From: Menglong Dong <dongmenglong.8@bytedance.com>
To: andrii@kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev,
eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, mykolal@fb.com,
shuah@kernel.org, mcoquelin.stm32@gmail.com,
alexandre.torgue@foss.st.com, thinker.li@gmail.com,
dongmenglong.8@bytedance.com, zhoufeng.zf@bytedance.com,
davemarchevsky@fb.com, dxu@dxuuu.xyz,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
linux-kselftest@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH bpf-next 1/5] bpf: tracing: add support to record and check the accessed args
Date: Tue, 20 Feb 2024 11:51:01 +0800 [thread overview]
Message-ID: <20240220035105.34626-2-dongmenglong.8@bytedance.com> (raw)
In-Reply-To: <20240220035105.34626-1-dongmenglong.8@bytedance.com>
In this commit, we add the 'accessed_args' field to struct bpf_prog_aux,
which is used to record the accessed index of the function args in
btf_ctx_access().
Meanwhile, we add the function btf_check_func_part_match() to compare the
accessed function args of two function prototype. This function will be
used in the following commit.
Signed-off-by: Menglong Dong <dongmenglong.8@bytedance.com>
---
include/linux/bpf.h | 4 ++
kernel/bpf/btf.c | 121 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 125 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index c7aa99b44dbd..0225b8dbdd9d 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1464,6 +1464,7 @@ struct bpf_prog_aux {
const struct btf_type *attach_func_proto;
/* function name for valid attach_btf_id */
const char *attach_func_name;
+ u64 accessed_args;
struct bpf_prog **func;
void *jit_data; /* JIT specific data. arch dependent */
struct bpf_jit_poke_descriptor *poke_tab;
@@ -2566,6 +2567,9 @@ struct bpf_reg_state;
int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog);
int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
struct btf *btf, const struct btf_type *t);
+int btf_check_func_part_match(struct btf *btf1, const struct btf_type *t1,
+ struct btf *btf2, const struct btf_type *t2,
+ u64 func_args);
const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
int comp_idx, const char *tag_key);
int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt,
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 6ff0bd1a91d5..3a6931402fe4 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6203,6 +6203,9 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
/* skip first 'void *__data' argument in btf_trace_##name typedef */
args++;
nr_args--;
+ prog->aux->accessed_args |= (1 << (arg + 1));
+ } else {
+ prog->aux->accessed_args |= (1 << arg);
}
if (arg > nr_args) {
@@ -7010,6 +7013,124 @@ int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *pr
return btf_check_func_type_match(log, btf1, t1, btf2, t2);
}
+static u32 get_ctx_arg_total_size(struct btf *btf, const struct btf_type *t)
+{
+ const struct btf_param *args;
+ u32 size = 0, nr_args;
+ int i;
+
+ nr_args = btf_type_vlen(t);
+ args = (const struct btf_param *)(t + 1);
+ for (i = 0; i < nr_args; i++) {
+ t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+ size += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
+ }
+
+ return size;
+}
+
+static int get_ctx_arg_idx_aligned(struct btf *btf, const struct btf_type *t,
+ int off)
+{
+ const struct btf_param *args;
+ u32 offset = 0, nr_args;
+ int i;
+
+ nr_args = btf_type_vlen(t);
+ args = (const struct btf_param *)(t + 1);
+ for (i = 0; i < nr_args; i++) {
+ if (offset == off)
+ return i;
+
+ t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+ offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
+ if (offset > off)
+ return -1;
+ }
+ return -1;
+}
+
+/* This function is similar to btf_check_func_type_match(), except that it
+ * only compare some function args of the function prototype t1 and t2.
+ */
+int btf_check_func_part_match(struct btf *btf1, const struct btf_type *func1,
+ struct btf *btf2, const struct btf_type *func2,
+ u64 func_args)
+{
+ const struct btf_param *args1, *args2;
+ u32 nargs1, i, offset = 0;
+ const char *s1, *s2;
+
+ if (!btf_type_is_func_proto(func1) || !btf_type_is_func_proto(func2))
+ return -EINVAL;
+
+ args1 = (const struct btf_param *)(func1 + 1);
+ args2 = (const struct btf_param *)(func2 + 1);
+ nargs1 = btf_type_vlen(func1);
+
+ for (i = 0; i <= nargs1; i++) {
+ const struct btf_type *t1, *t2;
+
+ if (!(func_args & (1 << i)))
+ goto next;
+
+ if (i < nargs1) {
+ int t2_index;
+
+ /* get the index of the arg corresponding to args1[i]
+ * by the offset.
