* [PATCH bpf-next 1/4] selftests/bpf: ensure no DWARF relocations for BPF object files
2019-11-21 7:07 [PATCH bpf-next 0/4] Support global variables Andrii Nakryiko
@ 2019-11-21 7:07 ` Andrii Nakryiko
2019-11-21 7:07 ` [PATCH bpf-next 2/4] libbpf: refactor relocation handling Andrii Nakryiko
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2019-11-21 7:07 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii.nakryiko, kernel-team, Andrii Nakryiko
Add -mattr=dwarfris attribute to llc to avoid having relocations against DWARF
data. These relocations make it impossible to inspect DWARF contents: all
strings are invalid.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
tools/testing/selftests/bpf/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 4fe4aec0367c..085678d88ef8 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -161,7 +161,7 @@ $(OUTPUT)/flow_dissector_load.o: flow_dissector_load.h
define CLANG_BPF_BUILD_RULE
($(CLANG) $3 -O2 -target bpf -emit-llvm \
-c $1 -o - || echo "BPF obj compilation failed") | \
- $(LLC) -march=bpf -mcpu=probe $4 -filetype=obj -o $2
+ $(LLC) -mattr=dwarfris -march=bpf -mcpu=probe $4 -filetype=obj -o $2
endef
# Similar to CLANG_BPF_BUILD_RULE, but with disabled alu32
define CLANG_NOALU32_BPF_BUILD_RULE
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH bpf-next 2/4] libbpf: refactor relocation handling
2019-11-21 7:07 [PATCH bpf-next 0/4] Support global variables Andrii Nakryiko
2019-11-21 7:07 ` [PATCH bpf-next 1/4] selftests/bpf: ensure no DWARF relocations for BPF object files Andrii Nakryiko
@ 2019-11-21 7:07 ` Andrii Nakryiko
2019-11-21 7:07 ` [PATCH bpf-next 3/4] libbpf: fix various errors and warning reported by checkpatch.pl Andrii Nakryiko
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2019-11-21 7:07 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii.nakryiko, kernel-team, Andrii Nakryiko
Relocation handling code is convoluted and unnecessarily deeply nested. Split
out per-relocation logic into separate function. Also refactor the logic to be
more a sequence of per-relocation type checks and processing steps, making it
simpler to follow control flow. This makes it easier to further extends it to
new kinds of relocations (e.g., support for extern variables).
This patch also makes relocation's section verification more robust.
Previously relocations against not yet supported externs were silently ignored
because of obj->efile.text_shndx was zero, when all BPF programs had custom
section names and there was no .text section. Also, invalid LDIMM64 relocations
against non-map sections were passed through, if they were pointing to a .text
section (or 0, which is invalid section). All these bugs are fixed within this
refactoring and checks are made more appropriate for each type of relocation.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
tools/lib/bpf/libbpf.c | 261 ++++++++++++++++++++++-------------------
1 file changed, 143 insertions(+), 118 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index a7d183f7ac72..4c3592c4ec5d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -276,8 +276,8 @@ struct bpf_object {
struct {
GElf_Shdr shdr;
Elf_Data *data;
- } *reloc;
- int nr_reloc;
+ } *reloc_sects;
+ int nr_reloc_sects;
int maps_shndx;
int btf_maps_shndx;
int text_shndx;
@@ -575,8 +575,8 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
obj->efile.rodata = NULL;
obj->efile.bss = NULL;
- zfree(&obj->efile.reloc);
- obj->efile.nr_reloc = 0;
+ zfree(&obj->efile.reloc_sects);
+ obj->efile.nr_reloc_sects = 0;
zclose(obj->efile.fd);
obj->efile.obj_buf = NULL;
obj->efile.obj_buf_sz = 0;
@@ -1693,8 +1693,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
pr_debug("skip section(%d) %s\n", idx, name);
