[PATCH bpf-next v2 1/3] bpf: make bpf_prog_pack allocator portable

Puranjay Mohan
2023-06-07T09:18:40Z

The bpf_prog_pack allocator currently uses module_alloc() and
module_memfree() to allocate and free memory. This is not portable
because different architectures use different methods for allocating
memory for BPF programs. Like ARM64 uses vmalloc()/vfree().

Use bpf_jit_alloc_exec() and bpf_jit_free_exec() for memory management
in bpf_prog_pack allocator. Other architectures can override these with
their implementation and will be able to use bpf_prog_pack directly.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Acked-by: Song Liu <song@kernel.org>
---
Changes in v1 => v2:
- No code changes.
- Added Acked-by: Song Liu <song@kernel.org>

kernel/bpf/core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 7421487422d4..2bc9092bf9be 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -860,7 +860,7 @@ static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_ins
GFP_KERNEL);
if (!pack)
return NULL;
- pack->ptr = module_alloc(BPF_PROG_PACK_SIZE);
+ pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE);
if (!pack->ptr) {
kfree(pack);
return NULL;
@@ -884,7 +884,7 @@ void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns)
mutex_lock(&pack_mutex);
if (size > BPF_PROG_PACK_SIZE) {
size = round_up(size, PAGE_SIZE);
- ptr = module_alloc(size);
+ ptr = bpf_jit_alloc_exec(size);
if (ptr) {
bpf_fill_ill_insns(ptr, size);
set_vm_flush_reset_perms(ptr);
@@ -922,7 +922,7 @@ void bpf_prog_pack_free(struct bpf_binary_header *hdr)

mutex_lock(&pack_mutex);
if (hdr->size > BPF_PROG_PACK_SIZE) {
- module_memfree(hdr);
+ bpf_jit_free_exec(hdr);
goto out;
}

@@ -946,7 +946,7 @@ void bpf_prog_pack_free(struct bpf_binary_header *hdr)
if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
BPF_PROG_CHUNK_COUNT, 0) == 0) {
list_del(&pack->list);
- module_memfree(pack->ptr);
+ bpf_jit_free_exec(pack->ptr);
kfree(pack);
}
out:
--
2.39.2