Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2020-08-15

The following pull-request contains BPF updates for your *net* tree.

We've added 23 non-merge commits during the last 4 day(s) which contain
a total of 32 files changed, 421 insertions(+), 141 deletions(-).

The main changes are:

1) Fix sock_ops ctx access splat due to register override, from John Fastabend.

2) Batch of various fixes to libbpf, bpftool, and selftests when testing build
   in 32-bit mode, from Andrii Nakryiko.

3) Fix vmlinux.h generation on ARM by mapping GCC built-in types (__Poly*_t)
   to equivalent ones clang can work with, from Jean-Philippe Brucker.

4) Fix build_id lookup in bpf_get_stackid() helper by walking all NOTE ELF
   sections instead of just first, from Jiri Olsa.

5) Avoid use of __builtin_offsetof() in libbpf for CO-RE, from Yonghong Song.

6) Fix segfault in test_mmap due to inconsistent length params, from Jianlin Lv.

7) Don't override errno in libbpf when logging errors, from Toke Høiland-Jørgensen.

8) Fix v4_to_v6 sockaddr conversion in sk_lookup test, from Stanislav Fomichev.

9) Add link to bpf-helpers(7) man page to BPF doc, from Joe Stringer.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 143 insertions, 17 deletions

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index bc14db706b88..e9a4ecddb7a5 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -40,7 +40,7 @@
  * Helper macro to manipulate data structures
  */
 #ifndef offsetof
-#define offsetof(TYPE, MEMBER)  __builtin_offsetof(TYPE, MEMBER)
+#define offsetof(TYPE, MEMBER)	((unsigned long)&((TYPE *)0)->MEMBER)
 #endif
 #ifndef container_of
 #define container_of(ptr, type, member)				\
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 4843e44916f7..7dfca7016aaa 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -41,6 +41,7 @@ struct btf {
 	__u32 types_size;
 	__u32 data_size;
 	int fd;
+	int ptr_sz;
 };
 
 static inline __u64 ptr_to_u64(const void *ptr)
@@ -221,6 +222,70 @@ const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
 	return btf->types[type_id];
 }
 
+static int determine_ptr_size(const struct btf *btf)
+{
+	const struct btf_type *t;
+	const char *name;
+	int i;
+
+	for (i = 1; i <= btf->nr_types; i++) {
+		t = btf__type_by_id(btf, i);
+		if (!btf_is_int(t))
+			continue;
+
+		name = btf__name_by_offset(btf, t->name_off);
+		if (!name)
+			continue;
+
+		if (strcmp(name, "long int") == 0 ||
+		    strcmp(name, "long unsigned int") == 0) {
+			if (t->size != 4 && t->size != 8)
+				continue;
+			return t->size;
+		}
+	}
+
+	return -1;
+}
+
+static size_t btf_ptr_sz(const struct btf *btf)
+{
+	if (!btf->ptr_sz)
+		((struct btf *)btf)->ptr_sz = determine_ptr_size(btf);
+	return btf->ptr_sz < 0 ? sizeof(void *) : btf->ptr_sz;
+}
+
+/* Return pointer size this BTF instance assumes. The size is heuristically
+ * determined by looking for 'long' or 'unsigned long' integer type and
+ * recording its size in bytes. If BTF type information doesn't have any such
+ * type, this function returns 0. In the latter case, native architecture's
+ * pointer size is assumed, so will be either 4 or 8, depending on
+ * architecture that libbpf was compiled for. It's possible to override
+ * guessed value by using btf__set_pointer_size() API.
+ */
+size_t btf__pointer_size(const struct btf *btf)
+{
+	if (!btf->ptr_sz)
+		((struct btf *)btf)->ptr_sz = determine_ptr_size(btf);
+
+	if (btf->ptr_sz < 0)
+		/* not enough BTF type info to guess */
+		return 0;
+
+	return btf->ptr_sz;
+}
+
+/* Override or set pointer size in bytes. Only values of 4 and 8 are
+ * supported.
+ */
+int btf__set_pointer_size(struct btf *btf, size_t ptr_sz)
+{
+	if (ptr_sz != 4 && ptr_sz != 8)
+		return -EINVAL;
+	btf->ptr_sz = ptr_sz;
+	return 0;
+}
+
 static bool btf_type_is_void(const struct btf_type *t)
 {
 	return t == &btf_void || btf_is_fwd(t);
@@ -253,7 +318,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
 			size = t->size;
 			goto done;
 		case BTF_KIND_PTR:
-			size = sizeof(void *);
+			size = btf_ptr_sz(btf);
 			goto done;
 		case BTF_KIND_TYPEDEF:
 		case BTF_KIND_VOLATILE:
@@ -293,9 +358,9 @@ int btf__align_of(const struct btf *btf, __u32 id)
 	switch (kind) {
 	case BTF_KIND_INT:
 	case BTF_KIND_ENUM:
-		return min(sizeof(void *), (size_t)t->size);
+		return min(btf_ptr_sz(btf), (size_t)t->size);
 	case BTF_KIND_PTR:
-		return sizeof(void *);
+		return btf_ptr_sz(btf);
 	case BTF_KIND_TYPEDEF:
 	case BTF_KIND_VOLATILE:
 	case BTF_KIND_CONST:
@@ -533,6 +598,18 @@ struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext)
 	if (IS_ERR(btf))
 		goto done;
 