}
} else if (sh.sh_type == SHT_REL) {
- int nr_reloc = obj->efile.nr_reloc;
- void *reloc = obj->efile.reloc;
+ int nr_sects = obj->efile.nr_reloc_sects;
+ void *sects = obj->efile.reloc_sects;
int sec = sh.sh_info; /* points to other section */
/* Only do relo for section with exec instructions */
@@ -1704,18 +1704,18 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
continue;
}
- reloc = reallocarray(reloc, nr_reloc + 1,
- sizeof(*obj->efile.reloc));
- if (!reloc) {
- pr_warn("realloc failed\n");
+ sects = reallocarray(sects, nr_sects + 1,
+ sizeof(*obj->efile.reloc_sects));
+ if (!sects) {
+ pr_warn("reloc_sects realloc failed\n");
return -ENOMEM;
}
- obj->efile.reloc = reloc;
- obj->efile.nr_reloc++;
+ obj->efile.reloc_sects = sects;
+ obj->efile.nr_reloc_sects++;
- obj->efile.reloc[nr_reloc].shdr = sh;
- obj->efile.reloc[nr_reloc].data = data;
+ obj->efile.reloc_sects[nr_sects].shdr = sh;
+ obj->efile.reloc_sects[nr_sects].data = data;
} else if (sh.sh_type == SHT_NOBITS && strcmp(name, ".bss") == 0) {
obj->efile.bss = data;
obj->efile.bss_shndx = idx;
@@ -1780,14 +1780,6 @@ static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
shndx == obj->efile.btf_maps_shndx;
}
-static bool bpf_object__relo_in_known_section(const struct bpf_object *obj,
- int shndx)
-{
- return shndx == obj->efile.text_shndx ||
- bpf_object__shndx_is_maps(obj, shndx) ||
- bpf_object__shndx_is_data(obj, shndx);
-}
-
static enum libbpf_map_type
bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
{
@@ -1801,14 +1793,124 @@ bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
return LIBBPF_MAP_UNSPEC;
}
+static int bpf_program__record_reloc(struct bpf_program *prog,
+ struct reloc_desc *reloc_desc,
+ __u32 insn_idx, const char *name,
+ const GElf_Sym *sym, const GElf_Rel *rel)
+{
+ struct bpf_insn *insn = &prog->insns[insn_idx];
+ size_t map_idx, nr_maps = prog->obj->nr_maps;
+ struct bpf_object *obj = prog->obj;
+ __u32 shdr_idx = sym->st_shndx;
+ enum libbpf_map_type type;
+ struct bpf_map *map;
+
+ /* sub-program call relocation */
+ if (insn->code == (BPF_JMP | BPF_CALL)) {
+ if (insn->src_reg != BPF_PSEUDO_CALL) {
+ pr_warn("incorrect bpf_call opcode\n");
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ /* text_shndx can be 0, if no default "main" program exists */
+ if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
+ pr_warn("bad call relo against section %u\n", shdr_idx);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ if (sym->st_value % 8) {
+ pr_warn("bad call relo offset: %lu\n", sym->st_value);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ reloc_desc->type = RELO_CALL;
+ reloc_desc->insn_idx = insn_idx;
+ reloc_desc->text_off = sym->st_value / 8;
+ obj->has_pseudo_calls = true;
+ return 0;
+ }
+
+ if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) {
+ pr_warn("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
+ insn_idx, insn->code);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
+ pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n",
+ name, shdr_idx, insn_idx, insn->code);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+
+ type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
+
+ /* generic map reference relocation */
+ if (type == LIBBPF_MAP_UNSPEC) {
+ if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
+ pr_warn("bad map relo against section %u\n",
+ shdr_idx);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+ map = &obj->maps[map_idx];
+ if (map->libbpf_type != type ||
+ map->sec_idx != sym->st_shndx ||
+ map->sec_offset != sym->st_value)
+ continue;
+ pr_debug("found map %zd (%s, sec %d, off %zu) for insn %u\n",
+ map_idx, map->name, map->sec_idx,
+ map->sec_offset, insn_idx);
