argc != 1)
+		usage_with_options(resolve_btfids_usage, btfid_options);
+
+	obj.path = argv[0];
+
+	if (elf_collect(&obj))
+		goto out;
+
+	/*
+	 * We did not find .BTF_ids section or symbols section,
+	 * nothing to do..
+	 */
+	if (obj.efile.idlist_shndx == -1 ||
+	    obj.efile.symbols_shndx == -1) {
+		if (no_fail)
+			return 0;
+		pr_err("FAILED to find needed sections\n");
+		return -1;
+	}
+
+	if (symbols_collect(&obj))
+		goto out;
+
+	if (symbols_resolve(&obj))
+		goto out;
+
+	if (symbols_patch(&obj))
+		goto out;
+
+	err = 0;
+out:
+	if (obj.efile.elf)
+		elf_end(obj.efile.elf);
+	close(obj.efile.fd);
+	return err;
+}

tools/include/linux/btf_ids.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_BTF_IDS_H
+#define _LINUX_BTF_IDS_H
+
+#include <linux/compiler.h> /* for __PASTE */
+
+/*
+ * Following macros help to define lists of BTF IDs placed
+ * in .BTF_ids section. They are initially filled with zeros
+ * (during compilation) and resolved later during the
+ * linking phase by resolve_btfids tool.
+ *
+ * Any change in list layout must be reflected in resolve_btfids
+ * tool logic.
+ */
+
+#define BTF_IDS_SECTION ".BTF_ids"
+
+#define ____BTF_ID(symbol)				\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
+".local " #symbol " ;                          \n"	\
+".type  " #symbol ", @object;                  \n"	\
+".size  " #symbol ", 4;                        \n"	\
+#symbol ":                                     \n"	\
+".zero 4                                       \n"	\
+".popsection;                                  \n");
+
+#define __BTF_ID(symbol) \
+	____BTF_ID(symbol)
+
+#define __ID(prefix) \
+	__PASTE(prefix, __COUNTER__)
+
+/*
+ * The BTF_ID defines unique symbol for each ID pointing
+ * to 4 zero bytes.
+ */
+#define BTF_ID(prefix, name) \
+	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__))
+
+/*
+ * The BTF_ID_LIST macro defines pure (unsorted) list
+ * of BTF IDs, with following layout:
+ *
+ * BTF_ID_LIST(list1)
+ * BTF_ID(type1, name1)
+ * BTF_ID(type2, name2)
+ *
+ * list1:
+ * __BTF_ID__type1__name1__1:
+ * .zero 4
+ * __BTF_ID__type2__name2__2:
+ * .zero 4
+ *
+ */
+#define __BTF_ID_LIST(name)				\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
+".local " #name ";                             \n"	\
+#name ":;                                      \n"	\
+".popsection;                                  \n");	\
+
+#define BTF_ID_LIST(name)				\
+__BTF_ID_LIST(name)					\
+extern u32 name[];
+
+/*
+ * The BTF_ID_UNUSED macro defines 4 zero bytes.
+ * It's used when we want to define 'unused' entry
+ * in BTF_ID_LIST, like:
+ *
+ *   BTF_ID_LIST(bpf_skb_output_btf_ids)
+ *   BTF_ID(struct, sk_buff)
+ *   BTF_ID_UNUSED
+ *   BTF_ID(struct, task_struct)
+ */
+
+#define BTF_ID_UNUSED					\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
+".zero 4                                       \n"	\
+".popsection;                                  \n");
+
+
+#endif

tools/include/linux/compiler.h

···
 # define __fallthrough
 #endif
 
+/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
+#define ___PASTE(a, b) a##b
+#define __PASTE(a, b) ___PASTE(a, b)
+
 #endif /* _TOOLS_LINUX_COMPILER_H */

tools/include/uapi/linux/bpf.h

···
 	BPF_CGROUP_INET4_GETSOCKNAME,
 	BPF_CGROUP_INET6_GETSOCKNAME,
 	BPF_XDP_DEVMAP,
+	BPF_CGROUP_INET_SOCK_RELEASE,
 	__MAX_BPF_ATTACH_TYPE
 };
 

tools/include/uapi/linux/if_xdp.h

···
 };
 
 struct xdp_statistics {
-	__u64 rx_dropped; /* Dropped for reasons other than invalid desc */
+	__u64 rx_dropped; /* Dropped for other reasons */
 	__u64 rx_invalid_descs; /* Dropped due to invalid descriptor */
 	__u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
+	__u64 rx_ring_full; /* Dropped due to rx ring being full */
+	__u64 rx_fill_ring_empty_descs; /* Failed to retrieve item from fill ring */
+	__u64 tx_ring_empty_descs; /* Failed to retrieve item from tx ring */
 };
 
 struct xdp_options {

tools/lib/bpf/btf.c

···
 	if (!btf)
 		return;
 
