From patchwork Fri Nov 15 19:48:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vadim Fedorenko X-Patchwork-Id: 13876736 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1A5491E2843 for ; Fri, 15 Nov 2024 19:49:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731700169; cv=none; b=VqK/5b6FZrwEBfXo8aQ1tIdLRG9aAM4E6L9HodTwSlPzr9ou/lTRLpdYqAdJS0awxkZ+RDLZ7obD2ufu+0ciCxYsz0o4C4pavI/8Jiq56mbao3KyYxKLIj/AUhDLykYmey7u4RiUcb5IJfcS4YSsZQfkPc3+fn76X60vnhaEdoI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731700169; c=relaxed/simple; bh=z55QMGHuyU79Lo0rgWIuj7M6h2JF0d6bWRj3SaLRuMc=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=q2YWxtn6lW3+zcC3uIXj5SgK8aDrYtRVV+yyyu21EKFnoU2HWc2E/KW+cTS076QzcOMDhwm14jxD+0l5sWCLATJwJba6nY1U6/U/QlEJlLGOqriESTnF2uPdOQc9jD+m/sxPys9DXnM4xJJqZFwrduO/0Dsr2VBu7KpqOIBS2+E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b=MHLFIh7k; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b="MHLFIh7k" Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4AFIVHoG001670; Fri, 15 Nov 2024 11:48:53 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=s2048-2021-q4; bh=2L+peR7S2VvIoHrnyDWB/FySR1z6OXVk418UFVTrmvs=; b=MHLFIh7k7kel W1LtLjFP3BeP3ZG5qZqdR+u3XOalMcCBj4FbR35dG0ypVbA12kI/YC0Qe6a2Eng1 cr0tzB4zCfLPZtXnwA+4KrXeBpnhdnfW8K8HMJKPWh5I4x+qL6OB7j4lYLDvsKeD 6jdEe3fANo4F42z7ytJIR4i4iMuMQl0VKG1xou2PkZ0fauNNLl0tqFBnbzPWG2uI VdjGQedUdzPdasUiVfET5nJz+as6tmcizUh2QbdWp2nMwK7XAI+AJdHzG1HVnpTi QFXPyzdK4DL/F3lUFJKtCuC2vgbCo63anxe1fh3DOQfnSrVcMnDMWGIwc4HbS1GU XJDH9+sPPg== Received: from maileast.thefacebook.com ([163.114.135.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 42x6cmk29d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Fri, 15 Nov 2024 11:48:53 -0800 (PST) Received: from devvm4158.cln0.facebook.com (2620:10d:c0a8:1b::2d) by mail.thefacebook.com (2620:10d:c0a9:6f::237c) with Microsoft SMTP Server id 15.2.1544.11; Fri, 15 Nov 2024 19:48:51 +0000 From: Vadim Fedorenko To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Thomas Gleixner , Vadim Fedorenko , Mykola Lysenko CC: , , Vadim Fedorenko , Martin KaFai Lau Subject: [PATCH bpf-next v6 2/4] bpf: add bpf_cpu_cycles_to_ns helper Date: Fri, 15 Nov 2024 11:48:39 -0800 Message-ID: <20241115194841.2108634-3-vadfed@meta.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20241115194841.2108634-1-vadfed@meta.com> References: <20241115194841.2108634-1-vadfed@meta.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-GUID: 7XoHtLBla1uH8yg5Uwk71iP3hZzi_H-p X-Proofpoint-ORIG-GUID: 7XoHtLBla1uH8yg5Uwk71iP3hZzi_H-p X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-05_03,2024-10-04_01,2024-09-30_01 X-Patchwork-Delegate: bpf@iogearbox.net The new helper should be used to convert cycles received by bpf_get_cpu_cycle() into nanoseconds. Reviewed-by: Eduard Zingerman Signed-off-by: Vadim Fedorenko --- v4 -> v6: * add comment about simplified implementation (Eduard) v4: * change helper name to bpf_cpu_cycles_to_ns. * hide it behind CONFIG_GENERIC_GETTIMEOFDAY to avoid exposing on unsupported architectures. --- arch/x86/net/bpf_jit_comp.c | 22 ++++++++++++++++++++++ arch/x86/net/bpf_jit_comp32.c | 19 +++++++++++++++++++ include/linux/bpf.h | 1 + kernel/bpf/helpers.c | 13 ++++++++++++- 4 files changed, 54 insertions(+), 1 deletion(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 107bd921f104..b87233d41a75 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -2216,6 +2217,24 @@ st: if (is_imm8(insn->off)) break; } + if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && + imm32 == BPF_CALL_IMM(bpf_cpu_cycles_to_ns) && + boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) { + u32 mult, shift; + + clocks_calc_mult_shift(&mult, &shift, tsc_khz, USEC_PER_SEC, 0); + /* imul RAX, RDI, mult */ + maybe_emit_mod(&prog, BPF_REG_1, BPF_REG_0, true); + EMIT2_off32(0x69, add_2reg(0xC0, BPF_REG_1, BPF_REG_0), + mult); + + /* shr RAX, shift (which is less than 64) */ + maybe_emit_1mod(&prog, BPF_REG_0, true); + EMIT3(0xC1, add_1reg(0xE8, BPF_REG_0), shift); + + break; + } + func = (u8 *) __bpf_call_base + imm32; if (src_reg == BPF_PSEUDO_CALL && tail_call_reachable) { LOAD_TAIL_CALL_CNT_PTR(stack_depth); @@ -3828,5 +3847,8 @@ bool bpf_jit_inlines_kfunc_call(s32 imm) { if (imm == BPF_CALL_IMM(bpf_get_cpu_cycles)) return true; + if (imm == BPF_CALL_IMM(bpf_cpu_cycles_to_ns) && + boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) + return true; return false; } diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c index e6097a371b69..34f762f28c82 100644 --- a/arch/x86/net/bpf_jit_comp32.c +++ b/arch/x86/net/bpf_jit_comp32.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -2100,6 +2101,24 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, EMIT2(0x0F, 0x31); break; } + if (imm32 == BPF_CALL_IMM(bpf_cpu_cycles_to_ns) && + boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) { + u32 mult, shift; + + clocks_calc_mult_shift(&mult, &shift, tsc_khz, + USEC_PER_SEC, 0); + + /* move parameter to BPF_REG_0 */ + emit_ia32_mov_r64(true, bpf2ia32[BPF_REG_0], + bpf2ia32[BPF_REG_1], true, true, + &prog, bpf_prog->aux); + /* multiply parameter by mut */ + emit_ia32_mul_i64(bpf2ia32[BPF_REG_0], + mult, true, &prog); + /* shift parameter by shift which is less than 64 */ + emit_ia32_rsh_i64(bpf2ia32[BPF_REG_0], + shift, true, &prog); + } err = emit_kfunc_call(bpf_prog, image + addrs[i], diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 43a5207a1591..af47704afeaa 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3336,6 +3336,7 @@ u64 bpf_get_raw_cpu_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); /* Inlined kfuncs */ #if IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) u64 bpf_get_cpu_cycles(void); +u64 bpf_cpu_cycles_to_ns(u64 cycles); #endif #if defined(CONFIG_NET) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 12d40537e57b..e89eff53c340 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3073,8 +3073,18 @@ __bpf_kfunc u64 bpf_get_cpu_cycles(void) */ return __arch_get_hw_counter(vd->clock_mode, vd); } -#endif +__bpf_kfunc u64 bpf_cpu_cycles_to_ns(u64 cycles) +{ + const struct vdso_data *vd = __arch_get_k_vdso_data(); + + /* kfunc implementation does less manipulations than vDSO + * implementation. BPF use-case assumes two measurements are close + * in time and can simplify the logic. + */ + return mul_u64_u32_shr(cycles, vd->mult, vd->shift); +} +#endif __bpf_kfunc_end_defs(); BTF_KFUNCS_START(generic_btf_ids) @@ -3169,6 +3179,7 @@ BTF_ID_FLAGS(func, bpf_iter_kmem_cache_next, KF_ITER_NEXT | KF_RET_NULL | KF_SLE BTF_ID_FLAGS(func, bpf_iter_kmem_cache_destroy, KF_ITER_DESTROY | KF_SLEEPABLE) #if IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) BTF_ID_FLAGS(func, bpf_get_cpu_cycles, KF_FASTCALL) +BTF_ID_FLAGS(func, bpf_cpu_cycles_to_ns, KF_FASTCALL) #endif BTF_KFUNCS_END(common_btf_ids)