Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1123 insertions, 0 deletions

diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c
new file mode 100644
index 000000000..b74c82bb8
--- /dev/null
+++ b/tools/lib/bpf/gen_loader.c
@@ -0,0 +1,1123 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2021 Facebook */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <linux/filter.h>
+#include <sys/param.h>
+#include "btf.h"
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_internal.h"
+#include "hashmap.h"
+#include "bpf_gen_internal.h"
+#include "skel_internal.h"
+#include <asm/byteorder.h>
+
+#define MAX_USED_MAPS	64
+#define MAX_USED_PROGS	32
+#define MAX_KFUNC_DESCS 256
+#define MAX_FD_ARRAY_SZ (MAX_USED_MAPS + MAX_KFUNC_DESCS)
+
+/* The following structure describes the stack layout of the loader program.
+ * In addition R6 contains the pointer to context.
+ * R7 contains the result of the last sys_bpf command (typically error or FD).
+ * R9 contains the result of the last sys_close command.
+ *
+ * Naming convention:
+ * ctx - bpf program context
+ * stack - bpf program stack
+ * blob - bpf_attr-s, strings, insns, map data.
+ *        All the bytes that loader prog will use for read/write.
+ */
+struct loader_stack {
+	__u32 btf_fd;
+	__u32 inner_map_fd;
+	__u32 prog_fd[MAX_USED_PROGS];
+};
+
+#define stack_off(field) \
+	(__s16)(-sizeof(struct loader_stack) + offsetof(struct loader_stack, field))
+
+#define attr_field(attr, field) (attr + offsetof(union bpf_attr, field))
+
+static int blob_fd_array_off(struct bpf_gen *gen, int index)
+{
+	return gen->fd_array + index * sizeof(int);
+}
+
+static int realloc_insn_buf(struct bpf_gen *gen, __u32 size)
+{
+	size_t off = gen->insn_cur - gen->insn_start;
+	void *insn_start;
+
+	if (gen->error)
+		return gen->error;
+	if (size > INT32_MAX || off + size > INT32_MAX) {
+		gen->error = -ERANGE;
+		return -ERANGE;
+	}
+	insn_start = realloc(gen->insn_start, off + size);
+	if (!insn_start) {
+		gen->error = -ENOMEM;
+		free(gen->insn_start);
+		gen->insn_start = NULL;
+		return -ENOMEM;
+	}
+	gen->insn_start = insn_start;
+	gen->insn_cur = insn_start + off;
+	return 0;
+}
+
+static int realloc_data_buf(struct bpf_gen *gen, __u32 size)
+{
+	size_t off = gen->data_cur - gen->data_start;
+	void *data_start;
+
+	if (gen->error)
+		return gen->error;
+	if (size > INT32_MAX || off + size > INT32_MAX) {
+		gen->error = -ERANGE;
+		return -ERANGE;
+	}
+	data_start = realloc(gen->data_start, off + size);
+	if (!data_start) {
+		gen->error = -ENOMEM;
+		free(gen->data_start);
+		gen->data_start = NULL;
+		return -ENOMEM;
+	}
+	gen->data_start = data_start;
+	gen->data_cur = data_start + off;
+	return 0;
+}
+
+static void emit(struct bpf_gen *gen, struct bpf_insn insn)
+{
+	if (realloc_insn_buf(gen, sizeof(insn)))
+		return;
+	memcpy(gen->insn_cur, &insn, sizeof(insn));
+	gen->insn_cur += sizeof(insn);
+}
+
+static void emit2(struct bpf_gen *gen, struct bpf_insn insn1, struct bpf_insn insn2)
+{
+	emit(gen, insn1);
+	emit(gen, insn2);
+}
+
+static int add_data(struct bpf_gen *gen, const void *data, __u32 size);
+static void emit_sys_close_blob(struct bpf_gen *gen, int blob_off);
+
+void bpf_gen__init(struct bpf_gen *gen, int log_level, int nr_progs, int nr_maps)
+{
+	size_t stack_sz = sizeof(struct loader_stack), nr_progs_sz;
+	int i;
+
+	gen->fd_array = add_data(gen, NULL, MAX_FD_ARRAY_SZ * sizeof(int));
+	gen->log_level = log_level;
+	/* save ctx pointer into R6 */
+	emit(gen, BPF_MOV64_REG(BPF_REG_6, BPF_REG_1));
+
+	/* bzero stack */
+	emit(gen, BPF_MOV64_REG(BPF_REG_1, BPF_REG_10));
+	emit(gen, BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -stack_sz));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, stack_sz));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
+
+	/* amount of stack actually used, only used to calculate iterations, not stack offset */
+	nr_progs_sz = offsetof(struct loader_stack, prog_fd[nr_progs]);
+	/* jump over cleanup code */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0,
+			      /* size of cleanup code below (including map fd cleanup) */
+			      (nr_progs_sz / 4) * 3 + 2 +
+			      /* 6 insns for emit_sys_close_blob,
+			       * 6 insns for debug_regs in emit_sys_close_blob
+			       */
+			      nr_maps * (6 + (gen->log_level ? 6 : 0))));
+
+	/* remember the label where all error branches will jump to */
+	gen->cleanup_label = gen->insn_cur - gen->insn_start;
+	/* emit cleanup code: close all temp FDs */
+	for (i = 0; i < nr_progs_sz; i += 4) {
+		emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, -stack_sz + i));
+		emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0, 1));
+		emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close));
+	}
+	for (i = 0; i < nr_maps; i++)
+		emit_sys_close_blob(gen, blob_fd_array_off(gen, i));
+	/* R7 contains the error code from sys_bpf. Copy it into R0 and exit. */
+	emit(gen, BPF_MOV64_REG(BPF_REG_0, BPF_REG_7));
+	emit(gen, BPF_EXIT_INSN());
+}
+
+static int add_data(struct bpf_gen *gen, const void *data, __u32 size)
+{
+	__u32 size8 = roundup(size, 8);
+	__u64 zero = 0;
+	void *prev;
+
+	if (realloc_data_buf(gen, size8))
+		return 0;
+	prev = gen->data_cur;
+	if (data) {
+		memcpy(gen->data_cur, data, size);
+		memcpy(gen->data_cur + size, &zero, size8 - size);
+	} else {
+		memset(gen->data_cur, 0, size8);
+	}
+	gen->data_cur += size8;
+	return prev - gen->data_start;
+}
+
+/* Get index for map_fd/btf_fd slot in reserved fd_array, or in data relative
+ * to start of fd_array. Caller can decide if it is usable or not.
