BPF Archive on lore.kernel.org
 help / color / Atom feed
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>
Subject: [PATCH 06/14] bpf: Add bpf_kallsyms_tree tree
Date: Sat,  8 Feb 2020 16:42:01 +0100
Message-ID: <20200208154209.1797988-7-jolsa@kernel.org> (raw)
In-Reply-To: <20200208154209.1797988-1-jolsa@kernel.org>

The bpf_tree is used both for kallsyms iterations and searching
for exception tables of bpf programs, which is needed only for
bpf programs.

Adding bpf_kallsyms_tree that will hold symbols for all bpf_prog,
bpf_trampoline and bpf_dispatcher objects and keeping bpf_tree
only for bpf_prog objects exception tables search to keep it fast.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/bpf.h |  1 +
 kernel/bpf/core.c   | 60 ++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index da67ca3afa2f..151d7b1c8435 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -468,6 +468,7 @@ struct bpf_ksym {
 	unsigned long		 end;
 	char			 name[KSYM_NAME_LEN];
 	struct list_head	 lnode;
+	struct latch_tree_node	 tnode;
 };
 
 enum bpf_tramp_prog_type {
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index b9b7077e60f3..1daa72341450 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -606,8 +606,46 @@ static const struct latch_tree_ops bpf_tree_ops = {
 	.comp	= bpf_tree_comp,
 };
 
+static __always_inline unsigned long
+bpf_get_ksym_start(struct latch_tree_node *n)
+{
+	const struct bpf_ksym *ksym;
+
+	ksym = container_of(n, struct bpf_ksym, tnode);
+	return ksym->start;
+}
+
+static __always_inline bool
+bpf_ksym_tree_less(struct latch_tree_node *a,
+		   struct latch_tree_node *b)
+{
+	return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
+}
+
+static __always_inline int
+bpf_ksym_tree_comp(void *key, struct latch_tree_node *n)
+{
+	unsigned long val = (unsigned long)key;
+	const struct bpf_ksym *ksym;
+
+	ksym = container_of(n, struct bpf_ksym, tnode);
+
+	if (val < ksym->start)
+		return -1;
+	if (val >= ksym->end)
+		return  1;
+
+	return 0;
+}
+
+static const struct latch_tree_ops bpf_kallsyms_tree_ops = {
+	.less	= bpf_ksym_tree_less,
+	.comp	= bpf_ksym_tree_comp,
+};
+
 static DEFINE_SPINLOCK(bpf_lock);
 static LIST_HEAD(bpf_kallsyms);
+static struct latch_tree_root bpf_kallsyms_tree __cacheline_aligned;
 static struct latch_tree_root bpf_tree __cacheline_aligned;
 
 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
@@ -615,6 +653,7 @@ static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
 	WARN_ON_ONCE(!list_empty(&aux->ksym.lnode));
 	list_add_tail_rcu(&aux->ksym.lnode, &bpf_kallsyms);
 	latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
+	latch_tree_insert(&aux->ksym.tnode, &bpf_kallsyms_tree, &bpf_kallsyms_tree_ops);
 }
 
 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
@@ -623,6 +662,7 @@ static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
 		return;
 
 	latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
+	latch_tree_erase(&aux->ksym.tnode, &bpf_kallsyms_tree, &bpf_kallsyms_tree_ops);
 	list_del_rcu(&aux->ksym.lnode);
 }
 
@@ -671,19 +711,27 @@ static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
 	       NULL;
 }
 
+static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
+{
+	struct latch_tree_node *n;
+
+	n = latch_tree_find((void *)addr, &bpf_kallsyms_tree, &bpf_kallsyms_tree_ops);
+	return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
+}
+
 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
 				 unsigned long *off, char *sym)
 {
-	struct bpf_prog *prog;
+	struct bpf_ksym *ksym;
 	char *ret = NULL;
 
 	rcu_read_lock();
-	prog = bpf_prog_kallsyms_find(addr);
-	if (prog) {
-		unsigned long symbol_start = prog->aux->ksym.start;
-		unsigned long symbol_end = prog->aux->ksym.end;
+	ksym = bpf_ksym_find(addr);
+	if (ksym) {
+		unsigned long symbol_start = ksym->start;
+		unsigned long symbol_end = ksym->end;
 