-	if (btf->fd != -1)
+	if (btf->fd >= 0)
 		close(btf->fd);
 
 	free(btf->data);
···
 	free(btf);
 }
 
-struct btf *btf__new(__u8 *data, __u32 size)
+struct btf *btf__new(const void *data, __u32 size)
 {
 	struct btf *btf;
 	int err;
···
 int btf__fd(const struct btf *btf)
 {
 	return btf->fd;
+}
+
+void btf__set_fd(struct btf *btf, int fd)
+{
+	btf->fd = fd;
 }
 
 const void *btf__get_raw_data(const struct btf *btf, __u32 *size)

tools/lib/bpf/btf.h

···
 };
 
 LIBBPF_API void btf__free(struct btf *btf);
-LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
+LIBBPF_API struct btf *btf__new(const void *data, __u32 size);
 LIBBPF_API struct btf *btf__parse_elf(const char *path,
 				      struct btf_ext **btf_ext);
 LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf);
···
 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
 LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id);
 LIBBPF_API int btf__fd(const struct btf *btf);
+LIBBPF_API void btf__set_fd(struct btf *btf, int fd);
 LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
 LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
···
 	 * necessary indentation already
 	 */
 	int indent_level;
+	/* strip all the const/volatile/restrict mods */
+	bool strip_mods;
 };
-#define btf_dump_emit_type_decl_opts__last_field indent_level
+#define btf_dump_emit_type_decl_opts__last_field strip_mods
 
 LIBBPF_API int
 btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,

tools/lib/bpf/btf_dump.c

···
 	const struct btf_ext *btf_ext;
 	btf_dump_printf_fn_t printf_fn;
 	struct btf_dump_opts opts;
+	bool strip_mods;
 
 	/* per-type auxiliary state */
 	struct btf_dump_type_aux_state *type_states;
···
 
 	fname = OPTS_GET(opts, field_name, "");
 	lvl = OPTS_GET(opts, indent_level, 0);
+	d->strip_mods = OPTS_GET(opts, strip_mods, false);
 	btf_dump_emit_type_decl(d, id, fname, lvl);
+	d->strip_mods = false;
 	return 0;
 }
 
···
 
 	stack_start = d->decl_stack_cnt;
 	for (;;) {
+		t = btf__type_by_id(d->btf, id);
+		if (d->strip_mods && btf_is_mod(t))
+			goto skip_mod;
+
 		err = btf_dump_push_decl_stack_id(d, id);
 		if (err < 0) {
 			/*
···
 			d->decl_stack_cnt = stack_start;
 			return;
 		}
-
+skip_mod:
 		/* VOID */
 		if (id == 0)
 			break;
 
-		t = btf__type_by_id(d->btf, id);
 		switch (btf_kind(t)) {
 		case BTF_KIND_PTR:
 		case BTF_KIND_VOLATILE:

tools/lib/bpf/libbpf.c

···
 	return false;
 }
 
-static void bpf_object__sanitize_btf(struct bpf_object *obj)
+static bool btf_needs_sanitization(struct bpf_object *obj)
 {
 	bool has_func_global = obj->caps.btf_func_global;
 	bool has_datasec = obj->caps.btf_datasec;
 	bool has_func = obj->caps.btf_func;
-	struct btf *btf = obj->btf;
+
+	return !has_func || !has_datasec || !has_func_global;
+}
+
+static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
+{
+	bool has_func_global = obj->caps.btf_func_global;
+	bool has_datasec = obj->caps.btf_datasec;
+	bool has_func = obj->caps.btf_func;
 	struct btf_type *t;
 	int i, j, vlen;
-
-	if (!obj->btf || (has_func && has_datasec && has_func_global))
-		return;
 
 	for (i = 1; i <= btf__get_nr_types(btf); i++) {
 		t = (struct btf_type *)btf__type_by_id(btf, i);
···
 			/* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */
 			t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0);
 		}
-	}
-}
-
-static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
-{
-	if (!obj->btf_ext)
-		return;
-
-	if (!obj->caps.btf_func) {
-		btf_ext__free(obj->btf_ext);
-		obj->btf_ext = NULL;
 	}
 }
 
···
 		return 0;
 
 	err = btf__finalize_data(obj, obj->btf);
-	if (!err)
-		return 0;
-
-	pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
-	btf__free(obj->btf);
-	obj->btf = NULL;
-	btf_ext__free(obj->btf_ext);
-	obj->btf_ext = NULL;
-
-	if (libbpf_needs_btf(obj)) {
-		pr_warn("BTF is required, but is missing or corrupted.\n");
-		return -ENOENT;
+	if (err) {
+		pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
+		return err;
 	}
+
 	return 0;
 }
 
···
 
 static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
 {
+	struct btf *kern_btf = obj->btf;
+	bool btf_mandatory, sanitize;
 	int err = 0;
 
 	if (!obj->btf)
 		return 0;
 
-	bpf_object__sanitize_btf(obj);
-	bpf_object__sanitize_btf_ext(obj);
+	sanitize = btf_needs_sanitization(obj);
+	if (sanitize) {
+		const void *raw_data;
+		__u32 sz;
 
