On Wed, Jun 26, 2019 at 7:48 AM Matt Hart <matthew.hart@xxxxxxxxxx> wrote: > > Hi all, > > I noticed perf fails to build for armv7 on linux next, due to this > compile error: > $ make -C tools/perf ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- > > CC libbpf_probes.o > In file included from libbpf.c:27: > libbpf.c: In function ‘bpf_object__add_map’: > /home/matt/git/linux-next/tools/include/linux/kernel.h:45:17: error: > comparison of distinct pointer types lacks a cast [-Werror] > (void) (&_max1 == &_max2); \ > ^~ > libbpf.c:776:12: note: in expansion of macro ‘max’ > new_cap = max(4ul, obj->maps_cap * 3 / 2); > ^~~ > > So I bisected it and came down to this patch. > Commit bf82927125dd25003d76ed5541da704df21de57a > > Full verbose bisect script https://hastebin.com/odoyujofav.coffeescript > > Is this a case that perf code needs updating to match the change, or > is the change broken? Hi Matt, Thanks for reporting. This issue was already fixed in https://patchwork.ozlabs.org/patch/1122673/, so just pull latest bpf-next. > > > > On Tue, 25 Jun 2019 at 16:53, Andrii Nakryiko <andriin@xxxxxx> wrote: > > > > User and global data maps initialization has gotten pretty complicated > > and unnecessarily convoluted. This patch splits out the logic for global > > data map and user-defined map initialization. It also removes the > > restriction of pre-calculating how many maps will be initialized, > > instead allowing to keep adding new maps as they are discovered, which > > will be used later for BTF-defined map definitions. > > > > Signed-off-by: Andrii Nakryiko <andriin@xxxxxx> > > --- > > tools/lib/bpf/libbpf.c | 247 ++++++++++++++++++++++------------------- > > 1 file changed, 133 insertions(+), 114 deletions(-) > > > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > > index 7ee44d8877c5..88609dca4f7d 100644 > > --- a/tools/lib/bpf/libbpf.c > > +++ b/tools/lib/bpf/libbpf.c > > @@ -234,6 +234,7 @@ struct bpf_object { > > size_t nr_programs; > > struct bpf_map *maps; > > size_t nr_maps; > > + size_t maps_cap; > > struct bpf_secdata sections; > > > > bool loaded; > > @@ -763,21 +764,51 @@ int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, > > return -ENOENT; > > } > > > > -static bool bpf_object__has_maps(const struct bpf_object *obj) > > +static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) > > { > > - return obj->efile.maps_shndx >= 0 || > > - obj->efile.data_shndx >= 0 || > > - obj->efile.rodata_shndx >= 0 || > > - obj->efile.bss_shndx >= 0; > > + struct bpf_map *new_maps; > > + size_t new_cap; > > + int i; > > + > > + if (obj->nr_maps < obj->maps_cap) > > + return &obj->maps[obj->nr_maps++]; > > + > > + new_cap = max(4ul, obj->maps_cap * 3 / 2); > > + new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps)); > > + if (!new_maps) { > > + pr_warning("alloc maps for object failed\n"); > > + return ERR_PTR(-ENOMEM); > > + } > > + > > + obj->maps_cap = new_cap; > > + obj->maps = new_maps; > > + > > + /* zero out new maps */ > > + memset(obj->maps + obj->nr_maps, 0, > > + (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps)); > > + /* > > + * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin) > > + * when failure (zclose won't close negative fd)). > > + */ > > + for (i = obj->nr_maps; i < obj->maps_cap; i++) { > > + obj->maps[i].fd = -1; > > + obj->maps[i].inner_map_fd = -1; > > + } > > + > > + return &obj->maps[obj->nr_maps++]; > > } > > > > static int > > -bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map, > > - enum libbpf_map_type type, Elf_Data *data, > > - void **data_buff) > > +bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, > > + Elf_Data *data, void **data_buff) > > { > > - struct bpf_map_def *def = &map->def; > > char map_name[BPF_OBJ_NAME_LEN]; > > + struct bpf_map_def *def; > > + struct bpf_map *map; > > + > > + map = bpf_object__add_map(obj); > > + if (IS_ERR(map)) > > + return PTR_ERR(map); > > > > map->libbpf_type = type; > > map->offset = ~(typeof(map->offset))0; > > @@ -789,6 +820,7 @@ bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map, > > return -ENOMEM; > > } > > > > + def = &map->def; > > def->type = BPF_MAP_TYPE_ARRAY; > > def->key_size = sizeof(int); > > def->value_size = data->d_size; > > @@ -808,29 +840,58 @@ bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map, > > return 0; > > } > > > > -static int bpf_object__init_maps(struct bpf_object *obj, int flags) > > +static int bpf_object__init_global_data_maps(struct bpf_object *obj) > > +{ > > + int err; > > + > > + if (!obj->caps.global_data) > > + return 0; > > + /* > > + * Populate obj->maps with libbpf internal maps. > > + */ > > + if (obj->efile.data_shndx >= 0) { > > + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA, > > + obj->efile.data, > > + &obj->sections.data); > > + if (err) > > + return err; > > + } > > + if (obj->efile.rodata_shndx >= 0) { > > + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA, > > + obj->efile.rodata, > > + &obj->sections.rodata); > > + if (err) > > + return err; > > + } > > + if (obj->efile.bss_shndx >= 0) { > > + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, > > + obj->efile.bss, NULL); > > + if (err) > > + return err; > > + } > > + return 0; > > +} > > + > > +static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) > > { > > - int i, map_idx, map_def_sz = 0, nr_syms, nr_maps = 0, nr_maps_glob = 0; > > - bool strict = !(flags & MAPS_RELAX_COMPAT); > > Elf_Data *symbols = obj->efile.symbols; > > + int i, map_def_sz = 0, nr_maps = 0, nr_syms; > > Elf_Data *data = NULL; > > - int ret = 0; > > + Elf_Scn *scn; > > + > > + if (obj->efile.maps_shndx < 0) > > + return 0; > > > > if (!symbols) > > return -EINVAL; > > - nr_syms = symbols->d_size / sizeof(GElf_Sym); > > - > > - if (obj->efile.maps_shndx >= 0) { > > - Elf_Scn *scn = elf_getscn(obj->efile.elf, > > - obj->efile.maps_shndx); > > > > - if (scn) > > - data = elf_getdata(scn, NULL); > > - if (!scn || !data) { > > - pr_warning("failed to get Elf_Data from map section %d\n", > > - obj->efile.maps_shndx); > > - return -EINVAL; > > - } > > + scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx); > > + if (scn) > > + data = elf_getdata(scn, NULL); > > + if (!scn || !data) { > > + pr_warning("failed to get Elf_Data from map section %d\n", > > + obj->efile.maps_shndx); > > + return -EINVAL; > > } > > > > /* > > @@ -840,16 +901,8 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags) > > * > > * TODO: Detect array of map and report error. > > */ > > - if (obj->caps.global_data) { > > - if (obj->efile.data_shndx >= 0) > > - nr_maps_glob++; > > - if (obj->efile.rodata_shndx >= 0) > > - nr_maps_glob++; > > - if (obj->efile.bss_shndx >= 0) > > - nr_maps_glob++; > > - } > > - > > - for (i = 0; data && i < nr_syms; i++) { > > + nr_syms = symbols->d_size / sizeof(GElf_Sym); > > + for (i = 0; i < nr_syms; i++) { > > GElf_Sym sym; > > > > if (!gelf_getsym(symbols, i, &sym)) > > @@ -858,79 +911,56 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags) > > continue; > > nr_maps++; > > } > > - > > - if (!nr_maps && !nr_maps_glob) > > - return 0; > > - > > /* Assume equally sized map definitions */ > > - if (data) { > > - pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path, > > - nr_maps, data->d_size); > > - > > - map_def_sz = data->d_size / nr_maps; > > - if (!data->d_size || (data->d_size % nr_maps) != 0) { > > - pr_warning("unable to determine map definition size " > > - "section %s, %d maps in %zd bytes\n", > > - obj->path, nr_maps, data->d_size); > > - return -EINVAL; > > - } > > - } > > - > > - nr_maps += nr_maps_glob; > > - obj->maps = calloc(nr_maps, sizeof(obj->maps[0])); > > - if (!obj->maps) { > > - pr_warning("alloc maps for object failed\n"); > > - return -ENOMEM; > > - } > > - obj->nr_maps = nr_maps; > > - > > - for (i = 0; i < nr_maps; i++) { > > - /* > > - * fill all fd with -1 so won't close incorrect > > - * fd (fd=0 is stdin) when failure (zclose won't close > > - * negative fd)). > > - */ > > - obj->maps[i].fd = -1; > > - obj->maps[i].inner_map_fd = -1; > > + pr_debug("maps in %s: %d maps in %zd bytes\n", > > + obj->path, nr_maps, data->d_size); > > + > > + map_def_sz = data->d_size / nr_maps; > > + if (!data->d_size || (data->d_size % nr_maps) != 0) { > > + pr_warning("unable to determine map definition size " > > + "section %s, %d maps in %zd