+ break;
+ }
+ if (map_idx >= nr_maps) {
+ pr_warn("map relo failed to find map for sec %u, off %llu\n",
+ shdr_idx, (__u64)sym->st_value);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ reloc_desc->type = RELO_LD64;
+ reloc_desc->insn_idx = insn_idx;
+ reloc_desc->map_idx = map_idx;
+ return 0;
+ }
+
+ /* global data map relocation */
+ if (!bpf_object__shndx_is_data(obj, shdr_idx)) {
+ pr_warn("bad data relo against section %u\n", shdr_idx);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ if (GELF_ST_BIND(sym->st_info) == STB_GLOBAL) {
+ pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
+ name, insn_idx, insn->code);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ if (!obj->caps.global_data) {
+ pr_warn("relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
+ name, insn_idx);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+ map = &obj->maps[map_idx];
+ if (map->libbpf_type != type)
+ continue;
+ pr_debug("found data map %zd (%s, sec %d, off %zu) for insn %u\n",
+ map_idx, map->name, map->sec_idx, map->sec_offset,
+ insn_idx);
+ break;
+ }
+ if (map_idx >= nr_maps) {
+ pr_warn("data relo failed to find map for sec %u\n",
+ shdr_idx);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+
+ reloc_desc->type = RELO_DATA;
+ reloc_desc->insn_idx = insn_idx;
+ reloc_desc->map_idx = map_idx;
+ return 0;
+}
+
static int
bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
Elf_Data *data, struct bpf_object *obj)
{
Elf_Data *symbols = obj->efile.symbols;
- struct bpf_map *maps = obj->maps;
- size_t nr_maps = obj->nr_maps;
- int i, nrels;
+ int err, i, nrels;
pr_debug("collecting relocating info for: '%s'\n", prog->section_name);
nrels = shdr->sh_size / shdr->sh_entsize;
@@ -1821,12 +1923,8 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
prog->nr_reloc = nrels;
for (i = 0; i < nrels; i++) {
- struct bpf_insn *insns = prog->insns;
- enum libbpf_map_type type;
- unsigned int insn_idx;
- unsigned int shdr_idx;
const char *name;
- size_t map_idx;
+ __u32 insn_idx;
GElf_Sym sym;
GElf_Rel rel;
@@ -1834,101 +1932,28 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
pr_warn("relocation: failed to get %d reloc\n", i);
return -LIBBPF_ERRNO__FORMAT;
}
-
if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
pr_warn("relocation: symbol %"PRIx64" not found\n",
GELF_R_SYM(rel.r_info));
return -LIBBPF_ERRNO__FORMAT;
}
+ if (rel.r_offset % sizeof(struct bpf_insn))
+ return -LIBBPF_ERRNO__FORMAT;
+ insn_idx = rel.r_offset / sizeof(struct bpf_insn);
name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name) ? : "<?>";
- pr_debug("relo for %lld value %lld name %d (\'%s\')\n",
- (long long) (rel.r_info >> 32),
- (long long) sym.st_value, sym.st_name, name);
-
- shdr_idx = sym.st_shndx;
- insn_idx = rel.r_offset / sizeof(struct bpf_insn);
- pr_debug("relocation: insn_idx=%u, shdr_idx=%u\n",
- insn_idx, shdr_idx);
-
- if (shdr_idx >= SHN_LORESERVE) {
- pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n",
- name, shdr_idx, insn_idx,
- insns[insn_idx].code);
- return -LIBBPF_ERRNO__RELOC;
- }
- if (!bpf_object__relo_in_known_section(obj, shdr_idx)) {
- pr_warn("Program '%s' contains unrecognized relo data pointing to section %u\n",
- prog->section_name, shdr_idx);
- return -LIBBPF_ERRNO__RELOC;
- }
-
- if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
- if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
- pr_warn("incorrect bpf_call opcode\n");
- return -LIBBPF_ERRNO__RELOC;
- }
- if (sym.st_value % 8) {
- pr_warn("bad call relo offset: %lu\n", sym.st_value);
- return -LIBBPF_ERRNO__RELOC;
- }
- prog->reloc_desc[i].type = RELO_CALL;
- prog->reloc_desc[i].insn_idx = insn_idx;
- prog->reloc_desc[i].text_off = sym.st_value / 8;
