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authorLinus Torvalds2019-05-08 07:03:58 +0200
committerLinus Torvalds2019-05-08 07:03:58 +0200
commit80f232121b69cc69a31ccb2b38c1665d770b0710 (patch)
tree106263eac4ff03b899df695e00dd11e593e74fe2 /tools/bpf/bpftool/Documentation/bpftool-btf.rst
parentMerge tag 'devicetree-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/g... (diff)
parentMerge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net (diff)
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Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller: "Highlights: 1) Support AES128-CCM ciphers in kTLS, from Vakul Garg. 2) Add fib_sync_mem to control the amount of dirty memory we allow to queue up between synchronize RCU calls, from David Ahern. 3) Make flow classifier more lockless, from Vlad Buslov. 4) Add PHY downshift support to aquantia driver, from Heiner Kallweit. 5) Add SKB cache for TCP rx and tx, from Eric Dumazet. This reduces contention on SLAB spinlocks in heavy RPC workloads. 6) Partial GSO offload support in XFRM, from Boris Pismenny. 7) Add fast link down support to ethtool, from Heiner Kallweit. 8) Use siphash for IP ID generator, from Eric Dumazet. 9) Pull nexthops even further out from ipv4/ipv6 routes and FIB entries, from David Ahern. 10) Move skb->xmit_more into a per-cpu variable, from Florian Westphal. 11) Improve eBPF verifier speed and increase maximum program size, from Alexei Starovoitov. 12) Eliminate per-bucket spinlocks in rhashtable, and instead use bit spinlocks. From Neil Brown. 13) Allow tunneling with GUE encap in ipvs, from Jacky Hu. 14) Improve link partner cap detection in generic PHY code, from Heiner Kallweit. 15) Add layer 2 encap support to bpf_skb_adjust_room(), from Alan Maguire. 16) Remove SKB list implementation assumptions in SCTP, your's truly. 17) Various cleanups, optimizations, and simplifications in r8169 driver. From Heiner Kallweit. 18) Add memory accounting on TX and RX path of SCTP, from Xin Long. 19) Switch PHY drivers over to use dynamic featue detection, from Heiner Kallweit. 20) Support flow steering without masking in dpaa2-eth, from Ioana Ciocoi. 21) Implement ndo_get_devlink_port in netdevsim driver, from Jiri Pirko. 22) Increase the strict parsing of current and future netlink attributes, also export such policies to userspace. From Johannes Berg. 23) Allow DSA tag drivers to be modular, from Andrew Lunn. 24) Remove legacy DSA probing support, also from Andrew Lunn. 25) Allow ll_temac driver to be used on non-x86 platforms, from Esben Haabendal. 26) Add a generic tracepoint for TX queue timeouts to ease debugging, from Cong Wang. 27) More indirect call optimizations, from Paolo Abeni" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1763 commits) cxgb4: Fix error path in cxgb4_init_module net: phy: improve pause mode reporting in phy_print_status dt-bindings: net: Fix a typo in the phy-mode list for ethernet bindings net: macb: Change interrupt and napi enable order in open net: ll_temac: Improve error message on error IRQ net/sched: remove block pointer from common offload structure net: ethernet: support of_get_mac_address new ERR_PTR error net: usb: smsc: fix warning reported by kbuild test robot staging: octeon-ethernet: Fix of_get_mac_address ERR_PTR check net: dsa: support of_get_mac_address new ERR_PTR error net: dsa: sja1105: Fix status initialization in sja1105_get_ethtool_stats vrf: sit mtu should not be updated when vrf netdev is the link net: dsa: Fix error cleanup path in dsa_init_module l2tp: Fix possible NULL pointer dereference taprio: add null check on sched_nest to avoid potential null pointer dereference net: mvpp2: cls: fix less than zero check on a u32 variable net_sched: sch_fq: handle non connected flows net_sched: sch_fq: do not assume EDT packets are ordered net: hns3: use devm_kcalloc when allocating desc_cb net: hns3: some cleanup for struct hns3_enet_ring ...
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+================
+bpftool-btf
+================
+-------------------------------------------------------------------------------
+tool for inspection of BTF data
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+SYNOPSIS
+========
+
+ **bpftool** [*OPTIONS*] **btf** *COMMAND*
+
+ *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
+
+ *COMMANDS* := { **dump** | **help** }
+
+BTF COMMANDS
+=============
+
+| **bpftool** **btf dump** *BTF_SRC*
+| **bpftool** **btf help**
+|
+| *BTF_SRC* := { **id** *BTF_ID* | **prog** *PROG* | **map** *MAP* [{**key** | **value** | **kv** | **all**}] | **file** *FILE* }
+| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
+| *PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* }
+
+DESCRIPTION
+===========
+ **bpftool btf dump** *BTF_SRC*
+ Dump BTF entries from a given *BTF_SRC*.
+
+ When **id** is specified, BTF object with that ID will be
+ loaded and all its BTF types emitted.
+
+ When **map** is provided, it's expected that map has
+ associated BTF object with BTF types describing key and
+ value. It's possible to select whether to dump only BTF
+ type(s) associated with key (**key**), value (**value**),
+ both key and value (**kv**), or all BTF types present in
+ associated BTF object (**all**). If not specified, **kv**
+ is assumed.
+
+ When **prog** is provided, it's expected that program has
+ associated BTF object with BTF types.
+
+ When specifying *FILE*, an ELF file is expected, containing
+ .BTF section with well-defined BTF binary format data,
+ typically produced by clang or pahole.
+
+ **bpftool btf help**
+ Print short help message.
+
+OPTIONS
+=======
+ -h, --help
+ Print short generic help message (similar to **bpftool help**).
+
+ -V, --version
+ Print version number (similar to **bpftool version**).
