[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 w13, 1b

	/* Convert ns to us. */
	mov	x11, #1000
	udiv	x10, x10, x11
	stp	x9, x10, [x0, #TVAL_TV_SEC]
2:
	/* If tz is NULL, return 0. */
	cbz	x1, 3f
	ldp	w4, w5, [vdso_data, #VDSO_TZ_MINWEST]
	seqcnt_read w13
	seqcnt_check w13, 1b
	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 w13, 1b

	cmp	w0, #CLOCK_MONOTONIC
	b.ne	6f

	/* Get wtm timespec. */
	ldp	x14, x15, [vdso_data, #VDSO_WTM_CLK_SEC]

	/* Check the sequence counter. */
	seqcnt_read w13
	seqcnt_check w13, 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	x9, x10, [vdso_data, #VDSO_XTIME_CRS_SEC]

	cmp	w0, #CLOCK_MONOTONIC_COARSE
	b.ne	6f

	/* Get wtm timespec. */
	ldp	x14, x15, [vdso_data, #VDSO_WTM_CLK_SEC]

	/* Check the sequence counter. */
	seqcnt_read w13
	seqcnt_check w13, 3b
4:
	/* Add on wtm timespec. */
	add	x9, x9, x14
	add	x10, x10, x15

	/* Normalise the new timespec. */
	mov	x14, #NSEC_PER_SEC_LO16
	movk	x14, #NSEC_PER_SEC_HI16, lsl #16
	cmp	x10, x14
	b.lt	5f
	sub	x10, x10, x14
	add	x9, x9, #1
5:
	cmp	x10, #0
	b.ge	6f
	add	x10, x10, x14
	sub	x9, x9, #1

6:	/* Store to the user timespec. */
	stp	x9, x10, [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:
 *  - (x9, x10) = (ts->tv_sec, ts->tv_nsec)
 *  - (x11, x12) = (xtime->tv_sec, xtime->tv_nsec)
 *  - w13 = vDSO sequence counter
 */
ENTRY(__do_get_tspec)
	.cfi_startproc

	/* Read from the vDSO data page. */
	ldr	x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
	ldp	x11, x12, [vdso_data, #VDSO_XTIME_CLK_SEC]
	ldp	w14, w15, [vdso_data, #VDSO_CS_MULT]
	seqcnt_read w13

	/* Read the physical counter. */
	isb
	mrs	x9, cntpct_el0

	/* Calculate cycle delta and convert to ns. */
	sub	x10, x9, x10
	/* We can only guarantee 56 bits of precision. */
	movn	x9, #0xff00, lsl #48
	and	x10, x9, x10
	mul	x10, x10, x14
	lsr	x10, x10, x15

	/* Use the kernel time to calculate the new timespec. */
	add	x10, x12, x10
	mov	x14, #NSEC_PER_SEC_LO16
	movk	x14, #NSEC_PER_SEC_HI16, lsl #16
	udiv	x15, x10, x14
	add	x9, x15, x11
	mul	x14, x14, x15
	sub	x10, x10, x14

