1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Userland implementation of gettimeofday() for 64 bits processes in a 4 * ppc64 kernel for use in the vDSO 5 * 6 * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org), 7 * IBM Corp. 8 */ 9 #include <asm/processor.h> 10 #include <asm/ppc_asm.h> 11 #include <asm/vdso.h> 12 #include <asm/vdso_datapage.h> 13 #include <asm/asm-offsets.h> 14 #include <asm/unistd.h> 15 16 .text 17 /* 18 * Exact prototype of gettimeofday 19 * 20 * int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); 21 * 22 */ 23 V_FUNCTION_BEGIN(__kernel_gettimeofday) 24 .cfi_startproc 25 mflr r12 26 .cfi_register lr,r12 27 28 mr r11,r3 /* r11 holds tv */ 29 mr r10,r4 /* r10 holds tz */ 30 get_datapage r3, r0 31 cmpldi r11,0 /* check if tv is NULL */ 32 beq 2f 33 lis r7,1000000@ha /* load up USEC_PER_SEC */ 34 addi r7,r7,1000000@l 35 bl V_LOCAL_FUNC(__do_get_tspec) /* get sec/us from tb & kernel */ 36 std r4,TVAL64_TV_SEC(r11) /* store sec in tv */ 37 std r5,TVAL64_TV_USEC(r11) /* store usec in tv */ 38 2: cmpldi r10,0 /* check if tz is NULL */ 39 beq 1f 40 lwz r4,CFG_TZ_MINUTEWEST(r3)/* fill tz */ 41 lwz r5,CFG_TZ_DSTTIME(r3) 42 stw r4,TZONE_TZ_MINWEST(r10) 43 stw r5,TZONE_TZ_DSTTIME(r10) 44 1: mtlr r12 45 crclr cr0*4+so 46 li r3,0 /* always success */ 47 blr 48 .cfi_endproc 49 V_FUNCTION_END(__kernel_gettimeofday) 50 51 52 /* 53 * Exact prototype of clock_gettime() 54 * 55 * int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); 56 * 57 */ 58 V_FUNCTION_BEGIN(__kernel_clock_gettime) 59 .cfi_startproc 60 /* Check for supported clock IDs */ 61 cmpwi cr0,r3,CLOCK_REALTIME 62 cmpwi cr1,r3,CLOCK_MONOTONIC 63 cror cr0*4+eq,cr0*4+eq,cr1*4+eq 64 65 cmpwi cr5,r3,CLOCK_REALTIME_COARSE 66 cmpwi cr6,r3,CLOCK_MONOTONIC_COARSE 67 cror cr5*4+eq,cr5*4+eq,cr6*4+eq 68 69 cror cr0*4+eq,cr0*4+eq,cr5*4+eq 70 bne cr0,99f 71 72 mflr r12 /* r12 saves lr */ 73 .cfi_register lr,r12 74 mr r11,r4 /* r11 saves tp */ 75 get_datapage r3, r0 76 lis r7,NSEC_PER_SEC@h /* want nanoseconds */ 77 ori r7,r7,NSEC_PER_SEC@l 78 beq cr5,70f 79 50: bl V_LOCAL_FUNC(__do_get_tspec) /* get time from tb & kernel */ 80 bne cr1,80f /* if not monotonic, all done */ 81 82 /* 83 * CLOCK_MONOTONIC 84 */ 85 86 /* now we must fixup using wall to monotonic. We need to snapshot 87 * that value and do the counter trick again. Fortunately, we still 88 * have the counter value in r8 that was returned by __do_get_tspec. 89 * At this point, r4,r5 contain our sec/nsec values. 90 */ 91 92 ld r6,WTOM_CLOCK_SEC(r3) 93 lwa r9,WTOM_CLOCK_NSEC(r3) 94 95 /* We now have our result in r6,r9. We create a fake dependency 96 * on that result and re-check the counter 97 */ 98 or r0,r6,r9 99 xor r0,r0,r0 100 add r3,r3,r0 101 ld r0,CFG_TB_UPDATE_COUNT(r3) 102 cmpld cr0,r0,r8 /* check if updated */ 103 bne- 50b 104 b 78f 105 106 /* 107 * For coarse clocks we get data directly from the vdso data page, so 108 * we don't need to call __do_get_tspec, but we still need to do the 109 * counter trick. 110 */ 111 70: ld r8,CFG_TB_UPDATE_COUNT(r3) 112 andi. r0,r8,1 /* pending update ? loop */ 113 bne- 70b 114 add r3,r3,r0 /* r0 is already 0 */ 115 116 /* 117 * CLOCK_REALTIME_COARSE, below values are needed for MONOTONIC_COARSE 118 * too 119 */ 120 ld r4,STAMP_XTIME_SEC(r3) 121 ld r5,STAMP_XTIME_NSEC(r3) 122 bne cr6,75f 123 124 /* CLOCK_MONOTONIC_COARSE */ 125 ld r6,WTOM_CLOCK_SEC(r3) 126 lwa r9,WTOM_CLOCK_NSEC(r3) 127 128 /* check if counter has updated */ 129 or r0,r6,r9 130 75: or r0,r0,r4 131 or r0,r0,r5 132 xor r0,r0,r0 133 add r3,r3,r0 134 ld r0,CFG_TB_UPDATE_COUNT(r3) 135 cmpld cr0,r0,r8 /* check if updated */ 136 bne- 70b 137 138 /* Counter has not updated, so continue calculating proper values for 139 * sec and nsec if monotonic coarse, or just return with the proper 140 * values for realtime. 