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  1. 09 10月, 2021 12 次提交
  3. 08 10月, 2021 6 次提交
  5. 07 10月, 2021 16 次提交
  7. 06 10月, 2021 6 次提交
    • A
      selftests/bpf: Test new btf__add_btf() API · 9d057872
      由 Andrii Nakryiko 提交于 
      Add a test that validates that btf__add_btf() API is correctly copying
all the types from the source BTF into destination BTF object and
adjusts type IDs and string offsets properly.
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211006051107.17921-4-andrii@kernel.org
      9d057872
    • A
      selftests/bpf: Refactor btf_write selftest to reuse BTF generation logic · c65eb808
      由 Andrii Nakryiko 提交于 
      Next patch will need to reuse BTF generation logic, which tests every
supported BTF kind, for testing btf__add_btf() APIs. So restructure
existing selftests and make it as a single subtest that uses bulk
VALIDATE_RAW_BTF() macro for raw BTF dump checking.
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20211006051107.17921-3-andrii@kernel.org
      c65eb808
    • A
      libbpf: Add API that copies all BTF types from one BTF object to another · 7ca61121
      由 Andrii Nakryiko 提交于 
      Add a bulk copying api, btf__add_btf(), that speeds up and simplifies
appending entire contents of one BTF object to another one, taking care
of copying BTF type data, adjusting resulting BTF type IDs according to
their new locations in the destination BTF object, as well as copying
and deduplicating all the referenced strings and updating all the string
offsets in new BTF types as appropriate.

This API is intended to be used from tools that are generating and
otherwise manipulating BTFs generically, such as pahole. In pahole's
case, this API is useful for speeding up parallelized BTF encoding, as
it allows pahole to offload all the intricacies of BTF type copying to
libbpf and handle the parallelization aspects of the process.
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NSong Liu <songliubraving@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: https://lore.kernel.org/bpf/20211006051107.17921-2-andrii@kernel.org
      7ca61121
    • J
      bpf, x64: Save bytes for DIV by reducing reg copies · 57a610f1
      由 Jie Meng 提交于 
      Instead of unconditionally performing push/pop on %rax/%rdx in case of
division/modulo, we can save a few bytes in case of destination register
being either BPF r0 (%rax) or r3 (%rdx) since the result is written in
there anyway.

Also, we do not need to copy the source to %r11 unless the source is either
%rax, %rdx or an immediate.

For example, before the patch:

  22:   push   %rax
  23:   push   %rdx
  24:   mov    %rsi,%r11
  27:   xor    %edx,%edx
  29:   div    %r11
  2c:   mov    %rax,%r11
  2f:   pop    %rdx
  30:   pop    %rax
  31:   mov    %r11,%rax

After:

  22:   push   %rdx
  23:   xor    %edx,%edx
  25:   div    %rsi
  28:   pop    %rdx
Signed-off-by: NJie Meng <jmeng@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Tested-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211002035626.2041910-1-jmeng@fb.com
      57a610f1
    • A
      bpf: Avoid retpoline for bpf_for_each_map_elem · 0640c77c
      由 Andrey Ignatov 提交于 
      Similarly to 09772d92 ("bpf: avoid retpoline for
lookup/update/delete calls on maps") and 84430d42 ("bpf, verifier:
avoid retpoline for map push/pop/peek operation") avoid indirect call
while calling bpf_for_each_map_elem.

Before (a program fragment):

  ; if (rules_map) {
   142: (15) if r4 == 0x0 goto pc+8
   143: (bf) r3 = r10
  ; bpf_for_each_map_elem(rules_map, process_each_rule, &ctx, 0);
   144: (07) r3 += -24
   145: (bf) r1 = r4
   146: (18) r2 = subprog[+5]
   148: (b7) r4 = 0
   149: (85) call bpf_for_each_map_elem#143680  <-- indirect call via
                                                    helper

After (same program fragment):

   ; if (rules_map) {
    142: (15) if r4 == 0x0 goto pc+8
    143: (bf) r3 = r10
   ; bpf_for_each_map_elem(rules_map, process_each_rule, &ctx, 0);
    144: (07) r3 += -24
    145: (bf) r1 = r4
    146: (18) r2 = subprog[+5]
    148: (b7) r4 = 0
    149: (85) call bpf_for_each_array_elem#170336  <-- direct call

On a benchmark that calls bpf_for_each_map_elem() once and does many
other things (mostly checking fields in skb) with CONFIG_RETPOLINE=y it
makes program faster.

