Messages in this thread | | | Subject | Re: [PATCH v2] loongarch/bpf: Skip speculation barrier opcode, which caused ltp testcase bpf_prog02 to fail | From | Daniel Borkmann <> | Date | Tue, 28 Mar 2023 10:37:36 +0200 |
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On 3/28/23 9:52 AM, WANG Xuerui wrote: > On 2023/3/28 15:22, Daniel Borkmann wrote: >> On 3/28/23 9:13 AM, George Guo wrote: >>> Here just skip the opcode(BPF_ST | BPF_NOSPEC) that has no couterpart to the loongarch. >>> >>> <snip> >>> >>> diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c >>> index 288003a9f0ca..d3c6b1c4ccbb 100644 >>> --- a/arch/loongarch/net/bpf_jit.c >>> +++ b/arch/loongarch/net/bpf_jit.c >>> @@ -1022,6 +1022,11 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext >>> emit_atomic(insn, ctx); >>> break; >>> + /* Speculation barrier */ >>> + case BPF_ST | BPF_NOSPEC: >>> + pr_info_once("bpf_jit: skip speculation barrier opcode %0x2x\n", code); >>> + break; >> >> Thanks that looks better. Question to LoongArch folks (Cc): There is no equivalent >> to a speculation barrier here, correct? Either way, I think the pr_info_once() can >> just be removed given there is little value for a users to have this in the kernel >> log. I can take care of this while applying, that's fine. > > I can confirm there's currently no speculation barrier equivalent on lonogarch. (Loongson says there are builtin mitigations for Spectre-V1 and V2 on their chips, and AFAIK efforts to port the exploits to mips/loongarch have all failed a few years ago.) > > And yes I'd agree with removing the warning altogether. Thanks for the reviews! > > Acked-by: WANG Xuerui <git@xen0n.name>
Ok, sounds good. I've cleaned this up and applied to bpf tree. Thanks!
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=a6f6a95f25803500079513780d11a911ce551d76
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