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Diffstat (limited to 'tools/lib/bpf/libbpf.c')
-rw-r--r--tools/lib/bpf/libbpf.c144
1 files changed, 75 insertions, 69 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index fa7094ff3e66..6c2979f1b471 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -33,6 +33,7 @@
#include <linux/filter.h>
#include <linux/limits.h>
#include <linux/perf_event.h>
+#include <linux/bpf_perf_event.h>
#include <linux/ring_buffer.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
@@ -1013,6 +1014,19 @@ static bool bpf_map__is_struct_ops(const struct bpf_map *map)
return map->def.type == BPF_MAP_TYPE_STRUCT_OPS;
}
+static bool is_valid_st_ops_program(struct bpf_object *obj,
+ const struct bpf_program *prog)
+{
+ int i;
+
+ for (i = 0; i < obj->nr_programs; i++) {
+ if (&obj->programs[i] == prog)
+ return prog->type == BPF_PROG_TYPE_STRUCT_OPS;
+ }
+
+ return false;
+}
+
/* Init the map's fields that depend on kern_btf */
static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
{
@@ -1101,9 +1115,16 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
if (btf_is_ptr(mtype)) {
struct bpf_program *prog;
- prog = st_ops->progs[i];
+ /* Update the value from the shadow type */
+ prog = *(void **)mdata;
+ st_ops->progs[i] = prog;
if (!prog)
continue;
+ if (!is_valid_st_ops_program(obj, prog)) {
+ pr_warn("struct_ops init_kern %s: member %s is not a struct_ops program\n",
+ map->name, mname);
+ return -ENOTSUP;
+ }
kern_mtype = skip_mods_and_typedefs(kern_btf,
kern_mtype->type,
@@ -1228,6 +1249,7 @@ static int init_struct_ops_maps(struct bpf_object *obj, const char *sec_name,
map->name = strdup(var_name);
if (!map->name)
return -ENOMEM;
+ map->btf_value_type_id = type_id;
map->def.type = BPF_MAP_TYPE_STRUCT_OPS;
map->def.key_size = sizeof(int);
@@ -1524,11 +1546,20 @@ static Elf64_Sym *find_elf_var_sym(const struct bpf_object *obj, const char *nam
return ERR_PTR(-ENOENT);
}
+/* Some versions of Android don't provide memfd_create() in their libc
+ * implementation, so avoid complications and just go straight to Linux
+ * syscall.
+ */
+static int sys_memfd_create(const char *name, unsigned flags)
+{
+ return syscall(__NR_memfd_create, name, flags);
+}
+
static int create_placeholder_fd(void)
{
int fd;
- fd = ensure_good_fd(memfd_create("libbpf-placeholder-fd", MFD_CLOEXEC));
+ fd = ensure_good_fd(sys_memfd_create("libbpf-placeholder-fd", MFD_CLOEXEC));
if (fd < 0)
return -errno;
return fd;
@@ -4660,7 +4691,7 @@ bpf_object__probe_loading(struct bpf_object *obj)
bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
{
- if (obj && obj->gen_loader)
+ if (obj->gen_loader)
/* To generate loader program assume the latest kernel
* to avoid doing extra prog_load, map_create syscalls.
*/
@@ -4847,6 +4878,10 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
create_attr.btf_value_type_id = 0;
map->btf_key_type_id = 0;
map->btf_value_type_id = 0;
+ break;
+ case BPF_MAP_TYPE_STRUCT_OPS:
+ create_attr.btf_value_type_id = 0;
+ break;
default:
break;
}
@@ -6339,6 +6374,14 @@ static struct {
/* all other program types don't have "named" context structs */
};
+/* forward declarations for arch-specific underlying types of bpf_user_pt_regs_t typedef,
+ * for below __builtin_types_compatible_p() checks;
+ * with this approach we don't need any extra arch-specific #ifdef guards
+ */
+struct pt_regs;
+struct user_pt_regs;
+struct user_regs_struct;
+
static bool need_func_arg_type_fixup(const struct btf *btf, const struct bpf_program *prog,
const char *subprog_name, int arg_idx,
int arg_type_id, const char *ctx_name)
@@ -6379,11 +6422,21 @@ static bool need_func_arg_type_fixup(const struct btf *btf, const struct bpf_pro
/* special cases */
switch (prog->type) {
case BPF_PROG_TYPE_KPROBE:
- case BPF_PROG_TYPE_PERF_EVENT:
/* `struct pt_regs *` is expected, but we need to fix up */
if (btf_is_struct(t) && strcmp(tname, "pt_regs") == 0)
return true;
break;
+ case BPF_PROG_TYPE_PERF_EVENT:
+ if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) &&
+ btf_is_struct(t) && strcmp(tname, "pt_regs") == 0)
+ return true;
+ if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) &&
+ btf_is_struct(t) && strcmp(tname, "user_pt_regs") == 0)
+ return true;
+ if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) &&
+ btf_is_struct(t) && strcmp(tname, "user_regs_struct") == 0)
+ return true;
+ break;
case BPF_PROG_TYPE_RAW_TRACEPOINT:
case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
/* allow u64* as ctx */
@@ -6462,69 +6515,6 @@ static int clone_func_btf_info(struct btf *btf, int orig_fn_id, struct bpf_progr
return fn_id;
}
-static int probe_kern_arg_ctx_tag(void)
-{
- /* To minimize merge conflicts with BPF token series that refactors
- * feature detection code a lot, we don't integrate
- * probe_kern_arg_ctx_tag() into kernel_supports() feature-detection
- * framework yet, doing our own caching internally.
