Skip to content
  1. Mar 27, 2021
    • Martin KaFai Lau's avatar
      bpf: Support bpf program calling kernel function · e6ac2450
      Martin KaFai Lau authored 
      

This patch adds support to BPF verifier to allow bpf program calling
kernel function directly.

The use case included in this set is to allow bpf-tcp-cc to directly
call some tcp-cc helper functions (e.g. "tcp_cong_avoid_ai()").  Those
functions have already been used by some kernel tcp-cc implementations.

This set will also allow the bpf-tcp-cc program to directly call the
kernel tcp-cc implementation,  For example, a bpf_dctcp may only want to
implement its own dctcp_cwnd_event() and reuse other dctcp_*() directly
from the kernel tcp_dctcp.c instead of reimplementing (or
copy-and-pasting) them.

The tcp-cc kernel functions mentioned above will be white listed
for the struct_ops bpf-tcp-cc programs to use in a later patch.
The white listed functions are not bounded to a fixed ABI contract.
Those functions have already been used by the existing kernel tcp-cc.
If any of them has changed, both in-tree and out-of-tree kernel tcp-cc
implementations have to be changed.  The same goes for the struct_ops
bpf-tcp-cc programs which have to be adjusted accordingly.

This patch is to make the required changes in the bpf verifier.

First change is in btf.c, it adds a case in "btf_check_func_arg_match()".
When the passed in "btf->kernel_btf == true", it means matching the
verifier regs' states with a kernel function.  This will handle the
PTR_TO_BTF_ID reg.  It also maps PTR_TO_SOCK_COMMON, PTR_TO_SOCKET,
and PTR_TO_TCP_SOCK to its kernel's btf_id.

In the later libbpf patch, the insn calling a kernel function will
look like:

insn->code == (BPF_JMP | BPF_CALL)
insn->src_reg == BPF_PSEUDO_KFUNC_CALL /* <- new in this patch */
insn->imm == func_btf_id /* btf_id of the running kernel */

[ For the future calling function-in-kernel-module support, an array
  of module btf_fds can be passed at the load time and insn->off
  can be used to index into this array. ]

At the early stage of verifier, the verifier will collect all kernel
function calls into "struct bpf_kfunc_desc".  Those
descriptors are stored in "prog->aux->kfunc_tab" and will
be available to the JIT.  Since this "add" operation is similar
to the current "add_subprog()" and looking for the same insn->code,
they are done together in the new "add_subprog_and_kfunc()".

In the "do_check()" stage, the new "check_kfunc_call()" is added
to verify the kernel function call instruction:
1. Ensure the kernel function can be used by a particular BPF_PROG_TYPE.
   A new bpf_verifier_ops "check_kfunc_call" is added to do that.
   The bpf-tcp-cc struct_ops program will implement this function in
   a later patch.
2. Call "btf_check_kfunc_args_match()" to ensure the regs can be
   used as the args of a kernel function.
3. Mark the regs' type, subreg_def, and zext_dst.

At the later do_misc_fixups() stage, the new fixup_kfunc_call()
will replace the insn->imm with the function address (relative
to __bpf_call_base).  If needed, the jit can find the btf_func_model
by calling the new bpf_jit_find_kfunc_model(prog, insn).
With the imm set to the function address, "bpftool prog dump xlated"
will be able to display the kernel function calls the same way as
it displays other bpf helper calls.

gpl_compatible program is required to call kernel function.

This feature currently requires JIT.

The verifier selftests are adjusted because of the changes in
the verbose log in add_subprog_and_kfunc().

Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com
      e6ac2450
    • Martin KaFai Lau's avatar
      bpf: Refactor btf_check_func_arg_match · 34747c41
      Martin KaFai Lau authored 
      

This patch moved the subprog specific logic from
btf_check_func_arg_match() to the new btf_check_subprog_arg_match().
The core logic is left in btf_check_func_arg_match() which
will be reused later to check the kernel function call.

The "if (!btf_type_is_ptr(t))" is checked first to improve the
indentation which will be useful for a later patch.

Some of the "btf_kind_str[]" usages is replaced with the shortcut
"btf_type_str(t)".

Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015136.1544504-1-kafai@fb.com
      34747c41
    • Martin KaFai Lau's avatar
      bpf: Simplify freeing logic in linfo and jited_linfo · e16301fb
      Martin KaFai Lau authored 
      

This patch simplifies the linfo freeing logic by combining
"bpf_prog_free_jited_linfo()" and "bpf_prog_free_unused_jited_linfo()"
into the new "bpf_prog_jit_attempt_done()".
It is a prep work for the kernel function call support.  In a later
patch, freeing the kernel function call descriptors will also
be done in the "bpf_prog_jit_attempt_done()".

