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Date: Fri, 13 Dec 2019 16:48:03 -0800
From: Martin KaFai Lau <kafai@...com>
To: <bpf@...r.kernel.org>
CC: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
David Miller <davem@...emloft.net>, <kernel-team@...com>,
<netdev@...r.kernel.org>
Subject: [PATCH bpf-next 11/13] bpf: libbpf: Add STRUCT_OPS support
This patch adds BPF STRUCT_OPS support to libbpf.
The only sec_name convention is SEC("struct_ops") to identify the
struct ops implemented in BPF, e.g.
SEC("struct_ops")
struct tcp_congestion_ops dctcp = {
.init = (void *)dctcp_init, /* <-- a bpf_prog */
/* ... some more func prts ... */
.name = "bpf_dctcp",
};
In the bpf_object__open phase, libbpf will look for the "struct_ops"
elf section and find out what is the btf-type the "struct_ops" is
implementing. Note that the btf-type here is referring to
a type in the bpf_prog.o's btf. It will then collect (through SHT_REL)
where are the bpf progs that the func ptrs are referring to.
In the bpf_object__load phase, the prepare_struct_ops() will load
the btf_vmlinux and obtain the corresponding kernel's btf-type.
With the kernel's btf-type, it can then set the prog->type,
prog->attach_btf_id and the prog->expected_attach_type. Thus,
the prog's properties do not rely on its section name.
Currently, the bpf_prog's btf-type ==> btf_vmlinux's btf-type matching
process is as simple as: member-name match + btf-kind match + size match.
If these matching conditions fail, libbpf will reject.
The current targeting support is "struct tcp_congestion_ops" which
most of its members are function pointers.
The member ordering of the bpf_prog's btf-type can be different from
the btf_vmlinux's btf-type.
Once the prog's properties are all set,
the libbpf will proceed to load all the progs.
After that, register_struct_ops() will create a map, finalize the
map-value by populating it with the prog-fd, and then register this
"struct_ops" to the kernel by updating the map-value to the map.
By default, libbpf does not unregister the struct_ops from the kernel
during bpf_object__close(). It can be changed by setting the new
"unreg_st_ops" in bpf_object_open_opts.
Signed-off-by: Martin KaFai Lau <kafai@...com>
---
tools/lib/bpf/bpf.c | 10 +-
tools/lib/bpf/bpf.h | 5 +-
tools/lib/bpf/libbpf.c | 599 +++++++++++++++++++++++++++++++++-
tools/lib/bpf/libbpf.h | 3 +-
tools/lib/bpf/libbpf_probes.c | 2 +
5 files changed, 612 insertions(+), 7 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 98596e15390f..ebb9d7066173 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -95,7 +95,11 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
attr.btf_key_type_id = create_attr->btf_key_type_id;
attr.btf_value_type_id = create_attr->btf_value_type_id;
attr.map_ifindex = create_attr->map_ifindex;
- attr.inner_map_fd = create_attr->inner_map_fd;
+ if (attr.map_type == BPF_MAP_TYPE_STRUCT_OPS)
+ attr.btf_vmlinux_value_type_id =
+ create_attr->btf_vmlinux_value_type_id;
+ else
+ attr.inner_map_fd = create_attr->inner_map_fd;
return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}
@@ -228,7 +232,9 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
memset(&attr, 0, sizeof(attr));
attr.prog_type = load_attr->prog_type;
attr.expected_attach_type = load_attr->expected_attach_type;
- if (attr.prog_type == BPF_PROG_TYPE_TRACING) {
+ if (attr.prog_type == BPF_PROG_TYPE_STRUCT_OPS) {
+ attr.attach_btf_id = load_attr->attach_btf_id;
+ } else if (attr.prog_type == BPF_PROG_TYPE_TRACING) {
attr.attach_btf_id = load_attr->attach_btf_id;
attr.attach_prog_fd = load_attr->attach_prog_fd;
} else {
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 3c791fa8e68e..1ddbf7f33b83 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -48,7 +48,10 @@ struct bpf_create_map_attr {
__u32 btf_key_type_id;
__u32 btf_value_type_id;
__u32 map_ifindex;
- __u32 inner_map_fd;
+ union {
+ __u32 inner_map_fd;
+ __u32 btf_vmlinux_value_type_id;
+ };
};
LIBBPF_API int
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 27d5f7ecba32..ffb5cdd7db5a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -67,6 +67,10 @@
#define __printf(a, b) __attribute__((format(printf, a, b)))
+static struct btf *bpf_core_find_kernel_btf(void);
+static struct bpf_program *bpf_object__find_prog_by_idx(struct bpf_object *obj,
+ int idx);
+
static int __base_pr(enum libbpf_print_level level, const char *format,
va_list args)
{
@@ -128,6 +132,8 @@ void libbpf_print(enum libbpf_print_level level, const char *format, ...)
# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
#endif
+#define BPF_STRUCT_OPS_SEC_NAME "struct_ops"
+
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
@@ -233,6 +239,32 @@ struct bpf_map {
bool reused;
};
+struct bpf_struct_ops {
+ const char *var_name;
+ const char *tname;
+ const struct btf_type *type;
+ struct bpf_program **progs;
+ __u32 *kern_func_off;
+ /* e.g. struct tcp_congestion_ops in bpf_prog's btf format */
+ void *data;
+ /* e.g. struct __bpf_tcp_congestion_ops in btf_vmlinux's btf
+ * format.
+ * struct __bpf_tcp_congestion_ops {
+ * [... some other kernel fields ...]
+ * struct tcp_congestion_ops data;
+ * }
+ * kern_vdata in the sizeof(struct __bpf_tcp_congestion_ops).
+ * prepare_struct_ops() will populate the "data" into
+ * "kern_vdata".
+ */
+ void *kern_vdata;
+ __u32 type_id;
+ __u32 kern_vtype_id;
+ __u32 kern_vtype_size;
+ int fd;
+ bool unreg;
+};
+
struct bpf_secdata {
void *rodata;
void *data;
@@ -251,6 +283,7 @@ struct bpf_object {
size_t nr_maps;
size_t maps_cap;
struct bpf_secdata sections;
+ struct bpf_struct_ops st_ops;
bool loaded;
bool has_pseudo_calls;
@@ -270,6 +303,7 @@ struct bpf_object {
Elf_Data *data;
Elf_Data *rodata;
Elf_Data *bss;
+ Elf_Data *st_ops_data;
size_t strtabidx;
struct {
GElf_Shdr shdr;
@@ -282,6 +316,7 @@ struct bpf_object {
int data_shndx;
int rodata_shndx;
int bss_shndx;
+ int st_ops_shndx;
} efile;
/*
* All loaded bpf_object is linked in a list, which is
@@ -509,6 +544,508 @@ static __u32 get_kernel_version(void)
return KERNEL_VERSION(major, minor, patch);
}
+static int bpf_object__register_struct_ops(struct bpf_object *obj)
+{
+ struct bpf_create_map_attr map_attr = {};
+ struct bpf_struct_ops *st_ops;
+ const char *tname;
+ __u32 i, zero = 0;
+ int fd, err;
+
+ st_ops = &obj->st_ops;
+ if (!st_ops->kern_vdata)
+ return 0;
+
+ tname = st_ops->tname;
+ for (i = 0; i < btf_vlen(st_ops->type); i++) {
+ struct bpf_program *prog = st_ops->progs[i];
+ void *kern_data;
+ int prog_fd;
+
+ if (!prog)
+ continue;
+
+ prog_fd = bpf_program__nth_fd(prog, 0);
+ if (prog_fd < 0) {
+ pr_warn("struct_ops register %s: prog %s is not loaded\n",
+ tname, prog->name);
+ return -EINVAL;
+ }
+
+ kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i];
+ *(unsigned long *)kern_data = prog_fd;
+ }
+
+ map_attr.map_type = BPF_MAP_TYPE_STRUCT_OPS;
+ map_attr.key_size = sizeof(unsigned int);
+ map_attr.value_size = st_ops->kern_vtype_size;
+ map_attr.max_entries = 1;
+ map_attr.btf_fd = btf__fd(obj->btf);
