linux-kernel - [PATCH bpf-next v4 1/3] bpf: make bpf_prog

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Message-Id: <20230626085811.3192402-2-puranjay12@gmail.com>
Date:   Mon, 26 Jun 2023 08:58:09 +0000
From:   Puranjay Mohan <puranjay12@...il.com>
To:     ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
        martin.lau@...ux.dev, song@...nel.org, catalin.marinas@....com,
        mark.rutland@....com, bpf@...r.kernel.org, kpsingh@...nel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     puranjay12@...il.com
Subject: [PATCH bpf-next v4 1/3] bpf: make bpf_prog_pack allocator portable

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@...il.com>
Acked-by: Song Liu <song@...nel.org>
---
Changes in V3 => v4
- No changes

Changes in V2 => V3:
- No changes

Changes in v1 => v2:
- No code changes.
- Added Acked-by: Song Liu <song@...nel.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 dc85240a0134..599136cb5096 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:
-- 
2.40.1