ARM: 8930/1: Add support for generic vDSO
The arm vDSO library requires some adaptations to take advantage of the newly introduced generic vDSO library. Introduce the following changes: - Modification vdso.c to be compliant with the common vdso datapage - Use of lib/vdso for gettimeofday - Implementation of elf note Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Vincenzo Frascino
Russell King
Родитель
9f1984c6ae
Коммит
20e2fc4231
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@ -0,0 +1,74 @@
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/* 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/cp15.h>
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#include <asm/unistd.h>
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#include <uapi/linux/time.h>
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extern struct vdso_data *__get_datapage(void);
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static __always_inline int 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("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_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 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("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_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 u64 __arch_get_hw_counter(int clock_mode)
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{
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#ifdef CONFIG_ARM_ARCH_TIMER
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u64 cycle_now;
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isb();
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cycle_now = read_sysreg(CNTVCT);
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return cycle_now;
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#else
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return -EINVAL; /* use fallback */
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#endif
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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_datapage();
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_VDSO_GETTIMEOFDAY_H */
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@ -0,0 +1,71 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_VDSO_VSYSCALL_H
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#define __ASM_VDSO_VSYSCALL_H
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#ifndef __ASSEMBLY__
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#include <linux/timekeeper_internal.h>
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#include <vdso/datapage.h>
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#include <asm/cacheflush.h>
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extern struct vdso_data *vdso_data;
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extern bool cntvct_ok;
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static __always_inline
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bool tk_is_cntvct(const struct timekeeper *tk)
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{
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if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
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return false;
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if (!tk->tkr_mono.clock->archdata.vdso_direct)
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return false;
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return true;
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}
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/*
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* Update the vDSO data page to keep in sync with kernel timekeeping.
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*/
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static __always_inline
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struct vdso_data *__arm_get_k_vdso_data(void)
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{
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return vdso_data;
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}
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#define __arch_get_k_vdso_data __arm_get_k_vdso_data
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static __always_inline
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int __arm_update_vdso_data(void)
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{
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return !cntvct_ok;
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}
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#define __arch_update_vdso_data __arm_update_vdso_data
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static __always_inline
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int __arm_get_clock_mode(struct timekeeper *tk)
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{
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u32 __tk_is_cntvct = tk_is_cntvct(tk);
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return __tk_is_cntvct;
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}
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#define __arch_get_clock_mode __arm_get_clock_mode
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static __always_inline
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int __arm_use_vsyscall(struct vdso_data *vdata)
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{
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return vdata[CS_HRES_COARSE].clock_mode;
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}
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#define __arch_use_vsyscall __arm_use_vsyscall
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static __always_inline
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void __arm_sync_vdso_data(struct vdso_data *vdata)
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{
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flush_dcache_page(virt_to_page(vdata));
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}
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#define __arch_sync_vdso_data __arm_sync_vdso_data
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/* The asm-generic header needs to be included after the definitions above */
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#include <asm-generic/vdso/vsyscall.h>
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_VDSO_VSYSCALL_H */
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@ -11,35 +11,12 @@
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#ifndef __ASSEMBLY__
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#include <vdso/datapage.h>
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#include <asm/page.h>
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/* Try to be cache-friendly on systems that don't implement the
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* generic timer: fit the unconditionally updated fields in the first
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* 32 bytes.
