From patchwork Tue Oct 31 18:32:25 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Salyzyn X-Patchwork-Id: 10035153 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4AB54602B9 for ; Tue, 31 Oct 2017 18:34:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3F13F281E1 for ; Tue, 31 Oct 2017 18:34:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3384C2874C; Tue, 31 Oct 2017 18:34:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 07004285CD for ; Tue, 31 Oct 2017 18:34:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=C9HuRW1BBOCLsLtmWe1ss8YpcOBObgjdYBf/grEQGQw=; b=au9 CBdCKEwkthwQRx5l3m0r21fJhfLmArtX7l3Rd1LqaZM8AAaKXkG1EYVr7LhOP7oi598o0jiRlZGLT FPvVgoXEe2Gb2MRQrAKTxSKzbGqHNzlLXOXPaHA6HWY4NyUBv2/1IRChUAkciAuOLlZ0LIOhLH/MN nZVocV900zVA+dVleze0IiHz+X+ArqMF5LOhddZ0XaP0UYAWmlZDUYEfQbkVgtA4Qd/emp6oO/LSf sN3nSKz1c8sTAabKOe2ct8P4Is5VyRqJNn40gGgsS2ak0s6Gp7MUSQIbTnxA6FmZPBBNGCtpIAGfL kAbkQdxYd6yDQ6bFPqL4A58YJdKqOGA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1e9bMO-0007be-49; Tue, 31 Oct 2017 18:34:00 +0000 Received: from mail-io0-x242.google.com ([2607:f8b0:4001:c06::242]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1e9bLW-0006nR-0W for linux-arm-kernel@lists.infradead.org; Tue, 31 Oct 2017 18:33:31 +0000 Received: by mail-io0-x242.google.com with SMTP id e89so834035ioi.11 for ; Tue, 31 Oct 2017 11:32:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=android.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=OI/Zp2O7QaODPB325nAf6R/5JdgzTGFsrPuuU1s6hPA=; b=qUNglyQQONl4+QpPLC5LBs8xi/Tgt9lZgLcYWb6cWiFvD58Zq4yVDtsqxFvLMaJO7W oNOkkz5SPXrPSEeFSekUxwxRwJy8oY26XptZR1R6eSkFXoLuj9vLXzrWE7X9by10CpIP IJtmmk2Pv8fdUlkksqyQLtrDPbAXYPDvXxmtEKYVoiCFhpMhwmjpMZQSIiRn9sWcG+1a HqpftZ+p+W7t/u3xVS0dLZGY9bj3+hwlR4MnVUSf6HQtNTFq1jhbQQBXftRtUTcic0P3 xTgled/J5+V8GbIS0dG4JJizKNSNNu1EWXe9Z0AZwhyd4RQ996MDQUmnENujDR94JAH6 n08g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=OI/Zp2O7QaODPB325nAf6R/5JdgzTGFsrPuuU1s6hPA=; b=r1qwr00d0Q7uuKu7M61QcVGmRIZNPP23lEX3b67RMmiymqO4GgBrM2da/MzIJDpwX5 fDs2PaRe7jfVq1AJbHv+R9O1o5fW3tPBXg+kXY/3D/tNnXywD+XZpCRvhfX+lklHXdWe aVF9jxcXTChJ/gytsJK8+/iG624KjKarCPKA4uJjlP3HThvr1pO6z0TZ2EV6WUxlGP6z 6AWZxYQJTvi2IguIEhHeXbohLH+lkoHGFf/Vq6FgPqzKfcAI2e/0wup2nOr+1jTp+XWx K6/0X6JPc2IHryz9wf68J2UDGW2kzGrLPprlaeho+jp2NRv2wEU0Md8p8nXRmbV+sOSa sl7Q== X-Gm-Message-State: AMCzsaUf2d/GorCfeqG14Er21zWOvsR4cDyx1GLU81PybFgLLEEaP8ju MyQeCo9aLZN/oWZodHYRmCz/mA== X-Google-Smtp-Source: ABhQp+QIPYezQ/FKwiZdPn8wT2jHzPgzJdpfdNrHFLqTDJBoj4S8PU9Yb/7Xupaa20cM01auBZqOYQ== X-Received: by 10.107.38.79 with SMTP id m76mr3730313iom.187.1509474765019; Tue, 31 Oct 2017 11:32:45 -0700 (PDT) Received: from nebulus.mtv.corp.google.com ([100.98.120.17]) by smtp.gmail.com with ESMTPSA id o29sm937394ioi.29.2017.10.31.11.32.43 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 31 Oct 2017 11:32:44 -0700 (PDT) From: Mark Salyzyn To: linux-kernel@vger.kernel.org Subject: [PATCH v4 09/12] arm: vdso: move vgettimeofday.c to lib/vdso/ Date: Tue, 31 Oct 2017 11:32:25 -0700 Message-Id: <20171031183240.81311-1-salyzyn@android.com> X-Mailer: git-send-email 2.15.0.rc2.357.g7e34df9404-goog X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171031_113306_353285_F24258DA X-CRM114-Status: GOOD ( 23.