- * This will be cleaned up a bit later when bpf/bpf-next trees settle.
- */
- static int cached_result = -1;
- static const char strs[] = "\0a\0b\0arg:ctx\0";
- const __u32 types[] = {
- /* [1] INT */
- BTF_TYPE_INT_ENC(1 /* "a" */, BTF_INT_SIGNED, 0, 32, 4),
- /* [2] PTR -> VOID */
- BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 0),
- /* [3] FUNC_PROTO `int(void *a)` */
- BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 1),
- BTF_PARAM_ENC(1 /* "a" */, 2),
- /* [4] FUNC 'a' -> FUNC_PROTO (main prog) */
- BTF_TYPE_ENC(1 /* "a" */, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 3),
- /* [5] FUNC_PROTO `int(void *b __arg_ctx)` */
- BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 1),
- BTF_PARAM_ENC(3 /* "b" */, 2),
- /* [6] FUNC 'b' -> FUNC_PROTO (subprog) */
- BTF_TYPE_ENC(3 /* "b" */, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 5),
- /* [7] DECL_TAG 'arg:ctx' -> func 'b' arg 'b' */
- BTF_TYPE_DECL_TAG_ENC(5 /* "arg:ctx" */, 6, 0),
- };
- const struct bpf_insn insns[] = {
- /* main prog */
- BPF_CALL_REL(+1),
- BPF_EXIT_INSN(),
- /* global subprog */
- BPF_EMIT_CALL(BPF_FUNC_get_func_ip), /* needs PTR_TO_CTX */
- BPF_EXIT_INSN(),
- };
- const struct bpf_func_info_min func_infos[] = {
- { 0, 4 }, /* main prog -> FUNC 'a' */
- { 2, 6 }, /* subprog -> FUNC 'b' */
- };
- LIBBPF_OPTS(bpf_prog_load_opts, opts);
- int prog_fd, btf_fd, insn_cnt = ARRAY_SIZE(insns);
-
- if (cached_result >= 0)
- return cached_result;
-
- btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs), 0);
- if (btf_fd < 0)
- return 0;
-
- opts.prog_btf_fd = btf_fd;
- opts.func_info = &func_infos;
- opts.func_info_cnt = ARRAY_SIZE(func_infos);
- opts.func_info_rec_size = sizeof(func_infos[0]);
-
- prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, "det_arg_ctx",
- "GPL", insns, insn_cnt, &opts);
- close(btf_fd);
-
- cached_result = probe_fd(prog_fd);
- return cached_result;
-}
-
/* Check if main program or global subprog's function prototype has `arg:ctx`
* argument tags, and, if necessary, substitute correct type to match what BPF
* verifier would expect, taking into account specific program type. This
@@ -6549,7 +6539,7 @@ static int bpf_program_fixup_func_info(struct bpf_object *obj, struct bpf_progra
return 0;
/* don't do any fix ups if kernel natively supports __arg_ctx */
- if (probe_kern_arg_ctx_tag() > 0)
+ if (kernel_supports(obj, FEAT_ARG_CTX_TAG))
return 0;
/* some BPF program types just don't have named context structs, so
@@ -9340,7 +9330,9 @@ static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj,
return NULL;
}
-/* Collect the reloc from ELF and populate the st_ops->progs[] */
+/* Collect the reloc from ELF, populate the st_ops->progs[], and update
+ * st_ops->data for shadow type.
+ */
static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
Elf64_Shdr *shdr, Elf_Data *data)
{
@@ -9454,6 +9446,14 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
}
st_ops->progs[member_idx] = prog;
+
+ /* st_ops->data will be exposed to users, being returned by
+ * bpf_map__initial_value() as a pointer to the shadow
+ * type. All function pointers in the original struct type
+ * should be converted to a pointer to struct bpf_program
+ * in the shadow type.
+ */
+ *((struct bpf_program **)(st_ops->data + moff)) = prog;
}
return 0;
@@ -9912,6 +9912,12 @@ int bpf_map__set_initial_value(struct bpf_map *map,
void *bpf_map__initial_value(struct bpf_map *map, size_t *psize)
{
+ if (bpf_map__is_struct_ops(map)) {
+ if (psize)
+ *psize = map->def.value_size;
+ return map->st_ops->data;
+ }
+
if (!map->mmaped)
return NULL;
*psize = map->def.value_size;
generated by cgit (git 2.34.1) at 2024-05-28 09:34:58 +0000