[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 <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 */
	cmplwi	r10,0			/* check if tv is NULL */
	beq	3f
	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)

3:	cmplwi	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
	crclr	cr0*4+so
	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*4+eq,cr0*4+eq,cr1*4+eq
	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
	crclr	cr0*4+so
	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
	cmpl	cr0,r4,r5
	cmpli	cr1,r4,0
	blt	1f
	subf	r4,r5,r4
	addi	r3,r3,1
1:	bge	cr1,1f
	addi	r3,r3,-1
	add	r4,r4,r5
1:	stw	r3,TSPC32_TV_SEC(r11)
	stw	r4,TSPC32_TV_NSEC(r11)

	mtlr	r12
	crclr	cr0*4+so
	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*4+eq,cr0*4+eq,cr1*4+eq
	bne	cr0,99f

	li	r3,0
	cmpli	cr0,r4,0
	crclr	cr0*4+so
	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	*/
a7f290da BH	13	#include <asm/processor.h>
	14	#include <asm/ppc_asm.h>
	15	#include <asm/vdso.h>
	16	#include <asm/asm-offsets.h>
	17	#include <asm/unistd.h>
	18
	19	.text
	20	/*
	21	* Exact prototype of gettimeofday
	22	*
	23	* int __kernel_gettimeofday(struct timeval tv, struct timezone tz);
	24	*
	25	*/
	26	V_FUNCTION_BEGIN(__kernel_gettimeofday)
	27	.cfi_startproc
	28	mflr r12
	29	.cfi_register lr,r12
	30
	31	mr r10,r3 /* r10 saves tv */
	32	mr r11,r4 /* r11 saves tz */
	33	bl __get_datapage@local /* get data page */
	34	mr r9, r3 /* datapage ptr in r9 */
74609f45 TB	35	cmplwi r10,0 /* check if tv is NULL */
74609f45 TB	36	beq 3f
a7f290da BH	37	bl __do_get_xsec@local /* get xsec from tb & kernel */
	38	bne- 2f /* out of line -> do syscall */
	39
	40	/* seconds are xsec >> 20 */
	41	rlwinm r5,r4,12,20,31
	42	rlwimi r5,r3,12,0,19
	43	stw r5,TVAL32_TV_SEC(r10)
	44
	45	/* get remaining xsec and convert to usec. we scale
	46	* up remaining xsec by 12 bits and get the top 32 bits
	47	* of the multiplication
	48	*/
	49	rlwinm r5,r4,12,0,19
	50	lis r6,1000000@h
	51	ori r6,r6,1000000@l
	52	mulhwu r5,r5,r6
	53	stw r5,TVAL32_TV_USEC(r10)
	54
74609f45	55	3: cmplwi r11,0 /* check if tz is NULL */
a7f290da BH	56	beq 1f
	57	lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
	58	lwz r5,CFG_TZ_DSTTIME(r9)
	59	stw r4,TZONE_TZ_MINWEST(r11)
	60	stw r5,TZONE_TZ_DSTTIME(r11)
	61
	62	1: mtlr r12
5d66da3d	63	crclr cr0*4+so
a7f290da BH	64	li r3,0
	65	blr
	66
	67	2:
	68	mtlr r12
	69	mr r3,r10
	70	mr r4,r11
	71	li r0,__NR_gettimeofday
	72	sc
	73	blr
	74	.cfi_endproc
	75	V_FUNCTION_END(__kernel_gettimeofday)
	76
	77	/*
	78	* Exact prototype of clock_gettime()
	79	*
	80	* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp);
	81	*
	82	*/
