[bpf-next,v3,0/7] bpf trampoline for arm64

Message

Xu Kuohai April 24, 2022, 3:40 p.m. UTC

Add bpf trampoline support for arm64. Most of the logic is the same as
x86.

Tested on qemu, result:
 #18  bpf_tcp_ca:OK
 #51  dummy_st_ops:OK
 #55  fentry_fexit:OK
 #56  fentry_test:OK
 #57  fexit_bpf2bpf:OK
 #58  fexit_sleep:OK
 #59  fexit_stress:OK
 #60  fexit_test:OK
 #67  get_func_args_test:OK
 #68  get_func_ip_test:OK
 #101 modify_return:OK
 #233 xdp_bpf2bpf:OK

Also tested bpftrace kfunc/kretfunc and it worked fine. 

v3:
- Append test results for bpf_tcp_ca, dummy_st_ops, fexit_bpf2bpf,
  xdp_bpf2bpf
- Support to poke bpf progs
- Fix return value of arch_prepare_bpf_trampoline() to the total number
  of bytes instead of number of instructions 
- Do not check whether CONFIG_DYNAMIC_FTRACE_WITH_REGS is enabled in
  arch_prepare_bpf_trampoline, since the trampoline may be hooked to a bpf
  prog
- Restrict bpf_arch_text_poke() to poke bpf text only, as kernel functions
  are poked by ftrace
- Rewrite trace_direct_tramp() in inline assembly in trace_selftest.c
  to avoid messing entry-ftrace.S
- isolate arch_ftrace_set_direct_caller() with macro
  CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS to avoid compile error
  when this macro is disabled
- Some trivial code sytle fixes

v2: https://lore.kernel.org/bpf/[e-mail]/
- Add Song's ACK
- Change the multi-line comment in is_valid_bpf_tramp_flags() into net
  style (patch 3)
- Fix a deadloop issue in ftrace selftest (patch 2)
- Replace pt_regs->x0 with pt_regs->orig_x0 in patch 1 commit message 
- Replace "bpf trampoline" with "custom trampoline" in patch 1, as
  ftrace direct call is not only used by bpf trampoline.

v1: https://lore.kernel.org/bpf/[e-mail]/

Xu Kuohai (7):
  arm64: ftrace: Add ftrace direct call support
  ftrace: Fix deadloop caused by direct call in ftrace selftest
  bpf: Move is_valid_bpf_tramp_flags() to the public trampoline code
  bpf, arm64: Impelment bpf_arch_text_poke() for arm64
  bpf, arm64: Support to poke bpf prog
  bpf, arm64: bpf trampoline for arm64
  selftests/bpf: Fix trivial typo in fentry_fexit.c

 arch/arm64/Kconfig                            |   2 +
 arch/arm64/include/asm/ftrace.h               |  12 +
 arch/arm64/kernel/asm-offsets.c               |   1 +
 arch/arm64/kernel/entry-ftrace.S              |  18 +-
 arch/arm64/net/bpf_jit.h                      |   8 +
 arch/arm64/net/bpf_jit_comp.c                 | 446 +++++++++++++++++-
 arch/x86/net/bpf_jit_comp.c                   |  20 -
 include/linux/bpf.h                           |   5 +
 kernel/bpf/bpf_struct_ops.c                   |   4 +-
 kernel/bpf/trampoline.c                       |  34 +-
 kernel/trace/trace_selftest.c                 |  16 +
 .../selftests/bpf/prog_tests/fentry_fexit.c   |   4 +-
 12 files changed, 531 insertions(+), 39 deletions(-)