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authorDaniel Borkmann <daniel@iogearbox.net>2018-05-24 09:20:50 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2018-05-24 09:20:51 +0200
commit30cfe3b4d0a0bb389d173cdcad66f9f558c021be (patch)
tree368c31f0f2cd07cab7ff8abd445b8dc84aa761ec
parenta2889a4c2d3aefdf6f2a636fa1531243653a7633 (diff)
parentf7f62c7134288a704f90b137097e1ee689ff25ab (diff)
Merge branch 'bpf-multi-prog-improvements'
Sandipan Das says: ==================== [1] Support for bpf-to-bpf function calls in the powerpc64 JIT compiler. [2] Provide a way for resolving function calls because of the way JITed images are allocated in powerpc64. [3] Fix to get JITed instruction dumps for multi-function programs from the bpf system call. [4] Fix for bpftool to show delimited multi-function JITed image dumps. v4: - Incorporate review comments from Jakub. - Fix JSON output for bpftool. v3: - Change base tree tag to bpf-next. - Incorporate review comments from Alexei, Daniel and Jakub. - Make sure that the JITed image does not grow or shrink after the last pass due to the way the instruction sequence used to load a callee's address maybe optimized. - Make additional changes to the bpf system call and bpftool to make multi-function JITed dumps easier to correlate. v2: - Incorporate review comments from Jakub. ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--arch/powerpc/net/bpf_jit_comp64.c110
-rw-r--r--include/uapi/linux/bpf.h4
-rw-r--r--kernel/bpf/syscall.c82
-rw-r--r--kernel/bpf/verifier.c22
-rw-r--r--tools/bpf/bpftool/prog.c97
-rw-r--r--tools/bpf/bpftool/xlated_dumper.c14
-rw-r--r--tools/bpf/bpftool/xlated_dumper.h3
-rw-r--r--tools/include/uapi/linux/bpf.h4
8 files changed, 301 insertions, 35 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 1bdb1aff0619..f1c95779843b 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -167,25 +167,37 @@ static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
static void bpf_jit_emit_func_call(u32 *image, struct codegen_context *ctx, u64 func)
{
+ unsigned int i, ctx_idx = ctx->idx;
+
+ /* Load function address into r12 */
+ PPC_LI64(12, func);
+
+ /* For bpf-to-bpf function calls, the callee's address is unknown
+ * until the last extra pass. As seen above, we use PPC_LI64() to
+ * load the callee's address, but this may optimize the number of
+ * instructions required based on the nature of the address.
+ *
+ * Since we don't want the number of instructions emitted to change,
+ * we pad the optimized PPC_LI64() call with NOPs to guarantee that
+ * we always have a five-instruction sequence, which is the maximum
+ * that PPC_LI64() can emit.
+ */
+ for (i = ctx->idx - ctx_idx; i < 5; i++)
+ PPC_NOP();
+
#ifdef PPC64_ELF_ABI_v1
- /* func points to the function descriptor */
- PPC_LI64(b2p[TMP_REG_2], func);
- /* Load actual entry point from function descriptor */
- PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
- /* ... and move it to LR */
- PPC_MTLR(b2p[TMP_REG_1]);
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
* function pointer (so caller will save/restore r2)
* and since we don't use a TOC ourself.
