summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--Documentation/ABI/testing/sysfs-kernel-btf8
-rw-r--r--include/linux/bpf.h2
-rw-r--r--include/linux/module.h4
-rw-r--r--include/uapi/linux/bpf.h3
-rw-r--r--kernel/bpf/btf.c406
-rw-r--r--kernel/bpf/sysfs_btf.c2
-rw-r--r--kernel/module.c32
-rw-r--r--lib/Kconfig.debug9
-rw-r--r--scripts/Makefile.modfinal20
-rw-r--r--tools/bpf/bpftool/btf.c28
-rw-r--r--tools/include/uapi/linux/bpf.h3
11 files changed, 459 insertions, 58 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-btf b/Documentation/ABI/testing/sysfs-kernel-btf
index 2c9744b2cd59..fe96efdc9b6c 100644
--- a/Documentation/ABI/testing/sysfs-kernel-btf
+++ b/Documentation/ABI/testing/sysfs-kernel-btf
@@ -15,3 +15,11 @@ Description:
information with description of all internal kernel types. See
Documentation/bpf/btf.rst for detailed description of format
itself.
+
+What: /sys/kernel/btf/<module-name>
+Date: Nov 2020
+KernelVersion: 5.11
+Contact: bpf@vger.kernel.org
+Description:
+ Read-only binary attribute exposing kernel module's BTF type
+ information as an add-on to the kernel's BTF (/sys/kernel/btf/vmlinux).
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 73d5381a5d5c..581b2a2e78eb 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -36,9 +36,11 @@ struct seq_operations;
struct bpf_iter_aux_info;
struct bpf_local_storage;
struct bpf_local_storage_map;
+struct kobject;
extern struct idr btf_idr;
extern spinlock_t btf_idr_lock;
+extern struct kobject *btf_kobj;
typedef int (*bpf_iter_init_seq_priv_t)(void *private_data,
struct bpf_iter_aux_info *aux);
diff --git a/include/linux/module.h b/include/linux/module.h
index a29187f7c360..20fce258ffba 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -475,6 +475,10 @@ struct module {
unsigned int num_bpf_raw_events;
struct bpf_raw_event_map *bpf_raw_events;
#endif
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+ unsigned int btf_data_size;
+ void *btf_data;
+#endif
#ifdef CONFIG_JUMP_LABEL
struct jump_entry *jump_entries;
unsigned int num_jump_entries;
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 9879d6793e90..162999b12790 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4466,6 +4466,9 @@ struct bpf_btf_info {
__aligned_u64 btf;
__u32 btf_size;
__u32 id;
+ __aligned_u64 name;
+ __u32 name_len;
+ __u32 kernel_btf;
} __attribute__((aligned(8)));
struct bpf_link_info {
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 6324de8c59f7..0f1fd2669d69 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -22,6 +22,8 @@
#include <linux/skmsg.h>
#include <linux/perf_event.h>
#include <linux/bsearch.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
#include <net/sock.h>
/* BTF (BPF Type Format) is the meta data format which describes
@@ -203,12 +205,19 @@ struct btf {
const char *strings;
void *nohdr_data;
struct btf_header hdr;
- u32 nr_types;
+ u32 nr_types; /* includes VOID for base BTF */
u32 types_size;
u32 data_size;
refcount_t refcnt;
u32 id;
struct rcu_head rcu;
+
+ /* split BTF support */
+ struct btf *base_btf;
+ u32 start_id; /* first type ID in this BTF (0 for base BTF) */
+ u32 start_str_off; /* first string offset (0 for base BTF) */
+ char name[MODULE_NAME_LEN];
+ bool kernel_btf;
};
enum verifier_phase {
@@ -449,14 +458,27 @@ static bool btf_type_is_datasec(const struct btf_type *t)
return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
}
+static u32 btf_nr_types_total(const struct btf *btf)
+{
+ u32 total = 0;
+
+ while (btf) {
+ total += btf->nr_types;
+ btf = btf->base_btf;
+ }
+
+ return total;
+}
+
s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
{
const struct btf_type *t;
const char *tname;
