gcc/doc/gcc/gcc-command-options/machine-dependent-options/ebpf-options.rst

   1 ..
   2   Copyright 1988-2022 Free Software Foundation, Inc.
   3   This is part of the GCC manual.
   4   For copying conditions, see the copyright.rst file.
   5
   6 .. program:: eBPF
   7
   8 .. index:: eBPF Options
   9
  10 .. _ebpf-options:
  11
  12 eBPF Options
  13 ^^^^^^^^^^^^
  14
  15 .. index:: eBPF Options
  16
  17 .. option:: -mframe-limit=bytes
  18
  19   This specifies the hard limit for frame sizes, in bytes.  Currently,
  20   the value that can be specified should be less than or equal to
  21   :samp:`32767`.  Defaults to whatever limit is imposed by the version of
  22   the Linux kernel targeted.
  23
  24 .. option:: -mkernel={version}
  25
  26   This specifies the minimum version of the kernel that will run the
  27   compiled program.  GCC uses this version to determine which
  28   instructions to use, what kernel helpers to allow, etc.  Currently,
  29   :samp:`{version}` can be one of :samp:`4.0`, :samp:`4.1`, :samp:`4.2`,
  30   :samp:`4.3`, :samp:`4.4`, :samp:`4.5`, :samp:`4.6`, :samp:`4.7`,
  31   :samp:`4.8`, :samp:`4.9`, :samp:`4.10`, :samp:`4.11`, :samp:`4.12`,
  32   :samp:`4.13`, :samp:`4.14`, :samp:`4.15`, :samp:`4.16`, :samp:`4.17`,
  33   :samp:`4.18`, :samp:`4.19`, :samp:`4.20`, :samp:`5.0`, :samp:`5.1`,
  34   :samp:`5.2`, :samp:`latest` and :samp:`native`.
  35
  36 .. option:: -mbig-endian
  37
  38   Generate code for a big-endian target.
  39
  40 .. option:: -mlittle-endian
  41
  42   Generate code for a little-endian target.  This is the default.
  43
  44 .. option:: -mjmpext
  45
  46   Enable generation of extra conditional-branch instructions.
  47   Enabled for CPU v2 and above.
  48
  49 .. option:: -mjmp32
  50
  51   Enable 32-bit jump instructions. Enabled for CPU v3 and above.
  52
  53 .. option:: -malu32
  54
  55   Enable 32-bit ALU instructions. Enabled for CPU v3 and above.
  56
  57 .. option:: -mcpu={version}
  58
  59   This specifies which version of the eBPF ISA to target. Newer versions
  60   may not be supported by all kernels. The default is :samp:`v3`.
  61
  62   Supported values for :samp:`{version}` are:
  63
  64   :samp:`v1`
  65     The first stable eBPF ISA with no special features or extensions.
  66
  67   :samp:`v2`
  68     Supports the jump extensions, as in :option:`-mjmpext`.
  69
  70   :samp:`v3`
  71     All features of v2, plus:
  72
  73     * 32-bit jump operations, as in :option:`-mjmp32`
  74
  75     * 32-bit ALU operations, as in :option:`-malu32`
  76
  77 .. option:: -mco-re
  78
  79   Enable BPF Compile Once - Run Everywhere (CO-RE) support. Requires and
  80   is implied by :option:`-gbtf`.
  81
  82 .. option:: -mno-co-re
  83
  84   Disable BPF Compile Once - Run Everywhere (CO-RE) support. BPF CO-RE
  85   support is enabled by default when generating BTF debug information for
  86   the BPF target.
  87
  88 .. option:: -mxbpf
  89
  90   Generate code for an expanded version of BPF, which relaxes some of
  91   the restrictions imposed by the BPF architecture:
  92
  93   * Save and restore callee-saved registers at function entry and
  94     exit, respectively.