20 Dec, 2016

3 commits

  • This function was declared in libbpf.c and was the only remaining
    function in this library, but has nothing to do with BPF. Shift it out
    into a new header, sock_example.h, and include it from the relevant
    samples.

    Signed-off-by: Joe Stringer
    Cc: Alexei Starovoitov
    Cc: Daniel Borkmann
    Cc: Wang Nan
    Link: http://lkml.kernel.org/r/20161209024620.31660-8-joe@ovn.org
    Signed-off-by: Arnaldo Carvalho de Melo

    Joe Stringer
     
  • Only one of the examples declare the bpf_insn bpf proggie as a const:

    $ grep 'struct bpf_insn [a-z]' samples/bpf/*.c
    samples/bpf/fds_example.c: static const struct bpf_insn insns[] = {
    samples/bpf/sock_example.c: struct bpf_insn prog[] = {
    samples/bpf/test_cgrp2_attach2.c: struct bpf_insn prog[] = {
    samples/bpf/test_cgrp2_attach.c: struct bpf_insn prog[] = {
    samples/bpf/test_cgrp2_sock.c: struct bpf_insn prog[] = {
    $

    Which causes this warning:

    [root@f5065a7d6272 linux]# make -j4 O=/tmp/build/linux samples/bpf/

    HOSTCC samples/bpf/fds_example.o
    /git/linux/samples/bpf/fds_example.c: In function 'bpf_prog_create':
    /git/linux/samples/bpf/fds_example.c:63:6: warning: passing argument 2 of 'bpf_load_program' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
    insns, insns_cnt, "GPL", 0,
    ^~~~~
    In file included from /git/linux/samples/bpf/libbpf.h:5:0,
    from /git/linux/samples/bpf/bpf_load.h:4,
    from /git/linux/samples/bpf/fds_example.c:15:
    /git/linux/tools/lib/bpf/bpf.h:31:5: note: expected 'struct bpf_insn *' but argument is of type 'const struct bpf_insn *'
    int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
    ^~~~~~~~~~~~~~~~
    HOSTCC samples/bpf/sockex1_user.o

    So just ditch that 'const' to reduce build noise, leaving changing the
    bpf_load_program() bpf_insn parameter to const to a later patch, if deemed
    adequate.

    Cc: Joe Stringer
    Cc: Alexei Starovoitov
    Cc: Daniel Borkmann
    Cc: Wang Nan
    Link: http://lkml.kernel.org/n/tip-1z5xee8n3oa66jf62bpv16ed@git.kernel.org
    Signed-off-by: Arnaldo Carvalho de Melo

    Arnaldo Carvalho de Melo
     
  • Now that libbpf under tools/lib/bpf/* is synced with the version from
    samples/bpf, we can get rid most of the libbpf library here.

    Committer notes:

    Built it in a docker fedora rawhide container and ran it in the f25 host, seems
    to work just like it did before this patch, i.e. the switch to tools/lib/bpf/
    doesn't seem to have introduced problems and Joe said he tested it with
    all the entries in samples/bpf/ and other code he found:

    [root@f5065a7d6272 linux]# make -j4 O=/tmp/build/linux headers_install

    [root@f5065a7d6272 linux]# rm -rf /tmp/build/linux/samples/bpf/
    [root@f5065a7d6272 linux]# make -j4 O=/tmp/build/linux samples/bpf/
    make[1]: Entering directory '/tmp/build/linux'
    CHK include/config/kernel.release
    HOSTCC scripts/basic/fixdep
    GEN ./Makefile
    CHK include/generated/uapi/linux/version.h
    Using /git/linux as source for kernel
    CHK include/generated/utsrelease.h
    HOSTCC scripts/basic/bin2c
    HOSTCC arch/x86/tools/relocs_32.o
    HOSTCC arch/x86/tools/relocs_64.o
    LD samples/bpf/built-in.o

    HOSTCC samples/bpf/fds_example.o
    HOSTCC samples/bpf/sockex1_user.o
    /git/linux/samples/bpf/fds_example.c: In function 'bpf_prog_create':
    /git/linux/samples/bpf/fds_example.c:63:6: warning: passing argument 2 of 'bpf_load_program' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
    insns, insns_cnt, "GPL", 0,
    ^~~~~
    In file included from /git/linux/samples/bpf/libbpf.h:5:0,
    from /git/linux/samples/bpf/bpf_load.h:4,
    from /git/linux/samples/bpf/fds_example.c:15:
    /git/linux/tools/lib/bpf/bpf.h:31:5: note: expected 'struct bpf_insn *' but argument is of type 'const struct bpf_insn *'
    int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
    ^~~~~~~~~~~~~~~~
    HOSTCC samples/bpf/sockex2_user.o