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Laura Abbott , Kees Cook , Ard Biesheuvel , Catalin Marinas , Kevin Brodsky , Will Deacon , Russell King , Andy Lutomirski , James Morse , Andrew Pinski , Dmitry Safonov , Andy Gross , John Stultz , Thomas Gleixner , Mark Salyzyn , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Take an effort to recode the arm64 vdso code from assembler to C previously submitted by Andrew Pinski , rework it for use in both arm and arm64, overlapping any optimizations for each architecture. But instead of landing it in arm64, land the result into lib/vdso and unify both implementations to simplify future maintenance. Declare arch/arm/vdso/vgettimeofday.c to be a candidate for a global implementation of the vdso timer calls. The hope is that new architectures can take advantage of the current unification of arm and arm64 implementations. We urge future efforts to merge their implementations into the global vgettimeofday.c file and thus provide functional parity. Signed-off-by: Mark Salyzyn Cc: James Morse Cc: Russell King Cc: Catalin Marinas Cc: Will Deacon Cc: Andy Lutomirski Cc: Dmitry Safonov Cc: John Stultz Cc: Mark Rutland Cc: Laura Abbott Cc: Kees Cook Cc: Ard Biesheuvel Cc: Andy Gross Cc: Kevin Brodsky Cc: Andrew Pinski Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org v3: - added this new change. - move arch/arm/vdso/vgettimeofday.c to lib/vdso/vgettimeofday.c. - adjust vgettimeofday.c to be a better global candidate, switch to using ARCH_PROVIDES_TIMER and __arch_counter_get() as more generic. v4: - update commit message to reflect overall reasoning. - adjust to reflect dropping of any forced inline. --- arch/arm/vdso/compiler.h | 4 + arch/arm/vdso/vgettimeofday.c | 338 +---------------------------------------- lib/vdso/compiler.h | 24 +++ lib/vdso/datapage.h | 24 +++ lib/vdso/vgettimeofday.c | 339 ++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 392 insertions(+), 337 deletions(-) create mode 100644 lib/vdso/compiler.h create mode 100644 lib/vdso/datapage.h create mode 100644 lib/vdso/vgettimeofday.c diff --git a/arch/arm/vdso/compiler.h b/arch/arm/vdso/compiler.h index 5e38eb1f03b6..6d2fb4d6c3d0 100644 --- a/arch/arm/vdso/compiler.h +++ b/arch/arm/vdso/compiler.h @@ -32,6 +32,10 @@ #error This code depends on AEABI system call conventions #endif +#ifdef CONFIG_ARM_ARCH_TIMER +#define ARCH_PROVIDES_TIMER +#endif + #define DEFINE_FALLBACK(name, type_arg1, name_arg1, type_arg2, name_arg2) \ static notrace long name##_fallback(type_arg1 _##name_arg1, \ type_arg2 _##name_arg2) \ diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c index bbacf4d0d6a2..4b241fe60d17 100644 --- a/arch/arm/vdso/vgettimeofday.c +++ b/arch/arm/vdso/vgettimeofday.c @@ -1,339 +1,3 @@ -/* - * Userspace implementations of gettimeofday() and friends. - * - * Copyright (C) 2017 Cavium, Inc. - * Copyright (C) 2015 Mentor Graphics Corporation - * Copyright (C) 2012 ARM Limited - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program. If not, see . - * - * Author: Will Deacon - * Rewriten from arch64 version into C by: Andrew Pinski - * Reworked and rebased over arm version by: Mark Salyzyn - */ - -#include -#include -#include - #include "compiler.h" #include "datapage.h" - -DEFINE_FALLBACK(gettimeofday, struct timeval *, tv, struct timezone *, tz) -DEFINE_FALLBACK(clock_gettime, clockid_t, clock, struct timespec *, ts) -DEFINE_FALLBACK(clock_getres, clockid_t, clock, struct timespec *, ts) - -static notrace u32 vdso_read_begin(const struct vdso_data *vd) -{ - u32 seq; - - do { - seq = READ_ONCE(vd->tb_seq_count); - - if ((seq & 1) == 0) - break; - - cpu_relax(); - } while (true); - - smp_rmb(); /* Pairs with second smp_wmb in