- obj->has_pseudo_calls = true;
- continue;
- }
-
- if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
- pr_warn("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
- insn_idx, insns[insn_idx].code);
- return -LIBBPF_ERRNO__RELOC;
- }
-
- if (bpf_object__shndx_is_maps(obj, shdr_idx) ||
- bpf_object__shndx_is_data(obj, shdr_idx)) {
- type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
- if (type != LIBBPF_MAP_UNSPEC) {
- if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL) {
- pr_warn("bpf: relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
- name, insn_idx, insns[insn_idx].code);
- return -LIBBPF_ERRNO__RELOC;
- }
- if (!obj->caps.global_data) {
- pr_warn("bpf: relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
- name, insn_idx);
- return -LIBBPF_ERRNO__RELOC;
- }
- }
-
- for (map_idx = 0; map_idx < nr_maps; map_idx++) {
- if (maps[map_idx].libbpf_type != type)
- continue;
- if (type != LIBBPF_MAP_UNSPEC ||
- (maps[map_idx].sec_idx == sym.st_shndx &&
- maps[map_idx].sec_offset == sym.st_value)) {
- pr_debug("relocation: found map %zd (%s, sec_idx %d, offset %zu) for insn %u\n",
- map_idx, maps[map_idx].name,
- maps[map_idx].sec_idx,
- maps[map_idx].sec_offset,
- insn_idx);
- break;
- }
- }
-
- if (map_idx >= nr_maps) {
- pr_warn("bpf relocation: map_idx %d larger than %d\n",
- (int)map_idx, (int)nr_maps - 1);
- return -LIBBPF_ERRNO__RELOC;
- }
+ pr_debug("relo for shdr %u, symb %llu, value %llu, type %d, bind %d, name %d (\'%s\'), insn %u\n",
+ (__u32)sym.st_shndx, (__u64)GELF_R_SYM(rel.r_info),
+ (__u64)sym.st_value, GELF_ST_TYPE(sym.st_info),
+ GELF_ST_BIND(sym.st_info), sym.st_name, name,
+ insn_idx);
- prog->reloc_desc[i].type = type != LIBBPF_MAP_UNSPEC ?
- RELO_DATA : RELO_LD64;
- prog->reloc_desc[i].insn_idx = insn_idx;
- prog->reloc_desc[i].map_idx = map_idx;
- }
+ err = bpf_program__record_reloc(prog, &prog->reloc_desc[i],
+ insn_idx, name, &sym, &rel);
+ if (err)
+ return err;
}
return 0;
}
@@ -3671,9 +3696,9 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
return -LIBBPF_ERRNO__INTERNAL;
}
- for (i = 0; i < obj->efile.nr_reloc; i++) {
- GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
- Elf_Data *data = obj->efile.reloc[i].data;
+ for (i = 0; i < obj->efile.nr_reloc_sects; i++) {
+ GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr;
+ Elf_Data *data = obj->efile.reloc_sects[i].data;
int idx = shdr->sh_info;
struct bpf_program *prog;
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH bpf-next 3/4] libbpf: fix various errors and warning reported by checkpatch.pl
2019-11-21 7:07 [PATCH bpf-next 0/4] Support global variables Andrii Nakryiko
2019-11-21 7:07 ` [PATCH bpf-next 1/4] selftests/bpf: ensure no DWARF relocations for BPF object files Andrii Nakryiko
2019-11-21 7:07 ` [PATCH bpf-next 2/4] libbpf: refactor relocation handling Andrii Nakryiko
@ 2019-11-21 7:07 ` Andrii Nakryiko
2019-11-21 7:07 ` [PATCH bpf-next 4/4] libbpf: support initialized global variables Andrii Nakryiko
2019-11-21 17:18 ` [PATCH bpf-next 0/4] Support " Alexei Starovoitov
4 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2019-11-21 7:07 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii.nakryiko, kernel-team, Andrii Nakryiko
Fix a bunch of warnings and errors reported by checkpatch.pl, to make it
easier to spot new problems.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
tools/lib/bpf/libbpf.c | 38 +++++++++++++++++++++-----------------
1 file changed, 21 insertions(+), 17 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 4c3592c4ec5d..64bc75fc6723 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -105,7 +105,7 @@ void libbpf_print(enum libbpf_print_level level, const char *format, ...)