	83	V_FUNCTION_BEGIN(__kernel_clock_gettime)
	84	.cfi_startproc
	85	/* Check for supported clock IDs */
	86	cmpli cr0,r3,CLOCK_REALTIME
	87	cmpli cr1,r3,CLOCK_MONOTONIC
0c37ec2a	88	cror cr04+eq,cr04+eq,cr1*4+eq
a7f290da BH	89	bne cr0,99f
	90
	91	mflr r12 /* r12 saves lr */
	92	.cfi_register lr,r12
	93	mr r10,r3 /* r10 saves id */
	94	mr r11,r4 /* r11 saves tp */
	95	bl __get_datapage@local /* get data page */
0c37ec2a	96	mr r9,r3 /* datapage ptr in r9 */
a7f290da BH	97	beq cr1,50f /* if monotonic -> jump there */
	98
	99	/*
	100	* CLOCK_REALTIME
	101	*/
	102
	103	bl __do_get_xsec@local /* get xsec from tb & kernel */
	104	bne- 98f /* out of line -> do syscall */
	105
	106	/* seconds are xsec >> 20 */
	107	rlwinm r5,r4,12,20,31
	108	rlwimi r5,r3,12,0,19
	109	stw r5,TSPC32_TV_SEC(r11)
	110
	111	/* get remaining xsec and convert to nsec. we scale
	112	* up remaining xsec by 12 bits and get the top 32 bits
	113	* of the multiplication, then we multiply by 1000
	114	*/
	115	rlwinm r5,r4,12,0,19
	116	lis r6,1000000@h
	117	ori r6,r6,1000000@l
	118	mulhwu r5,r5,r6
	119	mulli r5,r5,1000
	120	stw r5,TSPC32_TV_NSEC(r11)
	121	mtlr r12
5d66da3d	122	crclr cr0*4+so
a7f290da BH	123	li r3,0
	124	blr
	125
	126	/*
	127	* CLOCK_MONOTONIC
	128	*/
	129
	130	50: bl __do_get_xsec@local /* get xsec from tb & kernel */
	131	bne- 98f /* out of line -> do syscall */
	132
	133	/* seconds are xsec >> 20 */
	134	rlwinm r6,r4,12,20,31
	135	rlwimi r6,r3,12,0,19
	136
	137	/* get remaining xsec and convert to nsec. we scale
	138	* up remaining xsec by 12 bits and get the top 32 bits
	139	* of the multiplication, then we multiply by 1000
	140	*/
	141	rlwinm r7,r4,12,0,19
	142	lis r5,1000000@h
	143	ori r5,r5,1000000@l
	144	mulhwu r7,r7,r5
	145	mulli r7,r7,1000
	146
	147	/* now we must fixup using wall to monotonic. We need to snapshot
	148	* that value and do the counter trick again. Fortunately, we still
	149	* have the counter value in r8 that was returned by __do_get_xsec.
	150	* At this point, r6,r7 contain our sec/nsec values, r3,r4 and r5
	151	* can be used
	152	*/
	153
	154	lwz r3,WTOM_CLOCK_SEC(r9)
	155	lwz r4,WTOM_CLOCK_NSEC(r9)
	156
	157	/* We now have our result in r3,r4. We create a fake dependency
	158	* on that result and re-check the counter
	159	*/
	160	or r5,r4,r3
	161	xor r0,r5,r5
	162	add r9,r9,r0
	163	#ifdef CONFIG_PPC64
	164	lwz r0,(CFG_TB_UPDATE_COUNT+4)(r9)
	165	#else
	166	lwz r0,(CFG_TB_UPDATE_COUNT)(r9)
	167	#endif
	168	cmpl cr0,r8,r0 /* check if updated */
	169	bne- 50b
	170
	171	/* Calculate and store result. Note that this mimmics the C code,
	172	* which may cause funny results if nsec goes negative... is that
	173	* possible at all ?
