[bpf-next,v3,09/15] bpf, libbpf: refactor relocation handling
diff mbox series

Message ID 94818e3ea5da4ac475a63858472751e68383a451.1554314902.git.daniel@iogearbox.net
State RFC
Headers show
Series
  • BPF support for global data
Related show

Commit Message

Daniel Borkmann April 3, 2019, 6:23 p.m. UTC
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>
---
 tools/lib/bpf/libbpf.c | 62 ++++++++++++++++++++++++++------------------------
 1 file changed, 32 insertions(+), 30 deletions(-)

Patch
diff mbox series

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 11c25d9..9e25358 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -865,20 +865,20 @@  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;
@@ -1040,24 +1040,26 @@  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;
 }
@@ -1419,7 +1421,7 @@  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)