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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>
Subject: [PATCH 04/14] bpf: Add name to struct bpf_ksym
Date: Sat,  8 Feb 2020 16:41:59 +0100
Message-ID: <20200208154209.1797988-5-jolsa@kernel.org> (raw)
In-Reply-To: <20200208154209.1797988-1-jolsa@kernel.org>

Adding name to 'struct bpf_ksym' object to carry the name
of the symbol for bpf_prog, bpf_trampoline, bpf_dispatcher.

The current benefit is that name is now generated only when
the symbol is added to the list, so we don't need to generate
it every time it's accessed.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/bpf.h    | 2 ++
 include/linux/filter.h | 6 ------
 kernel/bpf/core.c      | 8 +++++---
 kernel/events/core.c   | 4 ++--
 4 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e39ded33fb0c..1327b07057a8 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -18,6 +18,7 @@
 #include <linux/refcount.h>
 #include <linux/mutex.h>
 #include <linux/module.h>
+#include <linux/kallsyms.h>
 
 struct bpf_verifier_env;
 struct bpf_verifier_log;
@@ -465,6 +466,7 @@ void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start);
 struct bpf_ksym {
 	unsigned long		 start;
 	unsigned long		 end;
+	char			 name[KSYM_NAME_LEN];
 };
 
 enum bpf_tramp_prog_type {
diff --git a/include/linux/filter.h b/include/linux/filter.h
index eafe72644282..a945c250ad53 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1062,7 +1062,6 @@ bpf_address_lookup(unsigned long addr, unsigned long *size,
 
 void bpf_prog_kallsyms_add(struct bpf_prog *fp);
 void bpf_prog_kallsyms_del(struct bpf_prog *fp);
-void bpf_get_prog_name(const struct bpf_prog *prog, char *sym);
 
 #else /* CONFIG_BPF_JIT */
 
@@ -1131,11 +1130,6 @@ static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp)
 {
 }
 
-static inline void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
-{
-	sym[0] = '\0';
-}
-
 #endif /* CONFIG_BPF_JIT */
 
 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp);
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 09b5939dcad3..f4f0b3ca95ae 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -535,8 +535,9 @@ bpf_get_prog_addr_region(const struct bpf_prog *prog)
 	prog->aux->ksym.end   = addr + hdr->pages * PAGE_SIZE;
 }
 
-void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
+static void bpf_get_prog_name(const struct bpf_prog *prog)
 {
+	char *sym = prog->aux->ksym.name;
 	const char *end = sym + KSYM_NAME_LEN;
 	const struct btf_type *type;
 	const char *func_name;
@@ -643,6 +644,7 @@ void bpf_prog_kallsyms_add(struct bpf_prog *fp)
 		return;
 
 	bpf_get_prog_addr_region(fp);
+	bpf_get_prog_name(fp);
 
 	spin_lock_bh(&bpf_lock);
 	bpf_prog_ksym_node_add(fp->aux);
@@ -681,7 +683,7 @@ const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
 		unsigned long symbol_start = prog->aux->ksym.start;
 		unsigned long symbol_end = prog->aux->ksym.end;
 
-		bpf_get_prog_name(prog, sym);
+		strncpy(sym, prog->aux->ksym.name, KSYM_NAME_LEN);
 
 		ret = sym;
 		if (size)
@@ -738,7 +740,7 @@ int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 		if (it++ != symnum)
 			continue;
 
-		bpf_get_prog_name(aux->prog, sym);
+		strncpy(sym, aux->ksym.name, KSYM_NAME_LEN);
 
 		*value = (unsigned long)aux->prog->bpf_func;
 		*type  = BPF_SYM_ELF_TYPE;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2173c23c25b4..c4b01ca30cd4 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8250,7 +8250,7 @@ static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
 	int i;
 
 	if (prog->aux->func_cnt == 0) {
-		bpf_get_prog_name(prog, sym);
+		strncpy(sym, prog->aux->ksym.name, KSYM_NAME_LEN);
 		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
 				   (u64)(unsigned long)prog->bpf_func,
 				   prog->jited_len, unregister, sym);
@@ -8258,7 +8258,7 @@ static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
 		for (i = 0; i < prog->aux->func_cnt; i++) {
 			struct bpf_prog *subprog = prog->aux->func[i];
 
-			bpf_get_prog_name(subprog, sym);
+			strncpy(sym, subprog->aux->ksym.name, KSYM_NAME_LEN);
 			perf_event_ksymbol(
 				PERF_RECORD_KSYMBOL_TYPE_BPF,
 				(u64)(unsigned long)subprog->bpf_func,
-- 
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 ` Jiri Olsa [this message]
2020-02-08 15:42 ` [PATCH 05/14] bpf: Add lnode list node to " Jiri Olsa
2020-02-08 15:42 ` [PATCH 06/14] bpf: Add bpf_kallsyms_tree tree Jiri Olsa
2020-02-11 18:21   ` 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

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