| Message ID | afebd15dd032f908e46871bec5be438063ae7458.1709676663.git.jcalvinowens@gmail.com (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | BPF |
| Headers | show |
| Series | Make bpf_jit and kprobes work with CONFIG_MODULES=n | expand |
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 > >
On Thursday 03/07 at 22:09 +0000, Christophe Leroy wrote: > > > 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 ? Similar to the other one, this was just a misguided attempt to avoid triggering -Wunused, I'll clean it up. This particular patch will look very different when rebased on bpf-next. > > 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 > > > >
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) static const struct btf_type *module_type; +static int bpf_struct_module_type_init(struct btf *btf) +{ + s32 module_id; + + 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) 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)
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(-)