err = action; \
if (err) \
goto out; \
-} while(0)
+} while (0)
/* Copied from tools/perf/util/util.h */
@@ -965,8 +965,7 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
obj->path, nr_maps, data->d_size);
if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
- pr_warn("unable to determine map definition size "
- "section %s, %d maps in %zd bytes\n",
+ pr_warn("unable to determine map definition size section %s, %d maps in %zd bytes\n",
obj->path, nr_maps, data->d_size);
return -EINVAL;
}
@@ -1030,12 +1029,11 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
* incompatible.
*/
char *b;
+
for (b = ((char *)def) + sizeof(struct bpf_map_def);
b < ((char *)def) + map_def_sz; b++) {
if (*b != 0) {
- pr_warn("maps section in %s: \"%s\" "
- "has unrecognized, non-zero "
- "options\n",
+ pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n",
obj->path, map_name);
if (strict)
return -EINVAL;
@@ -1073,7 +1071,8 @@ skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
*/
static bool get_map_field_int(const char *map_name, const struct btf *btf,
const struct btf_type *def,
- const struct btf_member *m, __u32 *res) {
+ const struct btf_member *m, __u32 *res)
+{
const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
const char *name = btf__name_by_offset(btf, m->name_off);
const struct btf_array *arr_info;
@@ -1387,7 +1386,8 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
for (i = 0; i < vlen; i++) {
err = bpf_object__init_user_btf_map(obj, sec, i,
obj->efile.btf_maps_shndx,
- data, strict, pin_root_path);
+ data, strict,
+ pin_root_path);
if (err)
return err;
}
@@ -1673,12 +1673,14 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
if (strcmp(name, ".text") == 0)
obj->efile.text_shndx = idx;
err = bpf_object__add_program(obj, data->d_buf,
- data->d_size, name, idx);
+ data->d_size,
+ name, idx);
if (err) {
char errmsg[STRERR_BUFSIZE];
- char *cp = libbpf_strerror_r(-err, errmsg,
- sizeof(errmsg));
+ char *cp;
+ cp = libbpf_strerror_r(-err, errmsg,
+ sizeof(errmsg));
pr_warn("failed to alloc program %s (%s): %s",
name, obj->path, cp);
return err;
@@ -1828,7 +1830,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
}
if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) {
- pr_warn("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
+ pr_warn("invalid relo for insns[%d].code 0x%x\n",
insn_idx, insn->code);
return -LIBBPF_ERRNO__RELOC;
}
@@ -2145,7 +2147,7 @@ bpf_object__probe_global_data(struct bpf_object *obj)
static int bpf_object__probe_btf_func(struct bpf_object *obj)
{
- const char strs[] = "\0int\0x\0a";
+ static const char strs[] = "\0int\0x\0a";
/* void x(int a) {} */
__u32 types[] = {
/* int */
@@ -2171,7 +2173,7 @@ static int bpf_object__probe_btf_func(struct bpf_object *obj)
static int bpf_object__probe_btf_datasec(struct bpf_object *obj)
{
- const char strs[] = "\0x\0.data";
+ static const char strs[] = "\0x\0.data";
/* static int a; */
__u32 types[] = {
/* int */
@@ -5112,7 +5114,7 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
*expected_attach_type = section_names[i].expected_attach_type;
return 0;
}
- pr_warn("failed to guess program type based on ELF section name '%s'\n", name);
+ pr_warn("failed to guess program type from ELF section '%s'\n", name);
type_names = libbpf_get_type_names(false);
if (type_names != NULL) {
pr_info("supported section(type) names are:%s\n", type_names);
@@ -6338,7 +6340,8 @@ static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
};
-static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, int offset)
+static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,
+ int offset)
{
__u32 *array = (__u32 *)info;
@@ -6347,7 +6350,8 @@ static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, int offse
return -(int)offset;
}
-static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info, int offset)
+static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,
+ int offset)
{
__u64 *array = (__u64 *)info;
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH bpf-next 4/4] libbpf: support initialized global variables
2019-11-21 7:07 [PATCH bpf-next 0/4] Support global variables Andrii Nakryiko
` (2 preceding siblings ...)
