subject:"\[RFC\]\[PATCH 2\/4\] bpf\: Allow BPF_JIT with CONFIG

Re: [RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n

2024-03-08 Thread Calvin Owens

On Thursday 03/07 at 22:09 +, Christophe Leroy wrote:
> 
> 
> Le 06/03/2024 à 21:05, Calvin Owens a écrit :
> > [Vous ne recevez pas souvent de courriers de jcalvinow...@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...@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 
> > ---
> >   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
> > 
> >

Re: [RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n

2024-03-07 Thread Christophe Leroy



Le 06/03/2024 à 21:05, Calvin Owens a écrit :
> [Vous ne recevez pas souvent de courriers de jcalvinow...@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...@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 
> ---
>   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
> 
>

[RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n

2024-03-06 Thread Calvin Owens

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...@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 
---
 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

Re: [RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n

Re: [RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n

[RFC][PATCH 2/4] bpf: Allow BPF_JIT with CONFIG_MODULES=n

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