Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 213 insertions, 0 deletions

diff --git a/Documentation/bpf/drgn.rst b/Documentation/bpf/drgn.rst
new file mode 100644
index 000000000..41f223c31
--- /dev/null
+++ b/Documentation/bpf/drgn.rst
@@ -0,0 +1,213 @@
+.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+==============
+BPF drgn tools
+==============
+
+drgn scripts is a convenient and easy to use mechanism to retrieve arbitrary
+kernel data structures. drgn is not relying on kernel UAPI to read the data.
+Instead it's reading directly from ``/proc/kcore`` or vmcore and pretty prints
+the data based on DWARF debug information from vmlinux.
+
+This document describes BPF related drgn tools.
+
+See `drgn/tools`_ for all tools available at the moment and `drgn/doc`_ for
+more details on drgn itself.
+
+bpf_inspect.py
+--------------
+
+Description
+===========
+
+`bpf_inspect.py`_ is a tool intended to inspect BPF programs and maps. It can
+iterate over all programs and maps in the system and print basic information
+about these objects, including id, type and name.
+
+The main use-case `bpf_inspect.py`_ covers is to show BPF programs of types
+``BPF_PROG_TYPE_EXT`` and ``BPF_PROG_TYPE_TRACING`` attached to other BPF
+programs via ``freplace``/``fentry``/``fexit`` mechanisms, since there is no
+user-space API to get this information.
+
+Getting started
+===============
+
+List BPF programs (full names are obtained from BTF)::
+
+    % sudo bpf_inspect.py prog
+        27: BPF_PROG_TYPE_TRACEPOINT         tracepoint__tcp__tcp_send_reset
+      4632: BPF_PROG_TYPE_CGROUP_SOCK_ADDR   tw_ipt_bind
+     49464: BPF_PROG_TYPE_RAW_TRACEPOINT     raw_tracepoint__sched_process_exit
+
+List BPF maps::
+
+      % sudo bpf_inspect.py map
+        2577: BPF_MAP_TYPE_HASH                tw_ipt_vips
+        4050: BPF_MAP_TYPE_STACK_TRACE         stack_traces
+        4069: BPF_MAP_TYPE_PERCPU_ARRAY        ned_dctcp_cntr
+
+Find BPF programs attached to BPF program ``test_pkt_access``::
+
+      % sudo bpf_inspect.py p | grep test_pkt_access
+         650: BPF_PROG_TYPE_SCHED_CLS          test_pkt_access
+         654: BPF_PROG_TYPE_TRACING            test_main                        linked:[650->25: BPF_TRAMP_FEXIT test_pkt_access->test_pkt_access()]
+         655: BPF_PROG_TYPE_TRACING            test_subprog1                    linked:[650->29: BPF_TRAMP_FEXIT test_pkt_access->test_pkt_access_subprog1()]
+         656: BPF_PROG_TYPE_TRACING            test_subprog2                    linked:[650->31: BPF_TRAMP_FEXIT test_pkt_access->test_pkt_access_subprog2()]
+         657: BPF_PROG_TYPE_TRACING            test_subprog3                    linked:[650->21: BPF_TRAMP_FEXIT test_pkt_access->test_pkt_access_subprog3()]
+         658: BPF_PROG_TYPE_EXT                new_get_skb_len                  linked:[650->16: BPF_TRAMP_REPLACE test_pkt_access->get_skb_len()]
+         659: BPF_PROG_TYPE_EXT                new_get_skb_ifindex              linked:[650->23: BPF_TRAMP_REPLACE test_pkt_access->get_skb_ifindex()]
+         660: BPF_PROG_TYPE_EXT                new_get_constant                 linked:[650->19: BPF_TRAMP_REPLACE test_pkt_access->get_constant()]
+
+It can be seen that there is a program ``test_pkt_access``, id 650 and there
+are multiple other tracing and ext programs attached to functions in
+``test_pkt_access``.
+
+For example the line::
+
+         658: BPF_PROG_TYPE_EXT                new_get_skb_len                  linked:[650->16: BPF_TRAMP_REPLACE test_pkt_access->get_skb_len()]
+
+, means that BPF program id 658, type ``BPF_PROG_TYPE_EXT``, name
+``new_get_skb_len`` replaces (``BPF_TRAMP_REPLACE``) function ``get_skb_len()``
+that has BTF id 16 in BPF program id 650, name ``test_pkt_access``.
+
+Getting help:
+
+.. code-block:: none
+
+    % sudo bpf_inspect.py
+    usage: bpf_inspect.py [-h] {prog,p,map,m} ...
+
+    drgn script to list BPF programs or maps and their properties
+    unavailable via kernel API.
+
+    See https://github.com/osandov/drgn/ for more details on drgn.
+
+    optional arguments:
+      -h, --help      show this help message and exit
+
+    subcommands:
+      {prog,p,map,m}
+        prog (p)      list BPF programs
+        map (m)       list BPF maps
+
+Customization
+=============
+
+The script is intended to be customized by developers to print relevant
+information about BPF programs, maps and other objects.