    HOSTCC samples/bpf/xdp_tx_iptunnel_user.o
    clang -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/6.2.1/include -I/git/linux/arch/x86/include -I./arch/x86/include/generated/uapi -I./arch/x86/include/generated -I/git/linux/include -I./include -I/git/linux/arch/x86/include/uapi -I/git/linux/include/uapi -I./include/generated/uapi -include /git/linux/include/linux/kconfig.h \
    -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \
    -Wno-compare-distinct-pointer-types \
    -Wno-gnu-variable-sized-type-not-at-end \
    -Wno-address-of-packed-member -Wno-tautological-compare \
    -O2 -emit-llvm -c /git/linux/samples/bpf/sockex1_kern.c -o -| llc -march=bpf -filetype=obj -o samples/bpf/sockex1_kern.o
    HOSTLD samples/bpf/tc_l2_redirect

    HOSTLD samples/bpf/lwt_len_hist
    HOSTLD samples/bpf/xdp_tx_iptunnel
    make[1]: Leaving directory '/tmp/build/linux'
    [root@f5065a7d6272 linux]#

    And then, in the host:

    [root@jouet bpf]# mount | grep "docker.*devicemapper\/"
    /dev/mapper/docker-253:0-1705076-9bd8aa1e0af33adce89ff42090847868ca676932878942be53941a06ec5923f9 on /var/lib/docker/devicemapper/mnt/9bd8aa1e0af33adce89ff42090847868ca676932878942be53941a06ec5923f9 type xfs (rw,relatime,context="system_u:object_r:container_file_t:s0:c73,c276",nouuid,attr2,inode64,sunit=1024,swidth=1024,noquota)
    [root@jouet bpf]# cd /var/lib/docker/devicemapper/mnt/9bd8aa1e0af33adce89ff42090847868ca676932878942be53941a06ec5923f9/rootfs/tmp/build/linux/samples/bpf/
    [root@jouet bpf]# file offwaketime
    offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=f423d171e0487b2f802b6a792657f0f3c8f6d155, not stripped
    [root@jouet bpf]# readelf -SW offwaketime
    offwaketime offwaketime_kern.o offwaketime_user.o
    [root@jouet bpf]# readelf -SW offwaketime_kern.o
    There are 11 section headers, starting at offset 0x700:

    Section Headers:
    [Nr] Name Type Address Off Size ES Flg Lk Inf Al
    [ 0] NULL 0000000000000000 000000 000000 00 0 0 0
    [ 1] .strtab STRTAB 0000000000000000 000658 0000a8 00 0 0 1
    [ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4
    [ 3] kprobe/try_to_wake_up PROGBITS 0000000000000000 000040 0000d8 00 AX 0 0 8
    [ 4] .relkprobe/try_to_wake_up REL 0000000000000000 0005a8 000020 10 10 3 8
    [ 5] tracepoint/sched/sched_switch PROGBITS 0000000000000000 000118 000318 00 AX 0 0 8
    [ 6] .reltracepoint/sched/sched_switch REL 0000000000000000 0005c8 000090 10 10 5 8
    [ 7] maps PROGBITS 0000000000000000 000430 000050 00 WA 0 0 4
    [ 8] license PROGBITS 0000000000000000 000480 000004 00 WA 0 0 1
    [ 9] version PROGBITS 0000000000000000 000484 000004 00 WA 0 0 4
    [10] .symtab SYMTAB 0000000000000000 000488 000120 18 1 4 8
    Key to Flags:
    W (write), A (alloc), X (execute), M (merge), S (strings)
    I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
    O (extra OS processing required) o (OS specific), p (processor specific)
    [root@jouet bpf]# ./offwaketime | head -3
    qemu-system-x86;entry_SYSCALL_64_fastpath;sys_ppoll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;hrtimer_wakeup;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;rest_init;start_kernel;x86_64_start_reservations;x86_64_start_kernel;start_cpu;;swapper/0 4
    firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 1
    swapper/2;start_cpu;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 61
    [root@jouet bpf]#

