[linux-block.git] / arch / powerpc / kernel / vdso32 / gettimeofday.S

/*
 * Userland implementation of gettimeofday() for 32 bits processes in a
 * ppc64 kernel for use in the vDSO
 *
 * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org,
 *                    IBM Corp.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#include <linux/config.h>
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/vdso.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>

	.text
/*
 * Exact prototype of gettimeofday
 *
 * int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz);
 *
 */
V_FUNCTION_BEGIN(__kernel_gettimeofday)
  .cfi_startproc
	mflr	r12
  .cfi_register lr,r12

	mr	r10,r3			/* r10 saves tv */
	mr	r11,r4			/* r11 saves tz */
	bl	__get_datapage@local	/* get data page */
	mr	r9, r3			/* datapage ptr in r9 */
	bl	__do_get_xsec@local	/* get xsec from tb & kernel */
	bne-	2f			/* out of line -> do syscall */

	/* seconds are xsec >> 20 */
	rlwinm	r5,r4,12,20,31
	rlwimi	r5,r3,12,0,19
	stw	r5,TVAL32_TV_SEC(r10)

	/* get remaining xsec and convert to usec. we scale
	 * up remaining xsec by 12 bits and get the top 32 bits
	 * of the multiplication
	 */
	rlwinm	r5,r4,12,0,19
	lis	r6,1000000@h
	ori	r6,r6,1000000@l
	mulhwu	r5,r5,r6
	stw	r5,TVAL32_TV_USEC(r10)

	cmpli	cr0,r11,0		/* check if tz is NULL */
	beq	1f
	lwz	r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
	lwz	r5,CFG_TZ_DSTTIME(r9)
	stw	r4,TZONE_TZ_MINWEST(r11)
	stw	r5,TZONE_TZ_DSTTIME(r11)

1:	mtlr	r12
	li	r3,0
	blr

2:
	mtlr	r12
	mr	r3,r10
	mr	r4,r11
	li	r0,__NR_gettimeofday
	sc
	blr
  .cfi_endproc
V_FUNCTION_END(__kernel_gettimeofday)

/*
 * Exact prototype of clock_gettime()
 *
 * int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp);
 *
 */
V_FUNCTION_BEGIN(__kernel_clock_gettime)
  .cfi_startproc
	/* Check for supported clock IDs */
	cmpli	cr0,r3,CLOCK_REALTIME
	cmpli	cr1,r3,CLOCK_MONOTONIC
	cror	cr0,cr0,cr1
	bne	cr0,99f

	mflr	r12			/* r12 saves lr */
  .cfi_register lr,r12
	mr	r10,r3			/* r10 saves id */
	mr	r11,r4			/* r11 saves tp */
	bl	__get_datapage@local	/* get data page */
	mr	r9, r3			/* datapage ptr in r9 */
	beq	cr1,50f			/* if monotonic -> jump there */

	/*
	 * CLOCK_REALTIME
	 */

	bl	__do_get_xsec@local	/* get xsec from tb & kernel */
	bne-	98f			/* out of line -> do syscall */

	/* seconds are xsec >> 20 */
	rlwinm	r5,r4,12,20,31
	rlwimi	r5,r3,12,0,19
	stw	r5,TSPC32_TV_SEC(r11)

	/* get remaining xsec and convert to nsec. we scale
	 * up remaining xsec by 12 bits and get the top 32 bits
	 * of the multiplication, then we multiply by 1000
	 */
	rlwinm	r5,r4,12,0,19
	lis	r6,1000000@h
	ori	r6,r6,1000000@l
	mulhwu	r5,r5,r6
	mulli	r5,r5,1000
	stw	r5,TSPC32_TV_NSEC(r11)
	mtlr	r12
	li	r3,0
	blr

	/*
	 * CLOCK_MONOTONIC
	 */

50:	bl	__do_get_xsec@local	/* get xsec from tb & kernel */
	bne-	98f			/* out of line -> do syscall */

	/* seconds are xsec >> 20 */
	rlwinm	r6,r4,12,20,31
	rlwimi	r6,r3,12,0,19

	/* get remaining xsec and convert to nsec. we scale
	 * up remaining xsec by 12 bits and get the top 32 bits
	 * of the multiplication, then we multiply by 1000
	 */
	rlwinm	r7,r4,12,0,19
	lis	r5,1000000@h
	ori	r5,r5,1000000@l
	mulhwu	r7,r7,r5
	mulli	r7,r7,1000

