Daniel Borkmann bea9e2fd18 bpf: Introduce BPF nospec instruction for mitigating Spectre v4 ... [ Upstream commit f5e81d1117501546b7be050c5fbafa6efd2c722c ] In case of JITs, each of the JIT backends compiles the BPF nospec instruction /either/ to a machine instruction which emits a speculation barrier /or/ to /no/ machine instruction in case the underlying architecture is not affected by Speculative Store Bypass or has different mitigations in place already. This covers both x86 and (implicitly) arm64: In case of x86, we use 'lfence' instruction for mitigation. In case of arm64, we rely on the firmware mitigation as controlled via the ssbd kernel parameter. Whenever the mitigation is enabled, it works for all of the kernel code with no need to provide any additional instructions here (hence only comment in arm64 JIT). Other archs can follow as needed. The BPF nospec instruction is specifically targeting Spectre v4 since i) we don't use a serialization barrier for the Spectre v1 case, and ii) mitigation instructions for v1 and v4 might be different on some archs. The BPF nospec is required for a future commit, where the BPF verifier does annotate intermediate BPF programs with speculation barriers. Co-developed-by: Piotr Krysiuk <piotras@gmail.com> Co-developed-by: Benedict Schlueter <benedict.schlueter@rub.de> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Piotr Krysiuk <piotras@gmail.com> Signed-off-by: Benedict Schlueter <benedict.schlueter@rub.de> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-08-04 12:46:44 +02:00
..
boot	Revert "dts: phy: add GPIO number and active state used for phy reset"	2021-02-17 11:02:20 +01:00
configs	riscv: defconfig: enable gpio support for HiFive Unleashed	2021-01-27 11:55:01 +01:00
include	riscv: Workaround mcount name prior to clang-13	2021-05-22 11:40:53 +02:00
kernel	sched/core: Initialize the idle task with preemption disabled	2021-07-14 16:55:50 +02:00
lib	riscv: use memcpy based uaccess for nommu again	2020-10-04 10:27:07 -07:00
mm	riscv: Get rid of MAX_EARLY_MAPPING_SIZE	2021-03-07 12:34:05 +01:00
net	bpf: Introduce BPF nospec instruction for mitigating Spectre v4	2021-08-04 12:46:44 +02:00
Kbuild	riscv: Allow device trees to be built into the kernel	2020-05-18 11:38:05 -07:00
Kconfig	riscv: Fix spelling mistake "SPARSEMEM" to "SPARSMEM"	2021-04-21 13:00:55 +02:00
Kconfig.debug
Kconfig.socs	RISC-V: Remove CLINT related code from timer and arch	2020-08-20 10:58:13 -07:00
Makefile	riscv32: Use medany C model for modules	2021-06-30 08:47:21 -04:00