[PATCH 1/2] arm64:vdso: Rewrite gettimeofday into C.
Andrew Pinski
apinski at cavium.com
Sun Apr 23 19:47:00 EDT 2017
This allows the compiler to optimize the divide by 1000.
And remove the other divide.
On ThunderX, gettimeofday improves by 32%. On ThunderX 2,
gettimeofday improves by 18%.
Signed-off-by: Andrew Pinski <apinski at cavium.com>
---
arch/arm64/kernel/vdso/Makefile | 13 +-
arch/arm64/kernel/vdso/gettimeofday.S | 329 --------------------------------
arch/arm64/kernel/vdso/gettimeofday.c | 342 ++++++++++++++++++++++++++++++++++
3 files changed, 348 insertions(+), 336 deletions(-)
delete mode 100644 arch/arm64/kernel/vdso/gettimeofday.S
create mode 100644 arch/arm64/kernel/vdso/gettimeofday.c
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index 62c84f7..55f352f 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -11,10 +11,15 @@ obj-vdso := gettimeofday.o note.o sigreturn.o
targets := $(obj-vdso) vdso.so vdso.so.dbg
obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
-ccflags-y := -shared -fno-common -fno-builtin
+ccflags-y := -shared -fno-common -fno-builtin -fno-stack-protector
+ccflags-y += -DDISABLE_BRANCH_PROFILING
ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \
$(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
+# Force -O2 to avoid libgcc dependencies
+CFLAGS_REMOVE_gettimeofday.o = -pg -Os
+CFLAGS_gettimeofday.o = -O2 -mcmodel=tiny
+
# Disable gcov profiling for VDSO code
GCOV_PROFILE := n
@@ -48,15 +53,9 @@ endef
include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
$(call if_changed,vdsosym)
-# Assembly rules for the .S files
-$(obj-vdso): %.o: %.S FORCE
- $(call if_changed_dep,vdsoas)
-
# Actual build commands
quiet_cmd_vdsold = VDSOL $@
cmd_vdsold = $(CC) $(c_flags) -Wl,-n -Wl,-T $^ -o $@
-quiet_cmd_vdsoas = VDSOA $@
- cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $<
# Install commands for the unstripped file
quiet_cmd_vdso_install = INSTALL $@
diff --git a/arch/arm64/kernel/vdso/gettimeofday.S b/arch/arm64/kernel/vdso/gettimeofday.S
deleted file mode 100644
index e00b467..0000000
--- a/arch/arm64/kernel/vdso/gettimeofday.S
+++ /dev/null
@@ -1,329 +0,0 @@
-/*
- * Userspace implementations of gettimeofday() and friends.
- *
- * Copyright (C) 2012 ARM Limited
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * 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. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- *
- * Author: Will Deacon <will.deacon at arm.com>
- */
-
-#include <linux/linkage.h>
-#include <asm/asm-offsets.h>
-#include <asm/unistd.h>
-
-#define NSEC_PER_SEC_LO16 0xca00
-#define NSEC_PER_SEC_HI16 0x3b9a
-
-vdso_data .req x6
-seqcnt .req w7
-w_tmp .req w8
-x_tmp .req x8
-
-/*
- * Conventions for macro arguments:
- * - An argument is write-only if its name starts with "res".
- * - All other arguments are read-only, unless otherwise specified.
- */
-
- .macro seqcnt_acquire
-9999: ldr seqcnt, [vdso_data, #VDSO_TB_SEQ_COUNT]
- tbnz seqcnt, #0, 9999b
- dmb ishld
- .endm
-
- .macro seqcnt_check fail
- dmb ishld
- ldr w_tmp, [vdso_data, #VDSO_TB_SEQ_COUNT]
- cmp w_tmp, seqcnt
- b.ne \fail
- .endm
-
- .macro syscall_check fail
- ldr w_tmp, [vdso_data, #VDSO_USE_SYSCALL]
- cbnz w_tmp, \fail
- .endm
-
- .macro get_nsec_per_sec res
- mov \res, #NSEC_PER_SEC_LO16
- movk \res, #NSEC_PER_SEC_HI16, lsl #16
- .endm
-
- /*
- * Returns the clock delta, in nanoseconds left-shifted by the clock
- * shift.
