diff options
Diffstat (limited to 'arch/sparc/vdso/vclock_gettime.c')
| -rw-r--r-- | arch/sparc/vdso/vclock_gettime.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/arch/sparc/vdso/vclock_gettime.c b/arch/sparc/vdso/vclock_gettime.c new file mode 100644 index 000000000000..3feb3d960ca5 --- /dev/null +++ b/arch/sparc/vdso/vclock_gettime.c @@ -0,0 +1,264 @@ +/* + * Copyright 2006 Andi Kleen, SUSE Labs. + * Subject to the GNU Public License, v.2 + * + * Fast user context implementation of clock_gettime, gettimeofday, and time. + * + * The code should have no internal unresolved relocations. + * Check with readelf after changing. + * Also alternative() doesn't work. + */ +/* + * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved. + */ + +/* Disable profiling for userspace code: */ +#ifndef DISABLE_BRANCH_PROFILING +#define DISABLE_BRANCH_PROFILING +#endif + +#include <linux/kernel.h> +#include <linux/time.h> +#include <linux/string.h> +#include <asm/io.h> +#include <asm/unistd.h> +#include <asm/timex.h> +#include <asm/clocksource.h> +#include <asm/vvar.h> + +#undef TICK_PRIV_BIT +#ifdef CONFIG_SPARC64 +#define TICK_PRIV_BIT (1UL << 63) +#else +#define TICK_PRIV_BIT (1ULL << 63) +#endif + +#define SYSCALL_STRING \ + "ta 0x6d;" \ + "sub %%g0, %%o0, %%o0;" \ + +#define SYSCALL_CLOBBERS \ + "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \ + "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \ + "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \ + "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \ + "f32", "f34", "f36", "f38", "f40", "f42", "f44", "f46", \ + "f48", "f50", "f52", "f54", "f56", "f58", "f60", "f62", \ + "cc", "memory" + +/* + * Compute the vvar page's address in the process address space, and return it + * as a pointer to the vvar_data. + */ +static notrace noinline struct vvar_data * +get_vvar_data(void) +{ + unsigned long ret; + + /* + * vdso data page is the first vDSO page so grab the return address + * and move up a page to get to the data page. + */ + ret = (unsigned long)__builtin_return_address(0); + ret &= ~(8192 - 1); + ret -= 8192; + + return (struct vvar_data *) ret; +} + +static notrace long +vdso_fallback_gettime(long clock, struct timespec *ts) +{ + register long num __asm__("g1") = __NR_clock_gettime; + register long o0 __asm__("o0") = clock; + register long o1 __asm__("o1") = (long) ts; + + __asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num), + "0" (o0), "r" (o1) : SYSCALL_CLOBBERS); + return o0; +} + +static notrace __always_inline long +vdso_fallback_gettimeofday(struct timeval *tv, struct timezone *tz) +{ + register long num __asm__("g1") = __NR_gettimeofday; + register long o0 __asm__("o0") = (long) tv; + register long o1 __asm__("o1") = (long) tz; + + __asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num), + "0" (o0), "r" (o1) : SYSCALL_CLOBBERS); + return o0; +} + +#ifdef CONFIG_SPARC64 +static notrace noinline u64 +vread_tick(void) { + u64 ret; + + __asm__ __volatile__("rd %%asr24, %0 \n" + ".section .vread_tick_patch, \"ax\" \n" + "rd %%tick, %0 \n" + ".previous \n" + : "=&r" (ret)); + return ret & ~TICK_PRIV_BIT; +} +#else +static notrace noinline u64 +vread_tick(void) +{ + unsigned int lo, hi; + + __asm__ __volatile__("rd %%asr24, %%g1\n\t" + "srlx %%g1, 32, %1\n\t" + "srl %%g1, 0, %0\n" + ".section .vread_tick_patch, \"ax\" \n" + "rd %%tick, %%g1\n" + ".previous \n" + : "=&r" (lo), "=&r" (hi) + : + : "g1"); + return