	ret
	.cfi_endproc
ENDPROC(__do_get_tspec)
Commit	Line	Data
9031fefd WD	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 w13, 1b
66
67	/* Convert ns to us. */
68	mov x11, #1000
69	udiv x10, x10, x11
70	stp x9, x10, [x0, #TVAL_TV_SEC]
71	2:
72	/* If tz is NULL, return 0. */
73	cbz x1, 3f
74	ldp w4, w5, [vdso_data, #VDSO_TZ_MINWEST]
75	seqcnt_read w13
76	seqcnt_check w13, 1b
77	stp w4, w5, [x1, #TZ_MINWEST]
78	3:
79	mov x0, xzr
80	ret x2
81	4:
82	/* Syscall fallback. */
83	mov x8, #__NR_gettimeofday
84	svc #0
85	ret x2
86	.cfi_endproc
87	ENDPROC(__kernel_gettimeofday)
88
89	/* int __kernel_clock_gettime(clockid_t clock_id, struct timespec tp); /
90	ENTRY(__kernel_clock_gettime)
91	.cfi_startproc
92	cmp w0, #CLOCK_REALTIME
93	ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
94	b.ne 2f
95
96	mov x2, x30
97	.cfi_register x30, x2
98
99	/* Get kernel timespec. */
100	adr vdso_data, _vdso_data
101	1: seqcnt_acquire
102	cbnz use_syscall, 7f
103
104	bl __do_get_tspec
105	seqcnt_check w13, 1b
106
107	cmp w0, #CLOCK_MONOTONIC
108	b.ne 6f
109
110	/* Get wtm timespec. */
111	ldp x14, x15, [vdso_data, #VDSO_WTM_CLK_SEC]
112
113	/* Check the sequence counter. */
114	seqcnt_read w13
115	seqcnt_check w13, 1b
116	b 4f
117	2:
118	cmp w0, #CLOCK_REALTIME_COARSE
119	ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne
120	b.ne 8f
121
122	/* Get coarse timespec. */
123	adr vdso_data, _vdso_data
124	3: seqcnt_acquire
125	ldp x9, x10, [vdso_data, #VDSO_XTIME_CRS_SEC]
126
127	cmp w0, #CLOCK_MONOTONIC_COARSE
128	b.ne 6f
129
130	/* Get wtm timespec. */
131	ldp x14, x15, [vdso_data, #VDSO_WTM_CLK_SEC]
132
133	/* Check the sequence counter. */
134	seqcnt_read w13
135	seqcnt_check w13, 3b
136	4:
137	/* Add on wtm timespec. */
138	add x9, x9, x14
139	add x10, x10, x15
140
141	/* Normalise the new timespec. */
142	mov x14, #NSEC_PER_SEC_LO16
143	movk x14, #NSEC_PER_SEC_HI16, lsl #16
144	cmp x10, x14
145	b.lt 5f
146	sub x10, x10, x14
147	add x9, x9, #1
148	5:
149	cmp x10, #0
150	b.ge 6f
151	add x10, x10, x14
152	sub x9, x9, #1
153
154	6: /* Store to the user timespec. */
155	stp x9, x10, [x1, #TSPEC_TV_SEC]
156	mov x0, xzr
157	ret x2
158	7:
159	mov x30, x2
160	8: /* Syscall fallback. */
161	mov x8, #__NR_clock_gettime
162	svc #0
163	ret
164	.cfi_endproc
165	ENDPROC(__kernel_clock_gettime)
166
167	/* int __kernel_clock_getres(clockid_t clock_id, struct timespec res); /
168	ENTRY(__kernel_clock_getres)
169	.cfi_startproc
170	cbz w1, 3f
171
172	cmp w0, #CLOCK_REALTIME
173	ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
174	b.ne 1f
175
176	ldr x2, 5f
177	b 2f
178	1:
179	cmp w0, #CLOCK_REALTIME_COARSE
180	ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne
181	b.ne 4f
182	ldr x2, 6f
183	2:
184	stp xzr, x2, [x1]
185
186	3: /* res == NULL. */
187	mov w0, wzr
188	ret
189
190	4: /* Syscall fallback. */
191	mov x8, #__NR_clock_getres
192	svc #0
193	ret
194	5:
195	.quad CLOCK_REALTIME_RES
196	6:
197	.quad CLOCK_COARSE_RES
198	.cfi_endproc
199	ENDPROC(__kernel_clock_getres)
200
201	/*
202	* Read the current time from the architected counter.
203	* Expects vdso_data to be initialised.
204	* Clobbers the temporary registers (x9 - x15).
205	* Returns:
206	* - (x9, x10) = (ts->tv_sec, ts->tv_nsec)
207	* - (x11, x12) = (xtime->tv_sec, xtime->tv_nsec)
208	* - w13 = vDSO sequence counter
209	*/
210	ENTRY(__do_get_tspec)
211	.cfi_startproc
212
213	/* Read from the vDSO data page. */
214	ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
215	ldp x11, x12, [vdso_data, #VDSO_XTIME_CLK_SEC]
216	ldp w14, w15, [vdso_data, #VDSO_CS_MULT]
217	seqcnt_read w13
218
219	/* Read the physical counter. */
220	isb
221	mrs x9, cntpct_el0
222
223	/* Calculate cycle delta and convert to ns. */
224	sub x10, x9, x10
225	/* We can only guarantee 56 bits of precision. */
251db453	226	movn x9, #0xff00, lsl #48
9031fefd WD	227	and x10, x9, x10
	228	mul x10, x10, x14
	229	lsr x10, x10, x15
	230
	231	/* Use the kernel time to calculate the new timespec. */
	232	add x10, x12, x10
	233	mov x14, #NSEC_PER_SEC_LO16
	234	movk x14, #NSEC_PER_SEC_HI16, lsl #16
	235	udiv x15, x10, x14
	236	add x9, x15, x11
	237	mul x14, x14, x15
	238	sub x10, x10, x14
	239
	240	ret
	241	.cfi_endproc
	242	ENDPROC(__do_get_tspec)