[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / arm64 / kernel / vdso / gettimeofday.S

/*
 * 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

	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

	/* 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	x2
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)
Commit	Line	Data
	1	/*
	2	* Userspace implementations of gettimeofday() and friends.
	3	*
	4	* Copyright (C) 2012 ARM Limited
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	*
	18	* Author: Will Deacon <will.deacon@arm.com>
	19	*/
	20
	21	#include <linux/linkage.h>
	22	#include <asm/asm-offsets.h>
	23	#include <asm/unistd.h>
	24
	25	#define NSEC_PER_SEC_LO16 0xca00
	26	#define NSEC_PER_SEC_HI16 0x3b9a
	27
	28	vdso_data .req x6
	29	use_syscall .req w7
	30	seqcnt .req w8
	31
	32	.macro seqcnt_acquire
	33	9999: ldr seqcnt, [vdso_data, #VDSO_TB_SEQ_COUNT]
	34	tbnz seqcnt, #0, 9999b
	35	dmb ishld
	36	ldr use_syscall, [vdso_data, #VDSO_USE_SYSCALL]
	37	.endm
	38
	39	.macro seqcnt_read, cnt
	40	dmb ishld
	41	ldr \cnt, [vdso_data, #VDSO_TB_SEQ_COUNT]
	42	.endm
	43
	44	.macro seqcnt_check, cnt, fail
	45	cmp \cnt, seqcnt
	46	b.ne \fail
	47	.endm
	48
	49	.text
	50
	51	/* int __kernel_gettimeofday(struct timeval tv, struct timezone tz); */
	52	ENTRY(__kernel_gettimeofday)
	53	.cfi_startproc
	54	mov x2, x30
	55	.cfi_register x30, x2
	56
	57	/* Acquire the sequence counter and get the timespec. */
	58	adr vdso_data, _vdso_data
	59	1: seqcnt_acquire
	60	cbnz use_syscall, 4f
	61
	62	/* If tv is NULL, skip to the timezone code. */
	63	cbz x0, 2f
	64	bl __do_get_tspec
	65	seqcnt_check w9, 1b
	66
	67	/* Convert ns to us. */
	68	mov x13, #1000
	69	lsl x13, x13, x12
	70	udiv x11, x11, x13
	71	stp x10, x11, [x0, #TVAL_TV_SEC]
	72	2:
	73	/* If tz is NULL, return 0. */
	74	cbz x1, 3f
	75	ldp w4, w5, [vdso_data, #VDSO_TZ_MINWEST]
	76	stp w4, w5, [x1, #TZ_MINWEST]
	77	3:
	78	mov x0, xzr
	79	ret x2
	80	4:
	81	/* Syscall fallback. */
	82	mov x8, #__NR_gettimeofday
	83	svc #0
	84	ret x2
	85	.cfi_endproc
	86	ENDPROC(__kernel_gettimeofday)
	87
	88	/* int __kernel_clock_gettime(clockid_t clock_id, struct timespec tp); /
	89	ENTRY(__kernel_clock_gettime)
	90	.cfi_startproc
	91	cmp w0, #CLOCK_REALTIME
	92	ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
	93	b.ne 2f
	94
	95	mov x2, x30
	96	.cfi_register x30, x2
	97
	98	/* Get kernel timespec. */
	99	adr vdso_data, _vdso_data
	100	1: seqcnt_acquire
	101	cbnz use_syscall, 7f
	102
	103	bl __do_get_tspec
	104	seqcnt_check w9, 1b
	105
	106	cmp w0, #CLOCK_MONOTONIC
	107	b.ne 6f
	108
	109	/* Get wtm timespec. */
	110	ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
	111
	112	/* Check the sequence counter. */
	113	seqcnt_read w9
	114	seqcnt_check w9, 1b
	115	b 4f
	116	2:
	117	cmp w0, #CLOCK_REALTIME_COARSE
	118	ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne
	119	b.ne 8f
	120
	121	/* Get coarse timespec. */
	122	adr vdso_data, _vdso_data
	123	3: seqcnt_acquire
