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Message-Id: <20210730215435.7095-7-quentin@isovalent.com>
Date: Fri, 30 Jul 2021 22:54:34 +0100
From: Quentin Monnet <quentin@...valent.com>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>
Cc: netdev@...r.kernel.org, bpf@...r.kernel.org,
Quentin Monnet <quentin@...valent.com>
Subject: [PATCH bpf-next v2 6/7] tools: bpftool: document and add bash completion for -L, -B options
The -L|--use-loader option for using loader programs when loading, or
when generating a skeleton, did not have any documentation or bash
completion. Same thing goes for -B|--base-btf, used to pass a path to a
base BTF object for split BTF such as BTF for kernel modules.
This patch documents and adds bash completion for those options.
Fixes: 75fa1777694c ("tools/bpftool: Add bpftool support for split BTF")
Fixes: d510296d331a ("bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command.")
Signed-off-by: Quentin Monnet <quentin@...valent.com>
---
.../bpf/bpftool/Documentation/bpftool-btf.rst | 48 ++++++++++++++++++-
.../bpf/bpftool/Documentation/bpftool-gen.rst | 9 +++-
.../bpftool/Documentation/bpftool-prog.rst | 30 +++++++++++-
tools/bpf/bpftool/bash-completion/bpftool | 8 ++--
tools/bpf/bpftool/btf.c | 3 +-
tools/bpf/bpftool/cgroup.c | 2 +-
tools/bpf/bpftool/gen.c | 3 +-
tools/bpf/bpftool/prog.c | 3 +-
8 files changed, 96 insertions(+), 10 deletions(-)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-btf.rst b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
index 1d37f3809842..88b28aa7431f 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-btf.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
@@ -12,7 +12,8 @@ SYNOPSIS
**bpftool** [*OPTIONS*] **btf** *COMMAND*
- *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | {**-d** | **--debug** } }
+ *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | {**-d** | **--debug** } |
+ { **-B** | **--base-btf** } }
*COMMANDS* := { **dump** | **help** }
@@ -73,6 +74,20 @@ OPTIONS
=======
.. include:: common_options.rst
+ -B, --base-btf *FILE*
+ Pass a base BTF object. Base BTF objects are typically used
+ with BTF objects for kernel modules. To avoid duplicating
+ all kernel symbols required by modules, BTF objects for
+ modules are "split", they are built incrementally on top of
+ the kernel (vmlinux) BTF object. So the base BTF reference
+ should usually point to the kernel BTF.
+
+ When the main BTF object to process (for example, the
+ module BTF to dump) is passed as a *FILE*, bpftool attempts
+ to autodetect the path for the base object, and passing
+ this option is optional. When the main BTF object is passed
+ through other handles, this option becomes necessary.
