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Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +11001/*
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 */
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110013#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
Paul Mackerras597bc5c2008-10-27 23:56:03 +000019/* Offset for the low 32-bit part of a field of long type */
20#ifdef CONFIG_PPC64
21#define LOPART 4
Paul Mackerras8fd63a92010-06-20 19:03:08 +000022#define TSPEC_TV_SEC TSPC64_TV_SEC+LOPART
Paul Mackerras597bc5c2008-10-27 23:56:03 +000023#else
24#define LOPART 0
Paul Mackerras8fd63a92010-06-20 19:03:08 +000025#define TSPEC_TV_SEC TSPC32_TV_SEC
Paul Mackerras597bc5c2008-10-27 23:56:03 +000026#endif
27
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110028 .text
29/*
30 * Exact prototype of gettimeofday
31 *
32 * int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz);
33 *
34 */
35V_FUNCTION_BEGIN(__kernel_gettimeofday)
36 .cfi_startproc
37 mflr r12
38 .cfi_register lr,r12
39
40 mr r10,r3 /* r10 saves tv */
41 mr r11,r4 /* r11 saves tz */
42 bl __get_datapage@local /* get data page */
43 mr r9, r3 /* datapage ptr in r9 */
Tony Breeds74609f42007-06-26 09:50:32 +100044 cmplwi r10,0 /* check if tv is NULL */
45 beq 3f
Paul Mackerras8fd63a92010-06-20 19:03:08 +000046 lis r7,1000000@ha /* load up USEC_PER_SEC */
47 addi r7,r7,1000000@l /* so we get microseconds in r4 */
48 bl __do_get_tspec@local /* get sec/usec from tb & kernel */
49 stw r3,TVAL32_TV_SEC(r10)
50 stw r4,TVAL32_TV_USEC(r10)
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110051
Tony Breeds74609f42007-06-26 09:50:32 +1000523: cmplwi r11,0 /* check if tz is NULL */
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110053 beq 1f
54 lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
55 lwz r5,CFG_TZ_DSTTIME(r9)
56 stw r4,TZONE_TZ_MINWEST(r11)
57 stw r5,TZONE_TZ_DSTTIME(r11)
58
591: mtlr r12
Benjamin Herrenschmidt5d66da32005-11-16 13:54:32 +110060 crclr cr0*4+so
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110061 li r3,0
62 blr
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110063 .cfi_endproc
64V_FUNCTION_END(__kernel_gettimeofday)
65
66/*
67 * Exact prototype of clock_gettime()
68 *
69 * int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp);
70 *
71 */
72V_FUNCTION_BEGIN(__kernel_clock_gettime)
73 .cfi_startproc
74 /* Check for supported clock IDs */
75 cmpli cr0,r3,CLOCK_REALTIME
76 cmpli cr1,r3,CLOCK_MONOTONIC
Benjamin Herrenschmidt0c37ec22005-11-14 14:55:58 +110077 cror cr0*4+eq,cr0*4+eq,cr1*4+eq
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110078 bne cr0,99f
79
80 mflr r12 /* r12 saves lr */
81 .cfi_register lr,r12
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110082 mr r11,r4 /* r11 saves tp */
83 bl __get_datapage@local /* get data page */
Benjamin Herrenschmidt0c37ec22005-11-14 14:55:58 +110084 mr r9,r3 /* datapage ptr in r9 */
Paul Mackerras8fd63a92010-06-20 19:03:08 +000085 lis r7,NSEC_PER_SEC@h /* want nanoseconds */
86 ori r7,r7,NSEC_PER_SEC@l
Paul Mackerras597bc5c2008-10-27 23:56:03 +00008750: bl __do_get_tspec@local /* get sec/nsec from tb & kernel */
88 bne cr1,80f /* not monotonic -> all done */
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110089
90 /*
91 * CLOCK_MONOTONIC
92 */
93
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110094 /* now we must fixup using wall to monotonic. We need to snapshot
95 * that value and do the counter trick again. Fortunately, we still
96 * have the counter value in r8 that was returned by __do_get_xsec.
