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author | Jakub Kicinski <kuba@kernel.org> | 2020-12-04 07:48:11 -0800 |
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committer | Jakub Kicinski <kuba@kernel.org> | 2020-12-04 07:48:12 -0800 |
commit | a1dd1d86973182458da7798a95f26cfcbea599b4 (patch) | |
tree | 1adda22ea30ccfac7651a7eed7b7c90356f8243a /kernel/bpf/btf.c | |
parent | 55fd59b003f6e8fd88cf16590e79823d7ccf3026 (diff) | |
parent | eceae70bdeaeb6b8ceb662983cf663ff352fbc96 (diff) | |
download | lwn-a1dd1d86973182458da7798a95f26cfcbea599b4.tar.gz lwn-a1dd1d86973182458da7798a95f26cfcbea599b4.zip |
Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:
====================
pull-request: bpf-next 2020-12-03
The main changes are:
1) Support BTF in kernel modules, from Andrii.
2) Introduce preferred busy-polling, from Björn.
3) bpf_ima_inode_hash() and bpf_bprm_opts_set() helpers, from KP Singh.
4) Memcg-based memory accounting for bpf objects, from Roman.
5) Allow bpf_{s,g}etsockopt from cgroup bind{4,6} hooks, from Stanislav.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (118 commits)
selftests/bpf: Fix invalid use of strncat in test_sockmap
libbpf: Use memcpy instead of strncpy to please GCC
selftests/bpf: Add fentry/fexit/fmod_ret selftest for kernel module
selftests/bpf: Add tp_btf CO-RE reloc test for modules
libbpf: Support attachment of BPF tracing programs to kernel modules
libbpf: Factor out low-level BPF program loading helper
bpf: Allow to specify kernel module BTFs when attaching BPF programs
bpf: Remove hard-coded btf_vmlinux assumption from BPF verifier
selftests/bpf: Add CO-RE relocs selftest relying on kernel module BTF
selftests/bpf: Add support for marking sub-tests as skipped
selftests/bpf: Add bpf_testmod kernel module for testing
libbpf: Add kernel module BTF support for CO-RE relocations
libbpf: Refactor CO-RE relocs to not assume a single BTF object
libbpf: Add internal helper to load BTF data by FD
bpf: Keep module's btf_data_size intact after load
bpf: Fix bpf_put_raw_tracepoint()'s use of __module_address()
selftests/bpf: Add Userspace tests for TCP_WINDOW_CLAMP
bpf: Adds support for setting window clamp
samples/bpf: Fix spelling mistake "recieving" -> "receiving"
bpf: Fix cold build of test_progs-no_alu32
...
====================
Link: https://lore.kernel.org/r/20201204021936.85653-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'kernel/bpf/btf.c')
-rw-r--r-- | kernel/bpf/btf.c | 70 |
1 files changed, 49 insertions, 21 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 6b2d508b33d4..8d6bdb4f4d61 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -1524,6 +1524,11 @@ static void btf_free_rcu(struct rcu_head *rcu) btf_free(btf); } +void btf_get(struct btf *btf) +{ + refcount_inc(&btf->refcnt); +} + void btf_put(struct btf *btf) { if (btf && refcount_dec_and_test(&btf->refcnt)) { @@ -4555,11 +4560,10 @@ struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog) { struct bpf_prog *tgt_prog = prog->aux->dst_prog; - if (tgt_prog) { + if (tgt_prog) return tgt_prog->aux->btf; - } else { - return btf_vmlinux; - } + else + return prog->aux->attach_btf; } static bool is_string_ptr(struct btf *btf, const struct btf_type *t) @@ -4700,6 +4704,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, if (ctx_arg_info->offset == off) { info->reg_type = ctx_arg_info->reg_type; + info->btf = btf_vmlinux; info->btf_id = ctx_arg_info->btf_id; return true; } @@ -4716,6 +4721,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg); if (ret > 0) { + info->btf = btf_vmlinux; info->btf_id = ret; return true; } else { @@ -4723,6 +4729,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, } } + info->btf = btf; info->btf_id = t->type; t = btf_type_by_id(btf, t->type); /* skip modifiers */ @@ -4749,7 +4756,7 @@ enum bpf_struct_walk_result { WALK_STRUCT, }; -static int btf_struct_walk(struct bpf_verifier_log *log, +static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, u32 *next_btf_id) { @@ -4760,7 +4767,7 @@ static int btf_struct_walk(struct bpf_verifier_log *log, u32 vlen, elem_id, mid; again: - tname = __btf_name_by_offset(btf_vmlinux, t->name_off); + tname = __btf_name_by_offset(btf, t->name_off); if (!btf_type_is_struct(t)) { bpf_log(log, "Type '%s' is not a struct\n", tname); return -EINVAL; @@ -4777,7 +4784,7 @@ again: goto error; member = btf_type_member(t) + vlen - 1; - mtype = btf_type_skip_modifiers(btf_vmlinux, member->type, + mtype = btf_type_skip_modifiers(btf, member->type, NULL); if (!btf_type_is_array(mtype)) goto error; @@ -4793,7 +4800,7 @@ again: /* Only allow structure for now, can be relaxed for * other types later. */ - t = btf_type_skip_modifiers(btf_vmlinux, array_elem->type, + t = btf_type_skip_modifiers(btf, array_elem->type, NULL); if (!btf_type_is_struct(t)) goto error; @@ -4851,10 +4858,10 @@ error: /* type of the field */ mid = member->type; - mtype = btf_type_by_id(btf_vmlinux, member->type); - mname = __btf_name_by_offset(btf_vmlinux, member->name_off); + mtype = btf_type_by_id(btf, member->type); + mname = __btf_name_by_offset(btf, member->name_off); - mtype = __btf_resolve_size(btf_vmlinux, mtype, &msize, + mtype = __btf_resolve_size(btf, mtype, &msize, &elem_type, &elem_id, &total_nelems, &mid); if (IS_ERR(mtype)) { @@ -4949,7 +4956,7 @@ error: mname, moff, tname, off, size); return -EACCES; } - stype = btf_type_skip_modifiers(btf_vmlinux, mtype->type, &id); + stype = btf_type_skip_modifiers(btf, mtype->type, &id); if (btf_type_is_struct(stype)) { *next_btf_id = id; return WALK_PTR; @@ -4975,7 +4982,7 @@ error: return -EINVAL; } -int btf_struct_access(struct bpf_verifier_log *log, +int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype __maybe_unused, u32 *next_btf_id) @@ -4984,7 +4991,7 @@ int btf_struct_access(struct bpf_verifier_log *log, u32 id; do { - err = btf_struct_walk(log, t, off, size, &id); + err = btf_struct_walk(log, btf, t, off, size, &id); switch (err) { case WALK_PTR: @@ -5000,7 +5007,7 @@ int btf_struct_access(struct bpf_verifier_log *log, * by diving in it. At this point the offset is * aligned with the new type, so set it to 0. */ - t = btf_type_by_id(btf_vmlinux, id); + t = btf_type_by_id(btf, id); off = 0; break; default: @@ -5016,21 +5023,37 @@ int btf_struct_access(struct bpf_verifier_log *log, return -EINVAL; } +/* Check that two BTF types, each specified as an BTF object + id, are exactly + * the same. Trivial ID check is not enough due to module BTFs, because we can + * end up with two different module BTFs, but IDs point to the common type in + * vmlinux BTF. + */ +static bool btf_types_are_same(const struct btf *btf1, u32 id1, + const struct btf *btf2, u32 id2) +{ + if (id1 != id2) + return false; + if (btf1 == btf2) + return true; + return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2); +} + bool btf_struct_ids_match(struct bpf_verifier_log *log, - int off, u32 id, u32 need_type_id) + const struct btf *btf, u32 id, int off, + const struct btf *need_btf, u32 need_type_id) { const struct btf_type *type; int err; /* Are we already done? */ - if (need_type_id == id && off == 0) + if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id)) return true; again: - type = btf_type_by_id(btf_vmlinux, id); + type = btf_type_by_id(btf, id); if (!type) return false; - err = btf_struct_walk(log, type, off, 1, &id); + err = btf_struct_walk(log, btf, type, off, 1, &id); if (err != WALK_STRUCT) return false; @@ -5039,7 +5062,7 @@ again: * continue the search with offset 0 in the new * type. */ - if (need_type_id != id) { + if (!btf_types_are_same(btf, id, need_btf, need_type_id)) { off = 0; goto again; } @@ -5710,11 +5733,16 @@ int btf_get_fd_by_id(u32 id) return fd; } -u32 btf_id(const struct btf *btf) +u32 btf_obj_id(const struct btf *btf) { return btf->id; } +bool btf_is_kernel(const struct btf *btf) +{ + return btf->kernel_btf; +} + static int btf_id_cmp_func(const void *a, const void *b) { const int *pa = a, *pb = b; |