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From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
	bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Martynas Pumputis <m@lambda.lt>
Subject: [PATCHv4 bpf-next 1/6] kprobes: Add new KPROBE_FLAG_ON_FUNC_ENTRY kprobe flag
Date: Thu, 22 Sep 2022 23:03:15 +0200	[thread overview]
Message-ID: <20220922210320.1076658-2-jolsa@kernel.org> (raw)
In-Reply-To: <20220922210320.1076658-1-jolsa@kernel.org>

Adding KPROBE_FLAG_ON_FUNC_ENTRY kprobe flag to indicate that
attach address is on function entry. This is used in following
changes in get_func_ip helper to return correct function address.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/kprobes.h | 1 +
 kernel/kprobes.c        | 6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 55041d2f884d..a0b92be98984 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -103,6 +103,7 @@ struct kprobe {
 				   * this flag is only for optimized_kprobe.
 				   */
 #define KPROBE_FLAG_FTRACE	8 /* probe is using ftrace */
+#define KPROBE_FLAG_ON_FUNC_ENTRY	16 /* probe is on the function entry */
 
 /* Has this kprobe gone ? */
 static inline bool kprobe_gone(struct kprobe *p)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 08350e35aba2..51adc3c94503 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1606,9 +1606,10 @@ int register_kprobe(struct kprobe *p)
 	struct kprobe *old_p;
 	struct module *probed_mod;
 	kprobe_opcode_t *addr;
+	bool on_func_entry;
 
 	/* Adjust probe address from symbol */
-	addr = kprobe_addr(p);
+	addr = _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry);
 	if (IS_ERR(addr))
 		return PTR_ERR(addr);
 	p->addr = addr;
@@ -1628,6 +1629,9 @@ int register_kprobe(struct kprobe *p)
 
 	mutex_lock(&kprobe_mutex);
 
+	if (on_func_entry)
+		p->flags |= KPROBE_FLAG_ON_FUNC_ENTRY;
+
 	old_p = get_kprobe(p->addr);
 	if (old_p) {
 		/* Since this may unoptimize 'old_p', locking 'text_mutex'. */
-- 
2.37.3


  reply	other threads:[~2022-09-22 21:03 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-22 21:03 [PATCHv4 bpf-next 0/6] bpf: Fixes for CONFIG_X86_KERNEL_IBT Jiri Olsa
2022-09-22 21:03 ` Jiri Olsa [this message]
2022-09-22 21:03 ` [PATCHv4 bpf-next 2/6] ftrace: Keep the resolved addr in kallsyms_callback Jiri Olsa
2022-09-22 21:03 ` [PATCHv4 bpf-next 3/6] bpf: Use given function address for trampoline ip arg Jiri Olsa
2022-09-22 21:03 ` [PATCHv4 bpf-next 4/6] bpf: Adjust kprobe_multi entry_ip for CONFIG_X86_KERNEL_IBT Jiri Olsa
2022-09-23 21:40   ` Andrii Nakryiko
2022-09-22 21:03 ` [PATCHv4 bpf-next 5/6] bpf: Return value in kprobe get_func_ip only for entry address Jiri Olsa
2022-09-23 21:42   ` Andrii Nakryiko
2022-09-26 13:58     ` Jiri Olsa
2022-09-25  5:42   ` Martynas Pumputis
2022-09-26 13:58     ` Jiri Olsa
2022-09-22 21:03 ` [PATCHv4 bpf-next 6/6] selftests/bpf: Fix get_func_ip offset test for CONFIG_X86_KERNEL_IBT Jiri Olsa
2022-09-23 21:43   ` Andrii Nakryiko

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