+ */
+static int add_map_fd(struct bpf_gen *gen)
+{
+	if (gen->nr_maps == MAX_USED_MAPS) {
+		pr_warn("Total maps exceeds %d\n", MAX_USED_MAPS);
+		gen->error = -E2BIG;
+		return 0;
+	}
+	return gen->nr_maps++;
+}
+
+static int add_kfunc_btf_fd(struct bpf_gen *gen)
+{
+	int cur;
+
+	if (gen->nr_fd_array == MAX_KFUNC_DESCS) {
+		cur = add_data(gen, NULL, sizeof(int));
+		return (cur - gen->fd_array) / sizeof(int);
+	}
+	return MAX_USED_MAPS + gen->nr_fd_array++;
+}
+
+static int insn_bytes_to_bpf_size(__u32 sz)
+{
+	switch (sz) {
+	case 8: return BPF_DW;
+	case 4: return BPF_W;
+	case 2: return BPF_H;
+	case 1: return BPF_B;
+	default: return -1;
+	}
+}
+
+/* *(u64 *)(blob + off) = (u64)(void *)(blob + data) */
+static void emit_rel_store(struct bpf_gen *gen, int off, int data)
+{
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, data));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, off));
+	emit(gen, BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0));
+}
+
+static void move_blob2blob(struct bpf_gen *gen, int off, int size, int blob_off)
+{
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_off));
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_2, 0));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, off));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
+}
+
+static void move_blob2ctx(struct bpf_gen *gen, int ctx_off, int size, int blob_off)
+{
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_off));
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_1, 0));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off));
+}
+
+static void move_ctx2blob(struct bpf_gen *gen, int off, int size, int ctx_off,
+				   bool check_non_zero)
+{
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_6, ctx_off));
+	if (check_non_zero)
+		/* If value in ctx is zero don't update the blob.
+		 * For example: when ctx->map.max_entries == 0, keep default max_entries from bpf.c
+		 */
+		emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, off));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
+}
+
+static void move_stack2blob(struct bpf_gen *gen, int off, int size, int stack_off)
+{
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_10, stack_off));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, off));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
+}
+
+static void move_stack2ctx(struct bpf_gen *gen, int ctx_off, int size, int stack_off)
+{
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_10, stack_off));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off));
+}
+
+static void emit_sys_bpf(struct bpf_gen *gen, int cmd, int attr, int attr_size)
+{
+	emit(gen, BPF_MOV64_IMM(BPF_REG_1, cmd));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, attr));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, attr_size));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_bpf));
+	/* remember the result in R7 */
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+}
+
+static bool is_simm16(__s64 value)
+{
+	return value == (__s64)(__s16)value;
+}
+
+static void emit_check_err(struct bpf_gen *gen)
+{
+	__s64 off = -(gen->insn_cur - gen->insn_start - gen->cleanup_label) / 8 - 1;
+
+	/* R7 contains result of last sys_bpf command.
+	 * if (R7 < 0) goto cleanup;
+	 */
+	if (is_simm16(off)) {
+		emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, off));
+	} else {
+		gen->error = -ERANGE;
+		emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, -1));
+	}
+}
+
+/* reg1 and reg2 should not be R1 - R5. They can be R0, R6 - R10 */
+static void emit_debug(struct bpf_gen *gen, int reg1, int reg2,
+		       const char *fmt, va_list args)
+{
+	char buf[1024];
+	int addr, len, ret;
+
+	if (!gen->log_level)
+		return;
+	ret = vsnprintf(buf, sizeof(buf), fmt, args);
+	if (ret < 1024 - 7 && reg1 >= 0 && reg2 < 0)
+		/* The special case to accommodate common debug_ret():
+		 * to avoid specifying BPF_REG_7 and adding " r=%%d" to
+		 * prints explicitly.
