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From: Daniel Borkmann <daniel@iogearbox.net>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, ast@kernel.org, joe@wand.net.nz,
	yhs@fb.com, andrii.nakryiko@gmail.com, kafai@fb.com,
	jannh@google.com, Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH bpf-next v6 10/16] bpf, libbpf: refactor relocation handling
Date: Tue,  9 Apr 2019 23:20:12 +0200	[thread overview]
Message-ID: <20190409212018.32423-11-daniel@iogearbox.net> (raw)
In-Reply-To: <20190409212018.32423-1-daniel@iogearbox.net>

From: Joe Stringer <joe@wand.net.nz>

Adjust the code for relocations slightly with no functional changes,
so that upcoming patches that will introduce support for relocations
into the .data, .rodata and .bss sections can be added independent
of these changes.

Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 tools/lib/bpf/libbpf.c | 62 ++++++++++++++++++++++--------------------
 1 file changed, 32 insertions(+), 30 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1ebfe7943d53..6dba0f01673b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -871,20 +871,20 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 				obj->efile.symbols = data;
 				obj->efile.strtabidx = sh.sh_link;
 			}
-		} else if ((sh.sh_type == SHT_PROGBITS) &&
-			   (sh.sh_flags & SHF_EXECINSTR) &&
-			   (data->d_size > 0)) {
-			if (strcmp(name, ".text") == 0)
-				obj->efile.text_shndx = idx;
-			err = bpf_object__add_program(obj, data->d_buf,
-						      data->d_size, name, idx);
-			if (err) {
-				char errmsg[STRERR_BUFSIZE];
-				char *cp = libbpf_strerror_r(-err, errmsg,
-							     sizeof(errmsg));
-
-				pr_warning("failed to alloc program %s (%s): %s",
-					   name, obj->path, cp);
+		} else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
+			if (sh.sh_flags & SHF_EXECINSTR) {
+				if (strcmp(name, ".text") == 0)
+					obj->efile.text_shndx = idx;
+				err = bpf_object__add_program(obj, data->d_buf,
+							      data->d_size, name, idx);
+				if (err) {
+					char errmsg[STRERR_BUFSIZE];
+					char *cp = libbpf_strerror_r(-err, errmsg,
+								     sizeof(errmsg));
+
+					pr_warning("failed to alloc program %s (%s): %s",
+						   name, obj->path, cp);
+				}
 			}
 		} else if (sh.sh_type == SHT_REL) {
 			void *reloc = obj->efile.reloc;
@@ -1046,24 +1046,26 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 			return -LIBBPF_ERRNO__RELOC;
 		}
 
-		/* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
-		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
-			if (maps[map_idx].offset == sym.st_value) {
-				pr_debug("relocation: find map %zd (%s) for insn %u\n",
-					 map_idx, maps[map_idx].name, insn_idx);
-				break;
+		if (sym.st_shndx == maps_shndx) {
+			/* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
+			for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+				if (maps[map_idx].offset == sym.st_value) {
+					pr_debug("relocation: find map %zd (%s) for insn %u\n",
+						 map_idx, maps[map_idx].name, insn_idx);
+					break;
+				}
 			}
-		}
 
-		if (map_idx >= nr_maps) {
-			pr_warning("bpf relocation: map_idx %d large than %d\n",
-				   (int)map_idx, (int)nr_maps - 1);
-			return -LIBBPF_ERRNO__RELOC;
-		}
+			if (map_idx >= nr_maps) {
+				pr_warning("bpf relocation: map_idx %d large than %d\n",
+					   (int)map_idx, (int)nr_maps - 1);
+				return -LIBBPF_ERRNO__RELOC;
+			}
 
-		prog->reloc_desc[i].type = RELO_LD64;
-		prog->reloc_desc[i].insn_idx = insn_idx;
-		prog->reloc_desc[i].map_idx = map_idx;
+			prog->reloc_desc[i].type = RELO_LD64;
+			prog->reloc_desc[i].insn_idx = insn_idx;
+			prog->reloc_desc[i].map_idx = map_idx;
+		}
 	}
 	return 0;
 }
@@ -1425,7 +1427,7 @@ bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
 			}
 			insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
 			insns[insn_idx].imm = obj->maps[map_idx].fd;
-		} else {
+		} else if (prog->reloc_desc[i].type == RELO_CALL) {
 			err = bpf_program__reloc_text(prog, obj,
 						      &prog->reloc_desc[i]);
 			if (err)
-- 
2.17.1


  parent reply	other threads:[~2019-04-09 21:21 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-09 21:20 [PATCH bpf-next v6 00/16] BPF support for global data Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 01/16] bpf: implement lookup-free direct value access for maps Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 02/16] bpf: do not retain flags that are not tied to map lifetime Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 03/16] bpf: add program side {rd, wr}only support for maps Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 04/16] bpf: add syscall side map freeze support Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 05/16] bpf: allow . char as part of the object name Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 06/16] bpf: add specification for BTF Var and DataSec kinds Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 07/16] bpf: kernel side support for BTF Var and DataSec Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 08/16] bpf: allow for key-less BTF in array map Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 09/16] bpf: sync {btf, bpf}.h uapi header from tools infrastructure Daniel Borkmann
2019-04-09 21:20 ` Daniel Borkmann [this message]
2019-04-09 21:20 ` [PATCH bpf-next v6 11/16] bpf, libbpf: support global data/bss/rodata sections Daniel Borkmann
2019-04-19  1:18   ` Andrii Nakryiko
2019-04-23  0:35     ` Daniel Borkmann
2019-04-23  4:06       ` Andrii Nakryiko
2019-04-23  8:31         ` Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 12/16] bpf, libbpf: add support for BTF Var and DataSec Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 13/16] bpf: bpftool support for dumping data/bss/rodata sections Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 14/16] bpf, selftest: test {rd, wr}only flags and direct value access Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 15/16] bpf, selftest: test global data/bss/rodata sections Daniel Borkmann
2019-04-09 21:20 ` [PATCH bpf-next v6 16/16] bpf, selftest: add test cases for BTF Var and DataSec Daniel Borkmann

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