From 5542fa708fb495857a2f0f11c381d912448a4fa8 Mon Sep 17 00:00:00 2001 From: Mark Salyzyn Date: Thu, 17 Aug 2017 09:16:27 -0700 Subject: [PATCH] FROMLIST: [PATCH v5 02/12] arm: vdso: add include file defining __get_datapage() (cherry picked from url https://patchwork.kernel.org/patch/10044481/) 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. Define the prototype for __get_datapage() in local datapage.h header. Rename all vdata variable that point to the datapage shortened to vd to relect a consistent and concise style. Make sure that all references to the datapage in vdso operations are readonly (const). Make sure datapage is first parameter to all subroutines to also be consistent. 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 Bug: 63737556 Bug: 20045882 Change-Id: I9512b49d36d53ca1b71d3ff82219a7c64e0fc613 --- arch/arm/vdso/datapage.h | 25 +++++++++ arch/arm/vdso/vgettimeofday.c | 99 +++++++++++++++++------------------ 2 files changed, 73 insertions(+), 51 deletions(-) create mode 100644 arch/arm/vdso/datapage.h diff --git a/arch/arm/vdso/datapage.h b/arch/arm/vdso/datapage.h new file mode 100644 index 000000000000..e3088bdfb946 --- /dev/null +++ b/arch/arm/vdso/datapage.h @@ -0,0 +1,25 @@ +/* + * 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 + +#include +#include + +extern const struct vdso_data *__get_datapage(void); + +#endif /* __VDSO_DATAPAGE_H */ diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c index 8cf13af1323c..2474c17dc356 100644 --- a/arch/arm/vdso/vgettimeofday.c +++ b/arch/arm/vdso/vgettimeofday.c @@ -30,20 +30,19 @@ #include #include #include -#include #ifndef CONFIG_AEABI #error This code depends on AEABI system call conventions #endif -extern struct vdso_data *__get_datapage(void); +#include "datapage.h" -static notrace u32 vdso_read_begin(const struct vdso_data *vdata) +static notrace u32 vdso_read_begin(const struct vdso_data *vd) { u32 seq; do { - seq = READ_ONCE(vdata->tb_seq_count); + seq = READ_ONCE(vd->tb_seq_count); if ((seq & 1) == 0) break; @@ -55,12 +54,12 @@ static notrace u32 vdso_read_begin(const struct vdso_data *vdata) return seq; } -static notrace int vdso_read_retry(const struct vdso_data *vdata, u32 start) +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(vdata->tb_seq_count); + seq = READ_ONCE(vd->tb_seq_count); return seq != start; } @@ -81,38 +80,38 @@ static notrace long clock_gettime_fallback(clockid_t _clkid, return ret; } -static notrace int do_realtime_coarse(struct timespec *ts, - struct vdso_data *vdata) +static notrace int do_realtime_coarse(const struct vdso_data *vd, + struct timespec *ts) { u32 seq; do { - seq = vdso_read_begin(vdata); + seq = vdso_read_begin(vd); - ts->tv_sec = vdata->xtime_coarse_sec; - ts->tv_nsec = vdata->xtime_coarse_nsec; + ts->tv_sec = vd->xtime_coarse_sec; + ts->tv_nsec = vd->xtime_coarse_nsec; - } while (vdso_read_retry(vdata, seq)); + } while (vdso_read_retry(vd, seq)); return 0; } -static notrace int do_monotonic_coarse(struct timespec *ts, - struct vdso_data *vdata) +static notrace int do_monotonic_coarse(const struct vdso_data *vd, + struct timespec *ts) { struct timespec tomono; u32 seq; do { - seq = vdso_read_begin(vdata); + seq = vdso_read_begin(vd); - ts->tv_sec = vdata->xtime_coarse_sec; - ts->tv_nsec = vdata->xtime_coarse_nsec; + ts->tv_sec = vd->xtime_coarse_sec; + ts->tv_nsec = vd->xtime_coarse_nsec; - tomono.tv_sec = vdata->wtm_clock_sec; - tomono.tv_nsec = vdata->wtm_clock_nsec; + tomono.tv_sec = vd->wtm_clock_sec; + tomono.tv_nsec = vd->wtm_clock_nsec; - } while (vdso_read_retry(vdata, seq)); + } while (vdso_read_retry(vd, seq)); ts->tv_sec += tomono.tv_sec; timespec_add_ns(ts, tomono.tv_nsec); @@ -122,7 +121,7 @@ static notrace int do_monotonic_coarse(struct timespec *ts, #ifdef CONFIG_ARM_ARCH_TIMER -static notrace u64 get_ns(struct vdso_data *vdata) +static notrace u64 get_ns(const struct vdso_data *vd) { u64 cycle_delta; u64 cycle_now; @@ -130,29 +129,29 @@ static notrace u64 get_ns(struct vdso_data *vdata) cycle_now = arch_counter_get_cntvct(); - cycle_delta = (cycle_now - vdata->cs_cycle_last) & vdata->cs_mask; + cycle_delta = (cycle_now - vd->cs_cycle_last) & vd->cs_mask; - nsec = (cycle_delta * vdata->cs_mono_mult) + vdata->xtime_clock_snsec; - nsec >>= vdata->cs_shift; + nsec = (cycle_delta * vd->cs_mono_mult) + vd->xtime_clock_snsec; + nsec >>= vd->cs_shift; return nsec; } -static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata) +static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts) { u64 nsecs; u32 seq; do { - seq = vdso_read_begin(vdata); + seq = vdso_read_begin(vd); - if (vdata->use_syscall) + if (vd->use_syscall) return -1; - ts->tv_sec = vdata->xtime_clock_sec; - nsecs = get_ns(vdata); + ts->tv_sec = vd->xtime_clock_sec; + nsecs = get_ns(vd); - } while (vdso_read_retry(vdata, seq)); + } while (vdso_read_retry(vd, seq)); ts->tv_nsec = 0; timespec_add_ns(ts, nsecs); @@ -160,25 +159,25 @@ static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata) return 0; } -static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata) +static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts) { struct timespec tomono; u64 nsecs; u32 seq; do { - seq = vdso_read_begin(vdata); + seq = vdso_read_begin(vd); - if (vdata->use_syscall) + if (vd->use_syscall) return -1; - ts->tv_sec = vdata->xtime_clock_sec; - nsecs = get_ns(vdata); + ts->tv_sec = vd->xtime_clock_sec; + nsecs = get_ns(vd); - tomono.tv_sec = vdata->wtm_clock_sec; - tomono.tv_nsec = vdata->wtm_clock_nsec; + tomono.tv_sec = vd->wtm_clock_sec; + tomono.tv_nsec = vd->wtm_clock_nsec; - } while (vdso_read_retry(vdata, seq)); + } while (vdso_read_retry(vd, seq)); ts->tv_sec += tomono.tv_sec; ts->tv_nsec = 0; @@ -189,12 +188,12 @@ static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata) #else /* CONFIG_ARM_ARCH_TIMER */ -static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata) +static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts) { return -1; } -static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata) +static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts) { return -1; } @@ -203,23 +202,22 @@ static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata) notrace int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts) { - struct vdso_data *vdata; int ret = -1; - vdata = __get_datapage(); + const struct vdso_data *vd = __get_datapage(); switch (clkid) { case CLOCK_REALTIME_COARSE: - ret = do_realtime_coarse(ts, vdata); + ret = do_realtime_coarse(vd, ts); break; case CLOCK_MONOTONIC_COARSE: - ret = do_monotonic_coarse(ts, vdata); + ret = do_monotonic_coarse(vd, ts); break; case CLOCK_REALTIME: - ret = do_realtime(ts, vdata); + ret = do_realtime(vd, ts); break; case CLOCK_MONOTONIC: - ret = do_monotonic(ts, vdata); + ret = do_monotonic(vd, ts); break; default: break; @@ -251,12 +249,11 @@ static notrace long gettimeofday_fallback(struct timeval *_tv, notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) { struct timespec ts; - struct vdso_data *vdata; int ret; - vdata = __get_datapage(); + const struct vdso_data *vd = __get_datapage(); - ret = do_realtime(&ts, vdata); + ret = do_realtime(vd, &ts); if (ret) return gettimeofday_fallback(tv, tz); @@ -265,8 +262,8 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) tv->tv_usec = ts.tv_nsec / 1000; } if (tz) { - tz->tz_minuteswest = vdata->tz_minuteswest; - tz->tz_dsttime = vdata->tz_dsttime; + tz->tz_minuteswest = vd->tz_minuteswest; + tz->tz_dsttime = vd->tz_dsttime; } return ret; -- 2.20.1