Paul Mackerras597bc5c2008-10-27 23:56:03 +000097 * At this point, r3,r4 contain our sec/nsec values, r5 and r6
98 * can be used, r7 contains NSEC_PER_SEC.
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110099 */
100
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000101 lwz r5,WTOM_CLOCK_SEC(r9)
102 lwz r6,WTOM_CLOCK_NSEC(r9)
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100103
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000104 /* We now have our offset in r5,r6. We create a fake dependency
105 * on that value and re-check the counter
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100106 */
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000107 or r0,r6,r5
108 xor r0,r0,r0
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100109 add r9,r9,r0
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000110 lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100111 cmpl cr0,r8,r0 /* check if updated */
112 bne- 50b
113
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000114 /* Calculate and store result. Note that this mimics the C code,
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100115 * which may cause funny results if nsec goes negative... is that
116 * possible at all ?
117 */
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000118 add r3,r3,r5
119 add r4,r4,r6
120 cmpw cr0,r4,r7
121 cmpwi cr1,r4,0
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100122 blt 1f
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000123 subf r4,r7,r4
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100124 addi r3,r3,1
Paul Mackerras597bc5c2008-10-27 23:56:03 +00001251: bge cr1,80f
Benjamin Herrenschmidt0c37ec22005-11-14 14:55:58 +1100126 addi r3,r3,-1
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000127 add r4,r4,r7
128
12980: stw r3,TSPC32_TV_SEC(r11)
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100130 stw r4,TSPC32_TV_NSEC(r11)
131
132 mtlr r12
Benjamin Herrenschmidt5d66da32005-11-16 13:54:32 +1100133 crclr cr0*4+so
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100134 li r3,0
135 blr
136
137 /*
138 * syscall fallback
139 */
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110014099:
141 li r0,__NR_clock_gettime
142 sc
143 blr
144 .cfi_endproc
145V_FUNCTION_END(__kernel_clock_gettime)
146
147
148/*
149 * Exact prototype of clock_getres()
150 *
151 * int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
152 *
153 */
154V_FUNCTION_BEGIN(__kernel_clock_getres)
155 .cfi_startproc
156 /* Check for supported clock IDs */
157 cmpwi cr0,r3,CLOCK_REALTIME
158 cmpwi cr1,r3,CLOCK_MONOTONIC
Benjamin Herrenschmidt0c37ec22005-11-14 14:55:58 +1100159 cror cr0*4+eq,cr0*4+eq,cr1*4+eq
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100160 bne cr0,99f
161
162 li r3,0
163 cmpli cr0,r4,0
Benjamin Herrenschmidt5d66da32005-11-16 13:54:32 +1100164 crclr cr0*4+so
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100165 beqlr
166 lis r5,CLOCK_REALTIME_RES@h
167 ori r5,r5,CLOCK_REALTIME_RES@l
168 stw r3,TSPC32_TV_SEC(r4)
169 stw r5,TSPC32_TV_NSEC(r4)
170 blr
171
172 /*
173 * syscall fallback
174 */
17599:
176 li r0,__NR_clock_getres
177 sc
178 blr
179 .cfi_endproc
180V_FUNCTION_END(__kernel_clock_getres)
181
182
183/*
Adhemerval Zanellafcb41a22013-04-22 09:29:33 +0000184 * Exact prototype of time()
185 *
186 * time_t time(time *t);
187 *
188 */
189V_FUNCTION_BEGIN(__kernel_time)
190 .cfi_startproc
191 mflr r12
192 .cfi_register lr,r12
193
194 mr r11,r3 /* r11 holds t */
195 bl __get_datapage@local
196 mr r9, r3 /* datapage ptr in r9 */
197
198 lwz r3,STAMP_XTIME+TSPEC_TV_SEC(r9)
199
200 cmplwi r11,0 /* check if t is NULL */
201 beq 2f
202 stw r3,0(r11) /* store result at *t */
2032: mtlr r12
204 crclr cr0*4+so
205 blr
206 .cfi_endproc
207V_FUNCTION_END(__kernel_time)
208
209/*
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000210 * This is the core of clock_gettime() and gettimeofday(),
211 * it returns the current time in r3 (seconds) and r4.