2019-11-21 7:07 ` [PATCH bpf-next 3/4] libbpf: fix various errors and warning reported by checkpatch.pl Andrii Nakryiko
@ 2019-11-21 7:07 ` Andrii Nakryiko
2019-11-21 17:18 ` [PATCH bpf-next 0/4] Support " Alexei Starovoitov
4 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2019-11-21 7:07 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii.nakryiko, kernel-team, Andrii Nakryiko
Initialized global variables are no different in ELF from static variables,
and don't require any extra support from libbpf. But they are matching
semantics of global data (backed by BPF maps) more closely, preventing
LLVM/Clang from aggressively inlining constant values and not requiring
volatile incantations to prevent those. This patch enables global variables.
It still disables uninitialized variables, which will be put into special COM
(common) ELF section, because BPF doesn't allow uninitialized data to be
accessed.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
tools/lib/bpf/libbpf.c | 9 ++-------
.../testing/selftests/bpf/progs/test_core_reloc_arrays.c | 4 ++--
.../bpf/progs/test_core_reloc_bitfields_direct.c | 4 ++--
.../bpf/progs/test_core_reloc_bitfields_probed.c | 4 ++--
.../selftests/bpf/progs/test_core_reloc_existence.c | 4 ++--
.../selftests/bpf/progs/test_core_reloc_flavors.c | 4 ++--
tools/testing/selftests/bpf/progs/test_core_reloc_ints.c | 4 ++--
.../testing/selftests/bpf/progs/test_core_reloc_kernel.c | 4 ++--
tools/testing/selftests/bpf/progs/test_core_reloc_misc.c | 4 ++--
tools/testing/selftests/bpf/progs/test_core_reloc_mods.c | 4 ++--
.../selftests/bpf/progs/test_core_reloc_nesting.c | 4 ++--
.../selftests/bpf/progs/test_core_reloc_primitives.c | 4 ++--
.../selftests/bpf/progs/test_core_reloc_ptr_as_arr.c | 4 ++--
tools/testing/selftests/bpf/progs/test_core_reloc_size.c | 4 ++--
14 files changed, 28 insertions(+), 33 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 64bc75fc6723..a4e250a369c6 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1835,8 +1835,8 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
return -LIBBPF_ERRNO__RELOC;
}
if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
- pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n",
- name, shdr_idx, insn_idx, insn->code);
+ pr_warn("invalid relo for \'%s\' in special section 0x%x; forgot to initialize global var?..\n",
+ name, shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
@@ -1876,11 +1876,6 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
pr_warn("bad data relo against section %u\n", shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
- if (GELF_ST_BIND(sym->st_info) == STB_GLOBAL) {
- pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
- name, insn_idx, insn->code);
- return -LIBBPF_ERRNO__RELOC;
- }
if (!obj->caps.global_data) {
pr_warn("relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
name, insn_idx);
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c b/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c
index 96b1f5f3b07a..89951b684282 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_arrays_output {
int a2;
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_direct.c b/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_direct.c
index 738b34b72655..edc0f7c9e56d 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_direct.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_direct.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_bitfields {
/* unsigned bitfields */
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_probed.c b/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_probed.c
index e466e3ab7de4..6c20e433558b 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_probed.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_probed.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_bitfields {
/* unsigned bitfields */
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_existence.c b/tools/testing/selftests/bpf/progs/test_core_reloc_existence.c
index c3cac95a19f1..1b7f0ae49cfb 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_existence.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_existence.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_existence_output {
