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  1. 22 9月, 2022 3 次提交
    • D
      bpf: Add bpf_user_ringbuf_drain() helper · 20571567
      由 David Vernet 提交于 
      In a prior change, we added a new BPF_MAP_TYPE_USER_RINGBUF map type which
will allow user-space applications to publish messages to a ring buffer
that is consumed by a BPF program in kernel-space. In order for this
map-type to be useful, it will require a BPF helper function that BPF
programs can invoke to drain samples from the ring buffer, and invoke
callbacks on those samples. This change adds that capability via a new BPF
helper function:

bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx,
                       u64 flags)

BPF programs may invoke this function to run callback_fn() on a series of
samples in the ring buffer. callback_fn() has the following signature:

long callback_fn(struct bpf_dynptr *dynptr, void *context);

Samples are provided to the callback in the form of struct bpf_dynptr *'s,
which the program can read using BPF helper functions for querying
struct bpf_dynptr's.

In order to support bpf_ringbuf_drain(), a new PTR_TO_DYNPTR register
type is added to the verifier to reflect a dynptr that was allocated by
a helper function and passed to a BPF program. Unlike PTR_TO_STACK
dynptrs which are allocated on the stack by a BPF program, PTR_TO_DYNPTR
dynptrs need not use reference tracking, as the BPF helper is trusted to
properly free the dynptr before returning. The verifier currently only
supports PTR_TO_DYNPTR registers that are also DYNPTR_TYPE_LOCAL.

Note that while the corresponding user-space libbpf logic will be added
in a subsequent patch, this patch does contain an implementation of the
.map_poll() callback for BPF_MAP_TYPE_USER_RINGBUF maps. This
.map_poll() callback guarantees that an epoll-waiting user-space
producer will receive at least one event notification whenever at least
one sample is drained in an invocation of bpf_user_ringbuf_drain(),
provided that the function is not invoked with the BPF_RB_NO_WAKEUP
flag. If the BPF_RB_FORCE_WAKEUP flag is provided, a wakeup
notification is sent even if no sample was drained.
Signed-off-by: NDavid Vernet <void@manifault.com>
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-3-void@manifault.com
      20571567
    • D
      bpf: Define new BPF_MAP_TYPE_USER_RINGBUF map type · 583c1f42
      由 David Vernet 提交于 
      We want to support a ringbuf map type where samples are published from
user-space, to be consumed by BPF programs. BPF currently supports a
kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF
map type.  We'll need to define a new map type for user-space -> kernel,
as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply
to a user-space producer ring buffer, and we'll want to add one or
more helper functions that would not apply for a kernel-producer
ring buffer.

This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type
definition. The map type is useless in its current form, as there is no
way to access or use it for anything until we one or more BPF helpers. A
follow-on patch will therefore add a new helper function that allows BPF
programs to run callbacks on samples that are published to the ring
buffer.
Signed-off-by: NDavid Vernet <void@manifault.com>
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Acked-by: NAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com
      583c1f42
    • W
      bpf: simplify code in btf_parse_hdr · 3a74904c
      由 William Dean 提交于 
      It could directly return 'btf_check_sec_info' to simplify code.
Signed-off-by: NWilliam Dean <williamsukatube@163.com>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220917084248.3649-1-williamsukatube@163.comSigned-off-by: NMartin KaFai Lau <martin.lau@kernel.org>
      3a74904c
  3. 21 9月, 2022 6 次提交
  5. 20 9月, 2022 2 次提交
  7. 17 9月, 2022 9 次提交
  9. 15 9月, 2022 1 次提交
    • D
      bpf: Add verifier check for BPF_PTR_POISON retval and arg · 47e34cb7
      由 Dave Marchevsky 提交于 
      BPF_PTR_POISON was added in commit c0a5a21c ("bpf: Allow storing
referenced kptr in map") to denote a bpf_func_proto btf_id which the
verifier will replace with a dynamically-determined btf_id at verification
time.

This patch adds verifier 'poison' functionality to BPF_PTR_POISON in
order to prepare for expanded use of the value to poison ret- and
arg-btf_id in ongoing work, namely rbtree and linked list patchsets
[0, 1]. Specifically, when the verifier checks helper calls, it assumes
that BPF_PTR_POISON'ed ret type will be replaced with a valid type before
- or in lieu of - the default ret_btf_id logic. Similarly for arg btf_id.

If poisoned btf_id reaches default handling block for either, consider
this a verifier internal error and fail verification. Otherwise a helper
w/ poisoned btf_id but no verifier logic replacing the type will cause a
crash as the invalid pointer is dereferenced.

Also move BPF_PTR_POISON to existing include/linux/posion.h header and
remove unnecessary shift.

  [0]: lore.kernel.org/bpf/20220830172759.4069786-1-davemarchevsky@fb.com
  [1]: lore.kernel.org/bpf/20220904204145.3089-1-memxor@gmail.com
Signed-off-by: NDave Marchevsky <davemarchevsky@fb.com>
Acked-by: NKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220912154544.1398199-1-davemarchevsky@fb.comSigned-off-by: NAlexei Starovoitov <ast@kernel.org>
      47e34cb7
  11. 11 9月, 2022 11 次提交
  13. 10 9月, 2022 4 次提交
  15. 09 9月, 2022 1 次提交
    • D
      libbpf: Remove gcc support for bpf_tail_call_static for now · 665f5d35
      由 Daniel Borkmann 提交于 
      This reverts commit 14e5ce79 ("libbpf: Add GCC support for
bpf_tail_call_static"). Reason is that gcc invented their own BPF asm
which is not conform with LLVM one, and going forward this would be
more painful to maintain here and in other areas of the library. Thus
remove it; ask to gcc folks is to align with LLVM one to use exact
same syntax.

Fixes: 14e5ce79 ("libbpf: Add GCC support for bpf_tail_call_static")
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Cc: James Hilliard <james.hilliard1@gmail.com>
Cc: Jose E. Marchesi <jose.marchesi@oracle.com>
      665f5d35
  17. 08 9月, 2022 3 次提交