-	err = btf__load(obj->btf);
-	if (err) {
-		pr_warn("Error loading %s into kernel: %d.\n",
-			BTF_ELF_SEC, err);
-		btf__free(obj->btf);
-		obj->btf = NULL;
-		/* btf_ext can't exist without btf, so free it as well */
-		if (obj->btf_ext) {
-			btf_ext__free(obj->btf_ext);
-			obj->btf_ext = NULL;
-		}
+		/* clone BTF to sanitize a copy and leave the original intact */
+		raw_data = btf__get_raw_data(obj->btf, &sz);
+		kern_btf = btf__new(raw_data, sz);
+		if (IS_ERR(kern_btf))
+			return PTR_ERR(kern_btf);
 
-		if (kernel_needs_btf(obj))
-			return err;
+		bpf_object__sanitize_btf(obj, kern_btf);
 	}
-	return 0;
+
+	err = btf__load(kern_btf);
+	if (sanitize) {
+		if (!err) {
+			/* move fd to libbpf's BTF */
+			btf__set_fd(obj->btf, btf__fd(kern_btf));
+			btf__set_fd(kern_btf, -1);
+		}
+		btf__free(kern_btf);
+	}
+	if (err) {
+		btf_mandatory = kernel_needs_btf(obj);
+		pr_warn("Error loading .BTF into kernel: %d. %s\n", err,
+			btf_mandatory ? "BTF is mandatory, can't proceed."
+				      : "BTF is optional, ignoring.");
+		if (!btf_mandatory)
+			err = 0;
+	}
+	return err;
 }
 
 static int bpf_object__elf_collect(struct bpf_object *obj)
···
 	create_attr.btf_fd = 0;
 	create_attr.btf_key_type_id = 0;
 	create_attr.btf_value_type_id = 0;
-	if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
+	if (obj->btf && btf__fd(obj->btf) >= 0 && !bpf_map_find_btf_info(obj, map)) {
 		create_attr.btf_fd = btf__fd(obj->btf);
 		create_attr.btf_key_type_id = map->btf_key_type_id;
 		create_attr.btf_value_type_id = map->btf_value_type_id;
···
 		load_attr.kern_version = kern_version;
 		load_attr.prog_ifindex = prog->prog_ifindex;
 	}
-	/* if .BTF.ext was loaded, kernel supports associated BTF for prog */
-	if (prog->obj->btf_ext)
-		btf_fd = bpf_object__btf_fd(prog->obj);
-	else
-		btf_fd = -1;
-	load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0;
-	load_attr.func_info = prog->func_info;
-	load_attr.func_info_rec_size = prog->func_info_rec_size;
-	load_attr.func_info_cnt = prog->func_info_cnt;
-	load_attr.line_info = prog->line_info;
-	load_attr.line_info_rec_size = prog->line_info_rec_size;
-	load_attr.line_info_cnt = prog->line_info_cnt;
+	/* specify func_info/line_info only if kernel supports them */
+	btf_fd = bpf_object__btf_fd(prog->obj);
+	if (btf_fd >= 0 && prog->obj->caps.btf_func) {
+		load_attr.prog_btf_fd = btf_fd;
+		load_attr.func_info = prog->func_info;
+		load_attr.func_info_rec_size = prog->func_info_rec_size;
+		load_attr.func_info_cnt = prog->func_info_cnt;
+		load_attr.line_info = prog->line_info;
+		load_attr.line_info_rec_size = prog->line_info_rec_size;
+		load_attr.line_info_cnt = prog->line_info_cnt;
+	}
 	load_attr.log_level = prog->log_level;
 	load_attr.prog_flags = prog->prog_flags;
 
···
 	BPF_APROG_SEC("cgroup_skb/egress",	BPF_PROG_TYPE_CGROUP_SKB,
 						BPF_CGROUP_INET_EGRESS),
 	BPF_APROG_COMPAT("cgroup/skb",		BPF_PROG_TYPE_CGROUP_SKB),
+	BPF_EAPROG_SEC("cgroup/sock_create",	BPF_PROG_TYPE_CGROUP_SOCK,
+						BPF_CGROUP_INET_SOCK_CREATE),
+	BPF_EAPROG_SEC("cgroup/sock_release",	BPF_PROG_TYPE_CGROUP_SOCK,
+						BPF_CGROUP_INET_SOCK_RELEASE),
 	BPF_APROG_SEC("cgroup/sock",		BPF_PROG_TYPE_CGROUP_SOCK,
 						BPF_CGROUP_INET_SOCK_CREATE),
 	BPF_EAPROG_SEC("cgroup/post_bind4",	BPF_PROG_TYPE_CGROUP_SOCK,
···
 					      struct perf_buffer_params *p)
 {
 	const char *online_cpus_file = "/sys/devices/system/cpu/online";
-	struct bpf_map_info map = {};
+	struct bpf_map_info map;
 	char msg[STRERR_BUFSIZE];
 	struct perf_buffer *pb;
 	bool *online = NULL;
···
 		return ERR_PTR(-EINVAL);
 	}
 