	/* now we must fixup using wall to monotonic. We need to snapshot
	 * that value and do the counter trick again. Fortunately, we still
	 * have the counter value in r8 that was returned by __do_get_xsec.
	 * At this point, r6,r7 contain our sec/nsec values, r3,r4 and r5
	 * can be used
	 */

	lwz	r3,WTOM_CLOCK_SEC(r9)
	lwz	r4,WTOM_CLOCK_NSEC(r9)

	/* We now have our result in r3,r4. We create a fake dependency
	 * on that result and re-check the counter
	 */
	or	r5,r4,r3
	xor	r0,r5,r5
	add	r9,r9,r0
#ifdef CONFIG_PPC64
	lwz	r0,(CFG_TB_UPDATE_COUNT+4)(r9)
#else
	lwz	r0,(CFG_TB_UPDATE_COUNT)(r9)
#endif
        cmpl    cr0,r8,r0		/* check if updated */
	bne-	50b

	/* Calculate and store result. Note that this mimmics the C code,
	 * which may cause funny results if nsec goes negative... is that
	 * possible at all ?
	 */
	add	r3,r3,r6
	add	r4,r4,r7
	lis	r5,NSEC_PER_SEC@h
	ori	r5,r5,NSEC_PER_SEC@l
	cmpli	cr0,r4,r5
	blt	1f
	subf	r4,r5,r4
	addi	r3,r3,1
1:	stw	r3,TSPC32_TV_SEC(r11)
	stw	r4,TSPC32_TV_NSEC(r11)

	mtlr	r12
	li	r3,0
	blr

	/*
	 * syscall fallback
	 */
98:
	mtlr	r12
	mr	r3,r10
	mr	r4,r11
99:
	li	r0,__NR_clock_gettime
	sc
	blr
  .cfi_endproc
V_FUNCTION_END(__kernel_clock_gettime)


/*
 * Exact prototype of clock_getres()
 *
 * int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
 *
 */
V_FUNCTION_BEGIN(__kernel_clock_getres)
  .cfi_startproc
	/* Check for supported clock IDs */
	cmpwi	cr0,r3,CLOCK_REALTIME
	cmpwi	cr1,r3,CLOCK_MONOTONIC
	cror	cr0,cr0,cr1
	bne	cr0,99f

	li	r3,0
	cmpli	cr0,r4,0
	beqlr
	lis	r5,CLOCK_REALTIME_RES@h
	ori	r5,r5,CLOCK_REALTIME_RES@l
	stw	r3,TSPC32_TV_SEC(r4)
	stw	r5,TSPC32_TV_NSEC(r4)
	blr

	/*
	 * syscall fallback
	 */
99:
	li	r0,__NR_clock_getres
	sc
	blr
  .cfi_endproc
V_FUNCTION_END(__kernel_clock_getres)


/*
 * This is the core of gettimeofday() & friends, it returns the xsec
 * value in r3 & r4 and expects the datapage ptr (non clobbered)
 * in r9. clobbers r0,r4,r5,r6,r7,r8.
 * When returning, r8 contains the counter value that can be reused
 * by the monotonic clock implementation
 */
__do_get_xsec:
  .cfi_startproc
	/* Check for update count & load values. We use the low
	 * order 32 bits of the update count
	 */
#ifdef CONFIG_PPC64
1:	lwz	r8,(CFG_TB_UPDATE_COUNT+4)(r9)
#else
1:	lwz	r8,(CFG_TB_UPDATE_COUNT)(r9)
#endif
	andi.	r0,r8,1			/* pending update ? loop */
	bne-	1b
	xor	r0,r8,r8		/* create dependency */
	add	r9,r9,r0

	/* Load orig stamp (offset to TB) */
	lwz	r5,CFG_TB_ORIG_STAMP(r9)
	lwz	r6,(CFG_TB_ORIG_STAMP+4)(r9)

	/* Get a stable TB value */
2:	mftbu	r3
	mftbl	r4
	mftbu	r0
	cmpl	cr0,r3,r0
	bne-	2b