- */
- .macro get_clock_shifted_nsec res, cycle_last, mult
- /* Read the virtual counter. */
- isb
- mrs x_tmp, cntvct_el0
- /* Calculate cycle delta and convert to ns. */
- sub \res, x_tmp, \cycle_last
- /* We can only guarantee 56 bits of precision. */
- movn x_tmp, #0xff00, lsl #48
- and \res, x_tmp, \res
- mul \res, \res, \mult
- .endm
-
- /*
- * Returns in res_{sec,nsec} the REALTIME timespec, based on the
- * "wall time" (xtime) and the clock_mono delta.
- */
- .macro get_ts_realtime res_sec, res_nsec, \
- clock_nsec, xtime_sec, xtime_nsec, nsec_to_sec
- add \res_nsec, \clock_nsec, \xtime_nsec
- udiv x_tmp, \res_nsec, \nsec_to_sec
- add \res_sec, \xtime_sec, x_tmp
- msub \res_nsec, x_tmp, \nsec_to_sec, \res_nsec
- .endm
-
- /*
- * Returns in res_{sec,nsec} the timespec based on the clock_raw delta,
- * used for CLOCK_MONOTONIC_RAW.
- */
- .macro get_ts_clock_raw res_sec, res_nsec, clock_nsec, nsec_to_sec
- udiv \res_sec, \clock_nsec, \nsec_to_sec
- msub \res_nsec, \res_sec, \nsec_to_sec, \clock_nsec
- .endm
-
- /* sec and nsec are modified in place. */
- .macro add_ts sec, nsec, ts_sec, ts_nsec, nsec_to_sec
- /* Add timespec. */
- add \sec, \sec, \ts_sec
- add \nsec, \nsec, \ts_nsec
-
- /* Normalise the new timespec. */
- cmp \nsec, \nsec_to_sec
- b.lt 9999f
- sub \nsec, \nsec, \nsec_to_sec
- add \sec, \sec, #1
-9999:
- cmp \nsec, #0
- b.ge 9998f
- add \nsec, \nsec, \nsec_to_sec
- sub \sec, \sec, #1
-9998:
- .endm
-
- .macro clock_gettime_return, shift=0
- .if \shift == 1
- lsr x11, x11, x12
- .endif
- stp x10, x11, [x1, #TSPEC_TV_SEC]
- mov x0, xzr
- ret
- .endm
-
- .macro jump_slot jumptable, index, label
- .if (. - \jumptable) != 4 * (\index)
- .error "Jump slot index mismatch"
- .endif
- b \label
- .endm
-
- .text
-
-/* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); */
-ENTRY(__kernel_gettimeofday)
- .cfi_startproc
- adr vdso_data, _vdso_data
- /* If tv is NULL, skip to the timezone code. */
- cbz x0, 2f
-
- /* Compute the time of day. */
-1: seqcnt_acquire
- syscall_check fail=4f
- ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
- /* w11 = cs_mono_mult, w12 = cs_shift */
- ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
- ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
- seqcnt_check fail=1b
-
- get_nsec_per_sec res=x9
- lsl x9, x9, x12
-
- get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
- get_ts_realtime res_sec=x10, res_nsec=x11, \
- clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
-
- /* Convert ns to us. */
- mov x13, #1000
- lsl x13, x13, x12
- udiv x11, x11, x13
- stp x10, x11, [x0, #TVAL_TV_SEC]
-2:
- /* If tz is NULL, return 0. */
- cbz x1, 3f
- ldp w4, w5, [vdso_data, #VDSO_TZ_MINWEST]
- stp w4, w5, [x1, #TZ_MINWEST]
-3:
- mov x0, xzr
- ret
-4:
- /* Syscall fallback. */
- mov x8, #__NR_gettimeofday
- svc #0
- ret
- .cfi_endproc
-ENDPROC(__kernel_gettimeofday)
-
-#define JUMPSLOT_MAX CLOCK_MONOTONIC_COARSE
-
-/* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); */
-ENTRY(__kernel_clock_gettime)
- .cfi_startproc
- cmp w0, #JUMPSLOT_MAX
- b.hi syscall
- adr vdso_data, _vdso_data
- adr x_tmp, jumptable
- add x_tmp, x_tmp, w0, uxtw #2
- br x_tmp
-
- ALIGN
-jumptable:
- jump_slot jumptable, CLOCK_REALTIME, realtime
- jump_slot jumptable, CLOCK_MONOTONIC, monotonic
- b syscall
- b syscall
- jump_slot jumptable, CLOCK_MONOTONIC_RAW, monotonic_raw
- jump_slot jumptable, CLOCK_REALTIME_COARSE, realtime_coarse
- jump_slot jumptable, CLOCK_MONOTONIC_COARSE, monotonic_coarse
-
- .if (. - jumptable) != 4 * (JUMPSLOT_MAX + 1)
- .error "Wrong jumptable size"
- .endif
-
- ALIGN
-realtime:
- seqcnt_acquire
- syscall_check fail=syscall
- ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
- /* w11 = cs_mono_mult, w12 = cs_shift */
- ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
- ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
- seqcnt_check fail=realtime
-
- /* All computations are done with left-shifted nsecs. */
- get_nsec_per_sec res=x9
- lsl x9, x9, x12
-
- get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
- get_ts_realtime res_sec=x10, res_nsec=x11, \
- clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
- clock_gettime_return, shift=1
-
- ALIGN
-monotonic:
- seqcnt_acquire
- syscall_check fail=syscall
- ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
- /* w11 = cs_mono_mult, w12 = cs_shift */
- ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
- ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
- ldp x3, x4, [vdso_data, #VDSO_WTM_CLK_SEC]
- seqcnt_check fail=monotonic
-
- /* All computations are done with left-shifted nsecs. */
- lsl x4, x4, x12
- get_nsec_per_sec res=x9
- lsl x9, x9, x12
-
- get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
- get_ts_realtime res_sec=x10, res_nsec=x11, \
- clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
-
- add_ts sec=x10, nsec=x11, ts_sec=x3, ts_nsec=x4, nsec_to_sec=x9
- clock_gettime_return, shift=1
-
- ALIGN
-monotonic_raw:
- seqcnt_acquire
- syscall_check fail=syscall
- ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
- /* w11 = cs_raw_mult, w12 = cs_shift */
- ldp w12, w11, [vdso_data, #VDSO_CS_SHIFT]
- ldp x13, x14, [vdso_data, #VDSO_RAW_TIME_SEC]
- seqcnt_check fail=monotonic_raw
-
- /* All computations are done with left-shifted nsecs. */
- lsl x14, x14, x12
- get_nsec_per_sec res=x9
- lsl x9, x9, x12
-
- get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
- get_ts_clock_raw res_sec=x10, res_nsec=x11, \
- clock_nsec=x15, nsec_to_sec=x9
-
- add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9
- clock_gettime_return, shift=1
-
- ALIGN
-realtime_coarse:
- seqcnt_acquire
- ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
- seqcnt_check fail=realtime_coarse
- clock_gettime_return
-
- ALIGN
-monotonic_coarse:
- seqcnt_acquire
- ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
- ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
- seqcnt_check fail=monotonic_coarse
-
- /* Computations are done in (non-shifted) nsecs. */
- get_nsec_per_sec res=x9
- add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9
- clock_gettime_return
-
- ALIGN
-syscall: /* Syscall fallback. */
- mov x8, #__NR_clock_gettime
- svc #0
- ret
- .cfi_endproc
-ENDPROC(__kernel_clock_gettime)
-
-/* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res); */
-ENTRY(__kernel_clock_getres)
- .cfi_startproc
- cmp w0, #CLOCK_REALTIME
- ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
- ccmp w0, #CLOCK_MONOTONIC_RAW, #0x4, ne
- b.ne 1f
-
- ldr x2, 5f
- b 2f
-1:
- cmp w0, #CLOCK_REALTIME_COARSE
- ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne
- b.ne 4f
- ldr x2, 6f
-2:
- cbz w1, 3f
- stp xzr, x2, [x1]
-
-3: /* res == NULL. */
- mov w0, wzr
- ret
-
-4: /* Syscall fallback. */
- mov x8, #__NR_clock_getres
- svc #0
- ret
-5:
- .quad CLOCK_REALTIME_RES
-6:
- .quad CLOCK_COARSE_RES
- .cfi_endproc
-ENDPROC(__kernel_clock_getres)
diff --git a/arch/arm64/kernel/vdso/gettimeofday.c b/arch/arm64/kernel/vdso/gettimeofday.c
new file mode 100644
index 0000000..a0ab8b1
--- /dev/null
+++ b/arch/arm64/kernel/vdso/gettimeofday.c
@@ -0,0 +1,342 @@
+/*
+ * Userspace implementations of gettimeofday() and friends.
+ *
+ * Copyright (C) 2017 Cavium, Inc.