+ map_attr.btf_vmlinux_value_type_id = st_ops->kern_vtype_id;
+ map_attr.name = st_ops->var_name;
+
+ fd = bpf_create_map_xattr(&map_attr);
+ if (fd < 0) {
+ err = -errno;
+ pr_warn("struct_ops register %s: Error in creating struct_ops map\n",
+ tname);
+ return err;
+ }
+
+ err = bpf_map_update_elem(fd, &zero, st_ops->kern_vdata, 0);
+ if (err) {
+ err = -errno;
+ close(fd);
+ pr_warn("struct_ops register %s: Error in updating struct_ops map\n",
+ tname);
+ return err;
+ }
+
+ st_ops->fd = fd;
+
+ return 0;
+}
+
+static int bpf_struct_ops__unregister(struct bpf_struct_ops *st_ops)
+{
+ if (st_ops->fd != -1) {
+ __u32 zero = 0;
+ int err = 0;
+
+ if (bpf_map_delete_elem(st_ops->fd, &zero))
+ err = -errno;
+ zclose(st_ops->fd);
+
+ return err;
+ }
+
+ return 0;
+}
+
+static const struct btf_type *
+resolve_ptr(const struct btf *btf, __u32 id, __u32 *res_id);
+static const struct btf_type *
+resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id);
+
+static const struct btf_member *
+find_member_by_offset(const struct btf_type *t, __u32 offset)
+{
+ struct btf_member *m;
+ int i;
+
+ for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
+ if (btf_member_bit_offset(t, i) == offset)
+ return m;
+ }
+
+ return NULL;
+}
+
+static const struct btf_member *
+find_member_by_name(const struct btf *btf, const struct btf_type *t,
+ const char *name)
+{
+ struct btf_member *m;
+ int i;
+
+ for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
+ if (!strcmp(btf__name_by_offset(btf, m->name_off), name))
+ return m;
+ }
+
+ return NULL;
+}
+
+#define STRUCT_OPS_VALUE_PREFIX "__bpf_"
+#define STRUCT_OPS_VALUE_PREFIX_LEN (sizeof(STRUCT_OPS_VALUE_PREFIX) - 1)
+
+static int
+bpf_struct_ops__get_kern_types(const struct btf *btf, const char *tname,
+ const struct btf_type **type, __u32 *type_id,
+ const struct btf_type **vtype, __u32 *vtype_id,
+ const struct btf_member **data_member)
+{
+ const struct btf_type *kern_type, *kern_vtype;
+ const struct btf_member *kern_data_member;
+ __s32 kern_vtype_id, kern_type_id;
+ char vtname[128] = STRUCT_OPS_VALUE_PREFIX;
+ __u32 i;
+
+ kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT);
+ if (kern_type_id < 0) {
+ pr_warn("struct_ops prepare: struct %s is not found in kernel BTF\n",
+ tname);
+ return -ENOTSUP;
+ }
+ kern_type = btf__type_by_id(btf, kern_type_id);
+
+ /* Find the corresponding "map_value" type that will be used
+ * in map_update(BPF_MAP_TYPE_STRUCT_OPS). For example,
+ * find "struct __bpf_tcp_congestion_ops" from the btf_vmlinux.
