Messages in this thread | | | Subject | Re: [PATCH 5/5] MIPS: Add support for eBPF JIT. | From | David Daney <> | Date | Fri, 26 May 2017 08:39:24 -0700 |
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On 05/26/2017 08:14 AM, Daniel Borkmann wrote: > On 05/26/2017 02:38 AM, David Daney wrote: >> Since the eBPF machine has 64-bit registers, we only support this in >> 64-bit kernels. As of the writing of this commit log test-bpf is >> showing: >> >> test_bpf: Summary: 316 PASSED, 0 FAILED, [308/308 JIT'ed] >> >> All current test cases are successfully compiled. >> >> Signed-off-by: David Daney <david.daney@cavium.com> > > Awesome work! > > Did you also manage to run tools/testing/selftests/bpf/ fine with > the JIT enabled?
I haven't done that yet, I will before the next revision.
> > [...] >> +struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) >> +{ >> + struct jit_ctx ctx; >> + unsigned int alloc_size; >> + >> + /* Only 64-bit kernel supports eBPF */ >> + if (!IS_ENABLED(CONFIG_64BIT) || !bpf_jit_enable) > > Isn't this already reflected by the following? > > select HAVE_EBPF_JIT if (64BIT && !CPU_MICROMIPS)
Not exactly. The eBPF JIT is in the same file as the classic-BPF JIT, so when HAVE_EBPF_JIT is false this will indeed never be called. But the kernel would otherwise contain all the JIT code.
By putting in !IS_ENABLED(CONFIG_64BIT) we allow gcc to eliminate all the dead code when compiling the JITs.
> >> + return prog; >> + >> + memset(&ctx, 0, sizeof(ctx)); >> + >> + ctx.offsets = kcalloc(prog->len + 1, sizeof(*ctx.offsets), >> GFP_KERNEL); >> + if (ctx.offsets == NULL) >> + goto out; >> + >> + ctx.reg_val_types = kcalloc(prog->len + 1, >> sizeof(*ctx.reg_val_types), GFP_KERNEL); >> + if (ctx.reg_val_types == NULL) >> + goto out; >> + >> + ctx.skf = prog; >> + >> + if (reg_val_propagate(&ctx)) >> + goto out; >> + >> + /* First pass discovers used resources */ >> + if (build_int_body(&ctx)) >> + goto out; >> + >> + /* Second pass generates offsets */ >> + ctx.idx = 0; >> + if (gen_int_prologue(&ctx)) >> + goto out; >> + if (build_int_body(&ctx)) >> + goto out; >> + if (build_int_epilogue(&ctx)) >> + goto out; >> + >> + alloc_size = 4 * ctx.idx; >> + >> + ctx.target = module_alloc(alloc_size); > > You would need to use bpf_jit_binary_alloc() like all other > eBPF JITs do, otherwise kallsyms of the JITed progs would > break.
OK, I was just copying code from the classic-BPF JIT in the same file. I will fix this.
> >> + if (ctx.target == NULL) >> + goto out; >> + >> + /* Clean it */ >> + memset(ctx.target, 0, alloc_size); >> + >> + /* Third pass generates the code */ >> + ctx.idx = 0; >> + if (gen_int_prologue(&ctx)) >> + goto out; >> + if (build_int_body(&ctx)) >> + goto out; >> + if (build_int_epilogue(&ctx)) >> + goto out; >> + /* Update the icache */ >> + flush_icache_range((ptr)ctx.target, (ptr)(ctx.target + ctx.idx)); >> + >> + if (bpf_jit_enable > 1) >> + /* Dump JIT code */ >> + bpf_jit_dump(prog->len, alloc_size, 2, ctx.target); >> + >> + prog->bpf_func = (void *)ctx.target; >> + prog->jited = 1; >> + >> +out: >> + kfree(ctx.offsets); >> + kfree(ctx.reg_val_types); >> + >> + return prog; >> +} >
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