bytes\n", > > + obj->path, nr_maps, data->d_size); > > + return -EINVAL; > > } > > > > - /* > > - * Fill obj->maps using data in "maps" section. > > - */ > > - for (i = 0, map_idx = 0; data && i < nr_syms; i++) { > > + /* Fill obj->maps using data in "maps" section. */ > > + for (i = 0; i < nr_syms; i++) { > > GElf_Sym sym; > > const char *map_name; > > struct bpf_map_def *def; > > + struct bpf_map *map; > > > > if (!gelf_getsym(symbols, i, &sym)) > > continue; > > if (sym.st_shndx != obj->efile.maps_shndx) > > continue; > > > > - map_name = elf_strptr(obj->efile.elf, > > - obj->efile.strtabidx, > > + map = bpf_object__add_map(obj); > > + if (IS_ERR(map)) > > + return PTR_ERR(map); > > + > > + map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, > > sym.st_name); > > if (!map_name) { > > pr_warning("failed to get map #%d name sym string for obj %s\n", > > - map_idx, obj->path); > > + i, obj->path); > > return -LIBBPF_ERRNO__FORMAT; > > } > > > > - obj->maps[map_idx].libbpf_type = LIBBPF_MAP_UNSPEC; > > - obj->maps[map_idx].offset = sym.st_value; > > + map->libbpf_type = LIBBPF_MAP_UNSPEC; > > + map->offset = sym.st_value; > > if (sym.st_value + map_def_sz > data->d_size) { > > pr_warning("corrupted maps section in %s: last map \"%s\" too small\n", > > obj->path, map_name); > > return -EINVAL; > > } > > > > - obj->maps[map_idx].name = strdup(map_name); > > - if (!obj->maps[map_idx].name) { > > + map->name = strdup(map_name); > > + if (!map->name) { > > pr_warning("failed to alloc map name\n"); > > return -ENOMEM; > > } > > - pr_debug("map %d is \"%s\"\n", map_idx, > > - obj->maps[map_idx].name); > > + pr_debug("map %d is \"%s\"\n", i, map->name); > > def = (struct bpf_map_def *)(data->d_buf + sym.st_value); > > /* > > * If the definition of the map in the object file fits in > > @@ -939,7 +969,7 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags) > > * calloc above. > > */ > > if (map_def_sz <= sizeof(struct bpf_map_def)) { > > - memcpy(&obj->maps[map_idx].def, def, map_def_sz); > > + memcpy(&map->def, def, map_def_sz); > > } else { > > /* > > * Here the map structure being read is bigger than what > > @@ -959,37 +989,30 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags) > > return -EINVAL; > > } > > } > > - memcpy(&obj->maps[map_idx].def, def, > > - sizeof(struct bpf_map_def)); > > + memcpy(&map->def, def, sizeof(struct bpf_map_def)); > > } > > - map_idx++; > > } > > + return 0; > > +} > > > > - if (!obj->caps.global_data) > > - goto finalize; > > +static int bpf_object__init_maps(struct bpf_object *obj, int flags) > > +{ > > + bool strict = !(flags & MAPS_RELAX_COMPAT); > > + int err; > > > > - /* > > - * Populate rest of obj->maps with libbpf internal maps. > > - */ > > - if (obj->efile.data_shndx >= 0) > > - ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++], > > - LIBBPF_MAP_DATA, > > - obj->efile.data, > > - &obj->sections.data); > > - if (!ret && obj->efile.rodata_shndx >= 0) > > - ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++], > > - LIBBPF_MAP_RODATA, > > - obj->efile.rodata, > > - &obj->sections.rodata); > > - if (!ret && obj->efile.bss_shndx >= 0) > > - ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++], > > - LIBBPF_MAP_BSS, > > - obj->efile.bss, NULL); > > -finalize: > > - if (!ret) > > + err = bpf_object__init_user_maps(obj, strict); > > + if (err) > > + return err; > > + > > + err = bpf_object__init_global_data_maps(obj); > > + if (err) > > + return err; > > + > > + if (obj->nr_maps) { > > qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), > > compare_bpf_map); > > - return ret; > > + } > > + return 0; > > } > > > > static bool section_have_execinstr(struct bpf_object *obj, int idx) > > @@ -1262,14 +1285,10 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags) > > return -LIBBPF_ERRNO__FORMAT; > > } > > err = bpf_object__load_btf(obj, btf_data, btf_ext_data); > > - if (err) > > - return err; > > - if (bpf_object__has_maps(obj)) { > > + if (!err) > > err = bpf_object__init_maps(obj, flags); > > - if (err) > > - return err; > > - } > > - err = bpf_object__init_prog_names(obj); > > + if (!err) > > + err = bpf_object__init_prog_names(obj); > > return err; > > } > > > > -- > > 2.17.1 > >