update_vsyscall */ - return seq; -} - -static notrace int vdso_read_retry(const struct vdso_data *vd, u32 start) -{ - u32 seq; - - smp_rmb(); /* Pairs with first smp_wmb in update_vsyscall */ - seq = READ_ONCE(vd->tb_seq_count); - return seq != start; -} - -static notrace int do_realtime_coarse(const struct vdso_data *vd, - struct timespec *ts) -{ - u32 seq; - - do { - seq = vdso_read_begin(vd); - - ts->tv_sec = vd->xtime_coarse_sec; - ts->tv_nsec = vd->xtime_coarse_nsec; - - } while (vdso_read_retry(vd, seq)); - - return 0; -} - -static notrace int do_monotonic_coarse(const struct vdso_data *vd, - struct timespec *ts) -{ - struct timespec tomono; - u32 seq; - - do { - seq = vdso_read_begin(vd); - - ts->tv_sec = vd->xtime_coarse_sec; - ts->tv_nsec = vd->xtime_coarse_nsec; - - tomono.tv_sec = vd->wtm_clock_sec; - tomono.tv_nsec = vd->wtm_clock_nsec; - - } while (vdso_read_retry(vd, seq)); - - ts->tv_sec += tomono.tv_sec; - timespec_add_ns(ts, tomono.tv_nsec); - - return 0; -} - -#ifdef CONFIG_ARM_ARCH_TIMER - -/* - * Returns the clock delta, in nanoseconds left-shifted by the clock - * shift. - */ -static notrace u64 get_clock_shifted_nsec(const u64 cycle_last, - const u32 mult, - const u64 mask) -{ - u64 res; - - /* Read the virtual counter. */ - res = arch_vdso_read_counter(); - - res = res - cycle_last; - - res &= mask; - return res * mult; -} - -static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts) -{ - u32 seq, mult, shift; - u64 nsec, cycle_last; -#ifdef ARCH_CLOCK_FIXED_MASK - static const u64 mask = ARCH_CLOCK_FIXED_MASK; -#else - u64 mask; -#endif - vdso_xtime_clock_sec_t sec; - - do { - seq = vdso_read_begin(vd); - - if (vd->use_syscall) - return -1; - - cycle_last = vd->cs_cycle_last; - - mult = vd->cs_mono_mult; - shift = vd->cs_shift; -#ifndef ARCH_CLOCK_FIXED_MASK - mask = vd->cs_mask; -#endif - - sec = vd->xtime_clock_sec; - nsec = vd->xtime_clock_snsec; - - } while (unlikely(vdso_read_retry(vd, seq))); - - nsec += get_clock_shifted_nsec(cycle_last, mult, mask); - nsec >>= shift; - /* open coding timespec_add_ns to save a ts->tv_nsec = 0 */ - ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec); - ts->tv_nsec = nsec; - - return 0; -} - -static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts) -{ - u32 seq, mult, shift; - u64 nsec, cycle_last; -#ifdef ARCH_CLOCK_FIXED_MASK - static const u64 mask = ARCH_CLOCK_FIXED_MASK; -#else - u64 mask; -#endif - vdso_wtm_clock_nsec_t wtm_nsec; - __kernel_time_t sec; - - do { - seq = vdso_read_begin(vd); - - if (vd->use_syscall) - return -1; - - cycle_last = vd->cs_cycle_last; - - mult = vd->cs_mono_mult; - shift = vd->cs_shift; -#ifndef ARCH_CLOCK_FIXED_MASK - mask = vd->cs_mask; -#endif - - sec = vd->xtime_clock_sec; - nsec = vd->xtime_clock_snsec; - - sec += vd->wtm_clock_sec; - wtm_nsec = vd->wtm_clock_nsec; - - } while (unlikely(vdso_read_retry(vd, seq))); - - nsec += get_clock_shifted_nsec(cycle_last, mult, mask); - nsec >>= shift; - nsec += wtm_nsec; - /* open coding timespec_add_ns to save a ts->tv_nsec = 0 */ - ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec); - ts->tv_nsec = nsec; - - return 0; -} - -static notrace int do_monotonic_raw(const struct vdso_data *vd, - struct timespec *ts) -{ - u32 seq, mult, shift; - u64 nsec, cycle_last; -#ifdef ARCH_CLOCK_FIXED_MASK - static const u64 mask = ARCH_CLOCK_FIXED_MASK; -#else - u64 mask; -#endif - vdso_raw_time_sec_t sec; - - do { - seq = vdso_read_begin(vd); - - if (vd->use_syscall) - return -1; - - cycle_last = vd->cs_cycle_last; - - mult = vd->cs_raw_mult; - shift = vd->cs_shift; -#ifndef ARCH_CLOCK_FIXED_MASK - mask = vd->cs_mask; -#endif - - sec = vd->raw_time_sec; - nsec = vd->raw_time_nsec; - - } while (unlikely(vdso_read_retry(vd, seq))); - - nsec += get_clock_shifted_nsec(cycle_last, mult, mask); - nsec >>= shift; - /* open coding timespec_add_ns to save a ts->tv_nsec = 0 */ - ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec); - ts->tv_nsec = nsec; - - return 0; -} - -#else /* CONFIG_ARM_ARCH_TIMER */ - -static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts) -{ - return -1; -} - -static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts) -{ - return -1; -} - -static notrace int do_monotonic_raw(const struct vdso_data *vd, - struct timespec *ts) -{ - return -1; -} - -#endif /* CONFIG_ARM_ARCH_TIMER */ - -notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts) -{ - const struct vdso_data *vd = __get_datapage(); - - switch (clock) { - case CLOCK_REALTIME_COARSE: - do_realtime_coarse(vd, ts); - break; - case CLOCK_MONOTONIC_COARSE: - do_monotonic_coarse(vd, ts); - break; - case CLOCK_REALTIME: - if (do_realtime(vd, ts)) - goto fallback; - break; - case CLOCK_MONOTONIC: - if (do_monotonic(vd, ts)) - goto fallback; - break; - case CLOCK_MONOTONIC_RAW: - if (do_monotonic_raw(vd, ts)) - goto fallback; - break; - default: - goto fallback; - } - - return 0; -fallback: - return clock_gettime_fallback(clock, ts); -} - -notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) -{ - const struct vdso_data *vd = __get_datapage(); - - if (likely(tv != NULL)) { - struct timespec ts; - - if (do_realtime(vd, &ts)) - return gettimeofday_fallback(tv, tz); - - tv->tv_sec = ts.tv_sec; - tv->tv_usec = ts.tv_nsec / 1000; - } - - if (unlikely(tz != NULL)) { - tz->tz_minuteswest = vd->tz_minuteswest; - tz->tz_dsttime = vd->tz_dsttime; - } - - return 0; -} - -int __vdso_clock_getres(clockid_t clock, struct timespec *res) -{ - long nsec; - - if (clock == CLOCK_REALTIME || - clock == CLOCK_MONOTONIC || - clock == CLOCK_MONOTONIC_RAW) - nsec = MONOTONIC_RES_NSEC; - else if (clock == CLOCK_REALTIME_COARSE || - clock == CLOCK_MONOTONIC_COARSE) - nsec = LOW_RES_NSEC; - else - return clock_getres_fallback(clock, res); - - if (likely(res != NULL)) { - res->tv_sec = 0; - res->tv_nsec = nsec; - } - - return 0; -} +#include "../../../lib/vdso/vgettimeofday.c" diff --git a/lib/vdso/compiler.h b/lib/vdso/compiler.h new file mode 100644 index 000000000000..0e618b73e064 --- /dev/null +++ b/lib/vdso/compiler.h @@ -0,0 +1,24 @@ +/* + * Userspace implementations of fallback calls + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#ifndef __VDSO_COMPILER_H +#define __VDSO_COMPILER_H + +#error "vdso: Provide architectural overrides such as ARCH_PROVIDES_TIMER," +#error " DEFINE_FALLBACK and __arch_counter_get or any overrides. eg:" +#error " vdso entry points or compilation time helpers." + +#endif /* __VDSO_COMPILER_H */ diff --git a/lib/vdso/datapage.h b/lib/vdso/datapage.h new file mode 100644 index 000000000000..df4427e42d51 --- /dev/null +++ b/lib/vdso/datapage.h @@ -0,0 +1,24 @@ +/* + * Userspace implementations of __get_datapage + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#ifndef __VDSO_DATAPAGE_H +#define __VDSO_DATAPAGE_H + +#error "vdso: Provide a user space architecture specific definition or" +#error "prototype for struct vdso_data *__get_datapage(void). Also define" +#error "ARCH_CLOCK_FIXED_MASK if not