+ */
+ strncat(vtname + STRUCT_OPS_VALUE_PREFIX_LEN, tname,
+ sizeof(vtname) - STRUCT_OPS_VALUE_PREFIX_LEN - 1);
+ kern_vtype_id = btf__find_by_name_kind(btf, vtname,
+ BTF_KIND_STRUCT);
+ if (kern_vtype_id < 0) {
+ pr_warn("struct_ops prepare: struct %s is not found in kernel BTF\n",
+ vtname);
+ return -ENOTSUP;
+ }
+ kern_vtype = btf__type_by_id(btf, kern_vtype_id);
+
+ /* Find "struct tcp_congestion_ops" from
+ * struct __bpf_tcp_congestion_ops {
+ * [ ... ]
+ * struct tcp_congestion_ops data;
+ * }
+ */
+ for (i = 0, kern_data_member = btf_members(kern_vtype);
+ i < btf_vlen(kern_vtype);
+ i++, kern_data_member++) {
+ if (kern_data_member->type == kern_type_id)
+ break;
+ }
+ if (i == btf_vlen(kern_vtype)) {
+ pr_warn("struct_ops prepare: struct %s data is not found in struct %s\n",
+ tname, vtname);
+ return -EINVAL;
+ }
+
+ *type = kern_type;
+ *type_id = kern_type_id;
+ *vtype = kern_vtype;
+ *vtype_id = kern_vtype_id;
+ *data_member = kern_data_member;
+
+ return 0;
+}
+
+static int bpf_object__prepare_struct_ops(struct bpf_object *obj)
+{
+ const struct btf_member *member, *kern_member, *kern_data_member;
+ const struct btf_type *type, *kern_type, *kern_vtype;
+ __u32 i, kern_type_id, kern_vtype_id, kern_data_off;
+ struct bpf_struct_ops *st_ops;
+ void *data, *kern_data;
+ const struct btf *btf;
+ struct btf *kern_btf;
+ const char *tname;
+ int err;
+
+ st_ops = &obj->st_ops;
+ if (!st_ops->data)
+ return 0;
+
+ btf = obj->btf;
+ type = st_ops->type;
+ tname = st_ops->tname;
+
+ kern_btf = bpf_core_find_kernel_btf();
+ if (IS_ERR(kern_btf))
+ return PTR_ERR(kern_btf);
+
+ err = bpf_struct_ops__get_kern_types(kern_btf, tname,
+ &kern_type, &kern_type_id,
+ &kern_vtype, &kern_vtype_id,
+ &kern_data_member);
+ if (err)
+ goto done;
+
+ pr_debug("struct_ops prepare %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n",
+ tname, st_ops->type_id, kern_type_id, kern_vtype_id);
+
+ kern_data_off = kern_data_member->offset / 8;
+ st_ops->kern_vtype_size = kern_vtype->size;
+ st_ops->kern_vtype_id = kern_vtype_id;
+
+ st_ops->kern_vdata = calloc(1, st_ops->kern_vtype_size);
+ if (!st_ops->kern_vdata) {
+ err = -ENOMEM;
+ goto done;
+ }
+
+ data = st_ops->data;
+ kern_data = st_ops->kern_vdata + kern_data_off;
+
+ err = -ENOTSUP;
+ for (i = 0, member = btf_members(type); i < btf_vlen(type);
+ i++, member++) {
+ const struct btf_type *mtype, *kern_mtype;
+ __u32 mtype_id, kern_mtype_id;
+ void *mdata, *kern_mdata;
+ __s64 msize, kern_msize;
+ __u32 moff, kern_moff;
+ __u32 kern_member_idx;
+ const char *mname;
+
+ mname = btf__name_by_offset(btf, member->name_off);
+ kern_member = find_member_by_name(kern_btf, kern_type, mname);
+ if (!kern_member) {
+ pr_warn("struct_ops prepare %s: Cannot find member %s in kernel BTF\n",
+ tname, mname);
+ goto done;
