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177 lines
4.3 KiB
177 lines
4.3 KiB
/* 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/barrier.h> |
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#include <asm/unistd.h> |
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#include <asm/errno.h> |
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#include <asm/vdso/compat_barrier.h> |
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#define VDSO_HAS_CLOCK_GETRES 1 |
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#define BUILD_VDSO32 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("r1") = _tz; |
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register struct __kernel_old_timeval *tv asm("r0") = _tv; |
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register long ret asm ("r0"); |
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register long nr asm("r7") = __NR_compat_gettimeofday; |
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asm volatile( |
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" swi #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("r1") = _ts; |
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register clockid_t clkid asm("r0") = _clkid; |
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register long ret asm ("r0"); |
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register long nr asm("r7") = __NR_compat_clock_gettime64; |
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asm volatile( |
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" swi #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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long clock_gettime32_fallback(clockid_t _clkid, struct old_timespec32 *_ts) |
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{ |
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register struct old_timespec32 *ts asm("r1") = _ts; |
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register clockid_t clkid asm("r0") = _clkid; |
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register long ret asm ("r0"); |
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register long nr asm("r7") = __NR_compat_clock_gettime; |
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asm volatile( |
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" swi #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("r1") = _ts; |
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register clockid_t clkid asm("r0") = _clkid; |
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register long ret asm ("r0"); |
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register long nr asm("r7") = __NR_compat_clock_getres_time64; |
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asm volatile( |
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" swi #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_getres32_fallback(clockid_t _clkid, struct old_timespec32 *_ts) |
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{ |
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register struct old_timespec32 *ts asm("r1") = _ts; |
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register clockid_t clkid asm("r0") = _clkid; |
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register long ret asm ("r0"); |
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register long nr asm("r7") = __NR_compat_clock_getres; |
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asm volatile( |
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" swi #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_ARCHTIMER) |
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return 0; |
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/* |
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* This isb() is required to prevent that the counter value |
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* is speculated. |
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*/ |
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isb(); |
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asm volatile("mrrc p15, 1, %Q0, %R0, c14" : "=r" (res)); |
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/* |
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* This isb() is required to prevent that the seq lock is |
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* speculated. |
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*/ |
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isb(); |
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return res; |
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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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const struct vdso_data *ret; |
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/* |
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* This simply puts &_vdso_data into ret. The reason why we don't use |
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* `ret = _vdso_data` is that the compiler tends to optimise this in a |
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* very suboptimal way: instead of keeping &_vdso_data in a register, |
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* it goes through a relocation almost every time _vdso_data must be |
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* accessed (even in subfunctions). This is both time and space |
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* consuming: each relocation uses a word in the code section, and it |
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* has to be loaded at runtime. |
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* |
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* This trick hides the assignment from the compiler. Since it cannot |
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* track where the pointer comes from, it will only use one relocation |
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* where __arch_get_vdso_data() is called, and then keep the result in |
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* a register. |
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*/ |
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asm volatile("mov %0, %1" : "=r"(ret) : "r"(_vdso_data)); |
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return ret; |
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} |
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#ifdef CONFIG_TIME_NS |
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static __always_inline const struct vdso_data *__arch_get_timens_vdso_data(void) |
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{ |
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const struct vdso_data *ret; |
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/* See __arch_get_vdso_data(). */ |
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asm volatile("mov %0, %1" : "=r"(ret) : "r"(_timens_data)); |
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return ret; |
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} |
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#endif |
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static inline bool vdso_clocksource_ok(const struct vdso_data *vd) |
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{ |
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return vd->clock_mode == VDSO_CLOCKMODE_ARCHTIMER; |
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} |
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#define vdso_clocksource_ok vdso_clocksource_ok |
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#endif /* !__ASSEMBLY__ */ |
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#endif /* __ASM_VDSO_GETTIMEOFDAY_H */
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