+	/* best-effort sanity checks */
+	memset(&map, 0, sizeof(map));
 	map_info_len = sizeof(map);
 	err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
 	if (err) {
 		err = -errno;
-		pr_warn("failed to get map info for map FD %d: %s\n",
-			map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
-		return ERR_PTR(err);
-	}
-
-	if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
-		pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
-			map.name);
-		return ERR_PTR(-EINVAL);
+		/* if BPF_OBJ_GET_INFO_BY_FD is supported, will return
+		 * -EBADFD, -EFAULT, or -E2BIG on real error
+		 */
+		if (err != -EINVAL) {
+			pr_warn("failed to get map info for map FD %d: %s\n",
+				map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
+			return ERR_PTR(err);
+		}
+		pr_debug("failed to get map info for FD %d; API not supported? Ignoring...\n",
+			 map_fd);
+	} else {
+		if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
+			pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
+				map.name);
+			return ERR_PTR(-EINVAL);
+		}
 	}
 
 	pb = calloc(1, sizeof(*pb));
···
 			err = pb->cpu_cnt;
 			goto error;
 		}
-		if (map.max_entries < pb->cpu_cnt)
+		if (map.max_entries && map.max_entries < pb->cpu_cnt)
 			pb->cpu_cnt = map.max_entries;
 	}
 

tools/lib/bpf/libbpf.map

···
 		bpf_map__value_size;
 		bpf_program__autoload;
 		bpf_program__set_autoload;
+		btf__set_fd;
 } LIBBPF_0.0.9;

tools/testing/selftests/bpf/Makefile

···
 BUILD_DIR := $(SCRATCH_DIR)/build
 INCLUDE_DIR := $(SCRATCH_DIR)/include
 BPFOBJ := $(BUILD_DIR)/libbpf/libbpf.a
+RESOLVE_BTFIDS := $(BUILD_DIR)/resolve_btfids/resolve_btfids
 
 # Define simple and short `make test_progs`, `make test_sysctl`, etc targets
 # to build individual tests.
···
 	$(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(BUILD_DIR)/libbpf/ \
 		    DESTDIR=$(SCRATCH_DIR) prefix= all install_headers
 
-$(BUILD_DIR)/libbpf $(BUILD_DIR)/bpftool $(INCLUDE_DIR):
+$(BUILD_DIR)/libbpf $(BUILD_DIR)/bpftool $(BUILD_DIR)/resolve_btfids $(INCLUDE_DIR):
 	$(call msg,MKDIR,,$@)
 	mkdir -p $@
 
···
 	$(call msg,CP,,$@)
 	cp "$(VMLINUX_H)" $@
 endif
+
+$(RESOLVE_BTFIDS): $(BPFOBJ) | $(BUILD_DIR)/resolve_btfids	\
+		       $(TOOLSDIR)/bpf/resolve_btfids/main.c	\
+		       $(TOOLSDIR)/lib/rbtree.c			\
+		       $(TOOLSDIR)/lib/zalloc.c			\
+		       $(TOOLSDIR)/lib/string.c			\
+		       $(TOOLSDIR)/lib/ctype.c			\
+		       $(TOOLSDIR)/lib/str_error_r.c
+	$(Q)$(MAKE) $(submake_extras) -C $(TOOLSDIR)/bpf/resolve_btfids	\
+		OUTPUT=$(BUILD_DIR)/resolve_btfids/ BPFOBJ=$(BPFOBJ)
 
 # Get Clang's default includes on this system, as opposed to those seen by
 # '-target bpf'. This fixes "missing" files on some architectures/distros,
···
 
 $(OUTPUT)/$(TRUNNER_BINARY): $(TRUNNER_TEST_OBJS)			\
 			     $(TRUNNER_EXTRA_OBJS) $$(BPFOBJ)		\
+			     $(RESOLVE_BTFIDS)				\
 			     | $(TRUNNER_BINARY)-extras
 	$$(call msg,BINARY,,$$@)
 	$$(CC) $$(CFLAGS) $$(filter %.a %.o,$$^) $$(LDLIBS) -o $$@
+	$(RESOLVE_BTFIDS) --no-fail --btf btf_data.o $$@
 
 endef
 

tools/testing/selftests/bpf/bpf_legacy.h

···
 #ifndef __BPF_LEGACY__
 #define __BPF_LEGACY__
 
-/*
- * legacy bpf_map_def with extra fields supported only by bpf_load(), do not
- * use outside of samples/bpf
- */
-struct bpf_map_def_legacy {
-	unsigned int type;
-	unsigned int key_size;
-	unsigned int value_size;
-	unsigned int max_entries;
-	unsigned int map_flags;
-	unsigned int inner_map_idx;
-	unsigned int numa_node;
-};
-
 #define BPF_ANNOTATE_KV_PAIR(name, type_key, type_val)		\
 	struct ____btf_map_##name {				\
 		type_key key;					\

