From: Alexei Starovoitov <ast@kernel.org>
Date: Tue, 19 Jan 2021 20:42:13 +0000 (-0800)
Subject: Merge branch 'bpf,x64: implement jump padding in jit'
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=86e6b4e993cf0c4dbe4c0ebfe052c89b9f9a2ade;p=linux.git

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

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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86e6b4e993cf0c4dbe4c0ebfe052c89b9f9a2ade