Merge branch 'bpf,x64: implement jump padding in jit'

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Gary Lin says:

====================
This patch series implements jump padding to x64 jit to cover some
corner cases that used to consume more than 20 jit passes and caused
failure.

v4:
  - Add the detailed comments about the possible padding bytes
  - Add the second test case which triggers jmp_cond padding and imm32 nop
    jmp padding.
  - Add the new test case as another subprog

v3:
  - Copy the instructions of prologue separately or the size calculation
    of the first BPF instruction would include the prologue.
  - Replace WARN_ONCE() with pr_err() and EFAULT
  - Use MAX_PASSES in the for loop condition check
  - Remove the "padded" flag from x64_jit_data. For the extra pass of
    subprogs, padding is always enabled since it won't hurt the images
    that converge without padding.
v2:
  - Simplify the sample code in the commit description and provide the
    jit code
  - Check the expected padding bytes with WARN_ONCE
  - Move the 'padded' flag to 'struct x64_jit_data'
  - Remove the EXPECTED_FAIL flag from bpf_fill_maxinsns11() in test_bpf
  - Add 2 verifier tests
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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This commit is contained in:

Alexei Starovoitov 2021-01-19 12:42:13 -08:00

parent d2e04b9dd6 79d1b684e2

commit 86e6b4e993

4 changed files with 209 additions and 34 deletions

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140

arch/x86/net/bpf_jit_comp.c

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7

lib/test_bpf.c

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72

tools/testing/selftests/bpf/test_verifier.c

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24

tools/testing/selftests/bpf/verifier/jit.c

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