From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: bpf@vger.kernel.org, "Alexei Starovoitov" <ast@kernel.org>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Joanne Koong" <joannelkoong@gmail.com>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Jesper Dangaard Brouer" <brouer@redhat.com>
Subject: Re: [PATCH bpf-next v6 03/13] bpf: Allow storing referenced kptr in map
Date: Mon, 25 Apr 2022 20:30:44 -0700 [thread overview]
Message-ID: <20220426033044.ifygawcnigdmg25y@MBP-98dd607d3435.dhcp.thefacebook.com> (raw)
In-Reply-To: <20220424214901.2743946-4-memxor@gmail.com>
On Mon, Apr 25, 2022 at 03:18:51AM +0530, Kumar Kartikeya Dwivedi wrote:
> +
> +static u32 bpf_kptr_xchg_btf_id;
> +
> +const struct bpf_func_proto bpf_kptr_xchg_proto = {
> + .func = bpf_kptr_xchg,
> + .gpl_only = false,
> + .ret_type = RET_PTR_TO_BTF_ID_OR_NULL,
> + .ret_btf_id = &bpf_kptr_xchg_btf_id,
> + .arg1_type = ARG_PTR_TO_KPTR,
> + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL | OBJ_RELEASE,
> + .arg2_btf_id = &bpf_kptr_xchg_btf_id,
> +};
I've tweaked above with:
+/* Unlike other PTR_TO_BTF_ID helpers the btf_id in bpf_kptr_xchg()
+ * helper is determined dynamically by the verifier.
+ */
+#define BPF_PTR_POISON ((void *)((0xeB9FUL << 2) + POISON_POINTER_DELTA))
+
+const struct bpf_func_proto bpf_kptr_xchg_proto = {
+ .func = bpf_kptr_xchg,
+ .gpl_only = false,
+ .ret_type = RET_PTR_TO_BTF_ID_OR_NULL,
+ .ret_btf_id = BPF_PTR_POISON,
+ .arg1_type = ARG_PTR_TO_KPTR,
+ .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL | OBJ_RELEASE,
+ .arg2_btf_id = BPF_PTR_POISON,
next prev parent reply other threads:[~2022-04-26 3:30 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-24 21:48 [PATCH bpf-next v6 00/13] Introduce typed pointer support in BPF maps Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 01/13] bpf: Allow storing unreferenced kptr in map Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 02/13] bpf: Tag argument to be released in bpf_func_proto Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 03/13] bpf: Allow storing referenced kptr in map Kumar Kartikeya Dwivedi
2022-04-26 3:30 ` Alexei Starovoitov [this message]
2022-04-24 21:48 ` [PATCH bpf-next v6 04/13] bpf: Prevent escaping of kptr loaded from maps Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 05/13] bpf: Adapt copy_map_value for multiple offset case Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 06/13] bpf: Populate pairs of btf_id and destructor kfunc in btf Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 07/13] bpf: Wire up freeing of referenced kptr Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 08/13] bpf: Teach verifier about kptr_get kfunc helpers Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 09/13] bpf: Make BTF type match stricter for release arguments Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 10/13] libbpf: Add kptr type tag macros to bpf_helpers.h Kumar Kartikeya Dwivedi
2022-04-24 21:48 ` [PATCH bpf-next v6 11/13] selftests/bpf: Add C tests for kptr Kumar Kartikeya Dwivedi
2022-04-24 21:49 ` [PATCH bpf-next v6 12/13] selftests/bpf: Add verifier " Kumar Kartikeya Dwivedi
2022-04-26 3:35 ` Alexei Starovoitov
2022-05-09 20:03 ` Kumar Kartikeya Dwivedi
2022-04-24 21:49 ` [PATCH bpf-next v6 13/13] selftests/bpf: Add test for strict BTF type check Kumar Kartikeya Dwivedi
2022-04-26 3:39 ` Alexei Starovoitov
2022-05-08 21:59 ` Alexei Starovoitov
2022-05-09 19:49 ` Kumar Kartikeya Dwivedi
2022-04-26 3:30 ` [PATCH bpf-next v6 00/13] Introduce typed pointer support in BPF maps patchwork-bot+netdevbpf
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