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

Xu Kuohai
2022-04-24T15:34:20Z

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/20220414162220.1985095-1-xukuohai@huawei.com/
- 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/20220413054959.1053668-1-xukuohai@huawei.com/

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(-)

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2.30.2