docs/repo-layout.md

   1 Repository Layout
   2 =================
   3
   4 The following directory listing is *not* meant to be exhaustive.  Rather, it
   5 is intended to demonstrate the general organization.  Deviations should be
   6 avoided but are by no means forbidden.
   7
   8 ```
   9 arch                            - architecture/platform specific code
  10 arch/sparc                      - sparc architecture/platform specific code
  11 arch/x86                        - x86 architecture/platform specific code
  12 bin                             - commands (/bin /usr/bin)
  13 contrib                         - 3rd party code
  14 docs                            - documentation
  15 include                         - headers (/usr/include)
  16 kernel                          - all arch/plat independent kernel code
  17 kernel/comstar                  - ... COMSTAR
  18 kernel/cpr                      - ... suspend & resume
  19 kernel/disp                     - ... dispatcher
  20 kernel/drivers                  - ... drivers
  21 kernel/drivers/block            - ... block device drivers
  22 kernel/drivers/net              - ... NIC drivers
  23 kernel/drivers/net/bar          - ... the 'bar' NIC driver
  24 kernel/fs                       - ... file system code
  25 kernel/fs/ufs                   - ... UFS kernel code
  26 kernel/krtld                    - ... linker
  27 kernel/mk                       - kernel build makefiles
  28 kernel/net                      - ... network code
  29 kernel/os                       - ... kernel code
  30 kernel/sched                    - ... scheduler code
  31 kernel/syscall                  - ... syscall code
  32 kernel/vm                       - ... vm code
  33 lib                             - libraries
  34 share                           - misc files (/usr/share)
  35 tools                           - build tools
  36 ```
  37
  38 Architecture Subdirectories
  39 ---------------------------
  40
  41 In general, the structure of each subdirectory in `arch` mirrors the same
  42 layout as the top level.  That is, there are sub-subdirectories such as
  43 `include` and `kernel`.  In other words, the contents are:
  44
  45 ```
  46 arch/x86/bin                    - x86 specific commands
  47 arch/x86/include                - x86 specific headers
  48 arch/x86/kernel                 - x86 specific kernel code
  49 arch/x86/lib                    - x86 specific libs
  50 ```
  51
  52 In general, every effort should be made to avoid putting code in
  53 architecture specific directories.  That is, if a feature is in theory
  54 architecture independent, the code code should be put in the architecture
  55 independent directories.  If only some architectures are not fully
  56 supported, proper Sconfig based build-time guards should be used.
  57
  58 Example 1: a PCI device driver that hasn't been ported to sparc should live
  59 in `kernel/drivers` even though it only builds on x86 since PCI devices are
  60 standard between architectures.
  61
  62 Example 2: a CPU microcode updating driver should be placed in `arch/x86`
  63 since microcode update procedures are architecture specific.