+ * Copyright (C) 2012 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Will Deacon <will.deacon at arm.com>
+ * Rewriten into C by: Andrew Pinski <apinski at cavium.com>
+ */
+
+#include <uapi/linux/time.h>
+#include <asm/unistd.h>
+#include <asm/vdso_datapage.h>
+#include <linux/math64.h>
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/hrtimer.h>
+
+extern struct vdso_data _vdso_data;
+
+static notrace int gettimeofday_fallback(struct timeval *_tv,
+ struct timezone *_tz)
+{
+ register struct timezone *tz asm("x1") = _tz;
+ register struct timeval *tv asm("x0") = _tv;
+ register long ret asm ("x0");
+ register long nr asm("x8") = __NR_gettimeofday;
+
+ asm volatile(
+ " svc #0\n"
+ : "=r" (ret)
+ : "r" (tv), "r" (tz), "r" (nr)
+ : "memory");
+
+ return ret;
+}
+
+static notrace long clock_gettime_fallback(clockid_t _clkid,
+ struct timespec *_ts)
+{
+ register struct timespec *ts asm("x1") = _ts;
+ register clockid_t clkid asm("x0") = _clkid;
+ register long ret asm ("x0");
+ register long nr asm("x8") = __NR_clock_gettime;
+
+ asm volatile(
+ " svc #0\n"
+ : "=r" (ret)
+ : "r" (clkid), "r" (ts), "r" (nr)
+ : "memory");
+
+ return ret;
+}
+
+static notrace int clock_getres_fallback(clockid_t _clkid,
+ struct timespec *_ts)
+{
+ register struct timespec *ts asm("x1") = _ts;
+ register clockid_t clkid asm("x0") = _clkid;
+ register long ret asm ("x0");
+ register long nr asm("x8") = __NR_clock_getres;
+
+ asm volatile(
+ " svc #0\n"
+ : "=r" (ret)
+ : "r" (clkid), "r" (ts), "r" (nr)
+ : "memory");
+
+ return ret;
+}
+
+static notrace u32 vdso_read_begin(const struct vdso_data *vd)
+{
+ u32 seq;
+
+ do {
+ seq = READ_ONCE(vd->tb_seq_count);
+
+ if ((seq & 1) == 0)
+ break;
+
+ asm volatile ("" : : : "memory");
+ } while (true);
+
+ smp_rmb(); /* Pairs with smp_wmb in vdso_write_end */
+ return seq;
+}
+
+static notrace u32 vdso_read_retry(const struct vdso_data *vd, u32 start)
+{
+ u32 seq;
+
+ smp_rmb(); /* Pairs with smp_wmb in vdso_write_begin */
+ seq = READ_ONCE(vd->tb_seq_count);
+ return seq != start;
+}
+
+
+/*
+ * Returns the clock delta, in nanoseconds left-shifted by the clock
+ * shift.
+ */
+static notrace u64 get_clock_shifted_nsec(u64 cycle_last, u64 mult)
+{
+ u64 res;
+
+ /* Read the virtual counter. */
+ isb();
+ asm volatile("mrs %0, cntvct_el0" : "=r" (res) :: "memory");
+
+ res = res - cycle_last;
+ /* We can only guarantee 56 bits of precision. */
+ res &= ~(0xff00ul<<48);
+ return res * mult;
+}
+
+
+/* Code size doesn't matter (vdso is 4k/16k/64k anyway) and this is faster. */
+static __always_inline notrace int do_realtime(const struct vdso_data *vd,
+ struct timespec *ts)
+{
+ u32 seq, cs_mono_mult, cs_shift;
+ u64 ns, sec, cycle_last;
+
+ do {
+ seq = vdso_read_begin(vd);
+
+ if (vd->use_syscall)
+ return -1;
+
+ cycle_last = vd->cs_cycle_last;
+
+ cs_mono_mult = vd->cs_mono_mult;
+ cs_shift = vd->cs_shift;
+
+ sec = vd->xtime_clock_sec;
+ ns = vd->xtime_clock_nsec;
+
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ ns += get_clock_shifted_nsec(cycle_last, cs_mono_mult);
+ ns >>= cs_shift;
+ ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+ ts->tv_nsec = ns;
+
+ return 0;
+}
+
+static notrace int do_monotonic(const struct vdso_data *vd,
+ struct timespec *ts)
+{
+ u32 seq, cs_mono_mult, cs_shift;
+ u64 ns, cycle_last, sec;
+
+ do {
+ seq = vdso_read_begin(vd);
+
+ if (vd->use_syscall)
+ return 1;
