linux/kernel/bpf/Kconfig
Mike Rapoport (IBM) 2c9e5d4a00 bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of
BPF just-in-time compiler depended on CONFIG_MODULES because it used
module_alloc() to allocate memory for the generated code.

Since code allocations are now implemented with execmem, drop dependency of
CONFIG_BPF_JIT on CONFIG_MODULES and make it select CONFIG_EXECMEM.

Suggested-by: Björn Töpel <bjorn@kernel.org>
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2024-05-14 00:36:29 -07:00

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# SPDX-License-Identifier: GPL-2.0-only
# BPF interpreter that, for example, classic socket filters depend on.
config BPF
bool
select CRYPTO_LIB_SHA1
# 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 NEED_TASKS_RCU
select TASKS_TRACE_RCU
select BINARY_PRINTF
select NET_SOCK_MSG if NET
select NET_XGRESS if NET
select PAGE_POOL if NET
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
select EXECMEM
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.
When CONFIG_BPF_JIT_ALWAYS_ON is enabled, /proc/sys/net/core/bpf_jit_enable
is permanently set to 1 and setting any other value than that will
return failure.
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"
default y
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).
Unprivileged BPF could be used to exploit certain potential
speculative execution side-channel vulnerabilities on unmitigated
affected hardware.
If you are unsure how to answer this question, answer Y.
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"