int a_exists;
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_flavors.c b/tools/testing/selftests/bpf/progs/test_core_reloc_flavors.c
index 71fd7cebc9d7..b5dbeef540fd 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_flavors.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_flavors.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_flavors {
int a;
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_ints.c b/tools/testing/selftests/bpf/progs/test_core_reloc_ints.c
index ad5c3f59c9c6..c78ab6d28a14 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_ints.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_ints.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_ints {
uint8_t u8_field;
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
index a4b5e0562ed5..5d499ebdc4bd 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_kernel_output {
int valid[10];
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_misc.c b/tools/testing/selftests/bpf/progs/test_core_reloc_misc.c
index 1a36b0856653..292a5c4ee76a 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_misc.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_misc.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_misc_output {
int a, b, c;
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_mods.c b/tools/testing/selftests/bpf/progs/test_core_reloc_mods.c
index 3199fafede2c..0b28bfacc8fd 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_mods.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_mods.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_mods_output {
int a, b, c, d, e, f, g, h;
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_nesting.c b/tools/testing/selftests/bpf/progs/test_core_reloc_nesting.c
index 98238cb64fbd..39279bf0c9db 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_nesting.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_nesting.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_nesting_substruct {
int a;
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_primitives.c b/tools/testing/selftests/bpf/progs/test_core_reloc_primitives.c
index 4f3ecb9127bb..ea57973cdd19 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_primitives.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_primitives.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
enum core_reloc_primitives_enum {
A = 0,
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_ptr_as_arr.c b/tools/testing/selftests/bpf/progs/test_core_reloc_ptr_as_arr.c
index 27f602f00419..d1eb59d4ea64 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_ptr_as_arr.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_ptr_as_arr.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_ptr_as_arr {
int a;
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_size.c b/tools/testing/selftests/bpf/progs/test_core_reloc_size.c
index 9a92998d9107..9e091124d3bd 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_size.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_size.c
@@ -8,10 +8,10 @@
char _license[] SEC("license") = "GPL";
-static volatile struct data {
+struct {
char in[256];
char out[256];
-} data;
+} data = {};
struct core_reloc_size_output {
int int_sz;
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH bpf-next 0/4] Support global variables
2019-11-21 7:07 [PATCH bpf-next 0/4] Support global variables Andrii Nakryiko
` (3 preceding siblings ...)
2019-11-21 7:07 ` [PATCH bpf-next 4/4] libbpf: support initialized global variables Andrii Nakryiko
@ 2019-11-21 17:18 ` Alexei Starovoitov
4 siblings, 0 replies; 6+ messages in thread
From: Alexei Starovoitov @ 2019-11-21 17:18 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: bpf, Network Development, Alexei Starovoitov, Daniel Borkmann,
Andrii Nakryiko, Kernel Team
On Wed, Nov 20, 2019 at 11:08 PM Andrii Nakryiko <andriin@fb.com> wrote:
>
> This patch set salvages all the non-extern-specific changes out of blocked
> externs patch set ([0]). In addition to small clean ups, it also refactors
> libbpf's handling of relocations and allows support for global (non-static)
> variables.
Applied. Thanks
^ permalink raw reply [flat|nested] 6+ messages in thread