- u32 i;
+ u32 i, total;
- for (i = 1; i <= btf->nr_types; i++) {
- t = btf->types[i];
+ total = btf_nr_types_total(btf);
+ for (i = 1; i < total; i++) {
+ t = btf_type_by_id(btf, i);
if (BTF_INFO_KIND(t->info) != kind)
continue;
@@ -599,8 +621,14 @@ static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
{
- return BTF_STR_OFFSET_VALID(offset) &&
- offset < btf->hdr.str_len;
+ if (!BTF_STR_OFFSET_VALID(offset))
+ return false;
+
+ while (offset < btf->start_str_off)
+ btf = btf->base_btf;
+
+ offset -= btf->start_str_off;
+ return offset < btf->hdr.str_len;
}
static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
@@ -614,10 +642,22 @@ static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
return true;
}
+static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
+{
+ while (offset < btf->start_str_off)
+ btf = btf->base_btf;
+
+ offset -= btf->start_str_off;
+ if (offset < btf->hdr.str_len)
+ return &btf->strings[offset];
+
+ return NULL;
+}
+
static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
{
/* offset must be valid */
- const char *src = &btf->strings[offset];
+ const char *src = btf_str_by_offset(btf, offset);
const char *src_limit;
if (!__btf_name_char_ok(*src, true, dot_ok))
@@ -650,27 +690,28 @@ static bool btf_name_valid_section(const struct btf *btf, u32 offset)
static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
{
+ const char *name;
+
if (!offset)
return "(anon)";
- else if (offset < btf->hdr.str_len)
- return &btf->strings[offset];
- else
- return "(invalid-name-offset)";
+
+ name = btf_str_by_offset(btf, offset);
+ return name ?: "(invalid-name-offset)";
}
const char *btf_name_by_offset(const struct btf *btf, u32 offset)
{
- if (offset < btf->hdr.str_len)
- return &btf->strings[offset];
-
- return NULL;
+ return btf_str_by_offset(btf, offset);
}
const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
{
- if (type_id > btf->nr_types)
- return NULL;
+ while (type_id < btf->start_id)
+ btf = btf->base_btf;
+ type_id -= btf->start_id;
+ if (type_id >= btf->nr_types)
+ return NULL;
return btf->types[type_id];
}
@@ -1390,17 +1431,13 @@ static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
{
struct btf *btf = env->btf;
- /* < 2 because +1 for btf_void which is always in btf->types[0].
- * btf_void is not accounted in btf->nr_types because btf_void
- * does not come from the BTF file.
- */
- if (btf->types_size - btf->nr_types < 2) {
+ if (btf->types_size == btf->nr_types) {
/* Expand 'types' array */
struct btf_type **new_types;
u32 expand_by, new_size;
- if (btf->types_size == BTF_MAX_TYPE) {
+ if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
btf_verifier_log(env, "Exceeded max num of types");
return -E2BIG;
}
@@ -1414,18 +1451,23 @@ static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
if (!new_types)
return -ENOMEM;
- if (btf->nr_types == 0)
- new_types[0] = &btf_void;
- else
+ if (btf->nr_types == 0) {
+ if (!btf->base_btf) {
+ /* lazily init VOID type */
+ new_types[0] = &btf_void;
+ btf->nr_types++;
+ }
+ } else {
memcpy(new_types, btf->types,
- sizeof(*btf->types) * (btf->nr_types + 1));
+ sizeof(*btf->types) * btf->nr_types);
+ }
kvfree(btf->types);
btf->types = new_types;
btf->types_size = new_size;
}
- btf->types[++(btf->nr_types)] = t;
+ btf->types[btf->nr_types++] = t;
return 0;
}
@@ -1498,18 +1540,17 @@ static int env_resolve_init(struct btf_verifier_env *env)
u32 *resolved_ids = NULL;
u8 *visit_states = NULL;
- /* +1 for btf_void */
- resolved_sizes = kvcalloc(nr_types + 1, sizeof(*resolved_sizes),
+ resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
GFP_KERNEL | __GFP_NOWARN);
if (!resolved_sizes)
goto nomem;