+
+ -j, --json
+ Generate JSON output. For commands that cannot produce JSON, this
+ option has no effect.
+
+ -p, --pretty
+ Generate human-readable JSON output. Implies **-j**.
+
+EXAMPLES
+========
+**# bpftool btf dump id 1226**
+::
+
+ [1] PTR '(anon)' type_id=2
+ [2] STRUCT 'dummy_tracepoint_args' size=16 vlen=2
+ 'pad' type_id=3 bits_offset=0
+ 'sock' type_id=4 bits_offset=64
+ [3] INT 'long long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
+ [4] PTR '(anon)' type_id=5
+ [5] FWD 'sock' fwd_kind=union
+
+This gives an example of default output for all supported BTF kinds.
+
+**$ cat prog.c**
+::
+
+ struct fwd_struct;
+
+ enum my_enum {
+ VAL1 = 3,
+ VAL2 = 7,
+ };
+
+ typedef struct my_struct my_struct_t;
+
+ struct my_struct {
+ const unsigned int const_int_field;
+ int bitfield_field: 4;
+ char arr_field[16];
+ const struct fwd_struct *restrict fwd_field;
+ enum my_enum enum_field;
+ volatile my_struct_t *typedef_ptr_field;
+ };
+
+ union my_union {
+ int a;
+ struct my_struct b;
+ };
+
+ struct my_struct struct_global_var __attribute__((section("data_sec"))) = {
+ .bitfield_field = 3,
+ .enum_field = VAL1,
+ };
+ int global_var __attribute__((section("data_sec"))) = 7;
+
+ __attribute__((noinline))
+ int my_func(union my_union *arg1, int arg2)
+ {
+ static int static_var __attribute__((section("data_sec"))) = 123;
+ static_var++;
+ return static_var;
+ }
+
+**$ bpftool btf dump file prog.o**
+::
+
+ [1] PTR '(anon)' type_id=2
+ [2] UNION 'my_union' size=48 vlen=2
+ 'a' type_id=3 bits_offset=0
+ 'b' type_id=4 bits_offset=0
+ [3] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
+ [4] STRUCT 'my_struct' size=48 vlen=6
+ 'const_int_field' type_id=5 bits_offset=0
+ 'bitfield_field' type_id=3 bits_offset=32 bitfield_size=4
+ 'arr_field' type_id=8 bits_offset=40
+ 'fwd_field' type_id=10 bits_offset=192
+ 'enum_field' type_id=14 bits_offset=256
+ 'typedef_ptr_field' type_id=15 bits_offset=320
+ [5] CONST '(anon)' type_id=6
+ [6] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)
+ [7] INT 'char' size=1 bits_offset=0 nr_bits=8 encoding=SIGNED
+ [8] ARRAY '(anon)' type_id=7 index_type_id=9 nr_elems=16
+ [9] INT '__ARRAY_SIZE_TYPE__' size=4 bits_offset=0 nr_bits=32 encoding=(none)
+ [10] RESTRICT '(anon)' type_id=11
+ [11] PTR '(anon)' type_id=12
+ [12] CONST '(anon)' type_id=13
+ [13] FWD 'fwd_struct' fwd_kind=union
+ [14] ENUM 'my_enum' size=4 vlen=2
+ 'VAL1' val=3
+ 'VAL2' val=7
+ [15] PTR '(anon)' type_id=16
+ [16] VOLATILE '(anon)' type_id=17
+ [17] TYPEDEF 'my_struct_t' type_id=4
+ [18] FUNC_PROTO '(anon)' ret_type_id=3 vlen=2
+ 'arg1' type_id=1
+ 'arg2' type_id=3
+ [19] FUNC 'my_func' type_id=18
+ [20] VAR 'struct_global_var' type_id=4, linkage=global-alloc
+ [21] VAR 'global_var' type_id=3, linkage=global-alloc
+ [22] VAR 'my_func.static_var' type_id=3, linkage=static
+ [23] DATASEC 'data_sec' size=0 vlen=3
+ type_id=20 offset=0 size=48
+ type_id=21 offset=0 size=4
+ type_id=22 offset=52 size=4
+
+The following commands print BTF types associated with specified map's key,
+value, both key and value, and all BTF types, respectively. By default, both
+key and value types will be printed.
+
+**# bpftool btf dump map id 123 key**
+
+::
+
+ [39] TYPEDEF 'u32' type_id=37
+
+**# bpftool btf dump map id 123 value**
+
+::
+
+ [86] PTR '(anon)' type_id=87
+
+**# bpftool btf dump map id 123 kv**
+
+::
+
+ [39] TYPEDEF 'u32' type_id=37
+ [86] PTR '(anon)' type_id=87
+
+**# bpftool btf dump map id 123 all**
+
+::
+
+ [1] PTR '(anon)' type_id=0
+ .
+ .
+ .
+ [2866] ARRAY '(anon)' type_id=52 index_type_id=51 nr_elems=4
+
+All the standard ways to specify map or program are supported:
+
+**# bpftool btf dump map id 123**
+
+**# bpftool btf dump map pinned /sys/fs/bpf/map_name**
+
+**# bpftool btf dump prog id 456**
+
+**# bpftool btf dump prog tag b88e0a09b1d9759d**
+
+**# bpftool btf dump prog pinned /sys/fs/bpf/prog_name**
+
+SEE ALSO
+========
+ **bpf**\ (2),
+ **bpf-helpers**\ (7),
+ **bpftool**\ (8),
+ **bpftool-map**\ (8),
+ **bpftool-prog**\ (8),
+ **bpftool-cgroup**\ (8),
+ **bpftool-feature**\ (8),
+ **bpftool-net**\ (8),
+ **bpftool-perf**\ (8)