+		 */
+		strcat(buf, " r=%d");
+	len = strlen(buf) + 1;
+	addr = add_data(gen, buf, len);
+
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, addr));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	if (reg1 >= 0)
+		emit(gen, BPF_MOV64_REG(BPF_REG_3, reg1));
+	if (reg2 >= 0)
+		emit(gen, BPF_MOV64_REG(BPF_REG_4, reg2));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_trace_printk));
+}
+
+static void debug_regs(struct bpf_gen *gen, int reg1, int reg2, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	emit_debug(gen, reg1, reg2, fmt, args);
+	va_end(args);
+}
+
+static void debug_ret(struct bpf_gen *gen, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	emit_debug(gen, BPF_REG_7, -1, fmt, args);
+	va_end(args);
+}
+
+static void __emit_sys_close(struct bpf_gen *gen)
+{
+	emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0,
+			      /* 2 is the number of the following insns
+			       * * 6 is additional insns in debug_regs
+			       */
+			      2 + (gen->log_level ? 6 : 0)));
+	emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_1));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close));
+	debug_regs(gen, BPF_REG_9, BPF_REG_0, "close(%%d) = %%d");
+}
+
+static void emit_sys_close_stack(struct bpf_gen *gen, int stack_off)
+{
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, stack_off));
+	__emit_sys_close(gen);
+}
+
+static void emit_sys_close_blob(struct bpf_gen *gen, int blob_off)
+{
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_off));
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0));
+	__emit_sys_close(gen);
+}
+
+int bpf_gen__finish(struct bpf_gen *gen, int nr_progs, int nr_maps)
+{
+	int i;
+
+	if (nr_progs < gen->nr_progs || nr_maps != gen->nr_maps) {
+		pr_warn("nr_progs %d/%d nr_maps %d/%d mismatch\n",
+			nr_progs, gen->nr_progs, nr_maps, gen->nr_maps);
+		gen->error = -EFAULT;
+		return gen->error;
+	}
+	emit_sys_close_stack(gen, stack_off(btf_fd));
+	for (i = 0; i < gen->nr_progs; i++)
+		move_stack2ctx(gen,
+			       sizeof(struct bpf_loader_ctx) +
+			       sizeof(struct bpf_map_desc) * gen->nr_maps +
+			       sizeof(struct bpf_prog_desc) * i +
+			       offsetof(struct bpf_prog_desc, prog_fd), 4,
+			       stack_off(prog_fd[i]));
+	for (i = 0; i < gen->nr_maps; i++)
+		move_blob2ctx(gen,
+			      sizeof(struct bpf_loader_ctx) +
+			      sizeof(struct bpf_map_desc) * i +
+			      offsetof(struct bpf_map_desc, map_fd), 4,
+			      blob_fd_array_off(gen, i));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_0, 0));
+	emit(gen, BPF_EXIT_INSN());
+	pr_debug("gen: finish %d\n", gen->error);
+	if (!gen->error) {
+		struct gen_loader_opts *opts = gen->opts;
+
+		opts->insns = gen->insn_start;
+		opts->insns_sz = gen->insn_cur - gen->insn_start;
+		opts->data = gen->data_start;
+		opts->data_sz = gen->data_cur - gen->data_start;
+	}
+	return gen->error;
+}
+
+void bpf_gen__free(struct bpf_gen *gen)
+{
+	if (!gen)
+		return;
+	free(gen->data_start);
+	free(gen->insn_start);
+	free(gen);
+}
+
+void bpf_gen__load_btf(struct bpf_gen *gen, const void *btf_raw_data,
+		       __u32 btf_raw_size)
+{
+	int attr_size = offsetofend(union bpf_attr, btf_log_level);
+	int btf_data, btf_load_attr;
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	pr_debug("gen: load_btf: size %d\n", btf_raw_size);
+	btf_data = add_data(gen, btf_raw_data, btf_raw_size);
+
+	attr.btf_size = btf_raw_size;
+	btf_load_attr = add_data(gen, &attr, attr_size);
+
+	/* populate union bpf_attr with user provided log details */
+	move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_level), 4,
+		      offsetof(struct bpf_loader_ctx, log_level), false);
+	move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_size), 4,
+		      offsetof(struct bpf_loader_ctx, log_size), false);
+	move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_buf), 8,
+		      offsetof(struct bpf_loader_ctx, log_buf), false);
+	/* populate union bpf_attr with a pointer to the BTF data */
+	emit_rel_store(gen, attr_field(btf_load_attr, btf), btf_data);
+	/* emit BTF_LOAD command */
+	emit_sys_bpf(gen, BPF_BTF_LOAD, btf_load_attr, attr_size);
+	debug_ret(gen, "btf_load size %d", btf_raw_size);
+	emit_check_err(gen);
+	/* remember btf_fd in the stack, if successful */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7, stack_off(btf_fd)));
+}
+
+void bpf_gen__map_create(struct bpf_gen *gen,
+			 enum bpf_map_type map_type,
+			 const char *map_name,
+			 __u32 key_size, __u32 value_size, __u32 max_entries,
+			 struct bpf_map_create_opts *map_attr, int map_idx)
+{
+	int attr_size = offsetofend(union bpf_attr, map_extra);
+	bool close_inner_map_fd = false;
+	int map_create_attr, idx;