- resolved_ids = kvcalloc(nr_types + 1, sizeof(*resolved_ids),
+ resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
GFP_KERNEL | __GFP_NOWARN);
if (!resolved_ids)
goto nomem;
- visit_states = kvcalloc(nr_types + 1, sizeof(*visit_states),
+ visit_states = kvcalloc(nr_types, sizeof(*visit_states),
GFP_KERNEL | __GFP_NOWARN);
if (!visit_states)
goto nomem;
@@ -1561,21 +1602,27 @@ static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
static bool env_type_is_resolved(const struct btf_verifier_env *env,
u32 type_id)
{
- return env->visit_states[type_id] == RESOLVED;
+ /* base BTF types should be resolved by now */
+ if (type_id < env->btf->start_id)
+ return true;
+
+ return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
}
static int env_stack_push(struct btf_verifier_env *env,
const struct btf_type *t, u32 type_id)
{
+ const struct btf *btf = env->btf;
struct resolve_vertex *v;
if (env->top_stack == MAX_RESOLVE_DEPTH)
return -E2BIG;
- if (env->visit_states[type_id] != NOT_VISITED)
+ if (type_id < btf->start_id
+ || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
return -EEXIST;
- env->visit_states[type_id] = VISITED;
+ env->visit_states[type_id - btf->start_id] = VISITED;
v = &env->stack[env->top_stack++];
v->t = t;
@@ -1605,6 +1652,7 @@ static void env_stack_pop_resolved(struct btf_verifier_env *env,
u32 type_id = env->stack[--(env->top_stack)].type_id;
struct btf *btf = env->btf;
+ type_id -= btf->start_id; /* adjust to local type id */
btf->resolved_sizes[type_id] = resolved_size;
btf->resolved_ids[type_id] = resolved_type_id;
env->visit_states[type_id] = RESOLVED;
@@ -1709,14 +1757,30 @@ btf_resolve_size(const struct btf *btf, const struct btf_type *type,
return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
}
+static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
+{
+ while (type_id < btf->start_id)
+ btf = btf->base_btf;
+
+ return btf->resolved_ids[type_id - btf->start_id];
+}
+
/* The input param "type_id" must point to a needs_resolve type */
static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
u32 *type_id)
{
- *type_id = btf->resolved_ids[*type_id];
+ *type_id = btf_resolved_type_id(btf, *type_id);
return btf_type_by_id(btf, *type_id);
}
+static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
+{
+ while (type_id < btf->start_id)
+ btf = btf->base_btf;
+
+ return btf->resolved_sizes[type_id - btf->start_id];
+}
+
const struct btf_type *btf_type_id_size(const struct btf *btf,
u32 *type_id, u32 *ret_size)
{
@@ -1731,7 +1795,7 @@ const struct btf_type *btf_type_id_size(const struct btf *btf,
if (btf_type_has_size(size_type)) {
size = size_type->size;
} else if (btf_type_is_array(size_type)) {
- size = btf->resolved_sizes[size_type_id];
+ size = btf_resolved_type_size(btf, size_type_id);
} else if (btf_type_is_ptr(size_type)) {
size = sizeof(void *);
} else {
@@ -1739,14 +1803,14 @@ const struct btf_type *btf_type_id_size(const struct btf *btf,
!btf_type_is_var(size_type)))
return NULL;
- size_type_id = btf->resolved_ids[size_type_id];
+ size_type_id = btf_resolved_type_id(btf, size_type_id);
size_type = btf_type_by_id(btf, size_type_id);
if (btf_type_nosize_or_null(size_type))
return NULL;
else if (btf_type_has_size(size_type))
size = size_type->size;
else if (btf_type_is_array(size_type))
- size = btf->resolved_sizes[size_type_id];
+ size = btf_resolved_type_size(btf, size_type_id);
else if (btf_type_is_ptr(size_type))
size = sizeof(void *);
else
@@ -3798,7 +3862,7 @@ static int btf_check_all_metas(struct btf_verifier_env *env)
cur = btf->nohdr_data + hdr->type_off;
end = cur + hdr->type_len;
- env->log_type_id = 1;
+ env->log_type_id = btf->base_btf ? btf->start_id : 1;
