[PATCHv2 bpf-next 04/24] bpf: Add bpf_get_func_ip helper support for uprobe link

Jiri Olsa
2023-06-20T08:36:34Z

Adding support for bpf_get_func_ip helper being called from
ebpf program attached by uprobe_multi link.

It returns the ip of the uprobe.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/trace/bpf_trace.c | 33 ++++++++++++++++++++++++++++++---
1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 5c5b543d7d03..dfba0bb479a2 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -88,6 +88,7 @@ static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx);
static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx);

static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx);
+static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx);

/**
* trace_call_bpf - invoke BPF program
@@ -1091,6 +1092,18 @@ static const struct bpf_func_proto bpf_get_attach_cookie_proto_kmulti = {
.arg1_type = ARG_PTR_TO_CTX,
};

+BPF_CALL_1(bpf_get_func_ip_uprobe_multi, struct pt_regs *, regs)
+{
+ return bpf_uprobe_multi_entry_ip(current->bpf_ctx);
+}
+
+static const struct bpf_func_proto bpf_get_func_ip_proto_uprobe_multi = {
+ .func = bpf_get_func_ip_uprobe_multi,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+};
+
BPF_CALL_1(bpf_get_attach_cookie_uprobe_multi, struct pt_regs *, regs)
{
return bpf_uprobe_multi_cookie(current->bpf_ctx);
@@ -1545,9 +1558,11 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_override_return_proto;
#endif
case BPF_FUNC_get_func_ip:
- return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI ?
- &bpf_get_func_ip_proto_kprobe_multi :
- &bpf_get_func_ip_proto_kprobe;
+ if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI)
+ return &bpf_get_func_ip_proto_kprobe_multi;
+ if (prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI)
+ return &bpf_get_func_ip_proto_uprobe_multi;
+ return &bpf_get_func_ip_proto_kprobe;
case BPF_FUNC_get_attach_cookie:
if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI)
return &bpf_get_attach_cookie_proto_kmulti;
@@ -3061,6 +3076,14 @@ uprobe_multi_link_ret_handler(struct uprobe_consumer *con, unsigned long func, s
return uprobe_prog_run(uprobe, func, regs);
}

+static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx)
+{
+ struct bpf_uprobe_multi_run_ctx *run_ctx;
+
+ run_ctx = container_of(current->bpf_ctx, struct bpf_uprobe_multi_run_ctx, run_ctx);
+ return run_ctx->entry_ip;
+}
+
static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx)
{
struct bpf_uprobe_multi_run_ctx *run_ctx;
@@ -3221,4 +3244,8 @@ static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx)
{
return 0;
}
+static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx)
+{
+ return 0;
+}
#endif /* CONFIG_UPROBES */
--
2.41.0