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/[email protected]/
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 <[email protected]>
---
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)
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)
--
2.43.0
Le 06/03/2024 à 21:05, Calvin Owens a écrit :
> [Vous ne recevez pas souvent de courriers de [email protected]. 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/[email protected]/
>
> 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 <[email protected]>
> ---
> 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 [email protected]. 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/[email protected]/
> >
> > 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 <[email protected]>
> > ---
> > 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
> >
> >