From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yonghong Song Subject: [PATCH bpf-next 0/2] bpf: support proper non-jit func info Date: Sat, 24 Nov 2018 23:20:43 -0800 Message-ID: <20181125072045.1389189-1-yhs@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: To: , , Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:44040 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726503AbeKYSLg (ORCPT ); Sun, 25 Nov 2018 13:11:36 -0500 Received: from pps.filterd (m0044008.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wAP7EQkq012726 for ; Sat, 24 Nov 2018 23:21:10 -0800 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2nynvqg3pp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Sat, 24 Nov 2018 23:21:10 -0800 Sender: netdev-owner@vger.kernel.org List-ID: Commit 838e96904ff3 ("bpf: Introduce bpf_func_info") added bpf func info support. The userspace is able to get better ksym's for bpf programs with jit, and is able to print out func prototypes. For a program containing func-to-func calls, the existing implementation returns user specified number of function calls and BTF types if jit is enabled. If the jit is not enabled, it only returns the type for the main function. This is undesirable. Interpreter may still be used and we should keep feature identical regardless of whether jit is enabled or not. This patch fixed this discrepancy. The following example shows bpftool output for the bpf program in selftests test_btf_haskv.o when jit is disabled: $ bpftool prog dump xlated id 1490 int _dummy_tracepoint(struct dummy_tracepoint_args * arg): 0: (85) call pc+2#__bpf_prog_run_args32 1: (b7) r0 = 0 2: (95) exit int test_long_fname_1(struct dummy_tracepoint_args * arg): 3: (85) call pc+1#__bpf_prog_run_args32 4: (95) exit int test_long_fname_2(struct dummy_tracepoint_args * arg): 5: (b7) r2 = 0 6: (63) *(u32 *)(r10 -4) = r2 7: (79) r1 = *(u64 *)(r1 +8) 8: (15) if r1 == 0x0 goto pc+9 9: (bf) r2 = r10 10: (07) r2 += -4 11: (18) r1 = map[id:1173] 13: (85) call bpf_map_lookup_elem#77088 14: (15) if r0 == 0x0 goto pc+3 15: (61) r1 = *(u32 *)(r0 +4) 16: (07) r1 += 1 17: (63) *(u32 *)(r0 +4) = r1 18: (95) exit $ bpftool prog dump jited id 1490 no instructions returned Yonghong Song (2): bpf: btf: support proper non-jit func info tools/bpf: change selftest test_btf for both jit and non-jit include/linux/bpf.h | 6 ++- include/linux/bpf_verifier.h | 1 - kernel/bpf/core.c | 3 +- kernel/bpf/syscall.c | 33 ++++------------ kernel/bpf/verifier.c | 55 ++++++++++++++++++-------- tools/testing/selftests/bpf/test_btf.c | 33 ++-------------- 6 files changed, 55 insertions(+), 76 deletions(-) -- 2.17.1