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From: Kui-Feng Lee <thinker.li@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev,
	song@kernel.org, kernel-team@meta.com, andrii@kernel.org
Cc: sinquersw@gmail.com, kuifeng@meta.com,
	Kui-Feng Lee <thinker.li@gmail.com>
Subject: [PATCH bpf-next 08/11] bpf: Enable and verify btf_field arrays.
Date: Tue,  9 Apr 2024 17:41:47 -0700	[thread overview]
Message-ID: <20240410004150.2917641-9-thinker.li@gmail.com> (raw)
In-Reply-To: <20240410004150.2917641-1-thinker.li@gmail.com>

Set the value of "nelems" of a btf_field with the length of the flattened
array if the btf_field represents an array. The "size" is the size of the
entire array rather than the size of an individual element.

Once "nelems" and "size" reflects the length and size of arrays
respectively, it allows BPF programs to easily declare multiple kptr,
btf_rb_root, or btf_list_head in a global array.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
 kernel/bpf/btf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 831073285ef2..d228360ee1c6 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -3836,7 +3836,7 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type
 	rec->timer_off = -EINVAL;
 	rec->refcount_off = -EINVAL;
 	for (i = 0; i < cnt; i++) {
-		field_type_size = btf_field_type_size(info_arr[i].type);
+		field_type_size = btf_field_type_size(info_arr[i].type) * info_arr[i].nelems;
 		if (info_arr[i].off + field_type_size > value_size) {
 			WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
 			ret = -EFAULT;
@@ -3852,7 +3852,7 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type
 		rec->fields[i].offset = info_arr[i].off;
 		rec->fields[i].type = info_arr[i].type;
 		rec->fields[i].size = field_type_size;
-		rec->fields[i].nelems = 1;
+		rec->fields[i].nelems = info_arr[i].nelems;
 
 		switch (info_arr[i].type) {
 		case BPF_SPIN_LOCK:
-- 
2.34.1


  parent reply	other threads:[~2024-04-10  0:42 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-10  0:41 [PATCH bpf-next 00/11] Enable BPF programs to declare arrays of kptr, bpf_rb_root, and bpf_list_head Kui-Feng Lee
2024-04-10  0:41 ` [PATCH bpf-next 01/11] bpf: Remove unnecessary checks on the offset of btf_field Kui-Feng Lee
2024-04-11 22:12   ` Eduard Zingerman
2024-04-10  0:41 ` [PATCH bpf-next 02/11] bpf: Remove unnecessary call to btf_field_type_size() Kui-Feng Lee
2024-04-11 22:12   ` Eduard Zingerman
2024-04-10  0:41 ` [PATCH bpf-next 03/11] bpf: Add nelems to struct btf_field_info and btf_field Kui-Feng Lee
2024-04-10  0:41 ` [PATCH bpf-next 04/11] bpf: check_map_kptr_access() compute the offset from the reg state Kui-Feng Lee
2024-04-11 22:13   ` Eduard Zingerman
2024-04-12  4:00     ` Kui-Feng Lee
2024-04-10  0:41 ` [PATCH bpf-next 05/11] bpf: initialize/free array of btf_field(s) Kui-Feng Lee
2024-04-11 22:13   ` Eduard Zingerman
2024-04-12  3:56     ` Kui-Feng Lee
2024-04-12 15:32       ` Eduard Zingerman
2024-04-12 17:00         ` Kui-Feng Lee
2024-04-10  0:41 ` [PATCH bpf-next 06/11] bpf: Find btf_field with the knowledge of arrays Kui-Feng Lee
2024-04-11 22:14   ` Eduard Zingerman
2024-04-12  2:00     ` Kui-Feng Lee
2024-04-10  0:41 ` [PATCH bpf-next 07/11] bpf: check_map_access() " Kui-Feng Lee
2024-04-11 22:14   ` Eduard Zingerman
2024-04-12 16:32     ` Kui-Feng Lee
2024-04-12 19:08       ` Eduard Zingerman
2024-04-12 19:29         ` Kui-Feng Lee
2024-04-12 19:50           ` Eduard Zingerman
2024-04-10  0:41 ` Kui-Feng Lee [this message]
2024-04-10  0:41 ` [PATCH bpf-next 09/11] selftests/bpf: Test global kptr arrays Kui-Feng Lee
2024-04-10  0:41 ` [PATCH bpf-next 10/11] selftests/bpf: Test global bpf_rb_root arrays Kui-Feng Lee
2024-04-10  0:41 ` [PATCH bpf-next 11/11] selftests/bpf: Test global bpf_list_head arrays Kui-Feng Lee

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