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Date: Thu, 18 Nov 2021 12:24:40 +0100
From: Jiri Olsa <jolsa@...hat.com>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>
Cc: netdev@...r.kernel.org, bpf@...r.kernel.org,
Martin KaFai Lau <kafai@...com>,
Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
John Fastabend <john.fastabend@...il.com>,
KP Singh <kpsingh@...omium.org>
Subject: [PATCH bpf-next 14/29] bpf: Add support to store multiple ids in bpf_tramp_id object
Adding support to store multiple ids in bpf_tramp_id object,
to have id for trampolines with multiple functions assigned.
Extra array of u32 values is allocated within bpf_tramp_id
object allocation.
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
include/linux/bpf.h | 6 ++++--
kernel/bpf/syscall.c | 6 +++---
kernel/bpf/trampoline.c | 39 +++++++++++++++++++++++++++++++--------
kernel/bpf/verifier.c | 2 +-
4 files changed, 39 insertions(+), 14 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 2dbc00904a84..47e25d8be600 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -672,8 +672,10 @@ struct bpf_tramp_image {
};
struct bpf_tramp_id {
+ u32 max;
+ u32 cnt;
u32 obj_id;
- u32 btf_id;
+ u32 *id;
void *addr;
};
@@ -749,7 +751,7 @@ static __always_inline __nocfi unsigned int bpf_dispatcher_nop_func(
return bpf_func(ctx, insnsi);
}
#ifdef CONFIG_BPF_JIT
-struct bpf_tramp_id *bpf_tramp_id_alloc(void);
+struct bpf_tramp_id *bpf_tramp_id_alloc(u32 cnt);
void bpf_tramp_id_free(struct bpf_tramp_id *id);
bool bpf_tramp_id_is_empty(struct bpf_tramp_id *id);
int bpf_tramp_id_is_equal(struct bpf_tramp_id *a, struct bpf_tramp_id *b);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a65c1862ab68..216fcce07326 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2704,7 +2704,7 @@ static int bpf_tracing_link_fill_link_info(const struct bpf_link *link,
info->tracing.attach_type = tr_link->attach_type;
info->tracing.target_obj_id = attach->id->obj_id;
- info->tracing.target_btf_id = attach->id->btf_id;
+ info->tracing.target_btf_id = attach->id->id[0];
return 0;
}
@@ -2766,7 +2766,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
goto out_put_prog;
}
- id = bpf_tramp_id_alloc();
+ id = bpf_tramp_id_alloc(1);
if (!id) {
err = -ENOMEM;
goto out_put_prog;
@@ -2829,7 +2829,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
goto out_unlock;
}
- id = bpf_tramp_id_alloc();
+ id = bpf_tramp_id_alloc(1);
if (!id) {
err = -ENOMEM;
goto out_unlock;
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 16fc4c14319b..d65f463c532d 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -60,27 +60,45 @@ void bpf_image_ksym_del(struct bpf_ksym *ksym)
PAGE_SIZE, true, ksym->name);
}
+static bool bpf_tramp_id_is_multi(struct bpf_tramp_id *id)
+{
+ return id->cnt > 1;
+}
+
static u64 bpf_tramp_id_key(struct bpf_tramp_id *id)
{
- return ((u64) id->obj_id << 32) | id->btf_id;
+ if (bpf_tramp_id_is_multi(id))
+ return (u64) &id;
+ else
+ return ((u64) id->obj_id << 32) | id->id[0];
}
bool bpf_tramp_id_is_empty(struct bpf_tramp_id *id)
{
- return !id || (!id->obj_id && !id->btf_id);
+ return !id || id->cnt == 0;
}
int bpf_tramp_id_is_equal(struct bpf_tramp_id *a,
struct bpf_tramp_id *b)
{
- return !memcmp(a, b, sizeof(*a));
+ return a->obj_id == b->obj_id && a->cnt == b->cnt &&
+ !memcmp(a->id, b->id, a->cnt * sizeof(*a->id));
}
-struct bpf_tramp_id *bpf_tramp_id_alloc(void)
+struct bpf_tramp_id *bpf_tramp_id_alloc(u32 max)
{
struct bpf_tramp_id *id;
- return kzalloc(sizeof(*id), GFP_KERNEL);
+ id = kzalloc(sizeof(*id), GFP_KERNEL);
+ if (id) {
+ id->id = kzalloc(sizeof(u32) * max, GFP_KERNEL);
+ if (!id->id) {
+ kfree(id);
+ return NULL;
+ }
+ id->max = max;
+ }
+ return id;
}
void bpf_tramp_id_init(struct bpf_tramp_id *id,
@@ -91,11 +109,15 @@ void bpf_tramp_id_init(struct bpf_tramp_id *id,
id->obj_id = tgt_prog->aux->id;
else
id->obj_id = btf_obj_id(btf);
- id->btf_id = btf_id;
+ id->id[0] = btf_id;
+ id->cnt = 1;
}
void bpf_tramp_id_free(struct bpf_tramp_id *id)
{
+ if (!id)
+ return;
+ kfree(id->id);
kfree(id);
}
@@ -362,7 +384,8 @@ bpf_tramp_image_alloc(struct bpf_tramp_id *id, u32 idx)
ksym = &im->ksym;
INIT_LIST_HEAD_RCU(&ksym->lnode);
key = bpf_tramp_id_key(id);
- snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu_%u", key, idx);
+ snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu_%u%s", key, idx,
+ bpf_tramp_id_is_multi(id) ? "_multi" : "");
bpf_image_ksym_add(image, ksym);
return im;
@@ -597,7 +620,7 @@ struct bpf_tramp_attach *bpf_tramp_attach(struct bpf_tramp_id *id,
if (!node)
goto out;
- err = bpf_check_attach_model(prog, tgt_prog, id->btf_id, &tr->func.model);
+ err = bpf_check_attach_model(prog, tgt_prog, id->id[0], &tr->func.model);
if (err)
goto out;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e05f39fd2708..1903d5d256b6 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13995,7 +13995,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
return -EINVAL;
}
- id = bpf_tramp_id_alloc();
+ id = bpf_tramp_id_alloc(1);
if (!id)
return -ENOMEM;
--
2.31.1
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