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From: Jiri Olsa <olsajiri@gmail.com>
To: Menglong Dong <dongmenglong.8@bytedance.com>
Cc: andrii@kernel.org, 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,
	mykolal@fb.com, shuah@kernel.org, mcoquelin.stm32@gmail.com,
	alexandre.torgue@foss.st.com, thinker.li@gmail.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: Re: [PATCH bpf-next 1/5] bpf: tracing: add support to record and check the accessed args
Date: Tue, 20 Feb 2024 18:18:40 +0100	[thread overview]
Message-ID: <ZdTe8LteoqR43d4q@krava> (raw)
In-Reply-To: <20240220035105.34626-2-dongmenglong.8@bytedance.com>

On Tue, Feb 20, 2024 at 11:51:01AM +0800, Menglong Dong wrote:

SNIP

> +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.
> + */

could we reuse btf_check_func_type_match instead? perhaps just
adding extra argument with arguments bitmap to it?

jirka

> +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
> 

  reply	other threads:[~2024-02-20 17:18 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 ` [PATCH bpf-next 1/5] bpf: tracing: add support to record and check the accessed args Menglong Dong
2024-02-20 17:18   ` Jiri Olsa [this message]
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

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