+
EXAMPLES
========
**# bpftool btf dump id 1226**
@@ -217,3 +232,34 @@ All the standard ways to specify map or program are supported:
**# bpftool btf dump prog tag b88e0a09b1d9759d**
**# bpftool btf dump prog pinned /sys/fs/bpf/prog_name**
+
+|
+| **# bpftool btf dump file /sys/kernel/btf/i2c_smbus**
+| (or)
+| **# I2C_SMBUS_ID=$(bpftool btf show -p | jq '.[] | select(.name=="i2c_smbus").id')**
+| **# bpftool btf dump id ${I2C_SMBUS_ID} -B /sys/kernel/btf/vmlinux**
+
+::
+
+ [104848] STRUCT 'i2c_smbus_alert' size=40 vlen=2
+ 'alert' type_id=393 bits_offset=0
+ 'ara' type_id=56050 bits_offset=256
+ [104849] STRUCT 'alert_data' size=12 vlen=3
+ 'addr' type_id=16 bits_offset=0
+ 'type' type_id=56053 bits_offset=32
+ 'data' type_id=7 bits_offset=64
+ [104850] PTR '(anon)' type_id=104848
+ [104851] PTR '(anon)' type_id=104849
+ [104852] FUNC 'i2c_register_spd' type_id=84745 linkage=static
+ [104853] FUNC 'smbalert_driver_init' type_id=1213 linkage=static
+ [104854] FUNC_PROTO '(anon)' ret_type_id=18 vlen=1
+ 'ara' type_id=56050
+ [104855] FUNC 'i2c_handle_smbus_alert' type_id=104854 linkage=static
+ [104856] FUNC 'smbalert_remove' type_id=104854 linkage=static
+ [104857] FUNC_PROTO '(anon)' ret_type_id=18 vlen=2
+ 'ara' type_id=56050
+ 'id' type_id=56056
+ [104858] FUNC 'smbalert_probe' type_id=104857 linkage=static
+ [104859] FUNC 'smbalert_work' type_id=9695 linkage=static
+ [104860] FUNC 'smbus_alert' type_id=71367 linkage=static
+ [104861] FUNC 'smbus_do_alert' type_id=84827 linkage=static
diff --git a/tools/bpf/bpftool/Documentation/bpftool-gen.rst b/tools/bpf/bpftool/Documentation/bpftool-gen.rst
index 709b93fe1da3..2ef2f2df0279 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-gen.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-gen.rst
@@ -12,7 +12,8 @@ SYNOPSIS
**bpftool** [*OPTIONS*] **gen** *COMMAND*
- *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } }
+ *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } |
+ { **-L** | **--use-loader** } }
*COMMAND* := { **object** | **skeleton** | **help** }
@@ -152,6 +153,12 @@ OPTIONS
=======
.. include:: common_options.rst
+ -L, --use-loader
+ For skeletons, generate a "light" skeleton (also known as "loader"
+ skeleton). A light skeleton contains a loader eBPF program. It does
+ not use the majority of the libbpf infrastructure, and does not need
+ libelf.
+
EXAMPLES
========
**$ cat example1.bpf.c**
diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index 4b8412fe2c60..2ea5df30ff21 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -13,7 +13,8 @@ SYNOPSIS
**bpftool** [*OPTIONS*] **prog** *COMMAND*
*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } |
- { **-f** | **--bpffs** } | { **-m** | **--mapcompat** } | { **-n** | **--nomount** } }
+ { **-f** | **--bpffs** } | { **-m** | **--mapcompat** } | { **-n** | **--nomount** } |
+ { **-L** | **--use-loader** } }
*COMMANDS* :=
{ **show** | **list** | **dump xlated** | **dump jited** | **pin** | **load**
@@ -224,6 +225,20 @@ OPTIONS
Do not automatically attempt to mount any virtual file system
(such as tracefs or BPF virtual file system) when necessary.
+ -L, --use-loader
+ Load program as a "loader" program. This is useful to debug
+ the generation of such programs. When this option is in
+ use, bpftool attempts to load the programs from the object
+ file into the kernel, but does not pin them (therefore, the
+ *PATH* must not be provided).
+
+ When combined with the **-d**\ \|\ **--debug** option,
+ additional debug messages are generated, and the execution
+ of the loader program will use the **bpf_trace_printk**\ ()
+ helper to log each step of loading BTF, creating the maps,
+ and loading the programs (see **bpftool prog tracelog** as
+ a way to dump those messages).
+
EXAMPLES
========
**# bpftool prog show**
@@ -327,3 +342,16 @@ EXAMPLES
40176203 cycles (83.05%)
42518139 instructions # 1.06 insns per cycle (83.39%)
123 llc_misses # 2.89 LLC misses per million insns (83.15%)
+
+|
+| Output below is for the trace logs.
