From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Calvin Owens <jcalvinowens@gmail.com>,
Luis Chamberlain <mcgrof@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Alexei Starovoitov <ast@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Naveen N Rao <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
David S Miller <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>
Cc: "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"linux-modules@vger.kernel.org" <linux-modules@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n
Date: Thu, 7 Mar 2024 22:09:31 +0000 [thread overview]
Message-ID: <a7ac9672-06d1-4f6a-b676-01c9868ea39c@csgroup.eu> (raw)
In-Reply-To: <afebd15dd032f908e46871bec5be438063ae7458.1709676663.git.jcalvinowens@gmail.com>
Le 06/03/2024 à 21:05, Calvin Owens a écrit :
> [Vous ne recevez pas souvent de courriers de jcalvinowens@gmail.com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]
>
> No BPF code has to change, except in struct_ops (for module refs).
>
> This conflicts with bpf-next because of this (relevant) series:
>
> https://lore.kernel.org/all/20240119225005.668602-1-thinker.li@gmail.com/
>
> If something like this is merged down the road, it can go through
> bpf-next at leisure once the module_alloc change is in: it's a one-way
> dependency.
>
> Signed-off-by: Calvin Owens <jcalvinowens@gmail.com>
> ---
> kernel/bpf/Kconfig | 2 +-
> kernel/bpf/bpf_struct_ops.c | 28 ++++++++++++++++++++++++----
> 2 files changed, 25 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig
> index 6a906ff93006..77df483a8925 100644
> --- a/kernel/bpf/Kconfig
> +++ b/kernel/bpf/Kconfig
> @@ -42,7 +42,7 @@ config BPF_JIT
> bool "Enable BPF Just In Time compiler"
> depends on BPF
> depends on HAVE_CBPF_JIT || HAVE_EBPF_JIT
> - depends on MODULES
> + select MODULE_ALLOC
> help
> BPF programs are normally handled by a BPF interpreter. This option
> allows the kernel to generate native code when a program is loaded
> diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
> index 02068bd0e4d9..fbf08a1bb00c 100644
> --- a/kernel/bpf/bpf_struct_ops.c
> +++ b/kernel/bpf/bpf_struct_ops.c
> @@ -108,11 +108,30 @@ const struct bpf_prog_ops bpf_struct_ops_prog_ops = {
> #endif
> };
>
> +#if IS_ENABLED(CONFIG_MODULES)
Can you avoid ifdefs as much as possible ?
> static const struct btf_type *module_type;
>
> +static int bpf_struct_module_type_init(struct btf *btf)
> +{
> + s32 module_id;
Could be:
if (!IS_ENABLED(CONFIG_MODULES))
return 0;
> +
> + module_id = btf_find_by_name_kind(btf, "module", BTF_KIND_STRUCT);
> + if (module_id < 0)
> + return 1;
> +
> + module_type = btf_type_by_id(btf, module_id);
> + return 0;
> +}
> +#else
> +static int bpf_struct_module_type_init(struct btf *btf)
> +{
> + return 0;
> +}
> +#endif
> +
> void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
> {
> - s32 type_id, value_id, module_id;
> + s32 type_id, value_id;
> const struct btf_member *member;
> struct bpf_struct_ops *st_ops;
> const struct btf_type *t;
> @@ -125,12 +144,10 @@ void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
> #include "bpf_struct_ops_types.h"
> #undef BPF_STRUCT_OPS_TYPE
>
> - module_id = btf_find_by_name_kind(btf, "module", BTF_KIND_STRUCT);
> - if (module_id < 0) {
> + if (bpf_struct_module_type_init(btf)) {
> pr_warn("Cannot find struct module in btf_vmlinux\n");
> return;
> }
> - module_type = btf_type_by_id(btf, module_id);
>
> for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
> st_ops = bpf_struct_ops[i];
> @@ -433,12 +450,15 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
>
> moff = __btf_member_bit_offset(t, member) / 8;
> ptype = btf_type_resolve_ptr(btf_vmlinux, member->type, NULL);
> +
> +#if IS_ENABLED(CONFIG_MODULES)
Can't see anything depending on CONFIG_MODULES here, can you instead do:
if (IS_ENABLED(CONFIG_MODULES) && ptype == module_type) {
> if (ptype == module_type) {
> if (*(void **)(udata + moff))
> goto reset_unlock;
> *(void **)(kdata + moff) = BPF_MODULE_OWNER;
> continue;
> }
> +#endif
>
> err = st_ops->init_member(t, member, kdata, udata);
> if (err < 0)
> --
> 2.43.0
>
>
next prev parent reply other threads:[~2024-03-07 22:09 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-06 20:05 [RFC][PATCH 0/4] Make bpf_jit and kprobes work with CONFIG_MODULES=n Calvin Owens
2024-03-06 20:05 ` [RFC][PATCH 1/4] module: mm: Make module_alloc() generally available Calvin Owens
2024-03-07 14:43 ` Christophe Leroy
2024-03-08 20:53 ` Calvin Owens
2024-03-08 2:16 ` Masami Hiramatsu
2024-03-08 20:43 ` Calvin Owens
2024-03-06 20:05 ` [RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n Calvin Owens
2024-03-07 22:09 ` Christophe Leroy [this message]
2024-03-08 21:04 ` Calvin Owens
2024-03-06 20:05 ` [RFC][PATCH 3/4] kprobes: Allow kprobes " Calvin Owens
2024-03-07 7:22 ` Mike Rapoport
2024-03-08 2:46 ` Masami Hiramatsu
2024-03-08 20:36 ` Calvin Owens
2024-03-07 22:16 ` Christophe Leroy
2024-03-08 21:02 ` Calvin Owens
2024-03-08 2:46 ` Masami Hiramatsu
2024-03-08 20:57 ` Calvin Owens
2024-03-06 20:05 ` [RFC][PATCH 4/4] selftests/bpf: Support testing the !MODULES case Calvin Owens
2024-03-06 21:34 ` [RFC][PATCH 0/4] Make bpf_jit and kprobes work with CONFIG_MODULES=n Luis Chamberlain
2024-03-06 23:23 ` Calvin Owens
2024-03-07 1:58 ` Song Liu
2024-03-08 2:50 ` Masami Hiramatsu
2024-03-08 2:55 ` Luis Chamberlain
2024-03-08 20:27 ` Calvin Owens
2024-03-07 7:13 ` Mike Rapoport
2024-03-08 2:45 ` Masami Hiramatsu
2024-03-25 22:46 ` Jarkko Sakkinen
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