	/* Substract tb orig stamp. If the high part is non-zero, we jump to
	 * the slow path which call the syscall.
	 * If it's ok, then we have our 32 bits tb_ticks value in r7
	 */
	subfc	r7,r6,r4
	subfe.	r0,r5,r3
	bne-	3f

	/* Load scale factor & do multiplication */
	lwz	r5,CFG_TB_TO_XS(r9)	/* load values */
	lwz	r6,(CFG_TB_TO_XS+4)(r9)
	mulhwu	r4,r7,r5
	mulhwu	r6,r7,r6
	mullw	r0,r7,r5
	addc	r6,r6,r0

	/* At this point, we have the scaled xsec value in r4 + XER:CA
	 * we load & add the stamp since epoch
	 */
	lwz	r5,CFG_STAMP_XSEC(r9)
	lwz	r6,(CFG_STAMP_XSEC+4)(r9)
	adde	r4,r4,r6
	addze	r3,r5

	/* We now have our result in r3,r4. We create a fake dependency
	 * on that result and re-check the counter
	 */
	or	r6,r4,r3
	xor	r0,r6,r6
	add	r9,r9,r0
#ifdef CONFIG_PPC64
	lwz	r0,(CFG_TB_UPDATE_COUNT+4)(r9)
#else
	lwz	r0,(CFG_TB_UPDATE_COUNT)(r9)
#endif
        cmpl    cr0,r8,r0		/* check if updated */
	bne-	1b