tools/testing/selftests/bpf/prog_tests/core_retro.c

···
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+#define _GNU_SOURCE
+#include <test_progs.h>
+#include "test_core_retro.skel.h"
+
+void test_core_retro(void)
+{
+	int err, zero = 0, res, duration = 0;
+	struct test_core_retro *skel;
+
+	/* load program */
+	skel = test_core_retro__open_and_load();
+	if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
+		goto out_close;
+
+	/* attach probe */
+	err = test_core_retro__attach(skel);
+	if (CHECK(err, "attach_kprobe", "err %d\n", err))
+		goto out_close;
+
+	/* trigger */
+	usleep(1);
+
+	err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.results), &zero, &res);
+	if (CHECK(err, "map_lookup", "failed to lookup result: %d\n", errno))
+		goto out_close;
+
+	CHECK(res != getpid(), "pid_check", "got %d != exp %d\n", res, getpid());
+
+out_close:
+	test_core_retro__destroy(skel);
+}

tools/testing/selftests/bpf/prog_tests/perf_buffer.c

···
 #include <sched.h>
 #include <sys/socket.h>
 #include <test_progs.h>
+#include "test_perf_buffer.skel.h"
 #include "bpf/libbpf_internal.h"
 
 /* AddressSanitizer sometimes crashes due to data dereference below, due to
···
 
 void test_perf_buffer(void)
 {
-	int err, prog_fd, on_len, nr_on_cpus = 0,  nr_cpus, i, duration = 0;
-	const char *prog_name = "kprobe/sys_nanosleep";
-	const char *file = "./test_perf_buffer.o";
+	int err, on_len, nr_on_cpus = 0,  nr_cpus, i, duration = 0;
 	struct perf_buffer_opts pb_opts = {};
-	struct bpf_map *perf_buf_map;
+	struct test_perf_buffer *skel;
 	cpu_set_t cpu_set, cpu_seen;
-	struct bpf_program *prog;
-	struct bpf_object *obj;
 	struct perf_buffer *pb;
-	struct bpf_link *link;
 	bool *online;
 
 	nr_cpus = libbpf_num_possible_cpus();
···
 			nr_on_cpus++;
 
 	/* load program */
-	err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
-	if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno)) {
-		obj = NULL;
-		goto out_close;
-	}
-
-	prog = bpf_object__find_program_by_title(obj, prog_name);
-	if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name))
+	skel = test_perf_buffer__open_and_load();
+	if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
 		goto out_close;
 
-	/* load map */
-	perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map");
-	if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n"))
-		goto out_close;
-
-	/* attach kprobe */
-	link = bpf_program__attach_kprobe(prog, false /* retprobe */,
-					  SYS_NANOSLEEP_KPROBE_NAME);
-	if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link)))
+	/* attach probe */
+	err = test_perf_buffer__attach(skel);
+	if (CHECK(err, "attach_kprobe", "err %d\n", err))
 		goto out_close;
 
 	/* set up perf buffer */
 	pb_opts.sample_cb = on_sample;
 	pb_opts.ctx = &cpu_seen;
-	pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts);
+	pb = perf_buffer__new(bpf_map__fd(skel->maps.perf_buf_map), 1, &pb_opts);
 	if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
-		goto out_detach;
+		goto out_close;
 
 	/* trigger kprobe on every CPU */
 	CPU_ZERO(&cpu_seen);
···
 					     &cpu_set);
 		if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n",
 				 i, err))
-			goto out_detach;
+			goto out_close;
 
 		usleep(1);
 	}
···
 
 out_free_pb:
 	perf_buffer__free(pb);
-out_detach:
-	bpf_link__destroy(link);
 out_close:
-	bpf_object__close(obj);
+	test_perf_buffer__destroy(skel);
 	free(online);
 }

