From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= <bjorn.topel@intel.com>
Date: Fri, 13 Dec 2019 18:51:07 +0100
Subject: bpf: Move trampoline JIT image allocation to a function
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Patch-mainline: v5.6-rc1
Git-commit: 98e8627efcada18ac043a77b9101b4b4c768090b
References: bsc#1177028
Refactor the image allocation in the BPF trampoline code into a
separate function, so it can be shared with the BPF dispatcher in
upcoming commits.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191213175112.30208-2-bjorn.topel@gmail.com
Acked-by: Gary Lin <glin@suse.com>
---
include/linux/bpf.h | 1 +
kernel/bpf/trampoline.c | 24 +++++++++++++++++-------
2 files changed, 18 insertions(+), 7 deletions(-)
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -476,6 +476,7 @@ struct bpf_trampoline *bpf_trampoline_lo
int bpf_trampoline_link_prog(struct bpf_prog *prog);
int bpf_trampoline_unlink_prog(struct bpf_prog *prog);
void bpf_trampoline_put(struct bpf_trampoline *tr);
+void *bpf_jit_alloc_exec_page(void);
#else
static inline struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
{
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -14,6 +14,22 @@ static struct hlist_head trampoline_tabl
/* serializes access to trampoline_table */
static DEFINE_MUTEX(trampoline_mutex);
+void *bpf_jit_alloc_exec_page(void)
+{
+ void *image;
+
+ image = bpf_jit_alloc_exec(PAGE_SIZE);
+ if (!image)
+ return NULL;
+
+ set_vm_flush_reset_perms(image);
+ /* Keep image as writeable. The alternative is to keep flipping ro/rw
+ * everytime new program is attached or detached.
+ */
+ set_memory_x((long)image, 1);
+ return image;
+}
+
struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
{
struct bpf_trampoline *tr;
@@ -34,7 +50,7 @@ struct bpf_trampoline *bpf_trampoline_lo
goto out;
/* is_root was checked earlier. No need for bpf_jit_charge_modmem() */
- image = bpf_jit_alloc_exec(PAGE_SIZE);
+ image = bpf_jit_alloc_exec_page();
if (!image) {
kfree(tr);
tr = NULL;
@@ -48,12 +64,6 @@ struct bpf_trampoline *bpf_trampoline_lo
mutex_init(&tr->mutex);
for (i = 0; i < BPF_TRAMP_MAX; i++)
INIT_HLIST_HEAD(&tr->progs_hlist[i]);
-
- set_vm_flush_reset_perms(image);
- /* Keep image as writeable. The alternative is to keep flipping ro/rw
- * everytime new program is attached or detached.
- */
- set_memory_x((long)image, 1);
tr->image = image;
out:
mutex_unlock(&trampoline_mutex);