From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: [PATCH bpf-next 2/3] bpf: emit RECORD_MMAP events for bpf prog load/unload Date: Wed, 19 Sep 2018 15:39:34 -0700 Message-ID: <20180919223935.999270-3-ast@kernel.org> References: <20180919223935.999270-1-ast@kernel.org> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , , To: "David S . Miller" Return-path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:47056 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725790AbeITETt (ORCPT ); Thu, 20 Sep 2018 00:19:49 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.22/8.16.0.22) with SMTP id w8JMW1fA021281 for ; Wed, 19 Sep 2018 15:39:43 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by m0001303.ppops.net with ESMTP id 2mkvck0nv7-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Wed, 19 Sep 2018 15:39:43 -0700 In-Reply-To: <20180919223935.999270-1-ast@kernel.org> Sender: netdev-owner@vger.kernel.org List-ID: use perf_event_mmap_bpf_prog() helper to notify user space about JITed bpf programs. Use RECORD_MMAP perf event to tell user space where JITed bpf program was loaded. Use empty program name as unload indication. Signed-off-by: Alexei Starovoitov --- kernel/bpf/core.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 3f5bf1af0826..ddf11fdafd36 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -384,7 +384,7 @@ bpf_get_prog_addr_region(const struct bpf_prog *prog, *symbol_end = addr + hdr->pages * PAGE_SIZE; } -static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) +static char *bpf_get_prog_name(const struct bpf_prog *prog, char *sym) { const char *end = sym + KSYM_NAME_LEN; @@ -402,9 +402,10 @@ static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); if (prog->aux->name[0]) - snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); + sym += snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); else *sym = 0; + return sym; } static __always_inline unsigned long @@ -480,23 +481,40 @@ static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) void bpf_prog_kallsyms_add(struct bpf_prog *fp) { + unsigned long symbol_start, symbol_end; + char buf[KSYM_NAME_LEN], *sym; + if (!bpf_prog_kallsyms_candidate(fp) || !capable(CAP_SYS_ADMIN)) return; + bpf_get_prog_addr_region(fp, &symbol_start, &symbol_end); + sym = bpf_get_prog_name(fp, buf); + sym++; /* sym - buf is the length of the name including trailing 0 */ + while (!IS_ALIGNED(sym - buf, sizeof(u64))) + *sym++ = 0; spin_lock_bh(&bpf_lock); bpf_prog_ksym_node_add(fp->aux); spin_unlock_bh(&bpf_lock); + perf_event_mmap_bpf_prog(symbol_start, symbol_end - symbol_start, + buf, sym - buf); } void bpf_prog_kallsyms_del(struct bpf_prog *fp) { + unsigned long symbol_start, symbol_end; + /* mmap_record.filename cannot be NULL and has to be u64 aligned */ + char buf[sizeof(u64)] = {}; + if (!bpf_prog_kallsyms_candidate(fp)) return; spin_lock_bh(&bpf_lock); bpf_prog_ksym_node_del(fp->aux); spin_unlock_bh(&bpf_lock); + bpf_get_prog_addr_region(fp, &symbol_start, &symbol_end); + perf_event_mmap_bpf_prog(symbol_start, symbol_end - symbol_start, + buf, sizeof(buf)); } static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr) -- 2.17.1