Merge branch 'support-global-data'

Daniel Borkmann says:

====================
This series is a major rework of previously submitted libbpf
patches [0] in order to add global data support for BPF. The
kernel has been extended to add proper infrastructure that allows
for full .bss/.data/.rodata sections on BPF loader side based
upon feedback from LPC discussions [1]. Latter support is then
also added into libbpf in this series which allows for more
natural C-like programming of BPF programs. For more information
on loader, please refer to 'bpf, libbpf: support global data/bss/
rodata sections' patch in this series.

Thanks a lot!

  v5 -> v6:
   - Removed synchronize_rcu() from map freeze (Jann)
   - Rest as-is
  v4 -> v5:
   - Removed index selection again for ldimm64 (Alexei)
   - Adapted related test cases and added new ones to test
     rejection of off != 0
  v3 -> v4:
   - Various fixes in BTF verification e.g. to disallow
     Var and DataSec to be an intermediate type during resolve (Martin)
   - More BTF test cases added
   - Few cleanups in key-less BTF commit (Martin)
   - Bump libbpf minor version from 2 to 3
   - Renamed and simplified read-only locking
   - Various minor improvements all over the place
  v2 -> v3:
   - Implement BTF support in kernel, libbpf, bpftool, add tests
   - Fix idx + off conversion (Andrii)
   - Document lower / higher bits for direct value access (Andrii)
   - Add tests with small value size (Andrii)
   - Add index selection into ldimm64 (Andrii)
   - Fix missing fdput() (Jann)
   - Reject invalid flags in BPF_F_*_PROG (Jakub)
   - Complete rework of libbpf support, includes:
    - Add objname to map name (Stanislav)
    - Make .rodata map full read-only after setup (Andrii)
    - Merge relocation handling into single one (Andrii)
    - Store global maps into obj->maps array (Andrii, Alexei)
    - Debug message when skipping section (Andrii)
    - Reject non-static global data till we have
      semantics for sharing them (Yonghong, Andrii, Alexei)
    - More test cases and completely reworked prog test (Alexei)
   - Fixes, cleanups, etc all over the set
   - Not yet addressed:
    - Make BTF mandatory for these maps (Alexei)
    -> Waiting till BTF support for these lands first
  v1 -> v2:
    - Instead of 32-bit static data, implement full global
      data support (Alexei)

  [0] https://patchwork.ozlabs.org/cover/1040290/
  [1] http://vger.kernel.org/lpc-bpf2018.html#session-3
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 59 insertions, 0 deletions

diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index e63bce0755eb..8cafb9b31467 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -309,6 +309,48 @@ static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
 	return ret;
 }
 
+static int btf_dumper_var(const struct btf_dumper *d, __u32 type_id,
+			  __u8 bit_offset, const void *data)
+{
+	const struct btf_type *t = btf__type_by_id(d->btf, type_id);
+	int ret;
+
+	jsonw_start_object(d->jw);
+	jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
+	ret = btf_dumper_do_type(d, t->type, bit_offset, data);
+	jsonw_end_object(d->jw);
+
+	return ret;
+}
+
+static int btf_dumper_datasec(const struct btf_dumper *d, __u32 type_id,
+			      const void *data)
+{
+	struct btf_var_secinfo *vsi;
+	const struct btf_type *t;
+	int ret = 0, i, vlen;
+
+	t = btf__type_by_id(d->btf, type_id);
+	if (!t)
+		return -EINVAL;
+
+	vlen = BTF_INFO_VLEN(t->info);
+	vsi = (struct btf_var_secinfo *)(t + 1);
+
+	jsonw_start_object(d->jw);
+	jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
+	jsonw_start_array(d->jw);
+	for (i = 0; i < vlen; i++) {
+		ret = btf_dumper_do_type(d, vsi[i].type, 0, data + vsi[i].offset);
+		if (ret)
+			break;
+	}
+	jsonw_end_array(d->jw);
+	jsonw_end_object(d->jw);
+
+	return ret;
+}
+
 static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
 			      __u8 bit_offset, const void *data)
 {
@@ -341,6 +383,10 @@ static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
 	case BTF_KIND_CONST:
 	case BTF_KIND_RESTRICT:
 		return btf_dumper_modifier(d, type_id, bit_offset, data);
+	case BTF_KIND_VAR:
+		return btf_dumper_var(d, type_id, bit_offset, data);
+	case BTF_KIND_DATASEC:
+		return btf_dumper_datasec(d, type_id, data);
 	default:
 		jsonw_printf(d->jw, "(unsupported-kind");
 		return -EINVAL;
@@ -377,6 +423,7 @@ static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
 {
 	const struct btf_type *proto_type;
 	const struct btf_array *array;
+	const struct btf_var *var;
 	const struct btf_type *t;
 
 	if (!type_id) {
@@ -440,6 +487,18 @@ static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
 		if (pos == -1)
 			return -1;
 		break;
+	case BTF_KIND_VAR:
+		var = (struct btf_var *)(t + 1);
+		if (var->linkage == BTF_VAR_STATIC)
+			BTF_PRINT_ARG("static ");
+		BTF_PRINT_TYPE(t->type);
+		BTF_PRINT_ARG(" %s",
+			      btf__name_by_offset(btf, t->name_off));
+		break;
+	case BTF_KIND_DATASEC:
+		BTF_PRINT_ARG("section (\"%s\") ",
+			      btf__name_by_offset(btf, t->name_off));
+		break;
 	case BTF_KIND_UNKN:
 	default:
 		return -1;