provided by cs_mask." + +#endif /* __VDSO_DATAPAGE_H */ diff --git a/lib/vdso/vgettimeofday.c b/lib/vdso/vgettimeofday.c new file mode 100644 index 000000000000..0b585081f4de --- /dev/null +++ b/lib/vdso/vgettimeofday.c @@ -0,0 +1,339 @@ +/* + * Userspace implementations of gettimeofday() and friends. + * + * Copyright (C) 2017 Cavium, Inc. + * Copyright (C) 2015 Mentor Graphics Corporation + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + * Author: Will Deacon + * Rewriten from arch64 version into C by: Andrew Pinski + * Reworked and rebased over arm version by: Mark Salyzyn + */ + +#include +#include +#include + +#include "compiler.h" +#include "datapage.h" + +DEFINE_FALLBACK(gettimeofday, struct timeval *, tv, struct timezone *, tz) +DEFINE_FALLBACK(clock_gettime, clockid_t, clock, struct timespec *, ts) +DEFINE_FALLBACK(clock_getres, clockid_t, clock, struct timespec *, ts) + +static notrace u32 vdso_read_begin(const struct vdso_data *vd) +{ + u32 seq; + + do { + seq = READ_ONCE(vd->tb_seq_count); + + if ((seq & 1) == 0) + break; + + cpu_relax(); + } while (true); + + smp_rmb(); /* Pairs with second smp_wmb in update_vsyscall */ + return seq; +} + +static notrace int vdso_read_retry(const struct vdso_data *vd, u32 start) +{ + u32 seq; + + smp_rmb(); /* Pairs with first smp_wmb in update_vsyscall */ + seq = READ_ONCE(vd->tb_seq_count); + return seq != start; +} + +static notrace int do_realtime_coarse(const struct vdso_data *vd, + struct timespec *ts) +{ + u32 seq; + + do { + seq = vdso_read_begin(vd); + + ts->tv_sec = vd->xtime_coarse_sec; + ts->tv_nsec = vd->xtime_coarse_nsec; + + } while (vdso_read_retry(vd, seq)); + + return 0; +} + +static notrace int do_monotonic_coarse(const struct vdso_data *vd, + struct timespec *ts) +{ + struct timespec tomono; + u32 seq; + + do { + seq = vdso_read_begin(vd); + + ts->tv_sec = vd->xtime_coarse_sec; + ts->tv_nsec = vd->xtime_coarse_nsec; + + tomono.tv_sec = vd->wtm_clock_sec; + tomono.tv_nsec = vd->wtm_clock_nsec; + + } while (vdso_read_retry(vd, seq)); + + ts->tv_sec += tomono.tv_sec; + timespec_add_ns(ts, tomono.tv_nsec); + + return 0; +} + +#ifdef ARCH_PROVIDES_TIMER + +/* + * Returns the clock delta, in nanoseconds left-shifted by the clock + * shift. + */ +static notrace u64 get_clock_shifted_nsec(const u64 cycle_last, + const u32 mult, + const u64 mask) +{ + u64 res; + + /* Read the virtual counter. */ + res = arch_vdso_read_counter(); + + res = res - cycle_last; + + res &= mask; + return res * mult; +} + +static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts) +{ + u32 seq, mult, shift; + u64 nsec, cycle_last; +#ifdef ARCH_CLOCK_FIXED_MASK + static const u64 mask = ARCH_CLOCK_FIXED_MASK; +#else + u64 mask; +#endif + vdso_xtime_clock_sec_t sec; + + do { + seq = vdso_read_begin(vd); + + if (vd->use_syscall) + return -1; + + cycle_last = vd->cs_cycle_last; + + mult = vd->cs_mono_mult; + shift = vd->cs_shift; +#ifndef ARCH_CLOCK_FIXED_MASK + mask = vd->cs_mask; +#endif + + sec = vd->xtime_clock_sec; + nsec = vd->xtime_clock_snsec; + + } while (unlikely(vdso_read_retry(vd, seq))); + + nsec += get_clock_shifted_nsec(cycle_last, mult, mask); + nsec >>= shift; + /* open coding timespec_add_ns to save a ts->tv_nsec = 0 */ + ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec); + ts->tv_nsec = nsec; + + return 0; +} + +static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts) +{ + u32 seq, mult, shift; + u64 nsec, cycle_last; +#ifdef ARCH_CLOCK_FIXED_MASK + static