
The libc provides a discovery mechanism for vDSO library and its symbols. When a symbol is not exposed by the vDSOs the libc falls back on the system calls. With the introduction of the unified vDSO library on mips this behavior is not honored anymore by the kernel in the case of gettimeofday(). The issue has been noticed and reported due to a dhclient failure on the CI20 board: root@letux:~# dhclient ../../../../lib/isc/unix/time.c:200: Operation not permitted root@letux:~# Restore the original behavior fixing gettimeofday() in the vDSO library. Reported-by: H. Nikolaus Schaller <hns@goldelico.com> Tested-by: H. Nikolaus Schaller <hns@goldelico.com> # CI20 with JZ4780 Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Paul Burton <paulburton@kernel.org> Cc: mips-creator-ci20-dev@googlegroups.com Cc: letux-kernel@openphoenux.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
212 lines
4.9 KiB
C
212 lines
4.9 KiB
C
/*
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* Copyright (C) 2018 ARM Limited
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* Copyright (C) 2015 Imagination Technologies
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* Author: Alex Smith <alex.smith@imgtec.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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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 <linux/compiler.h>
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#include <linux/time.h>
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#include <asm/vdso/vdso.h>
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#include <asm/clocksource.h>
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#include <asm/io.h>
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#include <asm/unistd.h>
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#include <asm/vdso.h>
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#define VDSO_HAS_CLOCK_GETRES 1
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#define __VDSO_USE_SYSCALL ULLONG_MAX
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static __always_inline long gettimeofday_fallback(
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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("a1") = _tz;
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register struct __kernel_old_timeval *tv asm("a0") = _tv;
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register long ret asm("v0");
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register long nr asm("v0") = __NR_gettimeofday;
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register long error asm("a3");
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asm volatile(
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" syscall\n"
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: "=r" (ret), "=r" (error)
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: "r" (tv), "r" (tz), "r" (nr)
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: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
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"$14", "$15", "$24", "$25", "hi", "lo", "memory");
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return error ? -ret : ret;
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}
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static __always_inline long clock_gettime_fallback(
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clockid_t _clkid,
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struct __kernel_timespec *_ts)
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{
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register struct __kernel_timespec *ts asm("a1") = _ts;
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register clockid_t clkid asm("a0") = _clkid;
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register long ret asm("v0");
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#if _MIPS_SIM == _MIPS_SIM_ABI64
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register long nr asm("v0") = __NR_clock_gettime;
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#else
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register long nr asm("v0") = __NR_clock_gettime64;
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#endif
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register long error asm("a3");
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asm volatile(
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" syscall\n"
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: "=r" (ret), "=r" (error)
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: "r" (clkid), "r" (ts), "r" (nr)
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: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
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"$14", "$15", "$24", "$25", "hi", "lo", "memory");
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return error ? -ret : ret;
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}
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static __always_inline int clock_getres_fallback(
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clockid_t _clkid,
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struct __kernel_timespec *_ts)
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{
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register struct __kernel_timespec *ts asm("a1") = _ts;
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register clockid_t clkid asm("a0") = _clkid;
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register long ret asm("v0");
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#if _MIPS_SIM == _MIPS_SIM_ABI64
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register long nr asm("v0") = __NR_clock_getres;
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#else
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register long nr asm("v0") = __NR_clock_getres_time64;
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#endif
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register long error asm("a3");
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asm volatile(
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" syscall\n"
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: "=r" (ret), "=r" (error)
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: "r" (clkid), "r" (ts), "r" (nr)
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: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
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"$14", "$15", "$24", "$25", "hi", "lo", "memory");
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return error ? -ret : ret;
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}
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#if _MIPS_SIM != _MIPS_SIM_ABI64
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#define VDSO_HAS_32BIT_FALLBACK 1
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static __always_inline long clock_gettime32_fallback(
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clockid_t _clkid,
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struct old_timespec32 *_ts)
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{
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register struct old_timespec32 *ts asm("a1") = _ts;
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register clockid_t clkid asm("a0") = _clkid;
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register long ret asm("v0");
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register long nr asm("v0") = __NR_clock_gettime;
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register long error asm("a3");
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asm volatile(
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" syscall\n"
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: "=r" (ret), "=r" (error)
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: "r" (clkid), "r" (ts), "r" (nr)
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: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
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"$14", "$15", "$24", "$25", "hi", "lo", "memory");
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return error ? -ret : ret;
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}
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static __always_inline int clock_getres32_fallback(
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clockid_t _clkid,
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struct old_timespec32 *_ts)
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{
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register struct old_timespec32 *ts asm("a1") = _ts;
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register clockid_t clkid asm("a0") = _clkid;
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register long ret asm("v0");
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register long nr asm("v0") = __NR_clock_getres;
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register long error asm("a3");
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asm volatile(
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" syscall\n"
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: "=r" (ret), "=r" (error)
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: "r" (clkid), "r" (ts), "r" (nr)
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: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
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"$14", "$15", "$24", "$25", "hi", "lo", "memory");
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return error ? -ret : ret;
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}
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#endif
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#ifdef CONFIG_CSRC_R4K
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static __always_inline u64 read_r4k_count(void)
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{
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unsigned int count;
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__asm__ __volatile__(
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" .set push\n"
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" .set mips32r2\n"
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" rdhwr %0, $2\n"
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" .set pop\n"
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: "=r" (count));
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return count;
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}
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#endif
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#ifdef CONFIG_CLKSRC_MIPS_GIC
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static __always_inline u64 read_gic_count(const struct vdso_data *data)
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{
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void __iomem *gic = get_gic(data);
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u32 hi, hi2, lo;
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do {
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hi = __raw_readl(gic + sizeof(lo));
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lo = __raw_readl(gic);
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hi2 = __raw_readl(gic + sizeof(lo));
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} while (hi2 != hi);
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return (((u64)hi) << 32) + lo;
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}
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#endif
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static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
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{
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#ifdef CONFIG_CLKSRC_MIPS_GIC
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const struct vdso_data *data = get_vdso_data();
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#endif
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u64 cycle_now;
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switch (clock_mode) {
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#ifdef CONFIG_CSRC_R4K
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case VDSO_CLOCK_R4K:
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cycle_now = read_r4k_count();
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break;
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#endif
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#ifdef CONFIG_CLKSRC_MIPS_GIC
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case VDSO_CLOCK_GIC:
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cycle_now = read_gic_count(data);
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break;
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#endif
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default:
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cycle_now = __VDSO_USE_SYSCALL;
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break;
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}
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return cycle_now;
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}
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static __always_inline const struct vdso_data *__arch_get_vdso_data(void)
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{
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return get_vdso_data();
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_VDSO_GETTIMEOFDAY_H */
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