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*/
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struct vdso_data {
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u32 seq_count; /* sequence count - odd during updates */
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u16 tk_is_cntvct; /* fall back to syscall if false */
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u16 cs_shift; /* clocksource shift */
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u32 xtime_coarse_sec; /* coarse time */
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u32 xtime_coarse_nsec;
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u32 wtm_clock_sec; /* wall to monotonic offset */
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u32 wtm_clock_nsec;
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u32 xtime_clock_sec; /* CLOCK_REALTIME - seconds */
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u32 cs_mult; /* clocksource multiplier */
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u64 cs_cycle_last; /* last cycle value */
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u64 cs_mask; /* clocksource mask */
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u64 xtime_clock_snsec; /* CLOCK_REALTIME sub-ns base */
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u32 tz_minuteswest; /* timezone info for gettimeofday(2) */
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u32 tz_dsttime;
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};
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union vdso_data_store {
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struct vdso_data data;
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u8 page[PAGE_SIZE];
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struct vdso_data data[CS_BASES];
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u8 page[PAGE_SIZE];
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};
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#endif /* !__ASSEMBLY__ */
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@ -23,6 +23,8 @@
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#include <asm/vdso.h>
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#include <asm/vdso_datapage.h>
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#include <clocksource/arm_arch_timer.h>
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#include <vdso/helpers.h>
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#include <vdso/vsyscall.h>
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#define MAX_SYMNAME 64
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@ -37,7 +39,7 @@ unsigned int vdso_total_pages __ro_after_init;
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* The VDSO data page.
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*/
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static union vdso_data_store vdso_data_store __page_aligned_data;
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static struct vdso_data *vdso_data = &vdso_data_store.data;
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struct vdso_data *vdso_data = vdso_data_store.data;
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static struct page *vdso_data_page __ro_after_init;
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static const struct vm_special_mapping vdso_data_mapping = {
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@ -77,7 +79,7 @@ struct elfinfo {
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/* Cached result of boot-time check for whether the arch timer exists,
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* and if so, whether the virtual counter is useable.
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*/
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static bool cntvct_ok __ro_after_init;
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bool cntvct_ok __ro_after_init;
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static bool __init cntvct_functional(void)
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{
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@ -262,84 +264,3 @@ void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
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mm->context.vdso = addr;
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}
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static void vdso_write_begin(struct vdso_data *vdata)
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{
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++vdso_data->seq_count;
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smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */
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}
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static void vdso_write_end(struct vdso_data *vdata)
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{
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smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */
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++vdso_data->seq_count;
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}
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static bool tk_is_cntvct(const struct timekeeper *tk)
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{
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if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
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return false;
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if (!tk->tkr_mono.clock->archdata.vdso_direct)
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return false;
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return true;
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}
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/**
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* update_vsyscall - update the vdso data page
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*
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* Increment the sequence counter, making it odd, indicating to
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* userspace that an update is in progress. Update the fields used
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* for coarse clocks and, if the architected system timer is in use,
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* the fields used for high precision clocks. Increment the sequence
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* counter again, making it even, indicating to userspace that the
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* update is finished.
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*
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* Userspace is expected to sample seq_count before reading any other
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* fields from the data page. If seq_count is odd, userspace is
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* expected to wait until it becomes even. After copying data from
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* the page, userspace must sample seq_count again; if it has changed
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* from its previous value, userspace must retry the whole sequence.
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*
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* Calls to update_vsyscall are serialized by the timekeeping core.
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*/
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void update_vsyscall(struct timekeeper *tk)
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{
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struct timespec64 *wtm = &tk->wall_to_monotonic;
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if (!cntvct_ok) {
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/* The entry points have been zeroed, so there is no
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* point in updating the data page.