while (cur < end) {
struct btf_type *t = cur;
s32 meta_size;
@@ -3825,8 +3889,8 @@ static bool btf_resolve_valid(struct btf_verifier_env *env,
return false;
if (btf_type_is_struct(t) || btf_type_is_datasec(t))
- return !btf->resolved_ids[type_id] &&
- !btf->resolved_sizes[type_id];
+ return !btf_resolved_type_id(btf, type_id) &&
+ !btf_resolved_type_size(btf, type_id);
if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
btf_type_is_var(t)) {
@@ -3846,7 +3910,7 @@ static bool btf_resolve_valid(struct btf_verifier_env *env,
elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
return elem_type && !btf_type_is_modifier(elem_type) &&
(array->nelems * elem_size ==
- btf->resolved_sizes[type_id]);
+ btf_resolved_type_size(btf, type_id));
}
return false;
@@ -3888,7 +3952,8 @@ static int btf_resolve(struct btf_verifier_env *env,
static int btf_check_all_types(struct btf_verifier_env *env)
{
struct btf *btf = env->btf;
- u32 type_id;
+ const struct btf_type *t;
+ u32 type_id, i;
int err;
err = env_resolve_init(env);
@@ -3896,8 +3961,9 @@ static int btf_check_all_types(struct btf_verifier_env *env)
return err;
env->phase++;
- for (type_id = 1; type_id <= btf->nr_types; type_id++) {
- const struct btf_type *t = btf_type_by_id(btf, type_id);
+ for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
+ type_id = btf->start_id + i;
+ t = btf_type_by_id(btf, type_id);
env->log_type_id = type_id;
if (btf_type_needs_resolve(t) &&
@@ -3934,7 +4000,7 @@ static int btf_parse_type_sec(struct btf_verifier_env *env)
return -EINVAL;
}
- if (!hdr->type_len) {
+ if (!env->btf->base_btf && !hdr->type_len) {
btf_verifier_log(env, "No type found");
return -EINVAL;
}
@@ -3961,13 +4027,18 @@ static int btf_parse_str_sec(struct btf_verifier_env *env)
return -EINVAL;
}
- if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
- start[0] || end[-1]) {
+ btf->strings = start;
+
+ if (btf->base_btf && !hdr->str_len)
+ return 0;
+ if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
+ btf_verifier_log(env, "Invalid string section");
+ return -EINVAL;
+ }
+ if (!btf->base_btf && start[0]) {
btf_verifier_log(env, "Invalid string section");
return -EINVAL;
}
-
- btf->strings = start;
return 0;
}
@@ -4362,6 +4433,8 @@ struct btf *btf_parse_vmlinux(void)
btf->data = __start_BTF;
btf->data_size = __stop_BTF - __start_BTF;
+ btf->kernel_btf = true;
+ snprintf(btf->name, sizeof(btf->name), "vmlinux");
err = btf_parse_hdr(env);
if (err)
@@ -4387,6 +4460,79 @@ struct btf *btf_parse_vmlinux(void)
bpf_struct_ops_init(btf, log);
+ refcount_set(&btf->refcnt, 1);
+
+ err = btf_alloc_id(btf);
+ if (err)
+ goto errout;
+
+ btf_verifier_env_free(env);
+ return btf;
+
+errout:
+ btf_verifier_env_free(env);
+ if (btf) {
+ kvfree(btf->types);
+ kfree(btf);
+ }
+ return ERR_PTR(err);
+}
+
+static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
+{
+ struct btf_verifier_env *env = NULL;
+ struct bpf_verifier_log *log;
+ struct btf *btf = NULL, *base_btf;
+ int err;
+
+ base_btf = bpf_get_btf_vmlinux();
+ if (IS_ERR(base_btf))
+ return base_btf;
+ if (!base_btf)
+ return ERR_PTR(-EINVAL);
+
+ env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
+ if (!env)
+ return ERR_PTR(-ENOMEM);
+
+ log = &env->log;
+ log->level = BPF_LOG_KERNEL;
+
+ btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
+ if (!btf) {
+ err = -ENOMEM;
+ goto errout;
+ }
+ env->btf = btf;
+
+ btf->base_btf = base_btf;
+ btf->start_id = base_btf->nr_types;
+ btf->start_str_off = base_btf->hdr.str_len;
+ btf->kernel_btf = true;
+ snprintf(btf->name, sizeof(btf->name), "%s", module_name);
+
+ btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
+ if (!btf->data) {
+ err = -ENOMEM;
