mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-17 01:04:19 +08:00
6bdacdb48e
Randy reported a randconfig build error recently on i386: ld: arch/x86/net/bpf_jit_comp32.o: in function `do_jit': bpf_jit_comp32.c:(.text+0x28c9): undefined reference to `__bpf_call_base' ld: arch/x86/net/bpf_jit_comp32.o: in function `bpf_int_jit_compile': bpf_jit_comp32.c:(.text+0x3694): undefined reference to `bpf_jit_blind_constants' ld: bpf_jit_comp32.c:(.text+0x3719): undefined reference to `bpf_jit_binary_free' ld: bpf_jit_comp32.c:(.text+0x3745): undefined reference to `bpf_jit_binary_alloc' ld: bpf_jit_comp32.c:(.text+0x37d3): undefined reference to `bpf_jit_prog_release_other' [...] The cause was thatb24abcff91("bpf, kconfig: Add consolidated menu entry for bpf with core options") moved BPF_JIT from net/Kconfig into kernel/bpf/Kconfig and previously BPF_JIT was guarded by a 'if NET'. However, there is no actual dependency on NET, it's just that menuconfig NET selects BPF. And the latter in turn causes kernel/bpf/core.o to be built which contains above symbols. Randy's randconfig didn't have NET set, and BPF wasn't either, but BPF_JIT otoh was. Detangle this by making BPF_JIT depend on BPF instead. arm64 was the only arch that pulled in its JIT in net/ via obj-$(CONFIG_NET), all others unconditionally pull this dir in via obj-y. Do the same since CONFIG_NET guard there is really useless as we compiled the JIT via obj-$(CONFIG_BPF_JIT) += bpf_jit_comp.o anyway. Fixes:b24abcff91("bpf, kconfig: Add consolidated menu entry for bpf with core options") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org>
90 lines
2.6 KiB
Plaintext
90 lines
2.6 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
|
|
|
|
# BPF interpreter that, for example, classic socket filters depend on.
|
|
config BPF
|
|
bool
|
|
|
|
# Used by archs to tell that they support BPF JIT compiler plus which
|
|
# flavour. Only one of the two can be selected for a specific arch since
|
|
# eBPF JIT supersedes the cBPF JIT.
|
|
|
|
# Classic BPF JIT (cBPF)
|
|
config HAVE_CBPF_JIT
|
|
bool
|
|
|
|
# Extended BPF JIT (eBPF)
|
|
config HAVE_EBPF_JIT
|
|
bool
|
|
|
|
# Used by archs to tell that they want the BPF JIT compiler enabled by
|
|
# default for kernels that were compiled with BPF JIT support.
|
|
config ARCH_WANT_DEFAULT_BPF_JIT
|
|
bool
|
|
|
|
menu "BPF subsystem"
|
|
|
|
config BPF_SYSCALL
|
|
bool "Enable bpf() system call"
|
|
select BPF
|
|
select IRQ_WORK
|
|
select TASKS_TRACE_RCU
|
|
select BINARY_PRINTF
|
|
select NET_SOCK_MSG if INET
|
|
default n
|
|
help
|
|
Enable the bpf() system call that allows to manipulate BPF programs
|
|
and maps via file descriptors.
|
|
|
|
config BPF_JIT
|
|
bool "Enable BPF Just In Time compiler"
|
|
depends on BPF
|
|
depends on HAVE_CBPF_JIT || HAVE_EBPF_JIT
|
|
depends on MODULES
|
|
help
|
|
BPF programs are normally handled by a BPF interpreter. This option
|
|
allows the kernel to generate native code when a program is loaded
|
|
into the kernel. This will significantly speed-up processing of BPF
|
|
programs.
|
|
|
|
Note, an admin should enable this feature changing:
|
|
/proc/sys/net/core/bpf_jit_enable
|
|
/proc/sys/net/core/bpf_jit_harden (optional)
|
|
/proc/sys/net/core/bpf_jit_kallsyms (optional)
|
|
|
|
config BPF_JIT_ALWAYS_ON
|
|
bool "Permanently enable BPF JIT and remove BPF interpreter"
|
|
depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
|
|
help
|
|
Enables BPF JIT and removes BPF interpreter to avoid speculative
|
|
execution of BPF instructions by the interpreter.
|
|
|
|
config BPF_JIT_DEFAULT_ON
|
|
def_bool ARCH_WANT_DEFAULT_BPF_JIT || BPF_JIT_ALWAYS_ON
|
|
depends on HAVE_EBPF_JIT && BPF_JIT
|
|
|
|
config BPF_UNPRIV_DEFAULT_OFF
|
|
bool "Disable unprivileged BPF by default"
|
|
depends on BPF_SYSCALL
|
|
help
|
|
Disables unprivileged BPF by default by setting the corresponding
|
|
/proc/sys/kernel/unprivileged_bpf_disabled knob to 2. An admin can
|
|
still reenable it by setting it to 0 later on, or permanently
|
|
disable it by setting it to 1 (from which no other transition to
|
|
0 is possible anymore).
|
|
|
|
source "kernel/bpf/preload/Kconfig"
|
|
|
|
config BPF_LSM
|
|
bool "Enable BPF LSM Instrumentation"
|
|
depends on BPF_EVENTS
|
|
depends on BPF_SYSCALL
|
|
depends on SECURITY
|
|
depends on BPF_JIT
|
|
help
|
|
Enables instrumentation of the security hooks with BPF programs for
|
|
implementing dynamic MAC and Audit Policies.
|
|
|
|
If you are unsure how to answer this question, answer N.
|
|
|
|
endmenu # "BPF subsystem"
|