	124	ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
	125
	126	/* Get wtm timespec. */
	127	ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
	128
	129	/* Check the sequence counter. */
	130	seqcnt_read w9
	131	seqcnt_check w9, 3b
	132
	133	cmp w0, #CLOCK_MONOTONIC_COARSE
	134	b.ne 6f
	135	4:
	136	/* Add on wtm timespec. */
	137	add x10, x10, x13
	138	lsl x14, x14, x12
	139	add x11, x11, x14
	140
	141	/* Normalise the new timespec. */
	142	mov x15, #NSEC_PER_SEC_LO16
	143	movk x15, #NSEC_PER_SEC_HI16, lsl #16
	144	lsl x15, x15, x12
	145	cmp x11, x15
	146	b.lt 5f
	147	sub x11, x11, x15
	148	add x10, x10, #1
	149	5:
	150	cmp x11, #0
	151	b.ge 6f
	152	add x11, x11, x15
	153	sub x10, x10, #1
	154
	155	6: /* Store to the user timespec. */
	156	lsr x11, x11, x12
	157	stp x10, x11, [x1, #TSPEC_TV_SEC]
	158	mov x0, xzr
	159	ret x2
	160	7:
	161	mov x30, x2
	162	8: /* Syscall fallback. */
	163	mov x8, #__NR_clock_gettime
	164	svc #0
	165	ret
	166	.cfi_endproc
	167	ENDPROC(__kernel_clock_gettime)
	168
	169	/* int __kernel_clock_getres(clockid_t clock_id, struct timespec res); /
	170	ENTRY(__kernel_clock_getres)
	171	.cfi_startproc
	172	cbz w1, 3f
	173
	174	cmp w0, #CLOCK_REALTIME
	175	ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
	176	b.ne 1f
	177
	178	ldr x2, 5f
	179	b 2f
	180	1:
	181	cmp w0, #CLOCK_REALTIME_COARSE
	182	ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne
	183	b.ne 4f
	184	ldr x2, 6f
	185	2:
	186	stp xzr, x2, [x1]
	187
	188	3: /* res == NULL. */
	189	mov w0, wzr
	190	ret
	191
	192	4: /* Syscall fallback. */
	193	mov x8, #__NR_clock_getres
	194	svc #0
	195	ret
	196	5:
	197	.quad CLOCK_REALTIME_RES
	198	6:
	199	.quad CLOCK_COARSE_RES
	200	.cfi_endproc
	201	ENDPROC(__kernel_clock_getres)
	202
	203	/*
	204	* Read the current time from the architected counter.
	205	* Expects vdso_data to be initialised.
	206	* Clobbers the temporary registers (x9 - x15).
	207	* Returns:
	208	* - w9 = vDSO sequence counter
	209	* - (x10, x11) = (ts->tv_sec, shifted ts->tv_nsec)
	210	* - w12 = cs_shift
	211	*/
	212	ENTRY(__do_get_tspec)
	213	.cfi_startproc
	214
	215	/* Read from the vDSO data page. */
	216	ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
	217	ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
	218	ldp w11, w12, [vdso_data, #VDSO_CS_MULT]
	219	seqcnt_read w9
	220
	221	/* Read the virtual counter. */
	222	isb
	223	mrs x15, cntvct_el0
	224
	225	/* Calculate cycle delta and convert to ns. */
	226	sub x10, x15, x10
	227	/* We can only guarantee 56 bits of precision. */
	228	movn x15, #0xff00, lsl #48
	229	and x10, x15, x10
	230	mul x10, x10, x11
	231
	232	/* Use the kernel time to calculate the new timespec. */
	233	mov x11, #NSEC_PER_SEC_LO16
	234	movk x11, #NSEC_PER_SEC_HI16, lsl #16
	235	lsl x11, x11, x12
	236	add x15, x10, x14
	237	udiv x14, x15, x11
	238	add x10, x13, x14
	239	mul x13, x14, x11
	240	sub x11, x15, x13
	241
	242	ret
	243	.cfi_endproc
	244	ENDPROC(__do_get_tspec)