+ }
+
+ kern_member_idx = kern_member - btf_members(kern_type);
+ if (btf_member_bitfield_size(type, i) ||
+ btf_member_bitfield_size(kern_type, kern_member_idx)) {
+ pr_warn("struct_ops prepare %s: bitfield %s is not supported\n",
+ tname, mname);
+ goto done;
+ }
+
+ moff = member->offset / 8;
+ kern_moff = kern_member->offset / 8;
+
+ mdata = data + moff;
+ kern_mdata = kern_data + kern_moff;
+
+ mtype_id = member->type;
+ kern_mtype_id = kern_member->type;
+
+ mtype = resolve_ptr(btf, mtype_id, NULL);
+ kern_mtype = resolve_ptr(kern_btf, kern_mtype_id, NULL);
+ if (mtype && kern_mtype) {
+ struct bpf_program *prog;
+
+ if (!btf_is_func_proto(mtype) ||
+ !btf_is_func_proto(kern_mtype)) {
+ pr_warn("struct_ops prepare %s: non func ptr %s is not supported\n",
+ tname, mname);
+ goto done;
+ }
+
+ prog = st_ops->progs[i];
+ if (!prog) {
+ pr_debug("struct_ops prepare %s: func ptr %s is not set\n",
+ tname, mname);
+ continue;
+ }
+
+ if (prog->type != BPF_PROG_TYPE_UNSPEC ||
+ prog->attach_btf_id) {
+ pr_warn("struct_ops prepare %s: cannot use prog %s with attach_btf_id %d for func ptr %s\n",
+ tname, prog->name, prog->attach_btf_id, mname);
+ err = -EINVAL;
+ goto done;
+ }
+
+ prog->type = BPF_PROG_TYPE_STRUCT_OPS;
+ prog->attach_btf_id = kern_type_id;
+ /* expected_attach_type is the member index */
+ prog->expected_attach_type = kern_member_idx;
+
+ st_ops->kern_func_off[i] = kern_data_off + kern_moff;
+
+ pr_debug("struct_ops prepare %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n",
+ tname, mname, prog->name, moff, kern_moff);
+
+ continue;
+ }
+
+ mtype_id = btf__resolve_type(btf, mtype_id);
+ kern_mtype_id = btf__resolve_type(kern_btf, kern_mtype_id);
+ if (mtype_id < 0 || kern_mtype_id < 0) {
+ pr_warn("struct_ops prepare %s: Cannot resolve the type for %s\n",
+ tname, mname);
+ goto done;
+ }
+
+ mtype = btf__type_by_id(btf, mtype_id);
+ kern_mtype = btf__type_by_id(kern_btf, kern_mtype_id);
+ if (BTF_INFO_KIND(mtype->info) !=
+ BTF_INFO_KIND(kern_mtype->info)) {
+ pr_warn("struct_ops prepare %s: Unmatched member type %s %u != %u(kernel)\n",
+ tname, mname,
+ BTF_INFO_KIND(mtype->info),
+ BTF_INFO_KIND(kern_mtype->info));
+ goto done;
+ }
+
+ msize = btf__resolve_size(btf, mtype_id);
+ kern_msize = btf__resolve_size(kern_btf, kern_mtype_id);
+ if (msize < 0 || kern_msize < 0 || msize != kern_msize) {
+ pr_warn("struct_ops prepare %s: Error in size of member %s: %zd != %zd(kernel)\n",
+ tname, mname,
+ (ssize_t)msize, (ssize_t)kern_msize);
+ goto done;
+ }
+
+ pr_debug("struct_ops prepare %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n",
+ tname, mname, (unsigned int)msize,
+ moff, kern_moff);
+ memcpy(kern_mdata, mdata, msize);
+ }
+
+ err = 0;
+
+done:
+ /* On error case, bpf_object__unload() will free the
+ * st_ops->kern_vdata.
