[v2,bpf-next,15/20] bpf: Tell bpf programs kernel's PAGE_SIZE

Commit Message

Alexei Starovoitov Feb. 9, 2024, 4:06 a.m. UTC

From: Alexei Starovoitov <[e-mail]>

vmlinux BTF includes all kernel enums.
Add __PAGE_SIZE = PAGE_SIZE enum, so that bpf programs
that include vmlinux.h can easily access it.

Signed-off-by: Alexei Starovoitov <[e-mail]>
---
 kernel/bpf/core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Kumar Kartikeya Dwivedi Feb. 10, 2024, 8:52 a.m. UTC | #1

On Fri, 9 Feb 2024 at 05:07, Alexei Starovoitov
<[e-mail]> wrote:
>
> From: Alexei Starovoitov <[e-mail]>
>
> vmlinux BTF includes all kernel enums.
> Add __PAGE_SIZE = PAGE_SIZE enum, so that bpf programs
> that include vmlinux.h can easily access it.
>
> Signed-off-by: Alexei Starovoitov <[e-mail]>
> ---

Acked-by: Kumar Kartikeya Dwivedi <[e-mail]>

Patch

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 2829077f0461..3aa3f56a4310 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -88,13 +88,18 @@  void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, uns
 	return NULL;
 }
 
+/* tell bpf programs that include vmlinux.h kernel's PAGE_SIZE */
+enum page_size_enum {
+	__PAGE_SIZE = PAGE_SIZE
+};
+
 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)
 {
 	gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
 	struct bpf_prog_aux *aux;
 	struct bpf_prog *fp;
 
-	size = round_up(size, PAGE_SIZE);
+	size = round_up(size, __PAGE_SIZE);
 	fp = __vmalloc(size, gfp_flags);
 	if (fp == NULL)
 		return NULL;