+
+For example, to print ``struct bpf_prog_aux`` for BPF program id 53077:
+
+.. code-block:: none
+
+    % git diff
+    diff --git a/tools/bpf_inspect.py b/tools/bpf_inspect.py
+    index 650e228..aea2357 100755
+    --- a/tools/bpf_inspect.py
+    +++ b/tools/bpf_inspect.py
+    @@ -112,7 +112,9 @@ def list_bpf_progs(args):
+             if linked:
+                 linked = f" linked:[{linked}]"
+
+    -        print(f"{id_:>6}: {type_:32} {name:32} {linked}")
+    +        if id_ == 53077:
+    +            print(f"{id_:>6}: {type_:32} {name:32}")
+    +            print(f"{bpf_prog.aux}")
+
+
+     def list_bpf_maps(args):
+
+It produces the output::
+
+    % sudo bpf_inspect.py p
+     53077: BPF_PROG_TYPE_XDP                tw_xdp_policer
+    *(struct bpf_prog_aux *)0xffff8893fad4b400 = {
+            .refcnt = (atomic64_t){
+                    .counter = (long)58,
+            },
+            .used_map_cnt = (u32)1,
+            .max_ctx_offset = (u32)8,
+            .max_pkt_offset = (u32)15,
+            .max_tp_access = (u32)0,
+            .stack_depth = (u32)8,
+            .id = (u32)53077,
+            .func_cnt = (u32)0,
+            .func_idx = (u32)0,
+            .attach_btf_id = (u32)0,
+            .linked_prog = (struct bpf_prog *)0x0,
+            .verifier_zext = (bool)0,
+            .offload_requested = (bool)0,
+            .attach_btf_trace = (bool)0,
+            .func_proto_unreliable = (bool)0,
+            .trampoline_prog_type = (enum bpf_tramp_prog_type)BPF_TRAMP_FENTRY,
+            .trampoline = (struct bpf_trampoline *)0x0,
+            .tramp_hlist = (struct hlist_node){
+                    .next = (struct hlist_node *)0x0,
+                    .pprev = (struct hlist_node **)0x0,
+            },
+            .attach_func_proto = (const struct btf_type *)0x0,
+            .attach_func_name = (const char *)0x0,
+            .func = (struct bpf_prog **)0x0,
+            .jit_data = (void *)0x0,
+            .poke_tab = (struct bpf_jit_poke_descriptor *)0x0,
+            .size_poke_tab = (u32)0,
+            .ksym_tnode = (struct latch_tree_node){
+                    .node = (struct rb_node [2]){
+                            {
+                                    .__rb_parent_color = (unsigned long)18446612956263126665,
+                                    .rb_right = (struct rb_node *)0x0,
+                                    .rb_left = (struct rb_node *)0xffff88a0be3d0088,
+                            },
+                            {
+                                    .__rb_parent_color = (unsigned long)18446612956263126689,
+                                    .rb_right = (struct rb_node *)0x0,
+                                    .rb_left = (struct rb_node *)0xffff88a0be3d00a0,
+                            },
+                    },
+            },
+            .ksym_lnode = (struct list_head){
+                    .next = (struct list_head *)0xffff88bf481830b8,
+                    .prev = (struct list_head *)0xffff888309f536b8,
+            },
+            .ops = (const struct bpf_prog_ops *)xdp_prog_ops+0x0 = 0xffffffff820fa350,
+            .used_maps = (struct bpf_map **)0xffff889ff795de98,
+            .prog = (struct bpf_prog *)0xffffc9000cf2d000,
+            .user = (struct user_struct *)root_user+0x0 = 0xffffffff82444820,
+            .load_time = (u64)2408348759285319,
+            .cgroup_storage = (struct bpf_map *[2]){},
+            .name = (char [16])"tw_xdp_policer",
+            .security = (void *)0xffff889ff795d548,
+            .offload = (struct bpf_prog_offload *)0x0,
+            .btf = (struct btf *)0xffff8890ce6d0580,
+            .func_info = (struct bpf_func_info *)0xffff889ff795d240,
+            .func_info_aux = (struct bpf_func_info_aux *)0xffff889ff795de20,
+            .linfo = (struct bpf_line_info *)0xffff888a707afc00,
+            .jited_linfo = (void **)0xffff8893fad48600,
+            .func_info_cnt = (u32)1,
+            .nr_linfo = (u32)37,
+            .linfo_idx = (u32)0,
+            .num_exentries = (u32)0,
+            .extable = (struct exception_table_entry *)0xffffffffa032d950,
+            .stats = (struct bpf_prog_stats *)0x603fe3a1f6d0,
+            .work = (struct work_struct){
+                    .data = (atomic_long_t){
+                            .counter = (long)0,
+                    },
+                    .entry = (struct list_head){
+                            .next = (struct list_head *)0x0,
+                            .prev = (struct list_head *)0x0,
+                    },
+                    .func = (work_func_t)0x0,
+            },
+            .rcu = (struct callback_head){
+                    .next = (struct callback_head *)0x0,
+                    .func = (void (*)(struct callback_head *))0x0,
+            },
+    }
+
+
+.. Links
+.. _drgn/doc: https://drgn.readthedocs.io/en/latest/
+.. _drgn/tools: https://github.com/osandov/drgn/tree/master/tools
+.. _bpf_inspect.py:
+   https://github.com/osandov/drgn/blob/master/tools/bpf_inspect.py