*/
- PPC_BPF_LL(2, b2p[TMP_REG_2], 8);
-#else
- /* We can clobber r12 */
- PPC_FUNC_ADDR(12, func);
- PPC_MTLR(12);
+ PPC_BPF_LL(2, 12, 8);
+ /* Load actual entry point from function descriptor */
+ PPC_BPF_LL(12, 12, 0);
#endif
+
+ PPC_MTLR(12);
PPC_BLRL();
}
@@ -256,7 +268,7 @@ static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32
/* Assemble the body code between the prologue & epilogue */
static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
struct codegen_context *ctx,
- u32 *addrs)
+ u32 *addrs, bool extra_pass)
{
const struct bpf_insn *insn = fp->insnsi;
int flen = fp->len;
@@ -712,11 +724,25 @@ emit_clear:
break;
/*
- * Call kernel helper
+ * Call kernel helper or bpf function
*/
case BPF_JMP | BPF_CALL:
ctx->seen |= SEEN_FUNC;
- func = (u8 *) __bpf_call_base + imm;
+
+ /* bpf function call */
+ if (insn[i].src_reg == BPF_PSEUDO_CALL)
+ if (!extra_pass)
+ func = NULL;
+ else if (fp->aux->func && off < fp->aux->func_cnt)
+ /* use the subprog id from the off
+ * field to lookup the callee address
+ */
+ func = (u8 *) fp->aux->func[off]->bpf_func;
+ else
+ return -EINVAL;
+ /* kernel helper call */
+ else
+ func = (u8 *) __bpf_call_base + imm;
bpf_jit_emit_func_call(image, ctx, (u64)func);
@@ -864,6 +890,14 @@ cond_branch:
return 0;
}
+struct powerpc64_jit_data {
+ struct bpf_binary_header *header;
+ u32 *addrs;
+ u8 *image;
+ u32 proglen;
+ struct codegen_context ctx;
+};
+
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
{
u32 proglen;
@@ -871,6 +905,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
u8 *image = NULL;
u32 *code_base;
u32 *addrs;
+ struct powerpc64_jit_data *jit_data;
struct codegen_context cgctx;
int pass;
int flen;
@@ -878,6 +913,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
struct bpf_prog *org_fp = fp;
struct bpf_prog *tmp_fp;
bool bpf_blinded = false;
+ bool extra_pass = false;
if (!fp->jit_requested)
return org_fp;
@@ -891,11 +927,32 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
fp = tmp_fp;
}
+ jit_data = fp->aux->jit_data;
+ if (!jit_data) {
+ jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
+ if (!jit_data) {
+ fp = org_fp;
+ goto out;
+ }
+ fp->aux->jit_data = jit_data;
+ }
+
flen = fp->len;
+ addrs = jit_data->addrs;
+ if (addrs) {
+ cgctx = jit_data->ctx;
+ image = jit_data->image;
+ bpf_hdr = jit_data->header;
+ proglen = jit_data->proglen;
+ alloclen = proglen + FUNCTION_DESCR_SIZE;
+ extra_pass = true;
+ goto skip_init_ctx;
+ }
+
addrs = kzalloc((flen+1) * sizeof(*addrs), GFP_KERNEL);
if (addrs == NULL) {
fp = org_fp;
- goto out;
+ goto out_addrs;
}
memset(&cgctx, 0, sizeof(struct codegen_context));
@@ -904,10 +961,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
cgctx.stack_size = round_up(fp->aux->stack_depth, 16);
/* Scouting faux-generate pass 0 */
- if (bpf_jit_build_body(fp, 0, &cgctx, addrs)) {
+ if (bpf_jit_build_body(fp, 0, &cgctx, addrs, false)) {
/* We hit something illegal or unsupported. */
fp = org_fp;
- goto out;
+ goto out_addrs;
}
/*
@@ -925,9 +982,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
bpf_jit_fill_ill_insns);
if (!bpf_hdr) {
fp = org_fp;
- goto out;
+ goto out_addrs;
}
+skip_init_ctx:
code_base = (u32 *)(image + FUNCTION_DESCR_SIZE);
/* Code generation passes 1-2 */
@@ -935,7 +993,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
/* Now build the prologue, body code & epilogue for real. */
cgctx.idx = 0;
bpf_jit_build_prologue(code_base, &cgctx);
- bpf_jit_build_body(fp, code_base, &cgctx, addrs);
+ bpf_jit_build_body(fp, code_base, &cgctx, addrs, extra_pass);
bpf_jit_build_epilogue(code_base, &cgctx);
if (bpf_jit_enable > 1)
@@ -961,10 +1019,20 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
fp->jited_len = alloclen;
bpf_flush_icache(bpf_hdr, (u8 *)bpf_hdr + (bpf_hdr->pages * PAGE_SIZE));
+ if (!fp->is_func || extra_pass) {
+out_addrs:
+ kfree(addrs);
+ kfree(jit_data);
+ fp->aux->jit_data = NULL;
+ } else {
+ jit_data->addrs = addrs;
+ jit_data->ctx = cgctx;
+ jit_data->proglen = proglen;
+ jit_data->image = image;
+ jit_data->header = bpf_hdr;
+ }
out:
- kfree(addrs);
-
if (bpf_blinded)
bpf_jit_prog_release_other(fp, fp == org_fp ? tmp_fp : org_fp);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c3e502d06bc3..344d2ddcef49 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2205,6 +2205,10 @@ struct bpf_prog_info {
__u32 gpl_compatible:1;
__u64 netns_dev;
__u64 netns_ino;
+ __u32 nr_jited_ksyms;
+ __u32 nr_jited_func_lens;
+ __aligned_u64 jited_ksyms;
+ __aligned_u64 jited_func_lens;
} __attribute__((aligned(8)));
struct bpf_map_info {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0b4c94551001..788456c18617 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1933,6 +1933,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
if (!capable(CAP_SYS_ADMIN)) {
info.jited_prog_len = 0;
info.xlated_prog_len = 0;
+ info.nr_jited_ksyms = 0;
goto done;
}
@@ -1969,18 +1970,93 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
* for offload.