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	attr.map_type = map_type;
+	attr.key_size = key_size;
+	attr.value_size = value_size;
+	attr.map_flags = map_attr->map_flags;
+	attr.map_extra = map_attr->map_extra;
+	if (map_name)
+		libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name));
+	attr.numa_node = map_attr->numa_node;
+	attr.map_ifindex = map_attr->map_ifindex;
+	attr.max_entries = max_entries;
+	attr.btf_key_type_id = map_attr->btf_key_type_id;
+	attr.btf_value_type_id = map_attr->btf_value_type_id;
+
+	pr_debug("gen: map_create: %s idx %d type %d value_type_id %d\n",
+		 attr.map_name, map_idx, map_type, attr.btf_value_type_id);
+
+	map_create_attr = add_data(gen, &attr, attr_size);
+	if (attr.btf_value_type_id)
+		/* populate union bpf_attr with btf_fd saved in the stack earlier */
+		move_stack2blob(gen, attr_field(map_create_attr, btf_fd), 4,
+				stack_off(btf_fd));
+	switch (attr.map_type) {
+	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+	case BPF_MAP_TYPE_HASH_OF_MAPS:
+		move_stack2blob(gen, attr_field(map_create_attr, inner_map_fd), 4,
+				stack_off(inner_map_fd));
+		close_inner_map_fd = true;
+		break;
+	default:
+		break;
+	}
+	/* conditionally update max_entries */
+	if (map_idx >= 0)
+		move_ctx2blob(gen, attr_field(map_create_attr, max_entries), 4,
+			      sizeof(struct bpf_loader_ctx) +
+			      sizeof(struct bpf_map_desc) * map_idx +
+			      offsetof(struct bpf_map_desc, max_entries),
+			      true /* check that max_entries != 0 */);
+	/* emit MAP_CREATE command */
+	emit_sys_bpf(gen, BPF_MAP_CREATE, map_create_attr, attr_size);
+	debug_ret(gen, "map_create %s idx %d type %d value_size %d value_btf_id %d",
+		  attr.map_name, map_idx, map_type, value_size,
+		  attr.btf_value_type_id);
+	emit_check_err(gen);
+	/* remember map_fd in the stack, if successful */
+	if (map_idx < 0) {
+		/* This bpf_gen__map_create() function is called with map_idx >= 0
+		 * for all maps that libbpf loading logic tracks.
+		 * It's called with -1 to create an inner map.
+		 */
+		emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7,
+				      stack_off(inner_map_fd)));
+	} else if (map_idx != gen->nr_maps) {
+		gen->error = -EDOM; /* internal bug */
+		return;
+	} else {
+		/* add_map_fd does gen->nr_maps++ */
+		idx = add_map_fd(gen);
+		emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+						 0, 0, 0, blob_fd_array_off(gen, idx)));
+		emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_7, 0));
+	}
+	if (close_inner_map_fd)
+		emit_sys_close_stack(gen, stack_off(inner_map_fd));
+}
+
+void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *attach_name,
+				   enum bpf_attach_type type)
+{
+	const char *prefix;
+	int kind, ret;
+
+	btf_get_kernel_prefix_kind(type, &prefix, &kind);
+	gen->attach_kind = kind;
+	ret = snprintf(gen->attach_target, sizeof(gen->attach_target), "%s%s",
+		       prefix, attach_name);
+	if (ret >= sizeof(gen->attach_target))
+		gen->error = -ENOSPC;
+}
+
+static void emit_find_attach_target(struct bpf_gen *gen)
+{
+	int name, len = strlen(gen->attach_target) + 1;
+
+	pr_debug("gen: find_attach_tgt %s %d\n", gen->attach_target, gen->attach_kind);
+	name = add_data(gen, gen->attach_target, len);
+
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, name));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, gen->attach_kind));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+	debug_ret(gen, "find_by_name_kind(%s,%d)",
+		  gen->attach_target, gen->attach_kind);
+	emit_check_err(gen);
+	/* if successful, btf_id is in lower 32-bit of R7 and
+	 * btf_obj_fd is in upper 32-bit
+	 */
+}
+
+void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
+			    bool is_typeless, int kind, int insn_idx)
+{
+	struct ksym_relo_desc *relo;
+
+	relo = libbpf_reallocarray(gen->relos, gen->relo_cnt + 1, sizeof(*relo));
+	if (!relo) {
+		gen->error = -ENOMEM;
+		return;
+	}
+	gen->relos = relo;
+	relo += gen->relo_cnt;
+	relo->name = name;
+	relo->is_weak = is_weak;
+	relo->is_typeless = is_typeless;
+	relo->kind = kind;
+	relo->insn_idx = insn_idx;
+	gen->relo_cnt++;
+}
+
+/* returns existing ksym_desc with ref incremented, or inserts a new one */
+static struct ksym_desc *get_ksym_desc(struct bpf_gen *gen, struct ksym_relo_desc *relo)
+{
+	struct ksym_desc *kdesc;
+	int i;
+
+	for (i = 0; i < gen->nr_ksyms; i++) {
+		if (!strcmp(gen->ksyms[i].name, relo->name)) {
+			gen->ksyms[i].ref++;
+			return &gen->ksyms[i];
+		}
+	}
+	kdesc = libbpf_reallocarray(gen->ksyms, gen->nr_ksyms + 1, sizeof(*kdesc));
+	if (!kdesc) {
+		gen->error = -ENOMEM;
+		return NULL;
+	}
+	gen->ksyms = kdesc;
+	kdesc = &gen->ksyms[gen->nr_ksyms++];
+	kdesc->name = relo->name;
+	kdesc->kind = relo->kind;
+	kdesc->ref = 1;
+	kdesc->off = 0;