	/* Warning ! The caller expects CR:EQ to be set to indicate a
	 * successful calculation (so it won't fallback to the syscall
	 * method). We have overriden that CR bit in the counter check,
	 * but fortunately, the loop exit condition _is_ CR:EQ set, so
	 * we can exit safely here. If you change this code, be careful
	 * of that side effect.
	 */
3:	blr
  .cfi_endproc
Commit	Line	Data
a7f290da BH	1	/*
	2	* Userland implementation of gettimeofday() for 32 bits processes in a
	3	* ppc64 kernel for use in the vDSO
	4	*
	5	* Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org,
	6	* IBM Corp.
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*/
	13	#include <linux/config.h>
	14	#include <asm/processor.h>
	15	#include <asm/ppc_asm.h>
	16	#include <asm/vdso.h>
	17	#include <asm/asm-offsets.h>
	18	#include <asm/unistd.h>
	19
	20	.text
	21	/*
	22	* Exact prototype of gettimeofday
	23	*
	24	* int __kernel_gettimeofday(struct timeval tv, struct timezone tz);
	25	*
	26	*/
	27	V_FUNCTION_BEGIN(__kernel_gettimeofday)
	28	.cfi_startproc
	29	mflr r12
	30	.cfi_register lr,r12
	31
	32	mr r10,r3 /* r10 saves tv */
	33	mr r11,r4 /* r11 saves tz */
	34	bl __get_datapage@local /* get data page */
	35	mr r9, r3 /* datapage ptr in r9 */
	36	bl __do_get_xsec@local /* get xsec from tb & kernel */
	37	bne- 2f /* out of line -> do syscall */
	38
	39	/* seconds are xsec >> 20 */
	40	rlwinm r5,r4,12,20,31
	41	rlwimi r5,r3,12,0,19
	42	stw r5,TVAL32_TV_SEC(r10)
	43
	44	/* get remaining xsec and convert to usec. we scale
	45	* up remaining xsec by 12 bits and get the top 32 bits
	46	* of the multiplication
	47	*/
	48	rlwinm r5,r4,12,0,19
	49	lis r6,1000000@h
	50	ori r6,r6,1000000@l
	51	mulhwu r5,r5,r6
	52	stw r5,TVAL32_TV_USEC(r10)
	53
	54	cmpli cr0,r11,0 /* check if tz is NULL */
	55	beq 1f
	56	lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
	57	lwz r5,CFG_TZ_DSTTIME(r9)
	58	stw r4,TZONE_TZ_MINWEST(r11)
	59	stw r5,TZONE_TZ_DSTTIME(r11)
	60
	61	1: mtlr r12
	62	li r3,0
	63	blr
	64
65	2:
66	mtlr r12
67	mr r3,r10
68	mr r4,r11
69	li r0,__NR_gettimeofday
70	sc
71	blr
72	.cfi_endproc
73	V_FUNCTION_END(__kernel_gettimeofday)
74
75	/*
76	* Exact prototype of clock_gettime()
77	*
78	* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp);
79	*
80	*/
81	V_FUNCTION_BEGIN(__kernel_clock_gettime)
82	.cfi_startproc
83	/* Check for supported clock IDs */
84	cmpli cr0,r3,CLOCK_REALTIME
85	cmpli cr1,r3,CLOCK_MONOTONIC
86	cror cr0,cr0,cr1
87	bne cr0,99f
88
89	mflr r12 /* r12 saves lr */
90	.cfi_register lr,r12
91	mr r10,r3 /* r10 saves id */
92	mr r11,r4 /* r11 saves tp */
93	bl __get_datapage@local /* get data page */
94	mr r9, r3 /* datapage ptr in r9 */
95	beq cr1,50f /* if monotonic -> jump there */
96
97	/*
98	* CLOCK_REALTIME
99	*/
100
101	bl __do_get_xsec@local /* get xsec from tb & kernel */
102	bne- 98f /* out of line -> do syscall */
103
104	/* seconds are xsec >> 20 */
105	rlwinm r5,r4,12,20,31
106	rlwimi r5,r3,12,0,19
107	stw r5,TSPC32_TV_SEC(r11)
108
109	/* get remaining xsec and convert to nsec. we scale
110	* up remaining xsec by 12 bits and get the top 32 bits
111	* of the multiplication, then we multiply by 1000
112	*/
113	rlwinm r5,r4,12,0,19
114	lis r6,1000000@h
115	ori r6,r6,1000000@l
116	mulhwu r5,r5,r6
117	mulli r5,r5,1000
118	stw r5,TSPC32_TV_NSEC(r11)
119	mtlr r12
120	li r3,0
121	blr
122
123	/*
124	* CLOCK_MONOTONIC
125	*/
126
127	50: bl __do_get_xsec@local /* get xsec from tb & kernel */
128	bne- 98f /* out of line -> do syscall */
129
130	/* seconds are xsec >> 20 */
131	rlwinm r6,r4,12,20,31
132	rlwimi r6,r3,12,0,19
133
134	/* get remaining xsec and convert to nsec. we scale
135	* up remaining xsec by 12 bits and get the top 32 bits
136	* of the multiplication, then we multiply by 1000
137	*/
138	rlwinm r7,r4,12,0,19
139	lis r5,1000000@h
140	ori r5,r5,1000000@l
141	mulhwu r7,r7,r5
142	mulli r7,r7,1000
143
144	/* now we must fixup using wall to monotonic. We need to snapshot
145	* that value and do the counter trick again. Fortunately, we still
146	* have the counter value in r8 that was returned by __do_get_xsec.
147	* At this point, r6,r7 contain our sec/nsec values, r3,r4 and r5
