2 * Userland implementation of gettimeofday() for 64 bits processes in a
3 * ppc64 kernel for use in the vDSO
5 * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org),
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.
13 #include <linux/config.h>
14 #include <asm/processor.h>
15 #include <asm/ppc_asm.h>
17 #include <asm/asm-offsets.h>
18 #include <asm/unistd.h>
22 * Exact prototype of gettimeofday
24 * int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz);
27 V_FUNCTION_BEGIN(__kernel_gettimeofday)
32 mr r11,r3 /* r11 holds tv */
33 mr r10,r4 /* r10 holds tz */
34 bl V_LOCAL_FUNC(__get_datapage) /* get data page */
35 bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
36 lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */
38 rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */
39 rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */
40 std r5,TVAL64_TV_SEC(r11) /* store sec in tv */
41 subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */
42 mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) /
46 cmpldi cr0,r10,0 /* check if tz is NULL */
47 std r0,TVAL64_TV_USEC(r11) /* store usec in tv */
49 lwz r4,CFG_TZ_MINUTEWEST(r3)/* fill tz */
50 lwz r5,CFG_TZ_DSTTIME(r3)
51 stw r4,TZONE_TZ_MINWEST(r10)
52 stw r5,TZONE_TZ_DSTTIME(r10)
54 li r3,0 /* always success */
57 V_FUNCTION_END(__kernel_gettimeofday)
61 * Exact prototype of clock_gettime()
63 * int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp);
66 V_FUNCTION_BEGIN(__kernel_clock_gettime)
68 /* Check for supported clock IDs */
69 cmpwi cr0,r3,CLOCK_REALTIME
70 cmpwi cr1,r3,CLOCK_MONOTONIC
74 mflr r12 /* r12 saves lr */
76 mr r10,r3 /* r10 saves id */
77 mr r11,r4 /* r11 saves tp */
78 bl V_LOCAL_FUNC(__get_datapage) /* get data page */
79 beq cr1,50f /* if monotonic -> jump there */
85 bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
87 lis r7,0x3b9a /* r7 = 1000000000 = NSEC_PER_SEC */
89 rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */
90 rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */
91 std r5,TSPC64_TV_SEC(r11) /* store sec in tv */
92 subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */
93 mulld r0,r0,r7 /* nsec = (xsec * NSEC_PER_SEC) /
97 std r0,TSPC64_TV_NSEC(r11) /* store nsec in tp */
107 50: bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
109 lis r7,0x3b9a /* r7 = 1000000000 = NSEC_PER_SEC */
111 rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */
112 rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */
113 subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */
114 mulld r0,r0,r7 /* nsec = (xsec * NSEC_PER_SEC) /
119 /* now we must fixup using wall to monotonic. We need to snapshot
120 * that value and do the counter trick again. Fortunately, we still
121 * have the counter value in r8 that was returned by __do_get_xsec.
122 * At this point, r5,r6 contain our sec/nsec values.
126 lwz r4,WTOM_CLOCK_SEC(r9)
127 lwz r7,WTOM_CLOCK_NSEC(r9)
129 /* We now have our result in r4,r7. We create a fake dependency
130 * on that result and re-check the counter
135 ld r0,CFG_TB_UPDATE_COUNT(r3)
136 cmpld cr0,r0,r8 /* check if updated */
139 /* Calculate and store result. Note that this mimmics the C code,
140 * which may cause funny results if nsec goes negative... is that
145 lis r9,NSEC_PER_SEC@h
146 ori r9,r9,NSEC_PER_SEC@l
151 1: std r4,TSPC64_TV_SEC(r11)
152 std r7,TSPC64_TV_NSEC(r11)
166 li r0,__NR_clock_gettime
170 V_FUNCTION_END(__kernel_clock_gettime)
174 * Exact prototype of clock_getres()
176 * int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
179 V_FUNCTION_BEGIN(__kernel_clock_getres)
181 /* Check for supported clock IDs */
182 cmpwi cr0,r3,CLOCK_REALTIME
183 cmpwi cr1,r3,CLOCK_MONOTONIC
190 lis r5,CLOCK_REALTIME_RES@h
191 ori r5,r5,CLOCK_REALTIME_RES@l
192 std r3,TSPC64_TV_SEC(r4)
193 std r5,TSPC64_TV_NSEC(r4)
200 li r0,__NR_clock_getres
204 V_FUNCTION_END(__kernel_clock_getres)
208 * This is the core of gettimeofday(), it returns the xsec
209 * value in r4 and expects the datapage ptr (non clobbered)
210 * in r3. clobbers r0,r4,r5,r6,r7,r8
211 * When returning, r8 contains the counter value that can be reused
213 V_FUNCTION_BEGIN(__do_get_xsec)
215 /* check for update count & load values */
216 1: ld r8,CFG_TB_UPDATE_COUNT(r3)
217 andi. r0,r4,1 /* pending update ? loop */
219 xor r0,r4,r4 /* create dependency */
222 /* Get TB & offset it */
224 ld r9,CFG_TB_ORIG_STAMP(r3)
228 ld r5,CFG_TB_TO_XS(r3)
231 /* Add stamp since epoch */
232 ld r6,CFG_STAMP_XSEC(r3)
237 ld r0,CFG_TB_UPDATE_COUNT(r3)
238 cmpld cr0,r0,r8 /* check if updated */
242 V_FUNCTION_END(__do_get_xsec)