+	kdesc->insn = 0;
+	return kdesc;
+}
+
+/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
+ * Returns result in BPF_REG_7
+ */
+static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_desc *relo)
+{
+	int name_off, len = strlen(relo->name) + 1;
+
+	name_off = add_data(gen, relo->name, len);
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, name_off));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, relo->kind));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+	debug_ret(gen, "find_by_name_kind(%s,%d)", relo->name, relo->kind);
+}
+
+/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
+ * Returns result in BPF_REG_7
+ * Returns u64 symbol addr in BPF_REG_9
+ */
+static void emit_bpf_kallsyms_lookup_name(struct bpf_gen *gen, struct ksym_relo_desc *relo)
+{
+	int name_off, len = strlen(relo->name) + 1, res_off;
+
+	name_off = add_data(gen, relo->name, len);
+	res_off = add_data(gen, NULL, 8); /* res is u64 */
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, name_off));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_4, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, res_off));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_4));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_kallsyms_lookup_name));
+	emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+	debug_ret(gen, "kallsyms_lookup_name(%s,%d)", relo->name, relo->kind);
+}
+
+/* Expects:
+ * BPF_REG_8 - pointer to instruction
+ *
+ * We need to reuse BTF fd for same symbol otherwise each relocation takes a new
+ * index, while kernel limits total kfunc BTFs to 256. For duplicate symbols,
+ * this would mean a new BTF fd index for each entry. By pairing symbol name
+ * with index, we get the insn->imm, insn->off pairing that kernel uses for
+ * kfunc_tab, which becomes the effective limit even though all of them may
+ * share same index in fd_array (such that kfunc_btf_tab has 1 element).
+ */
+static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
+{
+	struct ksym_desc *kdesc;
+	int btf_fd_idx;
+
+	kdesc = get_ksym_desc(gen, relo);
+	if (!kdesc)
+		return;
+	/* try to copy from existing bpf_insn */
+	if (kdesc->ref > 1) {
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + offsetof(struct bpf_insn, imm));
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, off), 2,
+			       kdesc->insn + offsetof(struct bpf_insn, off));
+		goto log;
+	}
+	/* remember insn offset, so we can copy BTF ID and FD later */
+	kdesc->insn = insn;
+	emit_bpf_find_by_name_kind(gen, relo);
+	if (!relo->is_weak)
+		emit_check_err(gen);
+	/* get index in fd_array to store BTF FD at */
+	btf_fd_idx = add_kfunc_btf_fd(gen);
+	if (btf_fd_idx > INT16_MAX) {
+		pr_warn("BTF fd off %d for kfunc %s exceeds INT16_MAX, cannot process relocation\n",
+			btf_fd_idx, relo->name);
+		gen->error = -E2BIG;
+		return;
+	}
+	kdesc->off = btf_fd_idx;
+	/* jump to success case */
+	emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
+	/* set value for imm, off as 0 */
+	emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
+	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
+	/* skip success case for ret < 0 */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 10));
+	/* store btf_id into insn[insn_idx].imm */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
+	/* obtain fd in BPF_REG_9 */
+	emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_7));
+	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
+	/* jump to fd_array store if fd denotes module BTF */
+	emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2));
+	/* set the default value for off */
+	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
+	/* skip BTF fd store for vmlinux BTF */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4));
+	/* load fd_array slot pointer */
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_fd_array_off(gen, btf_fd_idx)));
+	/* store BTF fd in slot */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0));
+	/* store index into insn[insn_idx].off */
+	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), btf_fd_idx));
+log:
+	if (!gen->log_level)
+		return;
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
+			      offsetof(struct bpf_insn, imm)));
+	emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8,
+			      offsetof(struct bpf_insn, off)));
+	debug_regs(gen, BPF_REG_7, BPF_REG_9, " func (%s:count=%d): imm: %%d, off: %%d",
+		   relo->name, kdesc->ref);
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_fd_array_off(gen, kdesc->off)));
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_0, 0));
+	debug_regs(gen, BPF_REG_9, -1, " func (%s:count=%d): btf_fd",
+		   relo->name, kdesc->ref);
+}
+