+| Run in separate terminals:
+| **# bpftool prog tracelog**
+| **# bpftool prog load -L -d file.o**
+
+::
+
+ bpftool-620059 [004] d... 2634685.517903: bpf_trace_printk: btf_load size 665 r=5
+ bpftool-620059 [004] d... 2634685.517912: bpf_trace_printk: map_create sample_map idx 0 type 2 value_size 4 value_btf_id 0 r=6
+ bpftool-620059 [004] d... 2634685.517997: bpf_trace_printk: prog_load sample insn_cnt 13 r=7
+ bpftool-620059 [004] d... 2634685.517999: bpf_trace_printk: close(5) = 0
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index 1521a725f07c..134135424e7f 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -260,7 +260,8 @@ _bpftool()
# Deal with options
if [[ ${words[cword]} == -* ]]; then
- local c='--version --json --pretty --bpffs --mapcompat --debug'
+ local c='--version --json --pretty --bpffs --mapcompat --debug \
+ --use-loader --base-btf'
COMPREPLY=( $( compgen -W "$c" -- "$cur" ) )
return 0
fi
@@ -278,7 +279,7 @@ _bpftool()
_sysfs_get_netdevs
return 0
;;
- file|pinned)
+ file|pinned|-B|--base-btf)
_filedir
return 0
;;
@@ -291,7 +292,8 @@ _bpftool()
# Remove all options so completions don't have to deal with them.
local i
for (( i=1; i < ${#words[@]}; )); do
- if [[ ${words[i]::1} == - ]]; then
+ if [[ ${words[i]::1} == - ]] &&
+ [[ ${words[i]} != "-B" ]] && [[ ${words[i]} != "--base-btf" ]]; then
words=( "${words[@]:0:i}" "${words[@]:i+1}" )
[[ $i -le $cword ]] && cword=$(( cword - 1 ))
else
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 3c5fc9b25c30..f7e5ff3586c9 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -981,7 +981,8 @@ static int do_help(int argc, char **argv)
" FORMAT := { raw | c }\n"
" " HELP_SPEC_MAP "\n"
" " HELP_SPEC_PROGRAM "\n"
- " " HELP_SPEC_OPTIONS " }\n"
+ " " HELP_SPEC_OPTIONS " |\n"
+ " {-B|--base-btf} }\n"
"",
bin_name, "btf");
diff --git a/tools/bpf/bpftool/cgroup.c b/tools/bpf/bpftool/cgroup.c
index c42f437a1015..3571a281c43f 100644
--- a/tools/bpf/bpftool/cgroup.c
+++ b/tools/bpf/bpftool/cgroup.c
@@ -502,7 +502,7 @@ static int do_help(int argc, char **argv)
" " HELP_SPEC_ATTACH_FLAGS "\n"
" " HELP_SPEC_PROGRAM "\n"
" " HELP_SPEC_OPTIONS " |\n"
- " {-f|--bpffs} }
+ " {-f|--bpffs} }\n"
"",
bin_name, argv[-2]);
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index d4225f7fbcee..d40d92bbf0e4 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -1026,7 +1026,8 @@ static int do_help(int argc, char **argv)
" %1$s %2$s skeleton FILE [name OBJECT_NAME]\n"
" %1$s %2$s help\n"
"\n"
- " " HELP_SPEC_OPTIONS " }\n"
+ " " HELP_SPEC_OPTIONS " |\n"
+ " {-L|--use-loader} }\n"
"",
bin_name, "gen");
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index a205f7124b38..9c3e343b7d87 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -2260,7 +2260,8 @@ static int do_help(int argc, char **argv)
" stream_parser | flow_dissector }\n"
" METRIC := { cycles | instructions | l1d_loads | llc_misses | itlb_misses | dtlb_misses }\n"
" " HELP_SPEC_OPTIONS " |\n"
- " {-f|--bpffs} | {-m|--mapcompat} | {-n|--nomount} }\n"
+ " {-f|--bpffs} | {-m|--mapcompat} | {-n|--nomount} |\n"
+ " {-L|--use-loader} }\n"
"",
bin_name, argv[-2]);
--
2.30.2
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