tools/testing/selftests/bpf/prog_tests/resolve_btfids.c

···
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/err.h>
+#include <string.h>
+#include <bpf/btf.h>
+#include <bpf/libbpf.h>
+#include <linux/btf.h>
+#include <linux/kernel.h>
+#include <linux/btf_ids.h>
+#include "test_progs.h"
+
+static int duration;
+
+struct symbol {
+	const char	*name;
+	int		 type;
+	int		 id;
+};
+
+struct symbol test_symbols[] = {
+	{ "unused",  BTF_KIND_UNKN,     0 },
+	{ "S",       BTF_KIND_TYPEDEF, -1 },
+	{ "T",       BTF_KIND_TYPEDEF, -1 },
+	{ "U",       BTF_KIND_TYPEDEF, -1 },
+	{ "S",       BTF_KIND_STRUCT,  -1 },
+	{ "U",       BTF_KIND_UNION,   -1 },
+	{ "func",    BTF_KIND_FUNC,    -1 },
+};
+
+BTF_ID_LIST(test_list)
+BTF_ID_UNUSED
+BTF_ID(typedef, S)
+BTF_ID(typedef, T)
+BTF_ID(typedef, U)
+BTF_ID(struct,  S)
+BTF_ID(union,   U)
+BTF_ID(func,    func)
+
+static int
+__resolve_symbol(struct btf *btf, int type_id)
+{
+	const struct btf_type *type;
+	const char *str;
+	unsigned int i;
+
+	type = btf__type_by_id(btf, type_id);
+	if (!type) {
+		PRINT_FAIL("Failed to get type for ID %d\n", type_id);
+		return -1;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(test_symbols); i++) {
+		if (test_symbols[i].id != -1)
+			continue;
+
+		if (BTF_INFO_KIND(type->info) != test_symbols[i].type)
+			continue;
+
+		str = btf__name_by_offset(btf, type->name_off);
+		if (!str) {
+			PRINT_FAIL("Failed to get name for BTF ID %d\n", type_id);
+			return -1;
+		}
+
+		if (!strcmp(str, test_symbols[i].name))
+			test_symbols[i].id = type_id;
+	}
+
+	return 0;
+}
+
+static int resolve_symbols(void)
+{
+	struct btf *btf;
+	int type_id;
+	__u32 nr;
+
+	btf = btf__parse_elf("btf_data.o", NULL);
+	if (CHECK(libbpf_get_error(btf), "resolve",
+		  "Failed to load BTF from btf_data.o\n"))
+		return -1;
+
+	nr = btf__get_nr_types(btf);
+
+	for (type_id = 1; type_id <= nr; type_id++) {
+		if (__resolve_symbol(btf, type_id))
+			break;
+	}
+
+	btf__free(btf);
+	return 0;
+}
+
+int test_resolve_btfids(void)
+{
+	unsigned int i;
+	int ret = 0;
+
+	if (resolve_symbols())
+		return -1;
+
+	/* Check BTF_ID_LIST(test_list) IDs */
+	for (i = 0; i < ARRAY_SIZE(test_symbols) && !ret; i++) {
+		ret = CHECK(test_list[i] != test_symbols[i].id,
+			    "id_check",
+			    "wrong ID for %s (%d != %d)\n", test_symbols[i].name,
+			    test_list[i], test_symbols[i].id);
+	}
+
+	return ret;
+}

tools/testing/selftests/bpf/prog_tests/skeleton.c

···
 	CHECK(bss->in4 != 0, "in4", "got %lld != exp %lld\n", bss->in4, 0LL);
 	CHECK(bss->out4 != 0, "out4", "got %lld != exp %lld\n", bss->out4, 0LL);
 
-	CHECK(rodata->in6 != 0, "in6", "got %d != exp %d\n", rodata->in6, 0);
+	CHECK(rodata->in.in6 != 0, "in6", "got %d != exp %d\n", rodata->in.in6, 0);
 	CHECK(bss->out6 != 0, "out6", "got %d != exp %d\n", bss->out6, 0);
 
 	/* validate we can pre-setup global variables, even in .bss */
···
 	data->in2 = 11;
 	bss->in3 = 12;
 	bss->in4 = 13;
-	rodata->in6 = 14;
+	rodata->in.in6 = 14;
 
 	err = test_skeleton__load(skel);
 	if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
···
 	CHECK(data->in2 != 11, "in2", "got %lld != exp %lld\n", data->in2, 11LL);
 	CHECK(bss->in3 != 12, "in3", "got %d != exp %d\n", bss->in3, 12);
 	CHECK(bss->in4 != 13, "in4", "got %lld != exp %lld\n", bss->in4, 13LL);
-	CHECK(rodata->in6 != 14, "in6", "got %d != exp %d\n", rodata->in6, 14);
+	CHECK(rodata->in.in6 != 14, "in6", "got %d != exp %d\n", rodata->in.in6, 14);
 
 	/* now set new values and attach to get them into outX variables */
 	data->in1 = 1;