+static void emit_ksym_relo_log(struct bpf_gen *gen, struct ksym_relo_desc *relo,
+			       int ref)
+{
+	if (!gen->log_level)
+		return;
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
+			      offsetof(struct bpf_insn, imm)));
+	emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) +
+			      offsetof(struct bpf_insn, imm)));
+	debug_regs(gen, BPF_REG_7, BPF_REG_9, " var t=%d w=%d (%s:count=%d): imm[0]: %%d, imm[1]: %%d",
+		   relo->is_typeless, relo->is_weak, relo->name, ref);
+	emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
+	debug_regs(gen, BPF_REG_9, -1, " var t=%d w=%d (%s:count=%d): insn.reg",
+		   relo->is_typeless, relo->is_weak, relo->name, ref);
+}
+
+/* Expects:
+ * BPF_REG_8 - pointer to instruction
+ */
+static void emit_relo_ksym_typeless(struct bpf_gen *gen,
+				    struct ksym_relo_desc *relo, int insn)
+{
+	struct ksym_desc *kdesc;
+
+	kdesc = get_ksym_desc(gen, relo);
+	if (!kdesc)
+		return;
+	/* try to copy from existing ldimm64 insn */
+	if (kdesc->ref > 1) {
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + offsetof(struct bpf_insn, imm));
+		move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
+		goto log;
+	}
+	/* remember insn offset, so we can copy ksym addr later */
+	kdesc->insn = insn;
+	/* skip typeless ksym_desc in fd closing loop in cleanup_relos */
+	kdesc->typeless = true;
+	emit_bpf_kallsyms_lookup_name(gen, relo);
+	emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_7, -ENOENT, 1));
+	emit_check_err(gen);
+	/* store lower half of addr into insn[insn_idx].imm */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, offsetof(struct bpf_insn, imm)));
+	/* store upper half of addr into insn[insn_idx + 1].imm */
+	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9,
+		      sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
+log:
+	emit_ksym_relo_log(gen, relo, kdesc->ref);
+}
+
+static __u32 src_reg_mask(void)
+{
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	return 0x0f; /* src_reg,dst_reg,... */
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	return 0xf0; /* dst_reg,src_reg,... */
+#else
+#error "Unsupported bit endianness, cannot proceed"
+#endif
+}
+
+/* Expects:
+ * BPF_REG_8 - pointer to instruction
+ */
+static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
+{
+	struct ksym_desc *kdesc;
+	__u32 reg_mask;
+
+	kdesc = get_ksym_desc(gen, relo);
+	if (!kdesc)
+		return;
+	/* try to copy from existing ldimm64 insn */
+	if (kdesc->ref > 1) {
+		move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + offsetof(struct bpf_insn, imm));
+		/* jump over src_reg adjustment if imm (btf_id) is not 0, reuse BPF_REG_0 from move_blob2blob
+		 * If btf_id is zero, clear BPF_PSEUDO_BTF_ID flag in src_reg of ld_imm64 insn
+		 */
+		emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3));
+		goto clear_src_reg;
+	}
+	/* remember insn offset, so we can copy BTF ID and FD later */
+	kdesc->insn = insn;
+	emit_bpf_find_by_name_kind(gen, relo);
+	if (!relo->is_weak)
+		emit_check_err(gen);
+	/* jump to success case */
+	emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
+	/* set values for insn[insn_idx].imm, insn[insn_idx + 1].imm as 0 */
+	emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
+	emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 0));
+	/* skip success case for ret < 0 */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4));
+	/* store btf_id into insn[insn_idx].imm */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
+	/* store btf_obj_fd into insn[insn_idx + 1].imm */
+	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7,
+			      sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
+	/* skip src_reg adjustment */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 3));
+clear_src_reg:
+	/* clear bpf_object__relocate_data's src_reg assignment, otherwise we get a verifier failure */
+	reg_mask = src_reg_mask();
+	emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
+	emit(gen, BPF_ALU32_IMM(BPF_AND, BPF_REG_9, reg_mask));
+	emit(gen, BPF_STX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, offsetofend(struct bpf_insn, code)));
+
+	emit_ksym_relo_log(gen, relo, kdesc->ref);
+}
+
+void bpf_gen__record_relo_core(struct bpf_gen *gen,
+			       const struct bpf_core_relo *core_relo)
+{
+	struct bpf_core_relo *relos;
+
+	relos = libbpf_reallocarray(gen->core_relos, gen->core_relo_cnt + 1, sizeof(*relos));
+	if (!relos) {
+		gen->error = -ENOMEM;
+		return;
+	}
+	gen->core_relos = relos;
+	relos += gen->core_relo_cnt;
+	memcpy(relos, core_relo, sizeof(*relos));
+	gen->core_relo_cnt++;
+}
+
+static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns)
+{
+	int insn;
+
+	pr_debug("gen: emit_relo (%d): %s at %d\n", relo->kind, relo->name, relo->insn_idx);