+ goto errout;
+ }
+ memcpy(btf->data, data, data_size);
+ btf->data_size = data_size;
+
+ err = btf_parse_hdr(env);
+ if (err)
+ goto errout;
+
+ btf->nohdr_data = btf->data + btf->hdr.hdr_len;
+
+ err = btf_parse_str_sec(env);
+ if (err)
+ goto errout;
+
+ err = btf_check_all_metas(env);
+ if (err)
+ goto errout;
+
btf_verifier_env_free(env);
refcount_set(&btf->refcnt, 1);
return btf;
@@ -4394,6 +4540,7 @@ struct btf *btf_parse_vmlinux(void)
errout:
btf_verifier_env_free(env);
if (btf) {
+ kvfree(btf->data);
kvfree(btf->types);
kfree(btf);
}
@@ -4908,7 +5055,7 @@ static int __get_type_size(struct btf *btf, u32 btf_id,
while (t && btf_type_is_modifier(t))
t = btf_type_by_id(btf, t->type);
if (!t) {
- *bad_type = btf->types[0];
+ *bad_type = btf_type_by_id(btf, 0);
return -EINVAL;
}
if (btf_type_is_ptr(t))
@@ -5486,7 +5633,9 @@ int btf_get_info_by_fd(const struct btf *btf,
struct bpf_btf_info info;
u32 info_copy, btf_copy;
void __user *ubtf;
- u32 uinfo_len;
+ char __user *uname;
+ u32 uinfo_len, uname_len, name_len;
+ int ret = 0;
uinfo = u64_to_user_ptr(attr->info.info);
uinfo_len = attr->info.info_len;
@@ -5503,11 +5652,37 @@ int btf_get_info_by_fd(const struct btf *btf,
return -EFAULT;
info.btf_size = btf->data_size;
+ info.kernel_btf = btf->kernel_btf;
+
+ uname = u64_to_user_ptr(info.name);
+ uname_len = info.name_len;
+ if (!uname ^ !uname_len)
+ return -EINVAL;
+
+ name_len = strlen(btf->name);
+ info.name_len = name_len;
+
+ if (uname) {
+ if (uname_len >= name_len + 1) {
+ if (copy_to_user(uname, btf->name, name_len + 1))
+ return -EFAULT;
+ } else {
+ char zero = '\0';
+
+ if (copy_to_user(uname, btf->name, uname_len - 1))
+ return -EFAULT;
+ if (put_user(zero, uname + uname_len - 1))
+ return -EFAULT;
+ /* let user-space know about too short buffer */
+ ret = -ENOSPC;
+ }
+ }
+
if (copy_to_user(uinfo, &info, info_copy) ||
put_user(info_copy, &uattr->info.info_len))
return -EFAULT;
- return 0;
+ return ret;
}
int btf_get_fd_by_id(u32 id)
@@ -5547,3 +5722,126 @@ bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
{
return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
}
+
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+struct btf_module {
+ struct list_head list;
+ struct module *module;
+ struct btf *btf;
+ struct bin_attribute *sysfs_attr;
+};
+
+static LIST_HEAD(btf_modules);
+static DEFINE_MUTEX(btf_module_mutex);
+
+static ssize_t
+btf_module_read(struct file *file, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t len)
+{
+ const struct btf *btf = bin_attr->private;
+
+ memcpy(buf, btf->data + off, len);
+ return len;
+}
+
+static int btf_module_notify(struct notifier_block *nb, unsigned long op,
+ void *module)
+{
+ struct btf_module *btf_mod, *tmp;
+ struct module *mod = module;
+ struct btf *btf;
+ int err = 0;
+
+ if (mod->btf_data_size == 0 ||
+ (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
+ goto out;
+
+ switch (op) {
+ case MODULE_STATE_COMING:
+ btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
+ if (!btf_mod) {
+ err = -ENOMEM;
+ goto out;
+ }
+ btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
+ if (IS_ERR(btf)) {
+ pr_warn("failed to validate module [%s] BTF: %ld\n",
+ mod->name, PTR_ERR(btf));
+ kfree(btf_mod);
+ err = PTR_ERR(btf);
+ goto out;
+ }
+ err = btf_alloc_id(btf);
+ if (err) {
+ btf_free(btf);
+ kfree(btf_mod);
+ goto out;
+ }
+
+ mutex_lock(&btf_module_mutex);
+ btf_mod->module = module;
+ btf_mod->btf = btf;
+ list_add(&btf_mod->list, &btf_modules);
+ mutex_unlock(&btf_module_mutex);
+
+ if (IS_ENABLED(CONFIG_SYSFS)) {
+ struct bin_attribute *attr;
+
+ attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+ if (!attr)
