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From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
	"Andrii Nakryiko" <andriin@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"Song Liu" <songliubraving@fb.com>,
	"Martin KaFai Lau" <kafai@fb.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"David Miller" <davem@redhat.com>,
	"Björn Töpel" <bjorn.topel@intel.com>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Jesper Dangaard Brouer" <hawk@kernel.org>,
	"Arnaldo Carvalho de Melo" <acme@redhat.com>,
	"Song Liu" <song@kernel.org>
Subject: [PATCH 11/15] bpf: Add trampolines to kallsyms
Date: Mon,  2 Mar 2020 15:31:50 +0100	[thread overview]
Message-ID: <20200302143154.258569-12-jolsa@kernel.org> (raw)
In-Reply-To: <20200302143154.258569-1-jolsa@kernel.org>

Adding trampolines to kallsyms. It's displayed as
  bpf_trampoline_<ID> [bpf]

where ID is the BTF id of the trampoline function.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/bpf.h     |  3 +++
 kernel/bpf/trampoline.c | 28 ++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 76934893bccf..c216af89254f 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -502,6 +502,7 @@ struct bpf_trampoline {
 	/* Executable image of trampoline */
 	void *image;
 	u64 selector;
+	struct bpf_ksym ksym;
 };
 
 #define BPF_DISPATCHER_MAX 48 /* Fits in 2048B */
@@ -573,6 +574,8 @@ struct bpf_image {
 #define BPF_IMAGE_SIZE (PAGE_SIZE - sizeof(struct bpf_image))
 bool is_bpf_image_address(unsigned long address);
 void *bpf_image_alloc(void);
+void bpf_image_ksym_add(void *data, struct bpf_ksym *ksym);
+void bpf_image_ksym_del(struct bpf_ksym *ksym);
 /* Called only from code, so there's no need for stubs. */
 void bpf_ksym_add(struct bpf_ksym *ksym);
 void bpf_ksym_del(struct bpf_ksym *ksym);
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 6b264a92064b..9212e715ac24 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;
@@ -356,6 +383,7 @@ 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 */
-- 
2.24.1


  parent reply	other threads:[~2020-03-02 14:33 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-02 14:31 [PATCHv4 00/15] bpf: Add trampoline and dispatcher to /proc/kallsyms Jiri Olsa
2020-03-02 14:31 ` [PATCH 01/15] x86/mm: Rename is_kernel_text to __is_kernel_text Jiri Olsa
2020-03-02 14:31 ` [PATCH 02/15] bpf: Add bpf_trampoline_ name prefix for DECLARE_BPF_DISPATCHER Jiri Olsa
2020-03-02 14:31 ` [PATCH 03/15] bpf: Add struct bpf_ksym Jiri Olsa
2020-03-02 14:31 ` [PATCH 04/15] bpf: Add name to " Jiri Olsa
2020-03-02 14:31 ` [PATCH 05/15] bpf: Move lnode list node " Jiri Olsa
2020-03-02 14:31 ` [PATCH 06/15] bpf: Add bpf_ksym_tree tree Jiri Olsa
2020-03-03 18:03   ` Alexei Starovoitov
2020-03-03 20:12     ` Jiri Olsa
2020-03-02 14:31 ` [PATCH 07/15] bpf: Move bpf_tree add/del from bpf_prog_ksym_node_add/del Jiri Olsa
2020-03-02 14:31 ` [PATCH 08/15] bpf: Separate kallsyms add/del functions Jiri Olsa
2020-03-02 14:31 ` [PATCH 09/15] bpf: Add bpf_ksym_add/del functions Jiri Olsa
2020-03-02 14:31 ` [PATCH 10/15] bpf: Rename bpf_tree to bpf_progs_tree Jiri Olsa
2020-03-02 14:31 ` Jiri Olsa [this message]
2020-03-02 14:31 ` [PATCH 12/15] bpf: Add dispatchers to kallsyms Jiri Olsa
2020-03-02 14:31 ` [PATCH 13/15] perf tools: Synthesize bpf_trampoline/dispatcher ksymbol event Jiri Olsa
2020-03-02 14:31 ` [PATCH 14/15] perf tools: Set ksymbol dso as loaded on arrival Jiri Olsa
2020-03-02 14:31 ` [PATCH 15/15] perf annotate: Add base support for bpf_image Jiri Olsa

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