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*/
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return;
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}
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vdso_write_begin(vdso_data);
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vdso_data->tk_is_cntvct = tk_is_cntvct(tk);
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vdso_data->xtime_coarse_sec = tk->xtime_sec;
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vdso_data->xtime_coarse_nsec = (u32)(tk->tkr_mono.xtime_nsec >>
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tk->tkr_mono.shift);
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vdso_data->wtm_clock_sec = wtm->tv_sec;
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vdso_data->wtm_clock_nsec = wtm->tv_nsec;
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if (vdso_data->tk_is_cntvct) {
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vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
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vdso_data->xtime_clock_sec = tk->xtime_sec;
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vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec;
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vdso_data->cs_mult = tk->tkr_mono.mult;
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vdso_data->cs_shift = tk->tkr_mono.shift;
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vdso_data->cs_mask = tk->tkr_mono.mask;
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}
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vdso_write_end(vdso_data);
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flush_dcache_page(virt_to_page(vdso_data));
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}
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void update_vsyscall_tz(void)
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{
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vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
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vdso_data->tz_dsttime = sys_tz.tz_dsttime;
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flush_dcache_page(virt_to_page(vdso_data));
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}
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@ -896,7 +896,10 @@ config VDSO
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bool "Enable VDSO for acceleration of some system calls"
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depends on AEABI && MMU && CPU_V7
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default y if ARM_ARCH_TIMER
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select HAVE_GENERIC_VDSO
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select GENERIC_TIME_VSYSCALL
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select GENERIC_VDSO_32
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select GENERIC_GETTIMEOFDAY
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help
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Place in the process address space an ELF shared object
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providing fast implementations of gettimeofday and
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@ -1,7 +1,13 @@
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# SPDX-License-Identifier: GPL-2.0
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# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
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# the inclusion of generic Makefile.
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ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32
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include $(srctree)/lib/vdso/Makefile
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hostprogs-y := vdsomunge
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obj-vdso := vgettimeofday.o datapage.o
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obj-vdso := vgettimeofday.o datapage.o note.o
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# Build rules
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targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.so.raw vdso.lds
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@ -24,7 +30,11 @@ CFLAGS_REMOVE_vdso.o = -pg
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# Force -O2 to avoid libgcc dependencies
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CFLAGS_REMOVE_vgettimeofday.o = -pg -Os
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ifeq ($(c-gettimeofday-y),)
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CFLAGS_vgettimeofday.o = -O2
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else
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CFLAGS_vgettimeofday.o = -O2 -include $(c-gettimeofday-y)
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endif
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# Disable gcov profiling for VDSO code
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GCOV_PROFILE := n
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@ -37,7 +47,7 @@ $(obj)/vdso.o : $(obj)/vdso.so
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# Link rule for the .so file
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$(obj)/vdso.so.raw: $(obj)/vdso.lds $(obj-vdso) FORCE
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$(call if_changed,ld)
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$(call if_changed,vdsold_and_vdso_check)
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$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/vdsomunge FORCE
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$(call if_changed,vdsomunge)
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@ -47,6 +57,10 @@ $(obj)/%.so: OBJCOPYFLAGS := -S
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$(obj)/%.so: $(obj)/%.so.dbg FORCE
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$(call if_changed,objcopy)
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# Actual build commands
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quiet_cmd_vdsold_and_vdso_check = LD $@
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cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
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quiet_cmd_vdsomunge = MUNGE $@
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cmd_vdsomunge = $(objtree)/$(obj)/vdsomunge $< $@
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@ -0,0 +1,15 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2012-2018 ARM Limited
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*
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* This supplies .note.* sections to go into the PT_NOTE inside the vDSO text.
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* Here we can supply some information useful to userland.
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*/
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#include <linux/uts.h>
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#include <linux/version.h>
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#include <linux/elfnote.h>
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#include <linux/build-salt.h>
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ELFNOTE32("Linux", 0, LINUX_VERSION_CODE);
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BUILD_SALT;
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@ -1,259 +1,22 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ARM userspace implementations of gettimeofday() and similar.
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*
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* Copyright 2015 Mentor Graphics Corporation.