+ goto out;
+
+ sysfs_bin_attr_init(attr);
+ attr->attr.name = btf->name;
+ attr->attr.mode = 0444;
+ attr->size = btf->data_size;
+ attr->private = btf;
+ attr->read = btf_module_read;
+
+ err = sysfs_create_bin_file(btf_kobj, attr);
+ if (err) {
+ pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
+ mod->name, err);
+ kfree(attr);
+ err = 0;
+ goto out;
+ }
+
+ btf_mod->sysfs_attr = attr;
+ }
+
+ break;
+ case MODULE_STATE_GOING:
+ mutex_lock(&btf_module_mutex);
+ list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
+ if (btf_mod->module != module)
+ continue;
+
+ list_del(&btf_mod->list);
+ if (btf_mod->sysfs_attr)
+ sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
+ btf_put(btf_mod->btf);
+ kfree(btf_mod->sysfs_attr);
+ kfree(btf_mod);
+ break;
+ }
+ mutex_unlock(&btf_module_mutex);
+ break;
+ }
+out:
+ return notifier_from_errno(err);
+}
+
+static struct notifier_block btf_module_nb = {
+ .notifier_call = btf_module_notify,
+};
+
+static int __init btf_module_init(void)
+{
+ register_module_notifier(&btf_module_nb);
+ return 0;
+}
+
+fs_initcall(btf_module_init);
+#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
diff --git a/kernel/bpf/sysfs_btf.c b/kernel/bpf/sysfs_btf.c
index 11b3380887fa..ef6911aee3bb 100644
--- a/kernel/bpf/sysfs_btf.c
+++ b/kernel/bpf/sysfs_btf.c
@@ -26,7 +26,7 @@ static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = {
.read = btf_vmlinux_read,
};
-static struct kobject *btf_kobj;
+struct kobject *btf_kobj;
static int __init btf_vmlinux_init(void)
{
diff --git a/kernel/module.c b/kernel/module.c
index a4fa44a652a7..f2996b02ab2e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -380,6 +380,35 @@ static void *section_objs(const struct load_info *info,
return (void *)info->sechdrs[sec].sh_addr;
}
+/* Find a module section: 0 means not found. Ignores SHF_ALLOC flag. */
+static unsigned int find_any_sec(const struct load_info *info, const char *name)
+{
+ unsigned int i;
+
+ for (i = 1; i < info->hdr->e_shnum; i++) {
+ Elf_Shdr *shdr = &info->sechdrs[i];
+ if (strcmp(info->secstrings + shdr->sh_name, name) == 0)
+ return i;
+ }
+ return 0;
+}
+
+/*
+ * Find a module section, or NULL. Fill in number of "objects" in section.
+ * Ignores SHF_ALLOC flag.
+ */
+static __maybe_unused void *any_section_objs(const struct load_info *info,
+ const char *name,
+ size_t object_size,
+ unsigned int *num)
+{
+ unsigned int sec = find_any_sec(info, name);
+
+ /* Section 0 has sh_addr 0 and sh_size 0. */
+ *num = info->sechdrs[sec].sh_size / object_size;
+ return (void *)info->sechdrs[sec].sh_addr;
+}
+
/* Provided by the linker */
extern const struct kernel_symbol __start___ksymtab[];
extern const struct kernel_symbol __stop___ksymtab[];
@@ -3250,6 +3279,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
sizeof(*mod->bpf_raw_events),
&mod->num_bpf_raw_events);
#endif
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+ mod->btf_data = any_section_objs(info, ".BTF", 1, &mod->btf_data_size);
+#endif
#ifdef CONFIG_JUMP_LABEL
mod->jump_entries = section_objs(info, "__jump_table",
sizeof(*mod->jump_entries),
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d7a7bc3b6098..1e78faaf20a5 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -274,6 +274,15 @@ config DEBUG_INFO_BTF
Turning this on expects presence of pahole tool, which will convert
DWARF type info into equivalent deduplicated BTF type info.
+config PAHOLE_HAS_SPLIT_BTF
+ def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
+
+config DEBUG_INFO_BTF_MODULES
+ def_bool y
+ depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
+ help
+ Generate compact split BTF type information for kernel modules.