*/
ulen = info.jited_prog_len;
- info.jited_prog_len = prog->jited_len;
+ if (prog->aux->func_cnt) {
+ u32 i;
+
+ info.jited_prog_len = 0;
+ for (i = 0; i < prog->aux->func_cnt; i++)
+ info.jited_prog_len += prog->aux->func[i]->jited_len;
+ } else {
+ info.jited_prog_len = prog->jited_len;
+ }
+
if (info.jited_prog_len && ulen) {
if (bpf_dump_raw_ok()) {
uinsns = u64_to_user_ptr(info.jited_prog_insns);
ulen = min_t(u32, info.jited_prog_len, ulen);
- if (copy_to_user(uinsns, prog->bpf_func, ulen))
- return -EFAULT;
+
+ /* for multi-function programs, copy the JITed
+ * instructions for all the functions
+ */
+ if (prog->aux->func_cnt) {
+ u32 len, free, i;
+ u8 *img;
+
+ free = ulen;
+ for (i = 0; i < prog->aux->func_cnt; i++) {
+ len = prog->aux->func[i]->jited_len;
+ len = min_t(u32, len, free);
+ img = (u8 *) prog->aux->func[i]->bpf_func;
+ if (copy_to_user(uinsns, img, len))
+ return -EFAULT;
+ uinsns += len;
+ free -= len;
+ if (!free)
+ break;
+ }
+ } else {
+ if (copy_to_user(uinsns, prog->bpf_func, ulen))
+ return -EFAULT;
+ }
} else {
info.jited_prog_insns = 0;
}
}
+ ulen = info.nr_jited_ksyms;
+ info.nr_jited_ksyms = prog->aux->func_cnt;
+ if (info.nr_jited_ksyms && ulen) {
+ if (bpf_dump_raw_ok()) {
+ u64 __user *user_ksyms;
+ ulong ksym_addr;
+ u32 i;
+
+ /* copy the address of the kernel symbol
+ * corresponding to each function
+ */
+ ulen = min_t(u32, info.nr_jited_ksyms, ulen);
+ user_ksyms = u64_to_user_ptr(info.jited_ksyms);
+ for (i = 0; i < ulen; i++) {
+ ksym_addr = (ulong) prog->aux->func[i]->bpf_func;
+ ksym_addr &= PAGE_MASK;
+ if (put_user((u64) ksym_addr, &user_ksyms[i]))
+ return -EFAULT;
+ }
+ } else {
+ info.jited_ksyms = 0;
+ }
+ }
+
+ ulen = info.nr_jited_func_lens;
+ info.nr_jited_func_lens = prog->aux->func_cnt;
+ if (info.nr_jited_func_lens && ulen) {
+ if (bpf_dump_raw_ok()) {
+ u32 __user *user_lens;
+ u32 func_len, i;
+
+ /* copy the JITed image lengths for each function */
+ ulen = min_t(u32, info.nr_jited_func_lens, ulen);
+ user_lens = u64_to_user_ptr(info.jited_func_lens);
+ for (i = 0; i < ulen; i++) {
+ func_len = prog->aux->func[i]->jited_len;
+ if (put_user(func_len, &user_lens[i]))
+ return -EFAULT;
+ }
+ } else {
+ info.jited_func_lens = 0;
+ }
+ }
+
done:
if (copy_to_user(uinfo, &info, info_len) ||
put_user(info_len, &uattr->info.info_len))
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index a9e4b1372da6..8c4d9d0fd3ab 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5383,11 +5383,24 @@ static int jit_subprogs(struct bpf_verifier_env *env)
insn->src_reg != BPF_PSEUDO_CALL)
continue;
subprog = insn->off;
- insn->off = 0;
insn->imm = (u64 (*)(u64, u64, u64, u64, u64))
func[subprog]->bpf_func -
__bpf_call_base;
}
+
+ /* we use the aux data to keep a list of the start addresses
+ * of the JITed images for each function in the program
+ *
+ * for some architectures, such as powerpc64, the imm field
+ * might not be large enough to hold the offset of the start
+ * address of the callee's JITed image from __bpf_call_base
+ *
+ * in such cases, we can lookup the start address of a callee
+ * by using its subprog id, available from the off field of
+ * the call instruction, as an index for this list
+ */
+ func[i]->aux->func = func;
+ func[i]->aux->func_cnt = env->subprog_cnt;
}
for (i = 0; i < env->subprog_cnt; i++) {
old_bpf_func = func[i]->bpf_func;
@@ -5413,17 +5426,12 @@ static int jit_subprogs(struct bpf_verifier_env *env)
* later look the same as if they were interpreted only.