	174	*/
	175	add r3,r3,r6
	176	add r4,r4,r7
	177	lis r5,NSEC_PER_SEC@h
	178	ori r5,r5,NSEC_PER_SEC@l
0c37ec2a BH	179	cmpl cr0,r4,r5
0c37ec2a BH	180	cmpli cr1,r4,0
a7f290da BH	181	blt 1f
	182	subf r4,r5,r4
	183	addi r3,r3,1
0c37ec2a BH	184	1: bge cr1,1f
	185	addi r3,r3,-1
	186	add r4,r4,r5
a7f290da BH	187	1: stw r3,TSPC32_TV_SEC(r11)
	188	stw r4,TSPC32_TV_NSEC(r11)
	189
	190	mtlr r12
5d66da3d	191	crclr cr0*4+so
a7f290da BH	192	li r3,0
	193	blr
	194
	195	/*
	196	* syscall fallback
	197	*/
	198	98:
	199	mtlr r12
	200	mr r3,r10
	201	mr r4,r11
	202	99:
	203	li r0,__NR_clock_gettime
	204	sc
	205	blr
	206	.cfi_endproc
	207	V_FUNCTION_END(__kernel_clock_gettime)
	208
	209
	210	/*
	211	* Exact prototype of clock_getres()
	212	*
	213	* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
	214	*
	215	*/
	216	V_FUNCTION_BEGIN(__kernel_clock_getres)
	217	.cfi_startproc
	218	/* Check for supported clock IDs */
	219	cmpwi cr0,r3,CLOCK_REALTIME
	220	cmpwi cr1,r3,CLOCK_MONOTONIC
0c37ec2a	221	cror cr04+eq,cr04+eq,cr1*4+eq
a7f290da BH	222	bne cr0,99f
	223
	224	li r3,0
	225	cmpli cr0,r4,0
5d66da3d	226	crclr cr0*4+so
a7f290da BH	227	beqlr
	228	lis r5,CLOCK_REALTIME_RES@h
	229	ori r5,r5,CLOCK_REALTIME_RES@l
	230	stw r3,TSPC32_TV_SEC(r4)
	231	stw r5,TSPC32_TV_NSEC(r4)
	232	blr
	233
	234	/*
	235	* syscall fallback
	236	*/
	237	99:
	238	li r0,__NR_clock_getres
	239	sc
	240	blr
	241	.cfi_endproc
	242	V_FUNCTION_END(__kernel_clock_getres)
	243
	244
	245	/*
	246	* This is the core of gettimeofday() & friends, it returns the xsec
	247	* value in r3 & r4 and expects the datapage ptr (non clobbered)
	248	* in r9. clobbers r0,r4,r5,r6,r7,r8.
	249	* When returning, r8 contains the counter value that can be reused
	250	* by the monotonic clock implementation
	251	*/
	252	__do_get_xsec:
	253	.cfi_startproc
	254	/* Check for update count & load values. We use the low
	255	* order 32 bits of the update count
	256	*/
	257	#ifdef CONFIG_PPC64
	258	1: lwz r8,(CFG_TB_UPDATE_COUNT+4)(r9)
	259	#else
	260	1: lwz r8,(CFG_TB_UPDATE_COUNT)(r9)
	261	#endif
	262	andi. r0,r8,1 /* pending update ? loop */
	263	bne- 1b
	264	xor r0,r8,r8 /* create dependency */
	265	add r9,r9,r0
	266
	267	/* Load orig stamp (offset to TB) */
	268	lwz r5,CFG_TB_ORIG_STAMP(r9)
	269	lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
	270
	271	/* Get a stable TB value */
	272	2: mftbu r3
	273	mftbl r4
	274	mftbu r0
	275	cmpl cr0,r3,r0
	276	bne- 2b
	277
	278	/* Substract tb orig stamp. If the high part is non-zero, we jump to
	279	* the slow path which call the syscall.
	280	* If it's ok, then we have our 32 bits tb_ticks value in r7
	281	*/
	282	subfc r7,r6,r4
	283	subfe. r0,r5,r3
	284	bne- 3f
	285
	286	/* Load scale factor & do multiplication */
	287	lwz r5,CFG_TB_TO_XS(r9) /* load values */
	288	lwz r6,(CFG_TB_TO_XS+4)(r9)
	289	mulhwu r4,r7,r5
	290	mulhwu r6,r7,r6
291	mullw r0,r7,r5
292	addc r6,r6,r0
293
294	/* At this point, we have the scaled xsec value in r4 + XER:CA
295	* we load & add the stamp since epoch
296	*/
297	lwz r5,CFG_STAMP_XSEC(r9)
298	lwz r6,(CFG_STAMP_XSEC+4)(r9)
299	adde r4,r4,r6
300	addze r3,r5
301
302	/* We now have our result in r3,r4. We create a fake dependency
303	* on that result and re-check the counter
304	*/
305	or r6,r4,r3
306	xor r0,r6,r6
307	add r9,r9,r0
308	#ifdef CONFIG_PPC64
309	lwz r0,(CFG_TB_UPDATE_COUNT+4)(r9)
310	#else
311	lwz r0,(CFG_TB_UPDATE_COUNT)(r9)
312	#endif
313	cmpl cr0,r8,r0 /* check if updated */
314	bne- 1b
315
316	/* Warning ! The caller expects CR:EQ to be set to indicate a
317	* successful calculation (so it won't fallback to the syscall
318	* method). We have overriden that CR bit in the counter check,
319	* but fortunately, the loop exit condition _is_ CR:EQ set, so
320	* we can exit safely here. If you change this code, be careful
321	* of that side effect.
322	*/
323	3: blr
324	.cfi_endproc