diff options
Diffstat (limited to 'arch/tile/kernel/vdso/vgettimeofday.c')
| -rw-r--r-- | arch/tile/kernel/vdso/vgettimeofday.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/arch/tile/kernel/vdso/vgettimeofday.c b/arch/tile/kernel/vdso/vgettimeofday.c new file mode 100644 index 000000000..8bb21eda0 --- /dev/null +++ b/arch/tile/kernel/vdso/vgettimeofday.c @@ -0,0 +1,198 @@ +/* + * Copyright 2012 Tilera Corporation. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + */ + +#define VDSO_BUILD /* avoid some shift warnings for -m32 in <asm/page.h> */ +#include <linux/time.h> +#include <asm/timex.h> +#include <asm/unistd.h> +#include <asm/vdso.h> + +#if CHIP_HAS_SPLIT_CYCLE() +static inline cycles_t get_cycles_inline(void) +{ + unsigned int high = __insn_mfspr(SPR_CYCLE_HIGH); + unsigned int low = __insn_mfspr(SPR_CYCLE_LOW); + unsigned int high2 = __insn_mfspr(SPR_CYCLE_HIGH); + + while (unlikely(high != high2)) { + low = __insn_mfspr(SPR_CYCLE_LOW); + high = high2; + high2 = __insn_mfspr(SPR_CYCLE_HIGH); + } + + return (((cycles_t)high) << 32) | low; +} +#define get_cycles get_cycles_inline +#endif + +struct syscall_return_value { + long value; + long error; +}; + +/* + * Find out the vDSO data page address in the process address space. + */ +inline unsigned long get_datapage(void) +{ + unsigned long ret; + + /* vdso data page located in the 2nd vDSO page. */ + asm volatile ("lnk %0" : "=r"(ret)); + ret &= ~(PAGE_SIZE - 1); + ret += PAGE_SIZE; + + return ret; +} + +static inline u64 vgetsns(struct vdso_data *vdso) +{ + return ((get_cycles() - vdso->cycle_last) & vdso->mask) * vdso->mult; +} + +static inline int do_realtime(struct vdso_data *vdso, struct timespec *ts) +{ + unsigned count; + u64 ns; + + do { + count = read_seqcount_begin(&vdso->tb_seq); + ts->tv_sec = vdso->wall_time_sec; + ns = vdso->wall_time_snsec; + ns += vgetsns(vdso); + ns >>= vdso->shift; + } while (unlikely(read_seqcount_retry(&vdso->tb_seq, count))); + + ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); + ts->tv_nsec = ns; + + return 0; +} + +static inline int do_monotonic(struct vdso_data *vdso, struct timespec *ts) +{ + unsigned count; + u64 ns; + + do { + count = read_seqcount_begin(&vdso->tb_seq); + ts->tv_sec = vdso->monotonic_time_sec; + ns = vdso->monotonic_time_snsec; + ns += vgetsns(vdso); + ns >>= vdso->shift; + } while (unlikely(read_seqcount_retry(&vdso->tb_seq, count))); + + ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); + ts->tv_nsec = ns; + + return 0; +} + +static inline int do_realtime_coarse(struct vdso_data *vdso, + struct timespec *ts) +{ + unsigned count; + + do { + count = read_seqcount_begin(&vdso->tb_seq); + ts->tv_sec = vdso->wall_time_coarse_sec; + ts->tv_nsec = vdso->wall_time_coarse_nsec; + } while (unlikely(read_seqcount_retry(&vdso->tb_seq, count))); + + return 0; +} + +static inline int do_monotonic_coarse(struct vdso_data *vdso, + struct timespec *ts) +{ + unsigned count; + + do { + count = read_seqcount_begin(&vdso->tb_seq); + ts->tv_sec = vdso->monotonic_time_coarse_sec; + ts->tv_nsec = vdso->monotonic_time_coarse_nsec; + } while (unlikely(read_seqcount_retry(&vdso->tb_seq, count))); + + return 0; +} + +struct syscall_return_value __vdso_gettimeofday(struct timeval *tv, + struct timezone *tz) +{ + struct syscall_return_value ret = { 0, 0 }; + unsigned count; + struct vdso_data *vdso = (struct vdso_data *)get_datapage(); + + /* The use of the timezone is obsolete, normally tz is NULL. */ + if (unlikely(tz != NULL)) { + do { + count = read_seqcount_begin(&vdso->tz_seq); + tz->tz_minuteswest = vdso->tz_minuteswest; + tz->tz_dsttime = vdso->tz_dsttime; + } while (unlikely(read_seqcount_retry(&vdso->tz_seq, count))); + } + + if (unlikely(tv == NULL)) + return ret; + + do_realtime(vdso, (struct timespec *)tv); + tv->tv_usec /= 1000; + + return ret; +} + +int gettimeofday(struct timeval *tv, struct timezone *tz) + __attribute__((weak, alias("__vdso_gettimeofday"))); + +static struct syscall_return_value vdso_fallback_gettime(long clock, + struct timespec *ts) +{ + struct syscall_return_value ret; + __asm__ __volatile__ ( + "swint1" + : "=R00" (ret.value), "=R01" (ret.error) + : "R10" (__NR_clock_gettime), "R00" (clock), "R01" (ts) + : "r2", "r3", "r4", "r5", "r6", "r7", + "r8", "r9", "r11", "r12", "r13", "r14", "r15", + "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23", + "r24", "r25", "r26", "r27", "r28", "r29", "memory"); + return ret; +} + +struct syscall_return_value __vdso_clock_gettime(clockid_t clock, + struct timespec *ts) +{ + struct vdso_data *vdso = (struct vdso_data *)get_datapage(); + struct syscall_return_value ret = { 0, 0 }; + + switch (clock) { + case CLOCK_REALTIME: + do_realtime(vdso, ts); + return ret; + case CLOCK_MONOTONIC: + do_monotonic(vdso, ts); + return ret; + case CLOCK_REALTIME_COARSE: + do_realtime_coarse(vdso, ts); + return ret; + case CLOCK_MONOTONIC_COARSE: + do_monotonic_coarse(vdso, ts); + return ret; + default: + return vdso_fallback_gettime(clock, ts); + } +} + +int clock_gettime(clockid_t clock, struct timespec *ts) + __attribute__((weak, alias("__vdso_clock_gettime"))); |