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If FEAT_ECV is implemented, the self-synchronized counter CNTVCTSS_EL0 can be used, removing the need for an ISB. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andre Przywara <andre.przywara@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20220830104833.34636-4-joey.gouly@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
119 lines
2.5 KiB
C
119 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2018 ARM Limited
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*/
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#ifndef __ASM_VDSO_GETTIMEOFDAY_H
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#define __ASM_VDSO_GETTIMEOFDAY_H
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#ifndef __ASSEMBLY__
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#include <asm/alternative.h>
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#include <asm/barrier.h>
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#include <asm/unistd.h>
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#include <asm/sysreg.h>
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#define VDSO_HAS_CLOCK_GETRES 1
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static __always_inline
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int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
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struct timezone *_tz)
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{
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register struct timezone *tz asm("x1") = _tz;
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register struct __kernel_old_timeval *tv asm("x0") = _tv;
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register long ret asm ("x0");
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register long nr asm("x8") = __NR_gettimeofday;
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asm volatile(
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" svc #0\n"
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: "=r" (ret)
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: "r" (tv), "r" (tz), "r" (nr)
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: "memory");
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return ret;
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}
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static __always_inline
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long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
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{
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register struct __kernel_timespec *ts asm("x1") = _ts;
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register clockid_t clkid asm("x0") = _clkid;
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register long ret asm ("x0");
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register long nr asm("x8") = __NR_clock_gettime;
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asm volatile(
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" svc #0\n"
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: "=r" (ret)
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: "r" (clkid), "r" (ts), "r" (nr)
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: "memory");
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return ret;
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}
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static __always_inline
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int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
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{
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register struct __kernel_timespec *ts asm("x1") = _ts;
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register clockid_t clkid asm("x0") = _clkid;
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register long ret asm ("x0");
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register long nr asm("x8") = __NR_clock_getres;
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asm volatile(
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" svc #0\n"
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: "=r" (ret)
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: "r" (clkid), "r" (ts), "r" (nr)
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: "memory");
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return ret;
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}
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static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
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const struct vdso_data *vd)
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{
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u64 res;
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/*
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* Core checks for mode already, so this raced against a concurrent
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* update. Return something. Core will do another round and then
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* see the mode change and fallback to the syscall.
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*/
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if (clock_mode == VDSO_CLOCKMODE_NONE)
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return 0;
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/*
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* If FEAT_ECV is available, use the self-synchronizing counter.
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* Otherwise the isb is required to prevent that the counter value
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* is speculated.
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*/
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asm volatile(
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ALTERNATIVE("isb\n"
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"mrs %0, cntvct_el0",
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"nop\n"
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__mrs_s("%0", SYS_CNTVCTSS_EL0),
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ARM64_HAS_ECV)
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: "=r" (res)
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:
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: "memory");
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arch_counter_enforce_ordering(res);
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return res;
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}
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static __always_inline
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const struct vdso_data *__arch_get_vdso_data(void)
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{
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return _vdso_data;
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}
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#ifdef CONFIG_TIME_NS
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static __always_inline
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const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd)
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{
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return _timens_data;
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}
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#endif
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_VDSO_GETTIMEOFDAY_H */
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