*/
for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
- unsigned long addr;
-
if (insn->code != (BPF_JMP | BPF_CALL) ||
insn->src_reg != BPF_PSEUDO_CALL)
continue;
insn->off = env->insn_aux_data[i].call_imm;
subprog = find_subprog(env, i + insn->off + 1);
- addr = (unsigned long)func[subprog]->bpf_func;
- addr &= PAGE_MASK;
- insn->imm = (u64 (*)(u64, u64, u64, u64, u64))
- addr - __bpf_call_base;
+ insn->imm = subprog;
}
prog->jited = 1;
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 9bdfdf2d3fbe..39b88e760367 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -420,7 +420,11 @@ static int do_show(int argc, char **argv)
static int do_dump(int argc, char **argv)
{
+ unsigned long *func_ksyms = NULL;
struct bpf_prog_info info = {};
+ unsigned int *func_lens = NULL;
+ unsigned int nr_func_ksyms;
+ unsigned int nr_func_lens;
struct dump_data dd = {};
__u32 len = sizeof(info);
unsigned int buf_size;
@@ -496,10 +500,34 @@ static int do_dump(int argc, char **argv)
return -1;
}
+ nr_func_ksyms = info.nr_jited_ksyms;
+ if (nr_func_ksyms) {
+ func_ksyms = malloc(nr_func_ksyms * sizeof(__u64));
+ if (!func_ksyms) {
+ p_err("mem alloc failed");
+ close(fd);
+ goto err_free;
+ }
+ }
+
+ nr_func_lens = info.nr_jited_func_lens;
+ if (nr_func_lens) {
+ func_lens = malloc(nr_func_lens * sizeof(__u32));
+ if (!func_lens) {
+ p_err("mem alloc failed");
+ close(fd);
+ goto err_free;
+ }
+ }
+
memset(&info, 0, sizeof(info));
*member_ptr = ptr_to_u64(buf);
*member_len = buf_size;
+ info.jited_ksyms = ptr_to_u64(func_ksyms);
+ info.nr_jited_ksyms = nr_func_ksyms;
+ info.jited_func_lens = ptr_to_u64(func_lens);
+ info.nr_jited_func_lens = nr_func_lens;
err = bpf_obj_get_info_by_fd(fd, &info, &len);
close(fd);
@@ -513,6 +541,16 @@ static int do_dump(int argc, char **argv)
goto err_free;
}
+ if (info.nr_jited_ksyms > nr_func_ksyms) {
+ p_err("too many addresses returned");
+ goto err_free;
+ }
+
+ if (info.nr_jited_func_lens > nr_func_lens) {
+ p_err("too many values returned");
+ goto err_free;
+ }
+
if ((member_len == &info.jited_prog_len &&
info.jited_prog_insns == 0) ||
(member_len == &info.xlated_prog_len &&
@@ -550,7 +588,57 @@ static int do_dump(int argc, char **argv)
goto err_free;
}
- disasm_print_insn(buf, *member_len, opcodes, name);
+ if (info.nr_jited_func_lens && info.jited_func_lens) {
+ struct kernel_sym *sym = NULL;
+ char sym_name[SYM_MAX_NAME];
+ unsigned char *img = buf;
+ __u64 *ksyms = NULL;
+ __u32 *lens;
+ __u32 i;
+
+ if (info.nr_jited_ksyms) {
+ kernel_syms_load(&dd);
+ ksyms = (__u64 *) info.jited_ksyms;
+ }
+
+ if (json_output)
+ jsonw_start_array(json_wtr);
+
+ lens = (__u32 *) info.jited_func_lens;
+ for (i = 0; i < info.nr_jited_func_lens; i++) {
+ if (ksyms) {
+ sym = kernel_syms_search(&dd, ksyms[i]);
+ if (sym)
+ sprintf(sym_name, "%s", sym->name);
+ else
+ sprintf(sym_name, "0x%016llx", ksyms[i]);
+ } else {
+ strcpy(sym_name, "unknown");
+ }
+
+ if (json_output) {
+ jsonw_start_object(json_wtr);
+ jsonw_name(json_wtr, "name");
+ jsonw_string(json_wtr, sym_name);
+ jsonw_name(json_wtr, "insns");
+ } else {
+ printf("%s:\n", sym_name);
+ }
+
+ disasm_print_insn(img, lens[i], opcodes, name);