lo | ((u64)hi << 32); +} +#endif + +static notrace inline u64 +vgetsns(struct vvar_data *vvar) +{ + u64 v; + u64 cycles; + + cycles = vread_tick(); + v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask; + return v * vvar->clock.mult; +} + +static notrace noinline int +do_realtime(struct vvar_data *vvar, struct timespec *ts) +{ + unsigned long seq; + u64 ns; + + ts->tv_nsec = 0; + do { + seq = vvar_read_begin(vvar); + ts->tv_sec = vvar->wall_time_sec; + ns = vvar->wall_time_snsec; + ns += vgetsns(vvar); + ns >>= vvar->clock.shift; + } while (unlikely(vvar_read_retry(vvar, seq))); + + timespec_add_ns(ts, ns); + + return 0; +} + +static notrace noinline int +do_monotonic(struct vvar_data *vvar, struct timespec *ts) +{ + unsigned long seq; + u64 ns; + + ts->tv_nsec = 0; + do { + seq = vvar_read_begin(vvar); + ts->tv_sec = vvar->monotonic_time_sec; + ns = vvar->monotonic_time_snsec; + ns += vgetsns(vvar); + ns >>= vvar->clock.shift; + } while (unlikely(vvar_read_retry(vvar, seq))); + + timespec_add_ns(ts, ns); + + return 0; +} + +static notrace noinline int +do_realtime_coarse(struct vvar_data *vvar, struct timespec *ts) +{ + unsigned long seq; + + do { + seq = vvar_read_begin(vvar); + ts->tv_sec = vvar->wall_time_coarse_sec; + ts->tv_nsec = vvar->wall_time_coarse_nsec; + } while (unlikely(vvar_read_retry(vvar, seq))); + return 0; +} + +static notrace noinline int +do_monotonic_coarse(struct vvar_data *vvar, struct timespec *ts) +{ + unsigned long seq; + + do { + seq = vvar_read_begin(vvar); + ts->tv_sec = vvar->monotonic_time_coarse_sec; + ts->tv_nsec = vvar->monotonic_time_coarse_nsec; + } while (unlikely(vvar_read_retry(vvar, seq))); + + return 0; +} + +notrace int +__vdso_clock_gettime(clockid_t clock, struct timespec *ts) +{ + struct vvar_data *vvd = get_vvar_data(); + + switch (clock) { + case CLOCK_REALTIME: + if (unlikely(vvd->vclock_mode == VCLOCK_NONE)) + break; + return do_realtime(vvd, ts); + case CLOCK_MONOTONIC: + if (unlikely(vvd->vclock_mode == VCLOCK_NONE)) + break; + return do_monotonic(vvd, ts); + case CLOCK_REALTIME_COARSE: + return do_realtime_coarse(vvd, ts); + case CLOCK_MONOTONIC_COARSE: + return do_monotonic_coarse(vvd, ts); + } + /* + * Unknown clock ID ? Fall back to the syscall. + */ + return vdso_fallback_gettime(clock, ts); +} +int +clock_gettime(clockid_t, struct timespec *) + __attribute__((weak, alias("__vdso_clock_gettime"))); + +notrace int +__vdso_gettimeofday(struct timeval *tv, struct timezone *tz) +{ + struct vvar_data *vvd = get_vvar_data(); + + if (likely(vvd->vclock_mode != VCLOCK_NONE)) { + if (likely(tv != NULL)) { + union tstv_t { + struct timespec ts; + struct timeval tv; + } *tstv = (union tstv_t *) tv; + do_realtime(vvd, &tstv->ts); + /* + * Assign before dividing to ensure that the division is + * done in the type of tv_usec, not tv_nsec. + * + * There cannot be > 1 billion usec in a second: + * do_realtime() has already distributed such overflow + * into tv_sec. So we can assign it to an int safely. + */ + tstv->tv.tv_usec = tstv->ts.tv_nsec; + tstv->tv.tv_usec /= 1000; + } + if (unlikely(tz != NULL)) { + /* Avoid memcpy. Some old compilers fail to inline it */ + tz->tz_minuteswest = vvd->tz_minuteswest; + tz->tz_dsttime = vvd->tz_dsttime; + } + return 0; + } + return vdso_fallback_gettimeofday(tv, tz); +} +int +gettimeofday(struct timeval *, struct timezone *) + __attribute__((weak, alias("__vdso_gettimeofday"))); |
