From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) (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 974BB25EFBA for ; Tue, 11 Mar 2025 15:49:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.153.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741708200; cv=none; b=eYYoTzI5M2pZzLEFwPDIgKHdUQhnEyH0lBhMv00QDytngi8eWSvxJZ6Yo7jbfabklrrYQaS9kRH4OH4RTmpejwyQqoPn3MxjIz4Lbr7DnsY7w6W8Yljvr3qnljagpdINAnOJbrfpWbanRnMcaKnDuX8J34/zK9deXthuYVXfio8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741708200; c=relaxed/simple; bh=fLKkkBXfBYpe2I7wvhJIWoPKOgMYDyTHaY2UoU0fpwc=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hC5Q3no8MinZKGVVsOwGGQW9hZu0Q46SOlYqQg9qj548xDOZ59LxA1pC2CtZ0AZGyP9APysxgU1gAzzCAppGRJSsfaypVqZozFDw+lwX0mV1HTWEbDLYgpMdTbCOZVd57AD156876FiPdv+8m5pa8GTVC4pwJ7fmXfROU+OmyQo= 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=RfWk/6qR; arc=none smtp.client-ip=67.231.153.30 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="RfWk/6qR" Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 52BBd2so022081; Tue, 11 Mar 2025 08:49:11 -0700 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=FGiRvDu5qMJvnFytUpRoQ6NMlmlPRC3o8wZMDSrWBx4=; b=RfWk/6qRyLYi teT95MHNYka8Q8FAjzt8bR4QcON2h2MdURAHYS9/jhTZFpF+KYT0yS8URO2sbo1w S1JJPiZKV0lsOfXJGB8xx01+6fyDnN5H3sxYDWKIdaHrFeD7xEDoLoaOPzjw5Vfs 0nnX2eak6smzziste+OSEi2xQotmCGKOxLi5IlLnKum94gd4chpLx4L6+qAknVZ2 guNZ5gNrKIJPOWRzqDx9ppVFVDsLQz0en+MnTbgUnLL2DMFrgqVzI7K9duTwGs0u gT4Iqa9JC5cNesVqiYqW7h8ezc+Js9N8gt0mjI0mktR4m0rz8EK5MHZz4HY+/oRY 2F/Iy0hBfQ== Received: from mail.thefacebook.com ([163.114.134.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 45amfx1ndy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Tue, 11 Mar 2025 08:49:10 -0700 (PDT) Received: from devvm4158.cln0.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c08b:78::2ac9) with Microsoft SMTP Server id 15.2.1544.14; Tue, 11 Mar 2025 15:49:07 +0000 From: Vadim Fedorenko To: Borislav Petkov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Thomas Gleixner , Yonghong Song , Vadim Fedorenko , Mykola Lysenko CC: , , Peter Zijlstra , Vadim Fedorenko , Martin KaFai Lau Subject: [PATCH bpf-next v10 2/4] bpf: add bpf_cpu_time_counter_to_ns helper Date: Tue, 11 Mar 2025 08:48:48 -0700 Message-ID: <20250311154850.3616840-3-vadfed@meta.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250311154850.3616840-1-vadfed@meta.com> References: <20250311154850.3616840-1-vadfed@meta.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Proofpoint-GUID: 1YjwnSh2eikBmS1fyzaT71TybA-XnTNL X-Proofpoint-ORIG-GUID: 1YjwnSh2eikBmS1fyzaT71TybA-XnTNL X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-11_04,2025-03-11_02,2024-11-22_01 The new helper should be used to convert deltas of values received by bpf_get_cpu_time_counter() into nanoseconds. It is not designed to do full conversion of time counter values to CLOCK_MONOTONIC_RAW nanoseconds and cannot guarantee monotonicity of 2 independent values, but rather to convert the difference of 2 close enough values of CPU timestamp counter into nanoseconds. This function is JITted into just several instructions and adds as low overhead as possible and perfectly suits benchmark use-cases. When the kfunc is not JITted it returns the value provided as argument because the kfunc in previous patch will return values in nanoseconds. Reviewed-by: Eduard Zingerman Acked-by: Andrii Nakryiko Signed-off-by: Vadim Fedorenko --- arch/x86/net/bpf_jit_comp.c | 27 ++++++++++++++++++++++++++- arch/x86/net/bpf_jit_comp32.c | 27 ++++++++++++++++++++++++++- include/linux/bpf.h | 1 + kernel/bpf/helpers.c | 6 ++++++ 4 files changed, 59 insertions(+), 2 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 92cd5945d630..56f7557048d1 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -2289,6 +2290,29 @@ st: if (is_imm8(insn->off)) break; } + if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && + imm32 == BPF_CALL_IMM(bpf_cpu_time_counter_to_ns) && + cpu_feature_enabled(X86_FEATURE_TSC) && + using_native_sched_clock() && sched_clock_stable()) { + struct cyc2ns_data data; + u32 mult, shift; + + cyc2ns_read_begin(&data); + mult = data.cyc2ns_mul; + shift = data.cyc2ns_shift; + cyc2ns_read_end(); + /* 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); @@ -3906,7 +3930,8 @@ bool bpf_jit_inlines_kfunc_call(s32 imm) { if (!IS_ENABLED(CONFIG_BPF_SYSCALL)) return false; - if (imm == BPF_CALL_IMM(bpf_get_cpu_time_counter) && + if ((imm == BPF_CALL_IMM(bpf_get_cpu_time_counter) || + imm == BPF_CALL_IMM(bpf_cpu_time_counter_to_ns)) && cpu_feature_enabled(X86_FEATURE_TSC) && using_native_sched_clock() && sched_clock_stable()) return true; diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c index 7f13509c66db..9791a3fb9d69 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 @@ -2115,6 +2116,29 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, EMIT2(0x0F, 0x31); break; } + if (IS_ENABLED(CONFIG_BPF_SYSCALL) && + imm32 == BPF_CALL_IMM(bpf_cpu_time_counter_to_ns) && + cpu_feature_enabled(X86_FEATURE_TSC) && + using_native_sched_clock() && sched_clock_stable()) { + struct cyc2ns_data data; + u32 mult, shift; + + cyc2ns_read_begin(&data); + mult = data.cyc2ns_mul; + shift = data.cyc2ns_shift; + cyc2ns_read_end(); + + /* 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], @@ -2648,7 +2672,8 @@ bool bpf_jit_inlines_kfunc_call(s32 imm) { if (!IS_ENABLED(CONFIG_BPF_SYSCALL)) return false; - if (imm == BPF_CALL_IMM(bpf_get_cpu_time_counter) && + if ((imm == BPF_CALL_IMM(bpf_get_cpu_time_counter) || + imm == BPF_CALL_IMM(bpf_cpu_time_counter_to_ns)) && cpu_feature_enabled(X86_FEATURE_TSC) && using_native_sched_clock() && sched_clock_stable()) return true; diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 599aaa854e4c..5c4d35019b22 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3389,6 +3389,7 @@ u64 bpf_get_raw_cpu_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); /* Inlined kfuncs */ u64 bpf_get_cpu_time_counter(void); +u64 bpf_cpu_time_counter_to_ns(u64 cycles); #if defined(CONFIG_NET) bool bpf_sock_common_is_valid_access(int off, int size, diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 43bf35a15f78..cc986d2048db 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3198,6 +3198,11 @@ __bpf_kfunc u64 bpf_get_cpu_time_counter(void) return ktime_get_raw_fast_ns(); } +__bpf_kfunc u64 bpf_cpu_time_counter_to_ns(u64 cycles) +{ + return cycles; +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(generic_btf_ids) @@ -3299,6 +3304,7 @@ BTF_ID_FLAGS(func, bpf_iter_kmem_cache_destroy, KF_ITER_DESTROY | KF_SLEEPABLE) BTF_ID_FLAGS(func, bpf_local_irq_save) BTF_ID_FLAGS(func, bpf_local_irq_restore) BTF_ID_FLAGS(func, bpf_get_cpu_time_counter, KF_FASTCALL) +BTF_ID_FLAGS(func, bpf_cpu_time_counter_to_ns, KF_FASTCALL) BTF_KFUNCS_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { -- 2.47.1