mirror of https://gitee.com/openkylin/linux.git
250 lines
5.1 KiB
ArmAsm
250 lines
5.1 KiB
ArmAsm
/*
|
|
* 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@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
|
|
use_syscall .req w7
|
|
seqcnt .req w8
|
|
|
|
.macro seqcnt_acquire
|
|
9999: ldr seqcnt, [vdso_data, #VDSO_TB_SEQ_COUNT]
|
|
tbnz seqcnt, #0, 9999b
|
|
dmb ishld
|
|
ldr use_syscall, [vdso_data, #VDSO_USE_SYSCALL]
|
|
.endm
|
|
|
|
.macro seqcnt_read, cnt
|
|
dmb ishld
|
|
ldr \cnt, [vdso_data, #VDSO_TB_SEQ_COUNT]
|
|
.endm
|
|
|
|
.macro seqcnt_check, cnt, fail
|
|
cmp \cnt, seqcnt
|
|
b.ne \fail
|
|
.endm
|
|
|
|
.text
|
|
|
|
/* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); */
|
|
ENTRY(__kernel_gettimeofday)
|
|
.cfi_startproc
|
|
mov x2, x30
|
|
.cfi_register x30, x2
|
|
|
|
/* Acquire the sequence counter and get the timespec. */
|
|
adr vdso_data, _vdso_data
|
|
1: seqcnt_acquire
|
|
cbnz use_syscall, 4f
|
|
|
|
/* If tv is NULL, skip to the timezone code. */
|
|
cbz x0, 2f
|
|
bl __do_get_tspec
|
|
seqcnt_check w9, 1b
|
|
|
|
/* 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 x2
|
|
4:
|
|
/* Syscall fallback. */
|
|
mov x8, #__NR_gettimeofday
|
|
svc #0
|
|
ret x2
|
|
.cfi_endproc
|
|
ENDPROC(__kernel_gettimeofday)
|
|
|
|
/* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); */
|
|
ENTRY(__kernel_clock_gettime)
|
|
.cfi_startproc
|
|
cmp w0, #CLOCK_REALTIME
|
|
ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
|
|
b.ne 2f
|
|
|
|
mov x2, x30
|
|
.cfi_register x30, x2
|
|
|
|
/* Get kernel timespec. */
|
|
adr vdso_data, _vdso_data
|
|
1: seqcnt_acquire
|
|
cbnz use_syscall, 7f
|
|
|
|
bl __do_get_tspec
|
|
seqcnt_check w9, 1b
|
|
|
|
mov x30, x2
|
|
|
|
cmp w0, #CLOCK_MONOTONIC
|
|
b.ne 6f
|
|
|
|
/* Get wtm timespec. */
|
|
ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
|
|
|
|
/* Check the sequence counter. */
|
|
seqcnt_read w9
|
|
seqcnt_check w9, 1b
|
|
b 4f
|
|
2:
|
|
cmp w0, #CLOCK_REALTIME_COARSE
|
|
ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne
|
|
b.ne 8f
|
|
|
|
/* xtime_coarse_nsec is already right-shifted */
|
|
mov x12, #0
|
|
|
|
/* Get coarse timespec. */
|
|
adr vdso_data, _vdso_data
|
|
3: seqcnt_acquire
|
|
ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
|
|
|
|
/* Get wtm timespec. */
|
|
ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
|
|
|
|
/* Check the sequence counter. */
|
|
seqcnt_read w9
|
|
seqcnt_check w9, 3b
|
|
|
|
cmp w0, #CLOCK_MONOTONIC_COARSE
|
|
b.ne 6f
|
|
4:
|
|
/* Add on wtm timespec. */
|
|
add x10, x10, x13
|
|
lsl x14, x14, x12
|
|
add x11, x11, x14
|
|
|
|
/* Normalise the new timespec. */
|
|
mov x15, #NSEC_PER_SEC_LO16
|
|
movk x15, #NSEC_PER_SEC_HI16, lsl #16
|
|
lsl x15, x15, x12
|
|
cmp x11, x15
|
|
b.lt 5f
|
|
sub x11, x11, x15
|
|
add x10, x10, #1
|
|
5:
|
|
cmp x11, #0
|
|
b.ge 6f
|
|
add x11, x11, x15
|
|
sub x10, x10, #1
|
|
|
|
6: /* Store to the user timespec. */
|
|
lsr x11, x11, x12
|
|
stp x10, x11, [x1, #TSPEC_TV_SEC]
|
|
mov x0, xzr
|
|
ret
|
|
7:
|
|
mov x30, x2
|
|
8: /* 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
|
|
cbz w1, 3f
|
|
|
|
cmp w0, #CLOCK_REALTIME
|
|
ccmp w0, #CLOCK_MONOTONIC, #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:
|
|
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)
|
|
|
|
/*
|
|
* Read the current time from the architected counter.
|
|
* Expects vdso_data to be initialised.
|
|
* Clobbers the temporary registers (x9 - x15).
|
|
* Returns:
|
|
* - w9 = vDSO sequence counter
|
|
* - (x10, x11) = (ts->tv_sec, shifted ts->tv_nsec)
|
|
* - w12 = cs_shift
|
|
*/
|
|
ENTRY(__do_get_tspec)
|
|
.cfi_startproc
|
|
|
|
/* Read from the vDSO data page. */
|
|
ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
|
|
ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
|
|
ldp w11, w12, [vdso_data, #VDSO_CS_MULT]
|
|
seqcnt_read w9
|
|
|
|
/* Read the virtual counter. */
|
|
isb
|
|
mrs x15, cntvct_el0
|
|
|
|
/* Calculate cycle delta and convert to ns. */
|
|
sub x10, x15, x10
|
|
/* We can only guarantee 56 bits of precision. */
|
|
movn x15, #0xff00, lsl #48
|
|
and x10, x15, x10
|
|
mul x10, x10, x11
|
|
|
|
/* Use the kernel time to calculate the new timespec. */
|
|
mov x11, #NSEC_PER_SEC_LO16
|
|
movk x11, #NSEC_PER_SEC_HI16, lsl #16
|
|
lsl x11, x11, x12
|
|
add x15, x10, x14
|
|
udiv x14, x15, x11
|
|
add x10, x13, x14
|
|
mul x13, x14, x11
|
|
sub x11, x15, x13
|
|
|
|
ret
|
|
.cfi_endproc
|
|
ENDPROC(__do_get_tspec)
|