+	switch (gelf_getclass(elf)) {
+	case ELFCLASS32:
+		btf__set_pointer_size(btf, 4);
+		break;
+	case ELFCLASS64:
+		btf__set_pointer_size(btf, 8);
+		break;
+	default:
+		pr_warn("failed to get ELF class (bitness) for %s\n", path);
+		break;
+	}
+
 	if (btf_ext && btf_ext_data) {
 		*btf_ext = btf_ext__new(btf_ext_data->d_buf,
 					btf_ext_data->d_size);
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index f4a1a1d2b9a3..1ca14448df4c 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -76,6 +76,8 @@ LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf,
 LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
 						  __u32 id);
+LIBBPF_API size_t btf__pointer_size(const struct btf *btf);
+LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz);
 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
 LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id);
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index cf711168d34a..fe39bd774697 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -13,6 +13,7 @@
 #include <errno.h>
 #include <linux/err.h>
 #include <linux/btf.h>
+#include <linux/kernel.h>
 #include "btf.h"
 #include "hashmap.h"
 #include "libbpf.h"
@@ -60,6 +61,7 @@ struct btf_dump {
 	const struct btf_ext *btf_ext;
 	btf_dump_printf_fn_t printf_fn;
 	struct btf_dump_opts opts;
+	int ptr_sz;
 	bool strip_mods;
 
 	/* per-type auxiliary state */
@@ -138,6 +140,7 @@ struct btf_dump *btf_dump__new(const struct btf *btf,
 	d->btf_ext = btf_ext;
 	d->printf_fn = printf_fn;
 	d->opts.ctx = opts ? opts->ctx : NULL;
+	d->ptr_sz = btf__pointer_size(btf) ? : sizeof(void *);
 
 	d->type_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
 	if (IS_ERR(d->type_names)) {
@@ -549,6 +552,9 @@ static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr)
 	}
 }
 
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
+					  const struct btf_type *t);
+
 static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
 				     const struct btf_type *t);
 static void btf_dump_emit_struct_def(struct btf_dump *d, __u32 id,
@@ -671,6 +677,9 @@ static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
 
 	switch (kind) {
 	case BTF_KIND_INT:
+		/* Emit type alias definitions if necessary */
+		btf_dump_emit_missing_aliases(d, id, t);
+
 		tstate->emit_state = EMITTED;
 		break;
 	case BTF_KIND_ENUM:
@@ -797,7 +806,7 @@ static void btf_dump_emit_bit_padding(const struct btf_dump *d,
 				      int align, int lvl)
 {
 	int off_diff = m_off - cur_off;
-	int ptr_bits = sizeof(void *) * 8;
+	int ptr_bits = d->ptr_sz * 8;
 
 	if (off_diff <= 0)
 		/* no gap */
@@ -870,7 +879,7 @@ static void btf_dump_emit_struct_def(struct btf_dump *d,
 			btf_dump_printf(d, ": %d", m_sz);
 			off = m_off + m_sz;
 		} else {
-			m_sz = max(0, btf__resolve_size(d->btf, m->type));
+			m_sz = max(0LL, btf__resolve_size(d->btf, m->type));
 			off = m_off + m_sz * 8;
 		}
 		btf_dump_printf(d, ";");
@@ -890,6 +899,32 @@ static void btf_dump_emit_struct_def(struct btf_dump *d,
 		btf_dump_printf(d, " __attribute__((packed))");
 }
 