+ */
+ btf__free(kern_btf);
+ return err;
+}
+
+static int bpf_object__collect_struct_ops_reloc(struct bpf_object *obj,
+ GElf_Shdr *shdr,
+ Elf_Data *data)
+{
+ const struct btf_member *member;
+ struct bpf_struct_ops *st_ops;
+ struct bpf_program *prog;
+ const char *name, *tname;
+ unsigned int shdr_idx;
+ const struct btf *btf;
+ Elf_Data *symbols;
+ unsigned int moff;
+ GElf_Sym sym;
+ GElf_Rel rel;
+ int i, nrels;
+
+ symbols = obj->efile.symbols;
+ btf = obj->btf;
+ st_ops = &obj->st_ops;
+ tname = st_ops->tname;
+
+ nrels = shdr->sh_size / shdr->sh_entsize;
+ for (i = 0; i < nrels; i++) {
+ if (!gelf_getrel(data, i, &rel)) {
+ pr_warn("struct_ops reloc %s: failed to get %d reloc\n",
+ tname, i);
+ return -LIBBPF_ERRNO__FORMAT;
+ }
+
+ if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
+ pr_warn("struct_ops reloc %s: symbol %" PRIx64 " not found\n",
+ tname, GELF_R_SYM(rel.r_info));
+ return -LIBBPF_ERRNO__FORMAT;
+ }
+
+ name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
+ sym.st_name) ? : "<?>";
+
+ pr_debug("%s relo for %lld value %lld name %d (\'%s\')\n",
+ tname,
+ (long long) (rel.r_info >> 32),
+ (long long) sym.st_value, sym.st_name, name);
+
+ shdr_idx = sym.st_shndx;
+ moff = rel.r_offset;
+ pr_debug("struct_ops reloc %s: moff=%u, shdr_idx=%u\n",
+ tname, moff, shdr_idx);
+
+ if (shdr_idx >= SHN_LORESERVE) {
+ pr_warn("struct_ops reloc %s: moff=%u shdr_idx=%u unsupported non-static function\n",
+ tname, moff, shdr_idx);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+
+ member = find_member_by_offset(st_ops->type, moff * 8);
+ if (!member) {
+ pr_warn("struct_ops reloc %s: cannot find member at moff=%u\n",
+ tname, moff);
+ return -EINVAL;
+ }
+ name = btf__name_by_offset(btf, member->name_off);
+
+ if (!resolve_func_ptr(btf, member->type, NULL)) {
+ pr_warn("struct_ops reloc %s: cannot relocate non func ptr %s\n",
+ tname, name);
+ return -EINVAL;
+ }
+
+ prog = bpf_object__find_prog_by_idx(obj, shdr_idx);
+ if (!prog) {
+ pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n",
+ tname, shdr_idx, name);
+ return -EINVAL;
+ }
+
+ st_ops->progs[member - btf_members(st_ops->type)] = prog;
+ }
+
+ return 0;
+}
+
+static int bpf_object__init_struct_ops(struct bpf_object *obj)
+{
+ const struct btf_type *type, *datasec;
+ const struct btf_var_secinfo *vsi;
+ struct bpf_struct_ops *st_ops;
+ const char *tname, *var_name;
+ __s32 type_id, datasec_id;
+ const struct btf *btf;
+
+ if (obj->efile.st_ops_shndx == -1)
+ return 0;
+
+ btf = obj->btf;
+ st_ops = &obj->st_ops;
+ datasec_id = btf__find_by_name_kind(btf, BPF_STRUCT_OPS_SEC_NAME,
+ BTF_KIND_DATASEC);
+ if (datasec_id < 0) {
+ pr_warn("struct_ops init: DATASEC %s not found\n",
+ BPF_STRUCT_OPS_SEC_NAME);
+ return -EINVAL;
+ }
+
+ datasec = btf__type_by_id(btf, datasec_id);
+ if (btf_vlen(datasec) != 1) {
+ pr_warn("struct_ops init: multiple VAR in DATASEC %s\n",
+ BPF_STRUCT_OPS_SEC_NAME);
+ return -ENOTSUP;
+ }
+ vsi = btf_var_secinfos(datasec);
+
+ type = btf__type_by_id(obj->btf, vsi->type);
+ if (!btf_is_var(type)) {
+ pr_warn("struct_ops init: vsi->type %u is not a VAR\n",
+ vsi->type);
+ return -EINVAL;
+ }
+ var_name = btf__name_by_offset(obj->btf, type->name_off);
+
+ type_id = btf__resolve_type(obj->btf, vsi->type);
+ if (type_id < 0) {
+ pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n",
+ vsi->type, BPF_STRUCT_OPS_SEC_NAME);
+ return -EINVAL;
+ }
+
+ type = btf__type_by_id(obj->btf, type_id);
+ tname = btf__name_by_offset(obj->btf, type->name_off);
+ if (!btf_is_struct(type)) {