+
+ cycle_last = vd->cs_cycle_last;
+
+ cs_mono_mult = vd->cs_mono_mult;
+ cs_shift = vd->cs_shift;
+
+ sec = vd->xtime_clock_sec;
+ ns = vd->xtime_clock_nsec;
+
+ sec += vd->wtm_clock_sec;
+ ns += vd->wtm_clock_nsec << cs_shift;
+
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ ns += get_clock_shifted_nsec(cycle_last, cs_mono_mult);
+ ns >>= cs_shift;
+
+ ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+ ts->tv_nsec = ns;
+
+ return 0;
+}
+
+static notrace int do_monotonic_raw(const struct vdso_data *vd,
+ struct timespec *ts)
+{
+ u32 seq, cs_raw_mult, cs_shift;
+ u64 ns, sec, cycle_last;
+
+ do {
+ seq = vdso_read_begin(vd);
+
+ if (vd->use_syscall)
+ return -1;
+
+ cycle_last = vd->cs_cycle_last;
+
+ cs_raw_mult = vd->cs_raw_mult;
+ cs_shift = vd->cs_shift;
+
+ sec = vd->raw_time_sec;
+ ns = vd->raw_time_nsec;
+
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ ns += get_clock_shifted_nsec(cycle_last, cs_raw_mult);
+ ns >>= cs_shift;
+ ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+ ts->tv_nsec = ns;
+
+ return 0;
+}
+
+
+static notrace void do_realtime_coarse(const struct vdso_data *vd,
+ struct timespec *ts)
+{
+ u32 seq;
+ u64 ns, sec;
+
+ do {
+ seq = vdso_read_begin(vd);
+
+ sec = vd->xtime_coarse_sec;
+ ns = vd->xtime_coarse_nsec;
+
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ ts->tv_sec = sec;
+ ts->tv_nsec = ns;
+}
+
+static notrace void do_monotonic_coarse(const struct vdso_data *vd,
+ struct timespec *ts)
+{
+ u32 seq;
+ u64 ns, sec, wtm_sec, wtm_ns;
+
+ do {
+
+ seq = vdso_read_begin(vd);
+
+ sec = vd->xtime_coarse_sec;
+ ns = vd->xtime_coarse_nsec;
+
+ wtm_sec = vd->wtm_clock_sec;
+ wtm_ns = vd->wtm_clock_nsec;
+
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ sec += wtm_sec;
+ ns += wtm_ns;
+ ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+ ts->tv_nsec = ns;
+}
+
+notrace int __kernel_clock_gettime(clockid_t clock, struct timespec *ts)
+{
+ const struct vdso_data *vd = &_vdso_data;
+
+ switch (clock) {
+ case CLOCK_REALTIME:
+ if (do_realtime(vd, ts))
+ goto fallback;
+ break;
+ case CLOCK_MONOTONIC:
+ if (do_monotonic(vd, ts))
+ goto fallback;
+ break;
+ case CLOCK_MONOTONIC_RAW:
+ do_monotonic_raw(vd, ts);
+ break;
+ case CLOCK_REALTIME_COARSE:
+ do_realtime_coarse(vd, ts);
+ break;
+ case CLOCK_MONOTONIC_COARSE:
+ do_monotonic_coarse(vd, ts);
+ break;
+ default:
+ goto fallback;
+ }
+
+ return 0;
+fallback:
+ return clock_gettime_fallback(clock, ts);
+}
+
+
+
+notrace int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz)
+{
+ const struct vdso_data *vd = &_vdso_data;
+
+ if (likely(tv != NULL)) {
+ struct timespec ts;
+
+ if (do_realtime(vd, &ts))
+ return gettimeofday_fallback(tv, tz);
+
+ tv->tv_sec = ts.tv_sec;
+ tv->tv_usec = ts.tv_nsec / 1000;
+ }
+
+ if (unlikely(tz != NULL)) {
+ tz->tz_minuteswest = vd->tz_minuteswest;
+ tz->tz_dsttime = vd->tz_dsttime;
+ }
+
+ return 0;
+}
+
+
+int __kernel_clock_getres(clockid_t clock_id, struct timespec *res)
+{
+ u64 ns;
+
+ if (clock_id == CLOCK_REALTIME ||
+ clock_id == CLOCK_MONOTONIC ||
+ clock_id == CLOCK_MONOTONIC_RAW)
+ ns = MONOTONIC_RES_NSEC;
+ else if (clock_id == CLOCK_REALTIME_COARSE ||
+ clock_id == CLOCK_MONOTONIC_COARSE)
+ ns = LOW_RES_NSEC;
+ else
+ return clock_getres_fallback(clock_id, res);
+
+ res->tv_sec = 0;
+ res->tv_nsec = ns;
+
+ return 0;
+}
--
2.7.4
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