+	insn = insns + sizeof(struct bpf_insn) * relo->insn_idx;
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn));
+	switch (relo->kind) {
+	case BTF_KIND_VAR:
+		if (relo->is_typeless)
+			emit_relo_ksym_typeless(gen, relo, insn);
+		else
+			emit_relo_ksym_btf(gen, relo, insn);
+		break;
+	case BTF_KIND_FUNC:
+		emit_relo_kfunc_btf(gen, relo, insn);
+		break;
+	default:
+		pr_warn("Unknown relocation kind '%d'\n", relo->kind);
+		gen->error = -EDOM;
+		return;
+	}
+}
+
+static void emit_relos(struct bpf_gen *gen, int insns)
+{
+	int i;
+
+	for (i = 0; i < gen->relo_cnt; i++)
+		emit_relo(gen, gen->relos + i, insns);
+}
+
+static void cleanup_core_relo(struct bpf_gen *gen)
+{
+	if (!gen->core_relo_cnt)
+		return;
+	free(gen->core_relos);
+	gen->core_relo_cnt = 0;
+	gen->core_relos = NULL;
+}
+
+static void cleanup_relos(struct bpf_gen *gen, int insns)
+{
+	int i, insn;
+
+	for (i = 0; i < gen->nr_ksyms; i++) {
+		/* only close fds for typed ksyms and kfuncs */
+		if (gen->ksyms[i].kind == BTF_KIND_VAR && !gen->ksyms[i].typeless) {
+			/* close fd recorded in insn[insn_idx + 1].imm */
+			insn = gen->ksyms[i].insn;
+			insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm);
+			emit_sys_close_blob(gen, insn);
+		} else if (gen->ksyms[i].kind == BTF_KIND_FUNC) {
+			emit_sys_close_blob(gen, blob_fd_array_off(gen, gen->ksyms[i].off));
+			if (gen->ksyms[i].off < MAX_FD_ARRAY_SZ)
+				gen->nr_fd_array--;
+		}
+	}
+	if (gen->nr_ksyms) {
+		free(gen->ksyms);
+		gen->nr_ksyms = 0;
+		gen->ksyms = NULL;
+	}
+	if (gen->relo_cnt) {
+		free(gen->relos);
+		gen->relo_cnt = 0;
+		gen->relos = NULL;
+	}
+	cleanup_core_relo(gen);
+}
+
+void bpf_gen__prog_load(struct bpf_gen *gen,
+			enum bpf_prog_type prog_type, const char *prog_name,
+			const char *license, struct bpf_insn *insns, size_t insn_cnt,
+			struct bpf_prog_load_opts *load_attr, int prog_idx)
+{
+	int prog_load_attr, license_off, insns_off, func_info, line_info, core_relos;
+	int attr_size = offsetofend(union bpf_attr, core_relo_rec_size);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	pr_debug("gen: prog_load: type %d insns_cnt %zd progi_idx %d\n",
+		 prog_type, insn_cnt, prog_idx);
+	/* add license string to blob of bytes */
+	license_off = add_data(gen, license, strlen(license) + 1);
+	/* add insns to blob of bytes */
+	insns_off = add_data(gen, insns, insn_cnt * sizeof(struct bpf_insn));
+
+	attr.prog_type = prog_type;
+	attr.expected_attach_type = load_attr->expected_attach_type;
+	attr.attach_btf_id = load_attr->attach_btf_id;
+	attr.prog_ifindex = load_attr->prog_ifindex;
+	attr.kern_version = 0;
+	attr.insn_cnt = (__u32)insn_cnt;
+	attr.prog_flags = load_attr->prog_flags;
+
+	attr.func_info_rec_size = load_attr->func_info_rec_size;
+	attr.func_info_cnt = load_attr->func_info_cnt;
+	func_info = add_data(gen, load_attr->func_info,
+			     attr.func_info_cnt * attr.func_info_rec_size);
+
+	attr.line_info_rec_size = load_attr->line_info_rec_size;
+	attr.line_info_cnt = load_attr->line_info_cnt;
+	line_info = add_data(gen, load_attr->line_info,
+			     attr.line_info_cnt * attr.line_info_rec_size);
+
+	attr.core_relo_rec_size = sizeof(struct bpf_core_relo);
+	attr.core_relo_cnt = gen->core_relo_cnt;
+	core_relos = add_data(gen, gen->core_relos,
+			     attr.core_relo_cnt * attr.core_relo_rec_size);
+
+	libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name));
+	prog_load_attr = add_data(gen, &attr, attr_size);
+
+	/* populate union bpf_attr with a pointer to license */
+	emit_rel_store(gen, attr_field(prog_load_attr, license), license_off);
+
+	/* populate union bpf_attr with a pointer to instructions */
+	emit_rel_store(gen, attr_field(prog_load_attr, insns), insns_off);
+
+	/* populate union bpf_attr with a pointer to func_info */
+	emit_rel_store(gen, attr_field(prog_load_attr, func_info), func_info);
+
+	/* populate union bpf_attr with a pointer to line_info */
+	emit_rel_store(gen, attr_field(prog_load_attr, line_info), line_info);
+
+	/* populate union bpf_attr with a pointer to core_relos */
+	emit_rel_store(gen, attr_field(prog_load_attr, core_relos), core_relos);
+
+	/* populate union bpf_attr fd_array with a pointer to data where map_fds are saved */
+	emit_rel_store(gen, attr_field(prog_load_attr, fd_array), gen->fd_array);
+
+	/* populate union bpf_attr with user provided log details */
+	move_ctx2blob(gen, attr_field(prog_load_attr, log_level), 4,
+		      offsetof(struct bpf_loader_ctx, log_level), false);
+	move_ctx2blob(gen, attr_field(prog_load_attr, log_size), 4,
+		      offsetof(struct bpf_loader_ctx, log_size), false);
+	move_ctx2blob(gen, attr_field(prog_load_attr, log_buf), 8,
+		      offsetof(struct bpf_loader_ctx, log_buf), false);