tools/testing/selftests/bpf/prog_tests/trace_printk.c

···
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Oracle and/or its affiliates. */
+
+#include <test_progs.h>
+
+#include "trace_printk.skel.h"
+
+#define TRACEBUF	"/sys/kernel/debug/tracing/trace_pipe"
+#define SEARCHMSG	"testing,testing"
+
+void test_trace_printk(void)
+{
+	int err, iter = 0, duration = 0, found = 0;
+	struct trace_printk__bss *bss;
+	struct trace_printk *skel;
+	char *buf = NULL;
+	FILE *fp = NULL;
+	size_t buflen;
+
+	skel = trace_printk__open();
+	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+		return;
+
+	err = trace_printk__load(skel);
+	if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
+		goto cleanup;
+
+	bss = skel->bss;
+
+	err = trace_printk__attach(skel);
+	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+		goto cleanup;
+
+	fp = fopen(TRACEBUF, "r");
+	if (CHECK(fp == NULL, "could not open trace buffer",
+		  "error %d opening %s", errno, TRACEBUF))
+		goto cleanup;
+
+	/* We do not want to wait forever if this test fails... */
+	fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
+
+	/* wait for tracepoint to trigger */
+	usleep(1);
+	trace_printk__detach(skel);
+
+	if (CHECK(bss->trace_printk_ran == 0,
+		  "bpf_trace_printk never ran",
+		  "ran == %d", bss->trace_printk_ran))
+		goto cleanup;
+
+	if (CHECK(bss->trace_printk_ret <= 0,
+		  "bpf_trace_printk returned <= 0 value",
+		  "got %d", bss->trace_printk_ret))
+		goto cleanup;
+
+	/* verify our search string is in the trace buffer */
+	while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
+		if (strstr(buf, SEARCHMSG) != NULL)
+			found++;
+		if (found == bss->trace_printk_ran)
+			break;
+		if (++iter > 1000)
+			break;
+	}
+
+	if (CHECK(!found, "message from bpf_trace_printk not found",
+		  "no instance of %s in %s", SEARCHMSG, TRACEBUF))
+		goto cleanup;
+
+cleanup:
+	trace_printk__destroy(skel);
+	free(buf);
+	if (fp)
+		fclose(fp);
+}

tools/testing/selftests/bpf/prog_tests/udp_limit.c

···
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "udp_limit.skel.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+static int duration;
+
+void test_udp_limit(void)
+{
+	struct udp_limit *skel;
+	int fd1 = -1, fd2 = -1;
+	int cgroup_fd;
+
+	cgroup_fd = test__join_cgroup("/udp_limit");
+	if (CHECK(cgroup_fd < 0, "cg-join", "errno %d", errno))
+		return;
+
+	skel = udp_limit__open_and_load();
+	if (CHECK(!skel, "skel-load", "errno %d", errno))
+		goto close_cgroup_fd;
+
+	skel->links.sock = bpf_program__attach_cgroup(skel->progs.sock, cgroup_fd);
+	skel->links.sock_release = bpf_program__attach_cgroup(skel->progs.sock_release, cgroup_fd);
+	if (CHECK(IS_ERR(skel->links.sock) || IS_ERR(skel->links.sock_release),
+		  "cg-attach", "sock %ld sock_release %ld",
+		  PTR_ERR(skel->links.sock),
+		  PTR_ERR(skel->links.sock_release)))
+		goto close_skeleton;
+
+	/* BPF program enforces a single UDP socket per cgroup,
+	 * verify that.
+	 */
+	fd1 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (CHECK(fd1 < 0, "fd1", "errno %d", errno))
+		goto close_skeleton;
+
+	fd2 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (CHECK(fd2 >= 0, "fd2", "errno %d", errno))
+		goto close_skeleton;
+
+	/* We can reopen again after close. */
+	close(fd1);
+	fd1 = -1;
+
+	fd1 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (CHECK(fd1 < 0, "fd1-again", "errno %d", errno))
+		goto close_skeleton;
+
+	/* Make sure the program was invoked the expected
+	 * number of times:
+	 * - open fd1           - BPF_CGROUP_INET_SOCK_CREATE
+	 * - attempt to openfd2 - BPF_CGROUP_INET_SOCK_CREATE
+	 * - close fd1          - BPF_CGROUP_INET_SOCK_RELEASE
+	 * - open fd1 again     - BPF_CGROUP_INET_SOCK_CREATE
+	 */
+	if (CHECK(skel->bss->invocations != 4, "bss-invocations",
+		  "invocations=%d", skel->bss->invocations))
+		goto close_skeleton;
+
+	/* We should still have a single socket in use */
+	if (CHECK(skel->bss->in_use != 1, "bss-in_use",
+		  "in_use=%d", skel->bss->in_use))
+		goto close_skeleton;
+
+close_skeleton:
+	if (fd1 >= 0)
+		close(fd1);
+	if (fd2 >= 0)
+		close(fd2);
+	udp_limit__destroy(skel);
+close_cgroup_fd:
+	close(cgroup_fd);
+}

tools/testing/selftests/bpf/progs/btf_data.c

···
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+struct S {
+	int	a;
+	int	b;
+	int	c;
+};
+
+union U {
+	int	a;
+	int	b;
+	int	c;
+};
+
+struct S1 {
+	int	a;
+	int	b;
+	int	c;
+};
+
+union U1 {
+	int	a;
+	int	b;
+	int	c;
+};
+
+typedef int T;
+typedef int S;
+typedef int U;
+typedef int T1;
+typedef int S1;
+typedef int U1;
+
+struct root_struct {
+	S		m_1;
+	T		m_2;
+	U		m_3;
+	S1		m_4;
+	T1		m_5;
+	U1		m_6;
+	struct S	m_7;
+	struct S1	m_8;
+	union  U	m_9;
+	union  U1	m_10;
+};
+
+int func(struct root_struct *root)
+{
+	return 0;
+}

tools/testing/selftests/bpf/progs/test_core_retro.c

···
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+
+struct task_struct {
+	int tgid;
+} __attribute__((preserve_access_index));
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, int);
+	__type(value, int);
+} results SEC(".maps");
+
+SEC("tp/raw_syscalls/sys_enter")
+int handle_sys_enter(void *ctx)
+{
+	struct task_struct *task = (void *)bpf_get_current_task();
+	int tgid = BPF_CORE_READ(task, tgid);
+	int zero = 0;
+
+	bpf_map_update_elem(&results, &zero, &tgid, 0);
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/test_perf_buffer.c