+ img += lens[i];
+
+ if (json_output)
+ jsonw_end_object(json_wtr);
+ else
+ printf("\n");
+ }
+
+ if (json_output)
+ jsonw_end_array(json_wtr);
+ } else {
+ disasm_print_insn(buf, *member_len, opcodes, name);
+ }
} else if (visual) {
if (json_output)
jsonw_null(json_wtr);
@@ -558,6 +646,9 @@ static int do_dump(int argc, char **argv)
dump_xlated_cfg(buf, *member_len);
} else {
kernel_syms_load(&dd);
+ dd.nr_jited_ksyms = info.nr_jited_ksyms;
+ dd.jited_ksyms = (__u64 *) info.jited_ksyms;
+
if (json_output)
dump_xlated_json(&dd, buf, *member_len, opcodes);
else
@@ -566,10 +657,14 @@ static int do_dump(int argc, char **argv)
}
free(buf);
+ free(func_ksyms);
+ free(func_lens);
return 0;
err_free:
free(buf);
+ free(func_ksyms);
+ free(func_lens);
return -1;
}
diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 7a3173b76c16..b97f1da60dd1 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -102,8 +102,8 @@ void kernel_syms_destroy(struct dump_data *dd)
free(dd->sym_mapping);
}
-static struct kernel_sym *kernel_syms_search(struct dump_data *dd,
- unsigned long key)
+struct kernel_sym *kernel_syms_search(struct dump_data *dd,
+ unsigned long key)
{
struct kernel_sym sym = {
.address = key,
@@ -174,7 +174,11 @@ static const char *print_call_pcrel(struct dump_data *dd,
unsigned long address,
const struct bpf_insn *insn)
{
- if (sym)
+ if (!dd->nr_jited_ksyms)
+ /* Do not show address for interpreted programs */
+ snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
+ "%+d", insn->off);
+ else if (sym)
snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
"%+d#%s", insn->off, sym->name);
else
@@ -203,6 +207,10 @@ static const char *print_call(void *private_data,
unsigned long address = dd->address_call_base + insn->imm;
struct kernel_sym *sym;
+ if (insn->src_reg == BPF_PSEUDO_CALL &&
+ (__u32) insn->imm < dd->nr_jited_ksyms)
+ address = dd->jited_ksyms[insn->imm];
+
sym = kernel_syms_search(dd, address);
if (insn->src_reg == BPF_PSEUDO_CALL)
return print_call_pcrel(dd, sym, address, insn);
diff --git a/tools/bpf/bpftool/xlated_dumper.h b/tools/bpf/bpftool/xlated_dumper.h
index b34affa7ef2d..33d86e2b369b 100644
--- a/tools/bpf/bpftool/xlated_dumper.h
+++ b/tools/bpf/bpftool/xlated_dumper.h
@@ -49,11 +49,14 @@ struct dump_data {
unsigned long address_call_base;
struct kernel_sym *sym_mapping;
__u32 sym_count;
+ __u64 *jited_ksyms;
+ __u32 nr_jited_ksyms;
char scratch_buff[SYM_MAX_NAME + 8];
};
void kernel_syms_load(struct dump_data *dd);
void kernel_syms_destroy(struct dump_data *dd);
+struct kernel_sym *kernel_syms_search(struct dump_data *dd, unsigned long key);
void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len,
bool opcodes);
void dump_xlated_plain(struct dump_data *dd, void *buf, unsigned int len,
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c3e502d06bc3..344d2ddcef49 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2205,6 +2205,10 @@ struct bpf_prog_info {
__u32 gpl_compatible:1;
__u64 netns_dev;
__u64 netns_ino;
+ __u32 nr_jited_ksyms;
+ __u32 nr_jited_func_lens;
+ __aligned_u64 jited_ksyms;
+ __aligned_u64 jited_func_lens;
} __attribute__((aligned(8)));
struct bpf_map_info {