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*/
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#include <linux/compiler.h>
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#include <linux/hrtimer.h>
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#include <linux/time.h>
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#include <asm/barrier.h>
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#include <asm/bug.h>
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#include <asm/cp15.h>
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#include <asm/page.h>
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#include <asm/unistd.h>
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#include <asm/vdso_datapage.h>
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#include <linux/types.h>
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#ifndef CONFIG_AEABI
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#error This code depends on AEABI system call conventions
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#endif
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extern struct vdso_data *__get_datapage(void);
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static notrace u32 __vdso_read_begin(const struct vdso_data *vdata)
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int __vdso_clock_gettime(clockid_t clock,
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struct old_timespec32 *ts)
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{
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u32 seq;
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repeat:
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seq = READ_ONCE(vdata->seq_count);
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if (seq & 1) {
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cpu_relax();
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goto repeat;
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}
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return seq;
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return __cvdso_clock_gettime32(clock, ts);
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}
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static notrace u32 vdso_read_begin(const struct vdso_data *vdata)
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int __vdso_gettimeofday(struct __kernel_old_timeval *tv,
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struct timezone *tz)
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{
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u32 seq;
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seq = __vdso_read_begin(vdata);
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smp_rmb(); /* Pairs with smp_wmb in vdso_write_end */
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return seq;
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}
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static notrace int vdso_read_retry(const struct vdso_data *vdata, u32 start)
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{
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smp_rmb(); /* Pairs with smp_wmb in vdso_write_begin */
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return vdata->seq_count != start;
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}
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static notrace long clock_gettime_fallback(clockid_t _clkid,
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struct timespec *_ts)
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{
|
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register struct timespec *ts asm("r1") = _ts;
|
||||
register clockid_t clkid asm("r0") = _clkid;
|
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register long ret asm ("r0");
|
||||
register long nr asm("r7") = __NR_clock_gettime;
|
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|
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asm volatile(
|
||||
" swi #0\n"
|
||||
: "=r" (ret)
|
||||
: "r" (clkid), "r" (ts), "r" (nr)
|
||||
: "memory");
|
||||
|
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return ret;
|
||||
}
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|
||||
static notrace int do_realtime_coarse(struct timespec *ts,
|
||||
struct vdso_data *vdata)
|
||||
{
|
||||
u32 seq;
|
||||
|
||||
do {
|
||||
seq = vdso_read_begin(vdata);
|
||||
|
||||