141 */ 142 bne cr6,80f 143 144 /* Add wall->monotonic offset and check for overflow or underflow */ 145 78: add r4,r4,r6 146 add r5,r5,r9 147 cmpd cr0,r5,r7 148 cmpdi cr1,r5,0 149 blt 79f 150 subf r5,r7,r5 151 addi r4,r4,1 152 79: bge cr1,80f 153 addi r4,r4,-1 154 add r5,r5,r7 155 156 80: std r4,TSPC64_TV_SEC(r11) 157 std r5,TSPC64_TV_NSEC(r11) 158 159 mtlr r12 160 crclr cr0*4+so 161 li r3,0 162 blr 163 164 /* 165 * syscall fallback 166 */ 167 99: 168 li r0,__NR_clock_gettime 169 .cfi_restore lr 170 sc 171 blr 172 .cfi_endproc 173 V_FUNCTION_END(__kernel_clock_gettime) 174 175 176 /* 177 * Exact prototype of clock_getres() 178 * 179 * int __kernel_clock_getres(clockid_t clock_id, struct timespec *res); 180 * 181 */ 182 V_FUNCTION_BEGIN(__kernel_clock_getres) 183 .cfi_startproc 184 /* Check for supported clock IDs */ 185 cmpwi cr0,r3,CLOCK_REALTIME 186 cmpwi cr1,r3,CLOCK_MONOTONIC 187 cror cr0*4+eq,cr0*4+eq,cr1*4+eq 188 bne cr0,99f 189 190 mflr r12 191 .cfi_register lr,r12 192 get_datapage r3, r0 193 lwz r5, CLOCK_HRTIMER_RES(r3) 194 mtlr r12 195 li r3,0 196 cmpldi cr0,r4,0 197 crclr cr0*4+so 198 beqlr 199 std r3,TSPC64_TV_SEC(r4) 200 std r5,TSPC64_TV_NSEC(r4) 201 blr 202 203 /* 204 * syscall fallback 205 */ 206 99: 207 li r0,__NR_clock_getres 208 sc 209 blr 210 .cfi_endproc 211 V_FUNCTION_END(__kernel_clock_getres) 212 213 /* 214 * Exact prototype of time() 215 * 216 * time_t time(time *t); 217 * 218 */ 219 V_FUNCTION_BEGIN(__kernel_time) 220 .cfi_startproc 221 mflr r12 222 .cfi_register lr,r12 223 224 mr r11,r3 /* r11 holds t */ 225 get_datapage r3, r0 226 227 ld r4,STAMP_XTIME_SEC(r3) 228 229 cmpldi r11,0 /* check if t is NULL */ 230 beq 2f 231 std r4,0(r11) /* store result at *t */ 232 2: mtlr r12 233 crclr cr0*4+so 234 mr r3,r4 235 blr 236 .cfi_endproc 237 V_FUNCTION_END(__kernel_time) 238 239 240 /* 241 * This is the core of clock_gettime() and gettimeofday(), 242 * it returns the current time in r4 (seconds) and r5. 243 * On entry, r7 gives the resolution of r5, either USEC_PER_SEC 244 * or NSEC_PER_SEC, giving r5 in microseconds or nanoseconds. 245 * It expects the datapage ptr in r3 and doesn't clobber it. 246 * It clobbers r0, r6 and r9. 247 * On return, r8 contains the counter value that can be reused. 248 * This clobbers cr0 but not any other cr field. 249 */ 250 V_FUNCTION_BEGIN(__do_get_tspec) 251 .cfi_startproc 252 /* check for update count & load values */ 253 1: ld r8,CFG_TB_UPDATE_COUNT(r3) 254 andi. r0,r8,1 /* pending update ? loop */ 255 bne- 1b 256 xor r0,r8,r8 /* create dependency */ 257 add r3,r3,r0 258 259 /* Get TB & offset it. We use the MFTB macro which will generate 260 * workaround code for Cell. 261 */ 262 MFTB(r6) 263 ld r9,CFG_TB_ORIG_STAMP(r3) 264 subf r6,r9,r6 265 266 /* Scale result */ 267 ld r5,CFG_TB_TO_XS(r3) 268 sldi r6,r6,12 /* compute time since stamp_xtime */ 269 mulhdu r6,r6,r5 /* in units of 2^-32 seconds */ 270 271 /* Add stamp since epoch */ 272 ld r4,STAMP_XTIME_SEC(r3) 273 lwz r5,STAMP_SEC_FRAC(r3) 274 or r0,r4,r5 275 or r0,r0,r6 276 xor r0,r0,r0 277 add r3,r3,r0 278 ld r0,CFG_TB_UPDATE_COUNT(r3) 279 cmpld r0,r8 /* check if updated */ 280 bne- 1b /* reload if so */ 281 282 /* convert to seconds & nanoseconds and add to stamp */ 283 add r6,r6,r5 /* add on fractional seconds of xtime */ 284 mulhwu r5,r6,r7 /* compute micro or nanoseconds and */ 285 srdi r6,r6,32 /* seconds since stamp_xtime */ 286 clrldi r5,r5,32 287 add r4,r4,r6 288 blr 289 .cfi_endproc 290 V_FUNCTION_END(__do_get_tspec) 291