212 * On entry, r7 gives the resolution of r4, either USEC_PER_SEC
213 * or NSEC_PER_SEC, giving r4 in microseconds or nanoseconds.
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000214 * It expects the datapage ptr in r9 and doesn't clobber it.
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000215 * It clobbers r0, r5 and r6.
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000216 * On return, r8 contains the counter value that can be reused.
217 * This clobbers cr0 but not any other cr field.
218 */
219__do_get_tspec:
220 .cfi_startproc
221 /* Check for update count & load values. We use the low
222 * order 32 bits of the update count
223 */
2241: lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
225 andi. r0,r8,1 /* pending update ? loop */
226 bne- 1b
227 xor r0,r8,r8 /* create dependency */
228 add r9,r9,r0
229
230 /* Load orig stamp (offset to TB) */
231 lwz r5,CFG_TB_ORIG_STAMP(r9)
232 lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
233
234 /* Get a stable TB value */
LEROY Christopheae2163b2013-11-22 17:57:31 +0100235#ifdef CONFIG_8xx
2362: mftbu r3
237 mftbl r4
238 mftbu r0
239#else
Scott Woodbeb2dc02013-08-20 19:33:12 -05002402: mfspr r3, SPRN_TBRU
241 mfspr r4, SPRN_TBRL
242 mfspr r0, SPRN_TBRU
LEROY Christopheae2163b2013-11-22 17:57:31 +0100243#endif
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000244 cmplw cr0,r3,r0
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000245 bne- 2b
246
247 /* Subtract tb orig stamp and shift left 12 bits.
248 */
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000249 subfc r4,r6,r4
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000250 subfe r0,r5,r3
251 slwi r0,r0,12
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000252 rlwimi. r0,r4,12,20,31
253 slwi r4,r4,12
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000254
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000255 /*
256 * Load scale factor & do multiplication.
257 * We only use the high 32 bits of the tb_to_xs value.
258 * Even with a 1GHz timebase clock, the high 32 bits of
259 * tb_to_xs will be at least 4 million, so the error from
260 * ignoring the low 32 bits will be no more than 0.25ppm.
261 * The error will just make the clock run very very slightly
262 * slow until the next time the kernel updates the VDSO data,
263 * at which point the clock will catch up to the kernel's value,
264 * so there is no long-term error accumulation.
265 */
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000266 lwz r5,CFG_TB_TO_XS(r9) /* load values */
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000267 mulhwu r4,r4,r5
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000268 li r3,0
269
270 beq+ 4f /* skip high part computation if 0 */
271 mulhwu r3,r0,r5
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000272 mullw r5,r0,r5
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000273 addc r4,r4,r5
274 addze r3,r3
Paul Mackerras8fd63a92010-06-20 19:03:08 +00002754:
276 /* At this point, we have seconds since the xtime stamp
277 * as a 32.32 fixed-point number in r3 and r4.
278 * Load & add the xtime stamp.
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000279 */
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000280 lwz r5,STAMP_XTIME+TSPEC_TV_SEC(r9)
281 lwz r6,STAMP_SEC_FRAC(r9)
282 addc r4,r4,r6
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000283 adde r3,r3,r5
284
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000285 /* We create a fake dependency on the result in r3/r4
286 * and re-check the counter
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000287 */
288 or r6,r4,r3
289 xor r0,r6,r6
290 add r9,r9,r0
291 lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000292 cmplw cr0,r8,r0 /* check if updated */
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000293 bne- 1b
294
Paul Mackerras8fd63a92010-06-20 19:03:08 +0000295 mulhwu r4,r4,r7 /* convert to micro or nanoseconds */
Paul Mackerras597bc5c2008-10-27 23:56:03 +0000296
297 blr
298 .cfi_endproc