const u64 mask = ARCH_CLOCK_FIXED_MASK; +#else + u64 mask; +#endif + vdso_wtm_clock_nsec_t wtm_nsec; + __kernel_time_t sec; + + do { + seq = vdso_read_begin(vd); + + if (vd->use_syscall) + return -1; + + cycle_last = vd->cs_cycle_last; + + mult = vd->cs_mono_mult; + shift = vd->cs_shift; +#ifndef ARCH_CLOCK_FIXED_MASK + mask = vd->cs_mask; +#endif + + sec = vd->xtime_clock_sec; + nsec = vd->xtime_clock_snsec; + + sec += vd->wtm_clock_sec; + wtm_nsec = vd->wtm_clock_nsec; + + } while (unlikely(vdso_read_retry(vd, seq))); + + nsec += get_clock_shifted_nsec(cycle_last, mult, mask); + nsec >>= shift; + nsec += wtm_nsec; + /* open coding timespec_add_ns to save a ts->tv_nsec = 0 */ + ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec); + ts->tv_nsec = nsec; + + return 0; +} + +static notrace int do_monotonic_raw(const struct vdso_data *vd, + struct timespec *ts) +{ + u32 seq, mult, shift; + u64 nsec, cycle_last; +#ifdef ARCH_CLOCK_FIXED_MASK + static const u64 mask = ARCH_CLOCK_FIXED_MASK; +#else + u64 mask; +#endif + vdso_raw_time_sec_t sec; + + do { + seq = vdso_read_begin(vd); + + if (vd->use_syscall) + return -1; + + cycle_last = vd->cs_cycle_last; + + mult = vd->cs_raw_mult; + shift = vd->cs_shift; +#ifndef ARCH_CLOCK_FIXED_MASK + mask = vd->cs_mask; +#endif + + sec = vd->raw_time_sec; + nsec = vd->raw_time_nsec; + + } while (unlikely(vdso_read_retry(vd, seq))); + + nsec += get_clock_shifted_nsec(cycle_last, mult, mask); + nsec >>= shift; + /* open coding timespec_add_ns to save a ts->tv_nsec = 0 */ + ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec); + ts->tv_nsec = nsec; + + return 0; +} + +#else /* ARCH_PROVIDES_TIMER */ + +static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts) +{ + return -1; +} + +static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts) +{ + return -1; +} + +static notrace int do_monotonic_raw(const struct vdso_data *vd, + struct timespec *ts) +{ + return -1; +} + +#endif /* ARCH_PROVIDES_TIMER */ + +notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts) +{ + const struct vdso_data *vd = __get_datapage(); + + switch (clock) { + case CLOCK_REALTIME_COARSE: + do_realtime_coarse(vd, ts); + break; + case CLOCK_MONOTONIC_COARSE: + do_monotonic_coarse(vd, ts); + break; + case CLOCK_REALTIME: + if (do_realtime(vd, ts)) + goto fallback; + break; + case CLOCK_MONOTONIC: + if (do_monotonic(vd, ts)) + goto fallback; + break; + case CLOCK_MONOTONIC_RAW: + if (do_monotonic_raw(vd, ts)) + goto fallback; + break; + default: + goto fallback; + } + + return 0; +fallback: + return clock_gettime_fallback(clock, ts); +} + +notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) +{ + const struct vdso_data *vd = __get_datapage(); + + if (likely(tv != NULL)) { + struct timespec ts; + + if (do_realtime(vd, &ts)) + return gettimeofday_fallback(tv, tz); + + tv->tv_sec = ts.tv_sec; + tv->tv_usec = ts.tv_nsec / 1000; + } + + if (unlikely(tz != NULL)) { + tz->tz_minuteswest = vd->tz_minuteswest; + tz->tz_dsttime = vd->tz_dsttime; + } + + return 0; +} + +int __vdso_clock_getres(clockid_t clock, struct timespec *res) +{ + long nsec; + + if (clock == CLOCK_REALTIME || + clock == CLOCK_MONOTONIC || + clock == CLOCK_MONOTONIC_RAW) + nsec = MONOTONIC_RES_NSEC; + else if (clock == CLOCK_REALTIME_COARSE || + clock == CLOCK_MONOTONIC_COARSE) + nsec = LOW_RES_NSEC; + else + return clock_getres_fallback(clock, res); + + if (likely(res != NULL)) { + res->tv_sec = 0; + res->tv_nsec = nsec; + } + + return 0; +}