-		strncpy(sym, prog->aux->ksym.name, KSYM_NAME_LEN);
+		strncpy(sym, ksym->name, KSYM_NAME_LEN);
 
 		ret = sym;
 		if (size)
-- 
2.24.1


  parent reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-08 15:41 [PATCH 00/14] bpf: Add trampoline and dispatcher to /proc/kallsyms Jiri Olsa
2020-02-08 15:41 ` [PATCH 01/14] x86/mm: Rename is_kernel_text to __is_kernel_text Jiri Olsa
2020-02-08 15:41 ` [PATCH 02/14] bpf: Add bpf_trampoline_ name prefix for DECLARE_BPF_DISPATCHER Jiri Olsa
2020-02-08 15:41 ` [PATCH 03/14] bpf: Add struct bpf_ksym Jiri Olsa
2020-02-08 15:41 ` [PATCH 04/14] bpf: Add name to " Jiri Olsa
2020-02-08 15:42 ` [PATCH 05/14] bpf: Add lnode list node " Jiri Olsa
2020-02-08 15:42 ` Jiri Olsa [this message]
2020-02-11 18:21   ` [PATCH 06/14] bpf: Add bpf_kallsyms_tree tree Andrii Nakryiko
2020-02-12 10:49     ` Jiri Olsa
2020-02-08 15:42 ` [PATCH 07/14] bpf: Move bpf_tree add/del from bpf_prog_ksym_node_add/del Jiri Olsa
2020-02-08 15:42 ` [PATCH 08/14] bpf: Separate kallsyms add/del functions Jiri Olsa
2020-02-08 15:42 ` [PATCH 09/14] bpf: Add bpf_ksym_add/del functions Jiri Olsa
2020-02-08 15:42 ` [PATCH 10/14] bpf: Re-initialize lnode in bpf_ksym_del Jiri Olsa
2020-02-11 18:28   ` Andrii Nakryiko
2020-02-12 10:43     ` Jiri Olsa
2020-02-08 15:42 ` [PATCH 11/14] bpf: Rename bpf_tree to bpf_progs_tree Jiri Olsa
2020-02-08 15:42 ` [PATCH 12/14] bpf: Add trampolines to kallsyms Jiri Olsa
2020-02-11 18:51   ` Andrii Nakryiko
2020-02-12 11:10     ` Jiri Olsa
2020-02-12 16:33       ` Andrii Nakryiko
2020-02-12 22:58         ` Jiri Olsa
2020-02-12 23:02         ` Jiri Olsa
2020-02-08 15:42 ` [PATCH 13/14] bpf: Add dispatchers " Jiri Olsa
2020-02-11 19:03   ` Andrii Nakryiko
2020-02-12 10:52     ` Jiri Olsa
2020-02-08 15:42 ` [PATCH 14/14] bpf: Sort bpf kallsyms symbols Jiri Olsa
2020-02-11 19:12   ` Andrii Nakryiko
2020-02-10 15:51 ` [PATCH 00/14] bpf: Add trampoline and dispatcher to /proc/kallsyms Björn Töpel
2020-02-10 16:17   ` Jiri Olsa
2020-02-11 19:32     ` Arnaldo Carvalho de Melo
2020-02-12 11:13       ` Jiri Olsa
2020-02-12 13:31         ` Arnaldo Carvalho de Melo
2020-02-12 22:40           ` Jiri Olsa
2020-02-13 16:23   ` Jiri Olsa
2020-02-11 19:13 ` Arnaldo Carvalho de Melo
2020-02-12 10:46   ` Jiri Olsa

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200208154209.1797988-7-jolsa@kernel.org \
    --to=jolsa@kernel.org \
    --cc=andriin@fb.com \
    --cc=ast@kernel.org \
    --cc=bjorn.topel@intel.com \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=davem@redhat.com \
    --cc=hawk@kernel.org \
    --cc=john.fastabend@gmail.com \
    --cc=kafai@fb.com \
    --cc=kuba@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=songliubraving@fb.com \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

BPF Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/bpf/0 bpf/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 bpf bpf/ https://lore.kernel.org/bpf \
		bpf@vger.kernel.org
	public-inbox-index bpf

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.bpf


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git