···
 	__uint(value_size, sizeof(int));
 } perf_buf_map SEC(".maps");
 
-SEC("kprobe/sys_nanosleep")
-int BPF_KPROBE(handle_sys_nanosleep_entry)
+SEC("tp/raw_syscalls/sys_enter")
+int handle_sys_enter(void *ctx)
 {
 	int cpu = bpf_get_smp_processor_id();
 

tools/testing/selftests/bpf/progs/test_skeleton.c

···
 struct s in5 = {};
 
 /* .rodata section */
-const volatile int in6 = 0;
+const volatile struct {
+	const int in6;
+} in = {};
 
 /* .data section */
 int out1 = -1;
···
 	out3 = in3;
 	out4 = in4;
 	out5 = in5;
-	out6 = in6;
+	out6 = in.in6;
 
 	bpf_syscall = CONFIG_BPF_SYSCALL;
 	kern_ver = LINUX_KERNEL_VERSION;

tools/testing/selftests/bpf/progs/trace_printk.c

···
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020, Oracle and/or its affiliates.
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+int trace_printk_ret = 0;
+int trace_printk_ran = 0;
+
+SEC("tp/raw_syscalls/sys_enter")
+int sys_enter(void *ctx)
+{
+	static const char fmt[] = "testing,testing %d\n";
+
+	trace_printk_ret = bpf_trace_printk(fmt, sizeof(fmt),
+					    ++trace_printk_ran);
+	return 0;
+}

tools/testing/selftests/bpf/progs/udp_limit.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <sys/socket.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+int invocations = 0, in_use = 0;
+
+SEC("cgroup/sock_create")
+int sock(struct bpf_sock *ctx)
+{
+	__u32 key;
+
+	if (ctx->type != SOCK_DGRAM)
+		return 1;
+
+	__sync_fetch_and_add(&invocations, 1);
+
+	if (in_use > 0) {
+		/* BPF_CGROUP_INET_SOCK_RELEASE is _not_ called
+		 * when we return an error from the BPF
+		 * program!
+		 */
+		return 0;
+	}
+
+	__sync_fetch_and_add(&in_use, 1);
+	return 1;
+}
+
+SEC("cgroup/sock_release")
+int sock_release(struct bpf_sock *ctx)
+{
+	__u32 key;
+
+	if (ctx->type != SOCK_DGRAM)
+		return 1;
+
+	__sync_fetch_and_add(&invocations, 1);
+	__sync_fetch_and_add(&in_use, -1);
+	return 1;
+}

tools/testing/selftests/bpf/test_progs.c

···
 #include <string.h>
 #include <execinfo.h> /* backtrace */
 
+#define EXIT_NO_TEST		2
+#define EXIT_ERR_SETUP_INFRA	3
+
 /* defined in test_progs.h */
 struct test_env env = {};
 
···
 	if (err < 0) {
 		stdio_restore();
 		fprintf(stderr, "Failed to reset process affinity: %d!\n", err);
-		exit(-1);
+		exit(EXIT_ERR_SETUP_INFRA);
 	}
 	err = pthread_setaffinity_np(pthread_self(), sizeof(cpuset), &cpuset);
 	if (err < 0) {
 		stdio_restore();
 		fprintf(stderr, "Failed to reset thread affinity: %d!\n", err);
-		exit(-1);
+		exit(EXIT_ERR_SETUP_INFRA);
 	}
 }
 
···
 	env.saved_netns_fd = open("/proc/self/ns/net", O_RDONLY);
 	if (env.saved_netns_fd == -1) {
 		perror("open(/proc/self/ns/net)");
-		exit(-1);
+		exit(EXIT_ERR_SETUP_INFRA);
 	}
 }
 
···
 	if (setns(env.saved_netns_fd, CLONE_NEWNET) == -1) {
 		stdio_restore();
 		perror("setns(CLONE_NEWNS)");
-		exit(-1);
+		exit(EXIT_ERR_SETUP_INFRA);
 	}
 }
 
···
 	close(env.saved_netns_fd);
 
 	if (env.succ_cnt + env.fail_cnt + env.skip_cnt == 0)
-		return EXIT_FAILURE;
+		return EXIT_NO_TEST;
 
 	return env.fail_cnt ? EXIT_FAILURE : EXIT_SUCCESS;
 }