+ pr_warn("struct_ops init: %s is not a struct\n", tname);
+ return -EINVAL;
+ }
+
+ if (type->size != obj->efile.st_ops_data->d_size) {
+ pr_warn("struct_ops init: %s unmatched size %u (BTF DATASEC) != %zu (ELF)\n",
+ tname, type->size, obj->efile.st_ops_data->d_size);
+ return -EINVAL;
+ }
+
+ st_ops->data = malloc(type->size);
+ st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs));
+ st_ops->kern_func_off = malloc(btf_vlen(type) *
+ sizeof(*st_ops->kern_func_off));
+ /* bpf_object__close() will take care of the free-ings */
+ if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off)
+ return -ENOMEM;
+ memcpy(st_ops->data, obj->efile.st_ops_data->d_buf, type->size);
+
+ st_ops->tname = tname;
+ st_ops->type = type;
+ st_ops->type_id = type_id;
+ st_ops->var_name = var_name;
+
+ pr_debug("struct_ops init: %s found. type_id:%u\n", tname, type_id);
+
+ return 0;
+}
+
static struct bpf_object *bpf_object__new(const char *path,
const void *obj_buf,
size_t obj_buf_sz,
@@ -550,6 +1087,9 @@ static struct bpf_object *bpf_object__new(const char *path,
obj->efile.data_shndx = -1;
obj->efile.rodata_shndx = -1;
obj->efile.bss_shndx = -1;
+ obj->efile.st_ops_shndx = -1;
+
+ obj->st_ops.fd = -1;
obj->kern_version = get_kernel_version();
obj->loaded = false;
@@ -572,6 +1112,7 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
obj->efile.data = NULL;
obj->efile.rodata = NULL;
obj->efile.bss = NULL;
+ obj->efile.st_ops_data = NULL;
zfree(&obj->efile.reloc_sects);
obj->efile.nr_reloc_sects = 0;
@@ -757,6 +1298,9 @@ int bpf_object__section_size(const struct bpf_object *obj, const char *name,
} else if (!strcmp(name, ".rodata")) {
if (obj->efile.rodata)
*size = obj->efile.rodata->d_size;
+ } else if (!strcmp(name, BPF_STRUCT_OPS_SEC_NAME)) {
+ if (obj->efile.st_ops_data)
+ *size = obj->efile.st_ops_data->d_size;
} else {
ret = bpf_object_search_section_size(obj, name, &d_size);
if (!ret)
@@ -1060,6 +1604,30 @@ skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
return t;
}
+static const struct btf_type *
+resolve_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
+{
+ const struct btf_type *t;
+
+ t = skip_mods_and_typedefs(btf, id, NULL);
+ if (!btf_is_ptr(t))
+ return NULL;
+
+ return skip_mods_and_typedefs(btf, t->type, res_id);
+}
+
+static const struct btf_type *
+resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
+{
+ const struct btf_type *t;
+
+ t = resolve_ptr(btf, id, res_id);
+ if (t && btf_is_func_proto(t))
+ return t;
+
+ return NULL;
+}
+
/*
* Fetch integer attribute of BTF map definition. Such attributes are
* represented using a pointer to an array, in which dimensionality of array
@@ -1509,7 +2077,7 @@ static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
{
- return obj->efile.btf_maps_shndx >= 0;
+ return obj->efile.btf_maps_shndx >= 0 || obj->efile.st_ops_shndx >= 0;
}
static int bpf_object__init_btf(struct bpf_object *obj,
@@ -1689,6 +2257,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
} else if (strcmp(name, ".rodata") == 0) {
obj->efile.rodata = data;
obj->efile.rodata_shndx = idx;
+ } else if (strcmp(name, BPF_STRUCT_OPS_SEC_NAME) == 0) {
+ obj->efile.st_ops_data = data;
+ obj->efile.st_ops_shndx = idx;
} else {
pr_debug("skip section(%d) %s\n", idx, name);
}
@@ -1698,7 +2269,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
int sec = sh.sh_info; /* points to other section */
/* Only do relo for section with exec instructions */
- if (!section_have_execinstr(obj, sec)) {
+ if (!section_have_execinstr(obj, sec) &&
