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authorJiri Olsa <jolsa@kernel.org>2020-03-12 20:56:05 +0100
committerAlexei Starovoitov <ast@kernel.org>2020-03-13 20:49:52 +0100
commita108f7dcfa010e3da825af90d77ac0a6a0240992 (patch)
tree620c483c6d3e73da1b2d46ff3cd2d4fd3bfe26aa /kernel/bpf
parentbpf: Add bpf_ksym_add/del functions (diff)
downloadlinux-a108f7dcfa010e3da825af90d77ac0a6a0240992.tar.xz
linux-a108f7dcfa010e3da825af90d77ac0a6a0240992.zip
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.c28
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 */