Before:

  ============================================================================
  Benchmark.cpp                                              time/iter iters/s
  ============================================================================
  IngressMatchByRemoteEndpoint                                80.78ns 12.38M
  IngressMatchByRemoteIP                                      80.66ns 12.40M
  IngressMatchByRemotePort                                    80.87ns 12.37M

After:

  ============================================================================
  Benchmark.cpp                                              time/iter iters/s
  ============================================================================
  IngressMatchByRemoteEndpoint                                73.49ns 13.61M
  IngressMatchByRemoteIP                                      71.48ns 13.99M
  IngressMatchByRemotePort                                    70.39ns 14.21M
Signed-off-by: NAndrey Ignatov <rdna@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211006001838.75607-1-rdna@fb.com
      0640c77c
    • A
      Merge branch 'Support kernel module function calls from eBPF' · 32a16f6b
      由 Alexei Starovoitov 提交于 
      Kumar Kartikeya says:

====================

This set enables kernel module function calls, and also modifies verifier logic
to permit invalid kernel function calls as long as they are pruned as part of
dead code elimination. This is done to provide better runtime portability for
BPF objects, which can conditionally disable parts of code that are pruned later
by the verifier (e.g. const volatile vars, kconfig options). libbpf
modifications are made along with kernel changes to support module function
calls.

It also converts TCP congestion control objects to use the module kfunc support
instead of relying on IS_BUILTIN ifdef.

Changelog:
----------
v6 -> v7
v6: https://lore.kernel.org/bpf/20210930062948.1843919-1-memxor@gmail.com

 * Let __bpf_check_kfunc_call take kfunc_btf_id_list instead of generating
   callbacks (Andrii)
 * Rename it to bpf_check_mod_kfunc_call to reflect usage
 * Remove OOM checks (Alexei)
 * Remove resolve_btfids invocation for bpf_testmod (Andrii)
 * Move fd_array_cnt initialization near fd_array alloc (Andrii)
 * Rename helper to btf_find_by_name_kind and pass start_id (Andrii)
 * memset when data is NULL in add_data (Alexei)
 * Fix other nits

v5 -> v6
v5: https://lore.kernel.org/bpf/20210927145941.1383001-1-memxor@gmail.com

 * Rework gen_loader relocation emits
   * Only emit bpf_btf_find_by_name_kind call when required (Alexei)
   * Refactor code to emit ksym var and func relo into separate helpers, this
     will be easier to add future weak/typeless ksym support to (for my followup)
   * Count references for both ksym var and funcs, and avoid calling helpers
     unless required for both of them. This also means we share fds between
     ksym vars for the module BTFs. Also be careful with this when closing
     BTF fd so that we only close one instance of the fd for each ksym

v4 -> v5
v4: https://lore.kernel.org/bpf/20210920141526.3940002-1-memxor@gmail.com

 * Address comments from Alexei
   * Use reserved fd_array area in loader map instead of creating a new map
   * Drop selftest testing the 256 kfunc limit, however selftest testing reuse
     of BTF fd for same kfunc in gen_loader and libbpf is kept
 * Address comments from Andrii
   * Make --no-fail the default for resolve_btfids, i.e. only fail if we find
     BTF section and cannot process it
   * Use obj->btf_modules array to store index in the fd_array, so that we don't
     have to do any searching to reuse the index, instead only set it the first
     time a module BTF's fd is used
   * Make find_ksym_btf_id to return struct module_btf * in last parameter
   * Improve logging when index becomes bigger than INT16_MAX
   * Add btf__find_by_name_kind_own internal helper to only start searching for
     kfunc ID in module BTF, since find_ksym_btf_id already checks vmlinux BTF
     before iterating over module BTFs.
   * Fix various other nits
 * Fixes for failing selftests on BPF CI
 * Rearrange/cleanup selftests
   * Avoid testing kfunc limit (Alexei)
   * Do test gen_loader and libbpf BTF fd index dedup with 256 calls
   * Move invalid kfunc failure test to verifier selftest
   * Minimize duplication
 * Use consistent bpf_<type>_check_kfunc_call naming for module kfunc callback
 * Since we try to add fd using add_data while we can, cherry pick Alexei's
   patch from CO-RE RFC series to align gen_loader data.

v3 -> v4
v3: https://lore.kernel.org/bpf/20210915050943.679062-1-memxor@gmail.com

 * Address comments from Alexei
   * Drop MAX_BPF_STACK change, instead move map_fd and BTF fd to BPF array map
     and pass fd_array using BPF_PSEUDO_MAP_IDX_VALUE
 * Address comments from Andrii
   * Fix selftest to store to variable for observing function call instead of
     printk and polluting CI logs
 * Drop use of raw_tp for testing, instead reuse classifier based prog_test_run
 * Drop index + 1 based insn->off convention for kfunc module calls
 * Expand selftests to cover more corner cases
 * Misc cleanups

v2 -> v3
v2: https://lore.kernel.org/bpf/20210914123750.460750-1-memxor@gmail.com

 * Fix issues pointed out by Kernel Test Robot
 * Fix find_kfunc_desc to also take offset into consideration when comparing

RFC v1 -> v2
v1: https://lore.kernel.org/bpf/20210830173424.1385796-1-memxor@gmail.com

 * Address comments from Alexei
   * Reuse fd_array instead of introducing kfunc_btf_fds array
   * Take btf and module reference as needed, instead of preloading
   * Add BTF_KIND_FUNC relocation support to gen_loader infrastructure
 * Address comments from Andrii
   * Drop hashmap in libbpf for finding index of existing BTF in fd_array
   * Preserve invalid kfunc calls only when the symbol is weak
 * Adjust verifier selftests
====================
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      32a16f6b