+ !strstr(name, BPF_STRUCT_OPS_SEC_NAME)) {
pr_debug("skip relo %s(%d) for section(%d)\n",
name, idx, sec);
continue;
@@ -1735,6 +2307,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
err = bpf_object__sanitize_and_load_btf(obj);
if (!err)
err = bpf_object__init_prog_names(obj);
+ if (!err)
+ err = bpf_object__init_struct_ops(obj);
return err;
}
@@ -3700,6 +4274,13 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
return -LIBBPF_ERRNO__INTERNAL;
}
+ if (idx == obj->efile.st_ops_shndx) {
+ err = bpf_object__collect_struct_ops_reloc(obj, shdr, data);
+ if (err)
+ return err;
+ continue;
+ }
+
prog = bpf_object__find_prog_by_idx(obj, idx);
if (!prog) {
pr_warn("relocation failed: no section(%d)\n", idx);
@@ -3734,7 +4315,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.insns = insns;
load_attr.insns_cnt = insns_cnt;
load_attr.license = license;
- if (prog->type == BPF_PROG_TYPE_TRACING) {
+ if (prog->type == BPF_PROG_TYPE_STRUCT_OPS) {
+ load_attr.attach_btf_id = prog->attach_btf_id;
+ } else if (prog->type == BPF_PROG_TYPE_TRACING) {
load_attr.attach_prog_fd = prog->attach_prog_fd;
load_attr.attach_btf_id = prog->attach_btf_id;
} else {
@@ -3952,6 +4535,7 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
if (IS_ERR(obj))
return obj;
+ obj->st_ops.unreg = OPTS_GET(opts, unreg_st_ops, false);
obj->relaxed_core_relocs = OPTS_GET(opts, relaxed_core_relocs, false);
relaxed_maps = OPTS_GET(opts, relaxed_maps, false);
pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
@@ -4077,6 +4661,10 @@ int bpf_object__unload(struct bpf_object *obj)
for (i = 0; i < obj->nr_programs; i++)
bpf_program__unload(&obj->programs[i]);
+ if (obj->st_ops.unreg)
+ bpf_struct_ops__unregister(&obj->st_ops);
+ zfree(&obj->st_ops.kern_vdata);
+
return 0;
}
@@ -4100,7 +4688,9 @@ int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
CHECK_ERR(bpf_object__create_maps(obj), err, out);
CHECK_ERR(bpf_object__relocate(obj, attr->target_btf_path), err, out);
+ CHECK_ERR(bpf_object__prepare_struct_ops(obj), err, out);
CHECK_ERR(bpf_object__load_progs(obj, attr->log_level), err, out);
+ CHECK_ERR(bpf_object__register_struct_ops(obj), err, out);
return 0;
out:
@@ -4690,6 +5280,9 @@ void bpf_object__close(struct bpf_object *obj)
bpf_program__exit(&obj->programs[i]);
}
zfree(&obj->programs);
+ zfree(&obj->st_ops.data);
+ zfree(&obj->st_ops.progs);
+ zfree(&obj->st_ops.kern_func_off);
list_del(&obj->list);
free(obj);
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 0dbf4bfba0c4..db255fce4948 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -109,8 +109,9 @@ struct bpf_object_open_opts {
*/
const char *pin_root_path;
__u32 attach_prog_fd;
+ bool unreg_st_ops;
};
-#define bpf_object_open_opts__last_field attach_prog_fd
+#define bpf_object_open_opts__last_field unreg_st_ops
LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
LIBBPF_API struct bpf_object *
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index a9eb8b322671..7f06942e9574 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -103,6 +103,7 @@ probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
case BPF_PROG_TYPE_CGROUP_SYSCTL:
case BPF_PROG_TYPE_CGROUP_SOCKOPT:
case BPF_PROG_TYPE_TRACING:
+ case BPF_PROG_TYPE_STRUCT_OPS:
default:
break;
}
@@ -251,6 +252,7 @@ bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
case BPF_MAP_TYPE_XSKMAP:
case BPF_MAP_TYPE_SOCKHASH:
case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
+ case BPF_MAP_TYPE_STRUCT_OPS:
default:
break;
}
--
2.17.1
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