+static const char *missing_base_types[][2] = {
+	/*
+	 * GCC emits typedefs to its internal __PolyX_t types when compiling Arm
+	 * SIMD intrinsics. Alias them to standard base types.
+	 */
+	{ "__Poly8_t",		"unsigned char" },
+	{ "__Poly16_t",		"unsigned short" },
+	{ "__Poly64_t",		"unsigned long long" },
+	{ "__Poly128_t",	"unsigned __int128" },
+};
+
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
+					  const struct btf_type *t)
+{
+	const char *name = btf_dump_type_name(d, id);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(missing_base_types); i++) {
+		if (strcmp(name, missing_base_types[i][0]) == 0) {
+			btf_dump_printf(d, "typedef %s %s;\n\n",
+					missing_base_types[i][1], name);
+			break;
+		}
+	}
+}
+
 static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
 				   const struct btf_type *t)
 {
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0a06124f7999..5d20b2da4427 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2434,6 +2434,8 @@ static int bpf_object__init_btf(struct bpf_object *obj,
 				BTF_ELF_SEC, err);
 			goto out;
 		}
+		/* enforce 8-byte pointers for BPF-targeted BTFs */
+		btf__set_pointer_size(obj->btf, 8);
 		err = 0;
 	}
 	if (btf_ext_data) {
@@ -2542,6 +2544,8 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
 		if (IS_ERR(kern_btf))
 			return PTR_ERR(kern_btf);
 
+		/* enforce 8-byte pointers for BPF-targeted BTFs */
+		btf__set_pointer_size(obj->btf, 8);
 		bpf_object__sanitize_btf(obj, kern_btf);
 	}
 
@@ -3478,10 +3482,11 @@ bpf_object__probe_global_data(struct bpf_object *obj)
 
 	map = bpf_create_map_xattr(&map_attr);
 	if (map < 0) {
-		cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
+		ret = -errno;
+		cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
 		pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
-			__func__, cp, errno);
-		return -errno;
+			__func__, cp, -ret);
+		return ret;
 	}
 
 	insns[0].imm = map;
@@ -5194,7 +5199,8 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
 static int bpf_object__collect_map_relos(struct bpf_object *obj,
 					 GElf_Shdr *shdr, Elf_Data *data)
 {
-	int i, j, nrels, new_sz, ptr_sz = sizeof(void *);
+	const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *);
+	int i, j, nrels, new_sz;
 	const struct btf_var_secinfo *vi = NULL;
 	const struct btf_type *sec, *var, *def;
 	const struct btf_member *member;
@@ -5243,7 +5249,7 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj,
 
 			vi = btf_var_secinfos(sec) + map->btf_var_idx;
 			if (vi->offset <= rel.r_offset &&
-			    rel.r_offset + sizeof(void *) <= vi->offset + vi->size)
+			    rel.r_offset + bpf_ptr_sz <= vi->offset + vi->size)
 				break;
 		}
 		if (j == obj->nr_maps) {
@@ -5279,17 +5285,20 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj,
 			return -EINVAL;
 
 		moff = rel.r_offset - vi->offset - moff;
-		if (moff % ptr_sz)
+		/* here we use BPF pointer size, which is always 64 bit, as we
+		 * are parsing ELF that was built for BPF target
+		 */
+		if (moff % bpf_ptr_sz)
 			return -EINVAL;
-		moff /= ptr_sz;
+		moff /= bpf_ptr_sz;
 		if (moff >= map->init_slots_sz) {
 			new_sz = moff + 1;
-			tmp = realloc(map->init_slots, new_sz * ptr_sz);
+			tmp = realloc(map->init_slots, new_sz * host_ptr_sz);
 			if (!tmp)
 				return -ENOMEM;
 			map->init_slots = tmp;
 			memset(map->init_slots + map->init_slots_sz, 0,
-			       (new_sz - map->init_slots_sz) * ptr_sz);
+			       (new_sz - map->init_slots_sz) * host_ptr_sz);
 			map->init_slots_sz = new_sz;
 		}
 		map->init_slots[moff] = targ_map;
@@ -6012,9 +6021,10 @@ int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
 	}
 
 	if (bpf_obj_pin(prog->instances.fds[instance], path)) {
-		cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
+		err = -errno;
+		cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
 		pr_warn("failed to pin program: %s\n", cp);
-		return -errno;
+		return err;
 	}
 	pr_debug("pinned program '%s'\n", path);
 
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 0c4722bfdd0a..e35bd6cdbdbf 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -295,5 +295,7 @@ LIBBPF_0.1.0 {
 		bpf_program__set_sk_lookup;
 		btf__parse;
 		btf__parse_raw;
+		btf__pointer_size;
 		btf__set_fd;
+		btf__set_pointer_size;
 } LIBBPF_0.0.9;