ts->tv_sec = vdata->xtime_coarse_sec;
|
||||
ts->tv_nsec = vdata->xtime_coarse_nsec;
|
||||
|
||||
} while (vdso_read_retry(vdata, seq));
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static notrace int do_monotonic_coarse(struct timespec *ts,
|
||||
struct vdso_data *vdata)
|
||||
{
|
||||
struct timespec tomono;
|
||||
u32 seq;
|
||||
|
||||
do {
|
||||
seq = vdso_read_begin(vdata);
|
||||
|
||||
ts->tv_sec = vdata->xtime_coarse_sec;
|
||||
ts->tv_nsec = vdata->xtime_coarse_nsec;
|
||||
|
||||
tomono.tv_sec = vdata->wtm_clock_sec;
|
||||
tomono.tv_nsec = vdata->wtm_clock_nsec;
|
||||
|
||||
} while (vdso_read_retry(vdata, seq));
|
||||
|
||||
ts->tv_sec += tomono.tv_sec;
|
||||
timespec_add_ns(ts, tomono.tv_nsec);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_ARM_ARCH_TIMER
|
||||
|
||||
static notrace u64 get_ns(struct vdso_data *vdata)
|
||||
{
|
||||
u64 cycle_delta;
|
||||
u64 cycle_now;
|
||||
u64 nsec;
|
||||
|
||||
isb();
|
||||
cycle_now = read_sysreg(CNTVCT);
|
||||
|
||||
cycle_delta = (cycle_now - vdata->cs_cycle_last) & vdata->cs_mask;
|
||||
|
||||
nsec = (cycle_delta * vdata->cs_mult) + vdata->xtime_clock_snsec;
|
||||
nsec >>= vdata->cs_shift;
|
||||
|
||||
return nsec;
|
||||
}
|
||||
|
||||
static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata)
|
||||
{
|
||||
u64 nsecs;
|
||||
u32 seq;
|
||||
|
||||
do {
|
||||
seq = vdso_read_begin(vdata);
|
||||
|
||||
if (!vdata->tk_is_cntvct)
|
||||
return -1;
|
||||
|
||||
ts->tv_sec = vdata->xtime_clock_sec;
|
||||
nsecs = get_ns(vdata);
|
||||
|
||||
} while (vdso_read_retry(vdata, seq));
|
||||
|
||||
ts->tv_nsec = 0;
|
||||
timespec_add_ns(ts, nsecs);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata)
|
||||
{
|
||||
struct timespec tomono;
|
||||
u64 nsecs;
|
||||
u32 seq;
|
||||
|
||||
do {
|
||||
seq = vdso_read_begin(vdata);
|
||||
|
||||
if (!vdata->tk_is_cntvct)
|
||||
return -1;
|
||||
|
||||
ts->tv_sec = vdata->xtime_clock_sec;
|
||||
nsecs = get_ns(vdata);
|
||||
|
||||
tomono.tv_sec = vdata->wtm_clock_sec;
|
||||
tomono.tv_nsec = vdata->wtm_clock_nsec;
|
||||
|
||||
} while (vdso_read_retry(vdata, seq));
|
||||
|
||||
ts->tv_sec += tomono.tv_sec;
|
||||
ts->tv_nsec = 0;
|
||||
timespec_add_ns(ts, nsecs + tomono.tv_nsec);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#else /* CONFIG_ARM_ARCH_TIMER */
|
||||
|
||||
static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata)
|
||||
{
|
||||
return -1;
|
||||
}
|
||||
|
||||
static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata)
|
||||
{
|
||||
return -1;
|
||||
}
|
||||
|
||||
#endif /* CONFIG_ARM_ARCH_TIMER */
|
||||
|
||||
notrace int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts)
|
||||
{
|
||||
struct vdso_data *vdata;
|
||||
int ret = -1;
|
||||
|
||||
vdata = __get_datapage();
|
||||
|
||||
switch (clkid) {
|
||||
case CLOCK_REALTIME_COARSE:
|
||||
ret = do_realtime_coarse(ts, vdata);
|
||||
break;
|
||||
case CLOCK_MONOTONIC_COARSE:
|
||||
ret = do_monotonic_coarse(ts, vdata);
|
||||
break;
|
||||
case CLOCK_REALTIME:
|
||||
ret = do_realtime(ts, vdata);
|
||||
break;
|
||||
case CLOCK_MONOTONIC:
|
||||
ret = do_monotonic(ts, vdata);
|
||||
break;
|
||||
default:
|
||||
break;
|
||||
}
|
||||
|
||||
if (ret)
|
||||
ret = clock_gettime_fallback(clkid, ts);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static notrace long gettimeofday_fallback(struct timeval *_tv,
|
||||
struct timezone *_tz)
|
||||
{
|
||||
register struct timezone *tz asm("r1") = _tz;
|
||||
register struct timeval *tv asm("r0") = _tv;
|
||||
register long ret asm ("r0");
|
||||
register long nr asm("r7") = __NR_gettimeofday;
|
||||
|
||||
asm volatile(
|
||||
" swi #0\n"
|
||||
: "=r" (ret)
|
||||
: "r" (tv), "r" (tz), "r" (nr)
|
||||
: "memory");
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
|
||||
{
|
||||
struct timespec ts;
|
||||
struct vdso_data *vdata;
|
||||
int ret;
|
||||
|
||||
vdata = __get_datapage();
|
||||
|
||||
ret = do_realtime(&ts, vdata);
|
||||
if (ret)
|
||||
return gettimeofday_fallback(tv, tz);
|
||||
|
||||
if (tv) {
|
||||
tv->tv_sec = ts.tv_sec;
|
||||
tv->tv_usec = ts.tv_nsec / 1000;
|
||||
}
|
||||
if (tz) {
|
||||
tz->tz_minuteswest = vdata->tz_minuteswest;
|
||||
tz->tz_dsttime = vdata->tz_dsttime;
|
||||
}
|
||||
|
||||
return ret;
|
||||
return __cvdso_gettimeofday(tv, tz);
|
||||
}
|
||||
|
||||
/* Avoid unresolved references emitted by GCC */
|
||||
|
|
|
|||
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