+	/* populate union bpf_attr with btf_fd saved in the stack earlier */
+	move_stack2blob(gen, attr_field(prog_load_attr, prog_btf_fd), 4,
+			stack_off(btf_fd));
+	if (gen->attach_kind) {
+		emit_find_attach_target(gen);
+		/* populate union bpf_attr with btf_id and btf_obj_fd found by helper */
+		emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+						 0, 0, 0, prog_load_attr));
+		emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7,
+				      offsetof(union bpf_attr, attach_btf_id)));
+		emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
+		emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7,
+				      offsetof(union bpf_attr, attach_btf_obj_fd)));
+	}
+	emit_relos(gen, insns_off);
+	/* emit PROG_LOAD command */
+	emit_sys_bpf(gen, BPF_PROG_LOAD, prog_load_attr, attr_size);
+	debug_ret(gen, "prog_load %s insn_cnt %d", attr.prog_name, attr.insn_cnt);
+	/* successful or not, close btf module FDs used in extern ksyms and attach_btf_obj_fd */
+	cleanup_relos(gen, insns_off);
+	if (gen->attach_kind) {
+		emit_sys_close_blob(gen,
+				    attr_field(prog_load_attr, attach_btf_obj_fd));
+		gen->attach_kind = 0;
+	}
+	emit_check_err(gen);
+	/* remember prog_fd in the stack, if successful */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7,
+			      stack_off(prog_fd[gen->nr_progs])));
+	gen->nr_progs++;
+}
+
+void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue,
+			      __u32 value_size)
+{
+	int attr_size = offsetofend(union bpf_attr, flags);
+	int map_update_attr, value, key;
+	union bpf_attr attr;
+	int zero = 0;
+
+	memset(&attr, 0, attr_size);
+	pr_debug("gen: map_update_elem: idx %d\n", map_idx);
+
+	value = add_data(gen, pvalue, value_size);
+	key = add_data(gen, &zero, sizeof(zero));
+
+	/* if (map_desc[map_idx].initial_value) {
+	 *    if (ctx->flags & BPF_SKEL_KERNEL)
+	 *        bpf_probe_read_kernel(value, value_size, initial_value);
+	 *    else
+	 *        bpf_copy_from_user(value, value_size, initial_value);
+	 * }
+	 */
+	emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_6,
+			      sizeof(struct bpf_loader_ctx) +
+			      sizeof(struct bpf_map_desc) * map_idx +
+			      offsetof(struct bpf_map_desc, initial_value)));
+	emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 8));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, value));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, value_size));
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
+			      offsetof(struct bpf_loader_ctx, flags)));
+	emit(gen, BPF_JMP_IMM(BPF_JSET, BPF_REG_0, BPF_SKEL_KERNEL, 2));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_copy_from_user));
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
+
+	map_update_attr = add_data(gen, &attr, attr_size);
+	move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
+		       blob_fd_array_off(gen, map_idx));
+	emit_rel_store(gen, attr_field(map_update_attr, key), key);
+	emit_rel_store(gen, attr_field(map_update_attr, value), value);
+	/* emit MAP_UPDATE_ELEM command */
+	emit_sys_bpf(gen, BPF_MAP_UPDATE_ELEM, map_update_attr, attr_size);
+	debug_ret(gen, "update_elem idx %d value_size %d", map_idx, value_size);
+	emit_check_err(gen);
+}
+
+void bpf_gen__populate_outer_map(struct bpf_gen *gen, int outer_map_idx, int slot,
+				 int inner_map_idx)
+{
+	int attr_size = offsetofend(union bpf_attr, flags);
+	int map_update_attr, key;
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	pr_debug("gen: populate_outer_map: outer %d key %d inner %d\n",
+		 outer_map_idx, slot, inner_map_idx);
+
+	key = add_data(gen, &slot, sizeof(slot));
+
+	map_update_attr = add_data(gen, &attr, attr_size);
+	move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
+		       blob_fd_array_off(gen, outer_map_idx));
+	emit_rel_store(gen, attr_field(map_update_attr, key), key);
+	emit_rel_store(gen, attr_field(map_update_attr, value),
+		       blob_fd_array_off(gen, inner_map_idx));
+
+	/* emit MAP_UPDATE_ELEM command */
+	emit_sys_bpf(gen, BPF_MAP_UPDATE_ELEM, map_update_attr, attr_size);
+	debug_ret(gen, "populate_outer_map outer %d key %d inner %d",
+		  outer_map_idx, slot, inner_map_idx);
+	emit_check_err(gen);
+}
+
+void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx)
+{
+	int attr_size = offsetofend(union bpf_attr, map_fd);
+	int map_freeze_attr;
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	pr_debug("gen: map_freeze: idx %d\n", map_idx);
+	map_freeze_attr = add_data(gen, &attr, attr_size);
+	move_blob2blob(gen, attr_field(map_freeze_attr, map_fd), 4,
+		       blob_fd_array_off(gen, map_idx));
+	/* emit MAP_FREEZE command */
+	emit_sys_bpf(gen, BPF_MAP_FREEZE, map_freeze_attr, attr_size);
+	debug_ret(gen, "map_freeze");
+	emit_check_err(gen);
+}