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Message-Id: <20210629192945.1071862-5-jolsa@kernel.org>
Date: Tue, 29 Jun 2021 21:29:44 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andriin@...com>
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>,
Masami Hiramatsu <mhiramat@...nel.org>
Subject: [PATCH bpf-next 4/5] bpf: Add bpf_get_func_ip helper for kprobe programs
Adding bpf_get_func_ip helper for BPF_PROG_TYPE_KPROBE programs,
so it's now possible to call bpf_get_func_ip from both kprobe and
kretprobe programs.
Taking the caller's address from 'struct kprobe::addr', which is
defined for both kprobe and kretprobe.
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
include/uapi/linux/bpf.h | 2 +-
kernel/bpf/verifier.c | 2 ++
kernel/trace/bpf_trace.c | 14 ++++++++++++++
kernel/trace/trace_kprobe.c | 20 ++++++++++++++++++--
kernel/trace/trace_probe.h | 5 +++++
tools/include/uapi/linux/bpf.h | 2 +-
6 files changed, 41 insertions(+), 4 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 83e87ffdbb6e..4894f99a1993 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4783,7 +4783,7 @@ union bpf_attr {
*
* u64 bpf_get_func_ip(void *ctx)
* Description
- * Get address of the traced function (for tracing programs).
+ * Get address of the traced function (for tracing and kprobe programs).
* Return
* Address of the traced function.
*/
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 701ff7384fa7..b66e0a7104f8 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5979,6 +5979,8 @@ static bool has_get_func_ip(struct bpf_verifier_env *env)
return -ENOTSUPP;
}
return 0;
+ } else if (type == BPF_PROG_TYPE_KPROBE) {
+ return 0;
}
verbose(env, "func %s#%d not supported for program type %d\n",
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 9edd3b1a00ad..1a5bddce9abd 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -961,6 +961,18 @@ static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = {
.arg1_type = ARG_PTR_TO_CTX,
};
+BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs)
+{
+ return trace_current_kprobe_addr();
+}
+
+static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = {
+ .func = bpf_get_func_ip_kprobe,
+ .gpl_only = true,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+};
+
const struct bpf_func_proto *
bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
@@ -1092,6 +1104,8 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
case BPF_FUNC_override_return:
return &bpf_override_return_proto;
#endif
+ case BPF_FUNC_get_func_ip:
+ return &bpf_get_func_ip_proto_kprobe;
default:
return bpf_tracing_func_proto(func_id, prog);
}
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index ea6178cb5e33..b07d5888db14 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1570,6 +1570,18 @@ static int kretprobe_event_define_fields(struct trace_event_call *event_call)
}
#ifdef CONFIG_PERF_EVENTS
+/* Used by bpf get_func_ip helper */
+DEFINE_PER_CPU(u64, current_kprobe_addr) = 0;
+
+u64 trace_current_kprobe_addr(void)
+{
+ return *this_cpu_ptr(¤t_kprobe_addr);
+}
+
+static void trace_current_kprobe_set(struct trace_kprobe *tk)
+{
+ __this_cpu_write(current_kprobe_addr, (u64) tk->rp.kp.addr);
+}
/* Kprobe profile handler */
static int
@@ -1585,6 +1597,7 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
unsigned long orig_ip = instruction_pointer(regs);
int ret;
+ trace_current_kprobe_set(tk);
ret = trace_call_bpf(call, regs);
/*
@@ -1631,8 +1644,11 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
int size, __size, dsize;
int rctx;
- if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
- return;
+ if (bpf_prog_array_valid(call)) {
+ trace_current_kprobe_set(tk);
+ if (!trace_call_bpf(call, regs))
+ return;
+ }
head = this_cpu_ptr(call->perf_events);
if (hlist_empty(head))
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 227d518e5ba5..19c979834916 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -199,6 +199,7 @@ DECLARE_BASIC_PRINT_TYPE_FUNC(symbol);
#ifdef CONFIG_KPROBE_EVENTS
bool trace_kprobe_on_func_entry(struct trace_event_call *call);
bool trace_kprobe_error_injectable(struct trace_event_call *call);
+u64 trace_current_kprobe_addr(void);
#else
static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call)
{
@@ -209,6 +210,10 @@ static inline bool trace_kprobe_error_injectable(struct trace_event_call *call)
{
return false;
}
+static inline u64 trace_current_kprobe_addr(void)
+{
+ return 0;
+}
#endif /* CONFIG_KPROBE_EVENTS */
struct probe_arg {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 83e87ffdbb6e..4894f99a1993 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4783,7 +4783,7 @@ union bpf_attr {
*
* u64 bpf_get_func_ip(void *ctx)
* Description
- * Get address of the traced function (for tracing programs).
+ * Get address of the traced function (for tracing and kprobe programs).
* Return
* Address of the traced function.
*/
--
2.31.1
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