+ */
+ t2_index = get_ctx_arg_idx_aligned(btf2, func2,
+ offset);
+ if (t2_index < 0)
+ return -EINVAL;
+
+ t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
+ t2 = btf_type_skip_modifiers(btf2, args2[t2_index].type,
+ NULL);
+ } else {
+ /* i == nargs1, this is the index of return value of t1 */
+ if (get_ctx_arg_total_size(btf1, func1) !=
+ get_ctx_arg_total_size(btf2, func2))
+ return -EINVAL;
+
+ /* check the return type of t1 and t2 */
+ t1 = btf_type_skip_modifiers(btf1, func1->type, NULL);
+ t2 = btf_type_skip_modifiers(btf2, func2->type, NULL);
+ }
+
+ if (t1->info != t2->info ||
+ (btf_type_has_size(t1) && t1->size != t2->size))
+ return -EINVAL;
+ if (btf_type_is_int(t1) || btf_is_any_enum(t1))
+ goto next;
+
+ if (btf_type_is_struct(t1))
+ goto on_struct;
+
+ if (!btf_type_is_ptr(t1))
+ return -EINVAL;
+
+ t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
+ t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
+ if (!btf_type_is_struct(t1) || !btf_type_is_struct(t2))
+ return -EINVAL;
+
+on_struct:
+ s1 = btf_name_by_offset(btf1, t1->name_off);
+ s2 = btf_name_by_offset(btf2, t2->name_off);
+ if (strcmp(s1, s2))
+ return -EINVAL;
+next:
+ if (i < nargs1) {
+ t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
+ offset += btf_type_is_ptr(t1) ? 8 : roundup(t1->size, 8);
+ }
+ }
+
+ return 0;
+}
+
static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t)
{
const char *name;
--
2.39.2
next prev parent reply other threads:[~2024-02-20 3:51 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-20 3:51 [PATCH bpf-next 0/5] bpf: make tracing program support multi-attach Menglong Dong
2024-02-20 3:51 ` Menglong Dong [this message]
2024-02-20 17:18 ` [PATCH bpf-next 1/5] bpf: tracing: add support to record and check the accessed args Jiri Olsa
2024-02-21 2:58 ` [External] " 梦龙董
2024-02-20 18:22 ` Kui-Feng Lee
2024-02-21 3:09 ` [External] " 梦龙董
2024-02-20 3:51 ` [PATCH bpf-next 2/5] bpf: tracing: support to attach program to multi hooks Menglong Dong
2024-02-20 17:18 ` Jiri Olsa
2024-02-21 5:31 ` Dan Carpenter
2024-02-20 3:51 ` [PATCH bpf-next 3/5] libbpf: allow to set coookie when target_btf_id is set in bpf_link_create Menglong Dong
2024-02-20 3:51 ` [PATCH bpf-next 4/5] libbpf: add the function libbpf_find_kernel_btf_id() Menglong Dong
2024-02-20 3:51 ` [PATCH bpf-next 5/5] selftests/bpf: add test cases for multiple attach of tracing program Menglong Dong
2024-02-21 1:24 ` [PATCH bpf-next 0/5] bpf: make tracing program support multi-attach Alexei Starovoitov
2024-02-21 2:35 ` [External] " 梦龙董
2024-02-21 2:45 ` 梦龙董
2024-02-21 3:02 ` Alexei Starovoitov
2024-02-21 3:06 ` 梦龙董
2024-02-21 3:18 ` Alexei Starovoitov
2024-02-21 3:57 ` 梦龙董
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240220035105.34626-2-dongmenglong.8@bytedance.com \
--to=dongmenglong.8@bytedance.com \
--cc=alexandre.torgue@foss.st.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davemarchevsky@fb.com \
--cc=dxu@dxuuu.xyz \
--cc=eddyz87@gmail.com \
--cc=haoluo@google.com \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=kpsingh@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-stm32@st-md-mailman.stormreply.com \
--cc=martin.lau@linux.dev \
--cc=mcoquelin.stm32@gmail.com \
--cc=mykolal@fb.com \
--cc=sdf@google.com \
--cc=shuah@kernel.org \
--cc=song@kernel.org \
--cc=thinker.li@gmail.com \
--cc=yonghong.song@linux.dev \
--cc=zhoufeng.zf@bytedance.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).