"bpf_prog_free_linfo()" is removed since it is only called by
"__bpf_prog_put_noref()".  The kvfree() are directly called
instead.

It also takes this chance to s/kcalloc/kvcalloc/ for the jited_linfo
allocation.

Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015130.1544323-1-kafai@fb.com
      e16301fb
    • Andrii Nakryiko's avatar
      libbpf: Preserve empty DATASEC BTFs during static linking · 36e79851
      Andrii Nakryiko authored 
      Ensure that BPF static linker preserves all DATASEC BTF types, even if some of
them might not have any variable information at all. This may happen if the
compiler promotes local initialized variable contents into .rodata section and
there are no global or static functions in the program.

For example,

  $ cat t.c
  struct t { char a; char b; char c; };
  void bar(struct t*);
  void find() {
     struct t tmp = {1, 2, 3};
     bar(&tmp);
  }

  $ clang -target bpf -O2 -g -S t.c
         .long   104                             # BTF_KIND_DATASEC(id = 8)
         .long   251658240                       # 0xf000000
         .long   0

         .ascii  ".rodata"                       # string offset=104

  $ clang -target bpf -O2 -g -c t.c
  $ readelf -S t.o | grep data
     [ 4] .rodata           PROGBITS         0000000000000000  00000090

Fixes: 8fd27bf6

 ("libbpf: Add BPF static linker BTF and BTF.ext support")
Reported-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210326043036.3081011-1-andrii@kernel.org
      36e79851
    • Wan Jiabing's avatar
      bpf: struct sock is declared twice in bpf_sk_storage header · fcb8d0d7
      Wan Jiabing authored 
      

struct sock has been declared twice, therefore remove the duplicate.

Signed-off-by: default avatarWan Jiabing <wanjiabing@vivo.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210325070602.858024-1-wanjiabing@vivo.com
      fcb8d0d7
  3. Mar 26, 2021
  5. Mar 25, 2021
    • Potnuri Bharat Teja's avatar
      RDMA/cxgb4: Fix adapter LE hash errors while destroying ipv6 listening server · 3408be14
      Potnuri Bharat Teja authored 
      Not setting the ipv6 bit while destroying ipv6 listening servers may
result in potential fatal adapter errors due to lookup engine memory hash
errors. Therefore always set ipv6 field while destroying ipv6 listening
servers.

Fixes: 830662f6 ("RDMA/cxgb4: Add support for active and passive open connection with IPv6 address")
Link: https://lore.kernel.org/r/20210324190453.8171-1-bharat@chelsio.com


Signed-off-by: default avatarPotnuri Bharat Teja <bharat@chelsio.com>
Reviewed-by: default avatarLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
      3408be14
    • Rich Wiley's avatar
      arm64: kernel: disable CNP on Carmel · 20109a85
      Rich Wiley authored 
      

On NVIDIA Carmel cores, CNP behaves differently than it does on standard
ARM cores. On Carmel, if two cores have CNP enabled and share an L2 TLB
entry created by core0 for a specific ASID, a non-shareable TLBI from
core1 may still see the shared entry. On standard ARM cores, that TLBI
will invalidate the shared entry as well.

This causes issues with patchsets that attempt to do local TLBIs based
on cpumasks instead of broadcast TLBIs. Avoid these issues by disabling
CNP support for NVIDIA Carmel cores.

Signed-off-by: default avatarRich Wiley <rwiley@nvidia.com>
Link: https://lore.kernel.org/r/20210324002809.30271-1-rwiley@nvidia.com


[will: Fix pre-existing whitespace issue]
Signed-off-by: default avatarWill Deacon <will@kernel.org>
      20109a85
    • Maninder Singh's avatar
      arm64/process.c: fix Wmissing-prototypes build warnings · baa96377
      Maninder Singh authored 
      Fix GCC warnings reported when building with "-Wmissing-prototypes":

  arch/arm64/kernel/process.c:261:6: warning: no previous prototype for '__show_regs' [-Wmissing-prototypes]
      261 | void __show_regs(struct pt_regs *regs)
          |      ^~~~~~~~~~~
  arch/arm64/kernel/process.c:307:6: warning: no previous prototype for '__show_regs_alloc_free' [-Wmissing-prototypes]
      307 | void __show_regs_alloc_free(struct pt_regs *regs)
          |      ^~~~~~~~~~~~~~~~~~~~~~
  arch/arm64/kernel/process.c:365:5: warning: no previous prototype for 'arch_dup_task_struct' [-Wmissing-prototypes]
      365 | int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
          |     ^~~~~~~~~~~~~~~~~~~~
  arch/arm64/kernel/process.c:546:41: warning: no previous prototype for '__switch_to' [-Wmissing-prototypes]
      546 | __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
          |                                         ^~~~~~~~~~~
  arch/arm64/kernel/process.c:710:25: warning: no previous prototype for 'arm64_preempt_schedule_irq' [-Wmissing-prototypes]
      710 | asmlinkage void __sched arm64_preempt_schedule_irq(void)
          |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~

