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From: Dave Marchevsky <davemarchevsky@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>, Yonghong Song <yhs@fb.com>,
	<netdev@vger.kernel.org>, Dave Marchevsky <davemarchevsky@fb.com>
Subject: [PATCH v5 bpf-next 1/9] bpf: merge printk and seq_printf VARARG max macros
Date: Sun, 12 Sep 2021 20:56:01 -0700	[thread overview]
Message-ID: <20210913035609.160722-2-davemarchevsky@fb.com> (raw)
In-Reply-To: <20210913035609.160722-1-davemarchevsky@fb.com>

MAX_SNPRINTF_VARARGS and MAX_SEQ_PRINTF_VARARGS are used by bpf helpers
bpf_snprintf and bpf_seq_printf to limit their varargs. Both call into
bpf_bprintf_prepare for print formatting logic and have convenience
macros in libbpf (BPF_SNPRINTF, BPF_SEQ_PRINTF) which use the same
helper macros to convert varargs to a byte array.

Changing shared functionality to support more varargs for either bpf
helper would affect the other as well, so let's combine the _VARARGS
macros to make this more obvious.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
---
 include/linux/bpf.h      | 2 ++
 kernel/bpf/helpers.c     | 4 +---
 kernel/trace/bpf_trace.c | 4 +---
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index f4c16f19f83e..be8d57e6e78a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2216,6 +2216,8 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
 struct btf_id_set;
 bool btf_id_set_contains(const struct btf_id_set *set, u32 id);
 
+#define MAX_BPRINTF_VARARGS		12
+
 int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 			u32 **bin_buf, u32 num_args);
 void bpf_bprintf_cleanup(void);
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 9aabf84afd4b..8f9f392c1322 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -979,15 +979,13 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 	return err;
 }
 
-#define MAX_SNPRINTF_VARARGS		12
-
 BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt,
 	   const void *, data, u32, data_len)
 {
 	int err, num_args;
 	u32 *bin_args;
 
-	if (data_len % 8 || data_len > MAX_SNPRINTF_VARARGS * 8 ||
+	if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 ||
 	    (data_len && !data))
 		return -EINVAL;
 	num_args = data_len / 8;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 8e2eb950aa82..10672ebc63b7 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -414,15 +414,13 @@ const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
 	return &bpf_trace_printk_proto;
 }
 
-#define MAX_SEQ_PRINTF_VARARGS		12
-
 BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size,
 	   const void *, data, u32, data_len)
 {
 	int err, num_args;
 	u32 *bin_args;
 
-	if (data_len & 7 || data_len > MAX_SEQ_PRINTF_VARARGS * 8 ||
+	if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 ||
 	    (data_len && !data))
 		return -EINVAL;
 	num_args = data_len / 8;
-- 
2.30.2


  reply	other threads:[~2021-09-13  3:56 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-13  3:56 [PATCH v5 bpf-next 0/9] bpf: implement variadic printk helper Dave Marchevsky
2021-09-13  3:56 ` Dave Marchevsky [this message]
2021-09-13  3:56 ` [PATCH v5 bpf-next 2/9] selftests/bpf: stop using bpf_program__load Dave Marchevsky
2021-09-13  3:56 ` [PATCH v5 bpf-next 3/9] bpf: add bpf_trace_vprintk helper Dave Marchevsky
2021-09-13  3:56 ` [PATCH v5 bpf-next 4/9] libbpf: Modify bpf_printk to choose helper based on arg count Dave Marchevsky
2021-09-13  3:56 ` [PATCH v5 bpf-next 5/9] libbpf: use static const fmt string in __bpf_printk Dave Marchevsky
2021-09-13  3:56 ` [PATCH v5 bpf-next 6/9] bpftool: only probe trace_vprintk feature in 'full' mode Dave Marchevsky
2021-09-13  3:56 ` [PATCH v5 bpf-next 7/9] selftests/bpf: Migrate prog_tests/trace_printk CHECKs to ASSERTs Dave Marchevsky
2021-09-13  3:56 ` [PATCH v5 bpf-next 8/9] selftests/bpf: add trace_vprintk test prog Dave Marchevsky
2021-09-13  3:56 ` [PATCH v5 bpf-next 9/9] bpf: clarify data_len param in bpf_snprintf and bpf_seq_printf comments Dave Marchevsky
2021-09-14  5:52 ` [PATCH v5 bpf-next 0/9] bpf: implement variadic printk helper Andrii Nakryiko

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