diff options
| author | Jiri Olsa <jolsa@kernel.org> | 2020-03-12 20:56:05 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-03-13 12:49:52 -0700 |
| commit | a108f7dcfa010e3da825af90d77ac0a6a0240992 (patch) | |
| tree | 620c483c6d3e73da1b2d46ff3cd2d4fd3bfe26aa /kernel/bpf | |
| parent | dba122fb5e122e8e07e2f11cdebc10ba4f425cf7 (diff) | |
bpf: Add trampolines to kallsyms
Adding trampolines to kallsyms. It's displayed as
bpf_trampoline_<ID> [bpf]
where ID is the BTF id of the trampoline function.
Adding bpf_image_ksym_add/del functions that setup
the start/end values and call KSYMBOL perf events
handlers.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200312195610.346362-11-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/trampoline.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 221a17af1f81..36549c9afec4 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -5,6 +5,7 @@ #include <linux/filter.h> #include <linux/ftrace.h> #include <linux/rbtree_latch.h> +#include <linux/perf_event.h> /* dummy _ops. The verifier will operate on target program's ops. */ const struct bpf_verifier_ops bpf_extension_verifier_ops = { @@ -96,6 +97,30 @@ bool is_bpf_image_address(unsigned long addr) return ret; } +void bpf_image_ksym_add(void *data, struct bpf_ksym *ksym) +{ + ksym->start = (unsigned long) data; + ksym->end = ksym->start + BPF_IMAGE_SIZE; + bpf_ksym_add(ksym); + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start, + BPF_IMAGE_SIZE, false, ksym->name); +} + +void bpf_image_ksym_del(struct bpf_ksym *ksym) +{ + bpf_ksym_del(ksym); + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start, + BPF_IMAGE_SIZE, true, ksym->name); +} + +static void bpf_trampoline_ksym_add(struct bpf_trampoline *tr) +{ + struct bpf_ksym *ksym = &tr->ksym; + + snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu", tr->key); + bpf_image_ksym_add(tr->image, ksym); +} + struct bpf_trampoline *bpf_trampoline_lookup(u64 key) { struct bpf_trampoline *tr; @@ -131,6 +156,8 @@ struct bpf_trampoline *bpf_trampoline_lookup(u64 key) for (i = 0; i < BPF_TRAMP_MAX; i++) INIT_HLIST_HEAD(&tr->progs_hlist[i]); tr->image = image; + INIT_LIST_HEAD_RCU(&tr->ksym.lnode); + bpf_trampoline_ksym_add(tr); out: mutex_unlock(&trampoline_mutex); return tr; @@ -368,6 +395,7 @@ void bpf_trampoline_put(struct bpf_trampoline *tr) goto out; if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[BPF_TRAMP_FEXIT]))) goto out; + bpf_image_ksym_del(&tr->ksym); image = container_of(tr->image, struct bpf_image, data); latch_tree_erase(&image->tnode, &image_tree, &image_tree_ops); /* wait for tasks to get out of trampoline before freeing it */ |