Link: https://lore.kernel.org/lkml/202103192250.AennsfXM-lkp@intel.com


Reported-by: default avatarkernel test robot <lkp@intel.com>
Signed-off-by: default avatarManinder Singh <maninder1.s@samsung.com>
Link: https://lore.kernel.org/r/1616568899-986-1-git-send-email-maninder1.s@samsung.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
      baa96377
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net · e1381380
      Linus Torvalds authored 
      Pull networking fixes from David Miller:
 "Various fixes, all over:

   1) Fix overflow in ptp_qoriq_adjfine(), from Yangbo Lu.

   2) Always store the rx queue mapping in veth, from Maciej
      Fijalkowski.

   3) Don't allow vmlinux btf in map_create, from Alexei Starovoitov.

   4) Fix memory leak in octeontx2-af from Colin Ian King.

   5) Use kvalloc in bpf x86 JIT for storing jit'd addresses, from
      Yonghong Song.

   6) Fix tx ptp stats in mlx5, from Aya Levin.

   7) Check correct ip version in tun decap, fropm Roi Dayan.

   8) Fix rate calculation in mlx5 E-Switch code, from arav Pandit.

   9) Work item memork leak in mlx5, from Shay Drory.

  10) Fix ip6ip6 tunnel crash with bpf, from Daniel Borkmann.

  11) Lack of preemptrion awareness in macvlan, from Eric Dumazet.

  12) Fix data race in pxa168_eth, from Pavel Andrianov.

  13) Range validate stab in red_check_params(), from Eric Dumazet.

  14) Inherit vlan filtering setting properly in b53 driver, from
      Florian Fainelli.

  15) Fix rtnl locking in igc driver, from Sasha Neftin.

  16) Pause handling fixes in igc driver, from Muhammad Husaini
      Zulkifli.

  17) Missing rtnl locking in e1000_reset_task, from Vitaly Lifshits.

  18) Use after free in qlcnic, from Lv Yunlong.

  19) fix crash in fritzpci mISDN, from Tong Zhang.

  20) Premature rx buffer reuse in igb, from Li RongQing.

  21) Missing termination of ip[a driver message handler arrays, from
      Alex Elder.

  22) Fix race between "x25_close" and "x25_xmit"/"x25_rx" in hdlc_x25
      driver, from Xie He.

  23) Use after free in c_can_pci_remove(), from Tong Zhang.

  24) Uninitialized variable use in nl80211, from Jarod Wilson.

  25) Off by one size calc in bpf verifier, from Piotr Krysiuk.

  26) Use delayed work instead of deferrable for flowtable GC, from
      Yinjun Zhang.

  27) Fix infinite loop in NPC unmap of octeontx2 driver, from
      Hariprasad Kelam.

  28) Fix being unable to change MTU of dwmac-sun8i devices due to lack
      of fifo sizes, from Corentin Labbe.

  29) DMA use after free in r8169 with WoL, fom Heiner Kallweit.

  30) Mismatched prototypes in isdn-capi, from Arnd Bergmann.

  31) Fix psample UAPI breakage, from Ido Schimmel"

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (171 commits)
  psample: Fix user API breakage
  math: Export mul_u64_u64_div_u64
  ch_ktls: fix enum-conversion warning
  octeontx2-af: Fix memory leak of object buf
  ptp_qoriq: fix overflow in ptp_qoriq_adjfine() u64 calcalation
  net: bridge: don't notify switchdev for local FDB addresses
  net/sched: act_ct: clear post_ct if doing ct_clear
  net: dsa: don't assign an error value to tag_ops
  isdn: capi: fix mismatched prototypes
  net/mlx5: SF, do not use ecpu bit for vhca state processing
  net/mlx5e: Fix division by 0 in mlx5e_select_queue
  net/mlx5e: Fix error path for ethtool set-priv-flag
  net/mlx5e: Offload tuple rewrite for non-CT flows
  net/mlx5e: Allow to match on MPLS parameters only for MPLS over UDP
  net/mlx5: Add back multicast stats for uplink representor
  net: ipconfig: ic_dev can be NULL in ic_close_devs
  MAINTAINERS: Combine "QLOGIC QLGE 10Gb ETHERNET DRIVER" sections into one
  docs: networking: Fix a typo
  r8169: fix DMA being used after buffer free if WoL is enabled
  net: ipa: fix init header command validation
  ...
      e1381380