    Signed-off-by: Joe Stringer
    Tested-by: Arnaldo Carvalho de Melo
    Cc: Alexei Starovoitov
    Cc: Daniel Borkmann
    Cc: Wang Nan
    Cc: netdev@vger.kernel.org
    Link: https://github.com/joestringer/linux/commit/5c40f54a52b1f437123c81e21873f4b4b1f9bd55.patch
    Link: http://lkml.kernel.org/n/tip-xr8twtx7sjh5821g8qw47yxk@git.kernel.org
    [ Use -I$(srctree)/tools/lib/ to support out of source code tree builds, as noticed by Wang Nan ]
    Signed-off-by: Arnaldo Carvalho de Melo

    Joe Stringer
     

16 Dec, 2016

1 commit

  • Switch all of the sample code to use the function names from
    tools/lib/bpf so that they're consistent with that, and to declare their
    own log buffers. This allow the next commit to be purely devoted to
    getting rid of the duplicate library in samples/bpf.

    Committer notes:

    Testing it:

    On a fedora rawhide container, with clang/llvm 3.9, sharing the host
    linux kernel git tree:

    # make O=/tmp/build/linux/ headers_install
    # make O=/tmp/build/linux -C samples/bpf/

    Since I forgot to make it privileged, just tested it outside the
    container, using what it generated:

    # uname -a
    Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux
    # cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/
    # ls -la offwaketime
    -rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime
    # file offwaketime
    offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped
    # readelf -SW offwaketime_kern.o | grep PROGBITS
    [ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4
    [ 3] kprobe/try_to_wake_up PROGBITS 0000000000000000 000040 0000d8 00 AX 0 0 8
    [ 5] tracepoint/sched/sched_switch PROGBITS 0000000000000000 000118 000318 00 AX 0 0 8
    [ 7] maps PROGBITS 0000000000000000 000430 000050 00 WA 0 0 4
    [ 8] license PROGBITS 0000000000000000 000480 000004 00 WA 0 0 1
    [ 9] version PROGBITS 0000000000000000 000484 000004 00 WA 0 0 4
    # ./offwaketime | head -5
    swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106
    CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2
    Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5
    firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13
    JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2
    #

    Signed-off-by: Joe Stringer
    Tested-by: Arnaldo Carvalho de Melo
    Cc: Alexei Starovoitov
    Cc: Daniel Borkmann
    Cc: Wang Nan
    Cc: netdev@vger.kernel.org
    Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org
    Signed-off-by: Arnaldo Carvalho de Melo

    Joe Stringer
     

09 Mar, 2016

1 commit


03 Nov, 2015

1 commit

  • This patch adds a couple of stand-alone examples on how BPF_OBJ_PIN
    and BPF_OBJ_GET commands can be used.

    Example with maps:

    # ./fds_example -F /sys/fs/bpf/m -P -m -k 1 -v 42
    bpf: map fd:3 (Success)
    bpf: pin ret:(0,Success)
    bpf: fd:3 u->(1:42) ret:(0,Success)
    # ./fds_example -F /sys/fs/bpf/m -G -m -k 1
    bpf: get fd:3 (Success)
    bpf: fd:3 l->(1):42 ret:(0,Success)
    # ./fds_example -F /sys/fs/bpf/m -G -m -k 1 -v 24
    bpf: get fd:3 (Success)
    bpf: fd:3 u->(1:24) ret:(0,Success)
    # ./fds_example -F /sys/fs/bpf/m -G -m -k 1
    bpf: get fd:3 (Success)
    bpf: fd:3 l->(1):24 ret:(0,Success)

    # ./fds_example -F /sys/fs/bpf/m2 -P -m
    bpf: map fd:3 (Success)
    bpf: pin ret:(0,Success)
    # ./fds_example -F /sys/fs/bpf/m2 -G -m -k 1
    bpf: get fd:3 (Success)
    bpf: fd:3 l->(1):0 ret:(0,Success)
    # ./fds_example -F /sys/fs/bpf/m2 -G -m
    bpf: get fd:3 (Success)

    Example with progs:

    # ./fds_example -F /sys/fs/bpf/p -P -p
    bpf: prog fd:3 (Success)
    bpf: pin ret:(0,Success)
    bpf sock:4
    Acked-by: Alexei Starovoitov
    Signed-off-by: David S. Miller

    Daniel Borkmann