+
config GDB_SCRIPTS
bool "Provide GDB scripts for kernel debugging"
help
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index ae01baf96f4e..02b892421f7a 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -6,6 +6,7 @@
PHONY := __modfinal
__modfinal:
+include include/config/auto.conf
include $(srctree)/scripts/Kbuild.include
# for c_flags
@@ -36,8 +37,23 @@ quiet_cmd_ld_ko_o = LD [M] $@
-T scripts/module.lds -o $@ $(filter %.o, $^); \
$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
-$(modules): %.ko: %.o %.mod.o scripts/module.lds FORCE
- +$(call if_changed,ld_ko_o)
+quiet_cmd_btf_ko = BTF [M] $@
+ cmd_btf_ko = LLVM_OBJCOPY=$(OBJCOPY) $(PAHOLE) -J --btf_base vmlinux $@
+
+# Same as newer-prereqs, but allows to exclude specified extra dependencies
+newer_prereqs_except = $(filter-out $(PHONY) $(1),$?)
+
+# Same as if_changed, but allows to exclude specified extra dependencies
+if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \
+ $(cmd); \
+ printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
+
+# Re-generate module BTFs if either module's .ko or vmlinux changed
+$(modules): %.ko: %.o %.mod.o scripts/module.lds vmlinux FORCE
+ +$(call if_changed_except,ld_ko_o,vmlinux)
+ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+ +$(if $(newer-prereqs),$(call cmd,btf_ko))
+endif
targets += $(modules) $(modules:.ko=.mod.o)
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index c96b56e8e3a4..ed5e97157241 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -742,9 +742,14 @@ show_btf_plain(struct bpf_btf_info *info, int fd,
struct btf_attach_table *btf_map_table)
{
struct btf_attach_point *obj;
+ const char *name = u64_to_ptr(info->name);
int n;
printf("%u: ", info->id);
+ if (info->kernel_btf)
+ printf("name [%s] ", name);
+ else if (name && name[0])
+ printf("name %s ", name);
printf("size %uB", info->btf_size);
n = 0;
@@ -771,6 +776,7 @@ show_btf_json(struct bpf_btf_info *info, int fd,
struct btf_attach_table *btf_map_table)
{
struct btf_attach_point *obj;
+ const char *name = u64_to_ptr(info->name);
jsonw_start_object(json_wtr); /* btf object */
jsonw_uint_field(json_wtr, "id", info->id);
@@ -796,6 +802,11 @@ show_btf_json(struct bpf_btf_info *info, int fd,
emit_obj_refs_json(&refs_table, info->id, json_wtr); /* pids */
+ jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
+
+ if (name && name[0])
+ jsonw_string_field(json_wtr, "name", name);
+
jsonw_end_object(json_wtr); /* btf object */
}
@@ -803,15 +814,30 @@ static int
show_btf(int fd, struct btf_attach_table *btf_prog_table,
struct btf_attach_table *btf_map_table)
{
- struct bpf_btf_info info = {};
+ struct bpf_btf_info info;
__u32 len = sizeof(info);
+ char name[64];
int err;
+ memset(&info, 0, sizeof(info));
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err) {
p_err("can't get BTF object info: %s", strerror(errno));
return -1;
}
+ /* if kernel support emitting BTF object name, pass name pointer */
+ if (info.name_len) {
+ memset(&info, 0, sizeof(info));
+ info.name_len = sizeof(name);
+ info.name = ptr_to_u64(name);
+ len = sizeof(info);
+
+ err = bpf_obj_get_info_by_fd(fd, &info, &len);
+ if (err) {
+ p_err("can't get BTF object info: %s", strerror(errno));
+ return -1;
+ }
+ }
if (json_output)
show_btf_json(&info, fd, btf_prog_table, btf_map_table);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 9879d6793e90..162999b12790 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4466,6 +4466,9 @@ struct bpf_btf_info {
__aligned_u64 btf;
__u32 btf_size;
__u32 id;
+ __aligned_u64 name;
+ __u32 name_len;
+ __u32 kernel_btf;
} __attribute__((aligned(8)));
struct bpf_link_info {
generated by cgit v1.2.3 (git 2.46.0) at 2025-07-22 05:11:28 +0000