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Message-ID: <2050196010b1bf1efa357cfddebd15a152582bb4.1737433945.git.dxu@dxuuu.xyz>
Date: Mon, 20 Jan 2025 21:35:11 -0700
From: Daniel Xu <dxu@...uu.xyz>
To: pabeni@...hat.com,
kuba@...nel.org,
hawk@...nel.org,
maciej.fijalkowski@...el.com,
ast@...nel.org,
edumazet@...gle.com,
daniel@...earbox.net,
davem@...emloft.net,
bjorn@...nel.org,
john.fastabend@...il.com,
magnus.karlsson@...el.com,
andrii@...nel.org
Cc: martin.lau@...ux.dev,
eddyz87@...il.com,
song@...nel.org,
yonghong.song@...ux.dev,
kpsingh@...nel.org,
sdf@...ichev.me,
haoluo@...gle.com,
jolsa@...nel.org,
jonathan.lemon@...il.com,
horms@...nel.org,
bpf@...r.kernel.org,
linux-kernel@...r.kernel.org,
netdev@...r.kernel.org
Subject: [PATCH bpf-next 2/3] bpf: map: Thread null elision metadata to map_gen_lookup
Add an extra parameter to map_gen_lookup callback so that if the lookup
is known to be inbounds, the bounds check can be omitted.
The next commit will take advantage of this new information.
Signed-off-by: Daniel Xu <dxu@...uu.xyz>
---
include/linux/bpf.h | 2 +-
kernel/bpf/arraymap.c | 11 ++++++++---
kernel/bpf/hashtab.c | 14 ++++++++++----
kernel/bpf/verifier.c | 2 +-
net/xdp/xskmap.c | 4 +++-
5 files changed, 23 insertions(+), 10 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index feda0ce90f5a..da8b420095c9 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -117,7 +117,7 @@ struct bpf_map_ops {
* may manipulate it, exists.
*/
void (*map_fd_put_ptr)(struct bpf_map *map, void *ptr, bool need_defer);
- int (*map_gen_lookup)(struct bpf_map *map, struct bpf_insn *insn_buf);
+ int (*map_gen_lookup)(struct bpf_map *map, struct bpf_insn *insn_buf, bool inbounds);
u32 (*map_fd_sys_lookup_elem)(void *ptr);
void (*map_seq_show_elem)(struct bpf_map *map, void *key,
struct seq_file *m);
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index eb28c0f219ee..8dbdceeead95 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -205,7 +205,9 @@ static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
}
/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
-static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+static int array_map_gen_lookup(struct bpf_map *map,
+ struct bpf_insn *insn_buf,
+ bool inbounds)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_insn *insn = insn_buf;
@@ -250,7 +252,9 @@ static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
}
/* emit BPF instructions equivalent to C code of percpu_array_map_lookup_elem() */
-static int percpu_array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+static int percpu_array_map_gen_lookup(struct bpf_map *map,
+ struct bpf_insn *insn_buf,
+ bool inbounds)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_insn *insn = insn_buf;
@@ -1392,7 +1396,8 @@ static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
}
static int array_of_map_gen_lookup(struct bpf_map *map,
- struct bpf_insn *insn_buf)
+ struct bpf_insn *insn_buf,
+ bool inbounds)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 elem_size = array->elem_size;
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 4a9eeb7aef85..103cdab85977 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -720,7 +720,9 @@ static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
* bpf_prog
* __htab_map_lookup_elem
*/
-static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+static int htab_map_gen_lookup(struct bpf_map *map,
+ struct bpf_insn *insn_buf,
+ bool inbounds)
{
struct bpf_insn *insn = insn_buf;
const int ret = BPF_REG_0;
@@ -760,7 +762,8 @@ static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
}
static int htab_lru_map_gen_lookup(struct bpf_map *map,
- struct bpf_insn *insn_buf)
+ struct bpf_insn *insn_buf,
+ bool inbounds)
{
struct bpf_insn *insn = insn_buf;
const int ret = BPF_REG_0;
@@ -2342,7 +2345,9 @@ static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
}
/* inline bpf_map_lookup_elem() call for per-CPU hashmap */
-static int htab_percpu_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+static int htab_percpu_map_gen_lookup(struct bpf_map *map,
+ struct bpf_insn *insn_buf,
+ bool inbounds)
{
struct bpf_insn *insn = insn_buf;
@@ -2626,7 +2631,8 @@ static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
}
static int htab_of_map_gen_lookup(struct bpf_map *map,
- struct bpf_insn *insn_buf)
+ struct bpf_insn *insn_buf,
+ bool inbounds)
{
struct bpf_insn *insn = insn_buf;
const int ret = BPF_REG_0;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e83145c2260d..2ed2fd3c42f2 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -21582,7 +21582,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
ops = map_ptr->ops;
if (insn->imm == BPF_FUNC_map_lookup_elem &&
ops->map_gen_lookup) {
- cnt = ops->map_gen_lookup(map_ptr, insn_buf);
+ cnt = ops->map_gen_lookup(map_ptr, insn_buf, aux->map_ptr_state.inbounds);
if (cnt == -EOPNOTSUPP)
goto patch_map_ops_generic;
if (cnt <= 0 || cnt >= INSN_BUF_SIZE) {
diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c
index afa457506274..78579583b0a1 100644
--- a/net/xdp/xskmap.c
+++ b/net/xdp/xskmap.c
@@ -118,7 +118,9 @@ static int xsk_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
return 0;
}
-static int xsk_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+static int xsk_map_gen_lookup(struct bpf_map *map,
+ struct bpf_insn *insn_buf,
+ bool inbounds)
{
const int ret = BPF_REG_0, mp = BPF_REG_1, index = BPF_REG_2;
struct bpf_insn *insn = insn_buf;
--
2.47.1
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