148	* can be used
149	*/
150
151	lwz r3,WTOM_CLOCK_SEC(r9)
152	lwz r4,WTOM_CLOCK_NSEC(r9)
153
154	/* We now have our result in r3,r4. We create a fake dependency
155	* on that result and re-check the counter
156	*/
157	or r5,r4,r3
158	xor r0,r5,r5
159	add r9,r9,r0
160	#ifdef CONFIG_PPC64
161	lwz r0,(CFG_TB_UPDATE_COUNT+4)(r9)
162	#else
163	lwz r0,(CFG_TB_UPDATE_COUNT)(r9)
164	#endif
165	cmpl cr0,r8,r0 /* check if updated */
166	bne- 50b
167
168	/* Calculate and store result. Note that this mimmics the C code,
169	* which may cause funny results if nsec goes negative... is that
170	* possible at all ?
171	*/
172	add r3,r3,r6
173	add r4,r4,r7
174	lis r5,NSEC_PER_SEC@h
175	ori r5,r5,NSEC_PER_SEC@l
176	cmpli cr0,r4,r5
177	blt 1f
178	subf r4,r5,r4
179	addi r3,r3,1
180	1: stw r3,TSPC32_TV_SEC(r11)
181	stw r4,TSPC32_TV_NSEC(r11)
182
183	mtlr r12
184	li r3,0
185	blr
186
187	/*
188	* syscall fallback
189	*/
190	98:
191	mtlr r12
192	mr r3,r10
193	mr r4,r11
194	99:
195	li r0,__NR_clock_gettime
196	sc
197	blr
198	.cfi_endproc
199	V_FUNCTION_END(__kernel_clock_gettime)
200
201
202	/*
203	* Exact prototype of clock_getres()
204	*
205	* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
206	*
207	*/
208	V_FUNCTION_BEGIN(__kernel_clock_getres)
209	.cfi_startproc
210	/* Check for supported clock IDs */
211	cmpwi cr0,r3,CLOCK_REALTIME
212	cmpwi cr1,r3,CLOCK_MONOTONIC
213	cror cr0,cr0,cr1
214	bne cr0,99f
215
216	li r3,0
217	cmpli cr0,r4,0
218	beqlr
219	lis r5,CLOCK_REALTIME_RES@h
220	ori r5,r5,CLOCK_REALTIME_RES@l
221	stw r3,TSPC32_TV_SEC(r4)
222	stw r5,TSPC32_TV_NSEC(r4)
223	blr
224
225	/*
226	* syscall fallback
227	*/
228	99:
229	li r0,__NR_clock_getres
230	sc
231	blr
232	.cfi_endproc
233	V_FUNCTION_END(__kernel_clock_getres)
234
235
236	/*
237	* This is the core of gettimeofday() & friends, it returns the xsec
238	* value in r3 & r4 and expects the datapage ptr (non clobbered)
239	* in r9. clobbers r0,r4,r5,r6,r7,r8.
240	* When returning, r8 contains the counter value that can be reused
241	* by the monotonic clock implementation
242	*/
243	__do_get_xsec:
244	.cfi_startproc
245	/* Check for update count & load values. We use the low
246	* order 32 bits of the update count
247	*/
248	#ifdef CONFIG_PPC64
249	1: lwz r8,(CFG_TB_UPDATE_COUNT+4)(r9)
250	#else
251	1: lwz r8,(CFG_TB_UPDATE_COUNT)(r9)
252	#endif
253	andi. r0,r8,1 /* pending update ? loop */
254	bne- 1b
255	xor r0,r8,r8 /* create dependency */
256	add r9,r9,r0
257
258	/* Load orig stamp (offset to TB) */
259	lwz r5,CFG_TB_ORIG_STAMP(r9)
260	lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
261
262	/* Get a stable TB value */
263	2: mftbu r3
264	mftbl r4
265	mftbu r0
266	cmpl cr0,r3,r0
267	bne- 2b
268
269	/* Substract tb orig stamp. If the high part is non-zero, we jump to
270	* the slow path which call the syscall.
271	* If it's ok, then we have our 32 bits tb_ticks value in r7
272	*/
273	subfc r7,r6,r4
274	subfe. r0,r5,r3
275	bne- 3f
276
277	/* Load scale factor & do multiplication */
278	lwz r5,CFG_TB_TO_XS(r9) /* load values */
279	lwz r6,(CFG_TB_TO_XS+4)(r9)
280	mulhwu r4,r7,r5
281	mulhwu r6,r7,r6
282	mullw r0,r7,r5
283	addc r6,r6,r0
284
285	/* At this point, we have the scaled xsec value in r4 + XER:CA
286	* we load & add the stamp since epoch
287	*/
288	lwz r5,CFG_STAMP_XSEC(r9)
289	lwz r6,(CFG_STAMP_XSEC+4)(r9)
290	adde r4,r4,r6
291	addze r3,r5
292
293	/* We now have our result in r3,r4. We create a fake dependency
294	* on that result and re-check the counter
295	*/
296	or r6,r4,r3
297	xor r0,r6,r6
298	add r9,r9,r0
299	#ifdef CONFIG_PPC64
300	lwz r0,(CFG_TB_UPDATE_COUNT+4)(r9)
301	#else
302	lwz r0,(CFG_TB_UPDATE_COUNT)(r9)
303	#endif
304	cmpl cr0,r8,r0 /* check if updated */
305	bne- 1b
306
307	/* Warning ! The caller expects CR:EQ to be set to indicate a
308	* successful calculation (so it won't fallback to the syscall
309	* method). We have overriden that CR bit in the counter check,
310	* but fortunately, the loop exit condition _is_ CR:EQ set, so
311	* we can exit safely here. If you change this code, be careful
312	* of that side effect.
313	*/
314	3: blr
315	.cfi_endproc