/* * Userland implementation of gettimeofday() for 64 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 #include #include #include #include .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 r11,r3 /* r11 holds tv */ mr r10,r4 /* r10 holds tz */ bl V_LOCAL_FUNC(__get_datapage) /* get data page */ bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */ lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */ ori r7,r7,16960 rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */ rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */ std r5,TVAL64_TV_SEC(r11) /* store sec in tv */ subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */ mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) / * XSEC_PER_SEC */ rldicl r0,r0,44,20 cmpldi cr0,r10,0 /* check if tz is NULL */ std r0,TVAL64_TV_USEC(r11) /* store usec in tv */ beq 1f lwz r4,CFG_TZ_MINUTEWEST(r3)/* fill tz */ lwz r5,CFG_TZ_DSTTIME(r3) stw r4,TZONE_TZ_MINWEST(r10) stw r5,TZONE_TZ_DSTTIME(r10) 1: mtlr r12 crclr cr0*4+so li r3,0 /* always success */ 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 */ cmpwi cr0,r3,CLOCK_REALTIME cmpwi 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 V_LOCAL_FUNC(__get_datapage) /* get data page */ beq cr1,50f /* if monotonic -> jump there */ /* * CLOCK_REALTIME */ bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */ lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */ ori r7,r7,16960 rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */ rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */ std r5,TSPC64_TV_SEC(r11) /* store sec in tv */ subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */ mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) / * XSEC_PER_SEC */ rldicl r0,r0,44,20 mulli r0,r0,1000 /* nsec = usec * 1000 */ std r0,TSPC64_TV_NSEC(r11) /* store nsec in tp */ mtlr r12 crclr cr0*4+so li r3,0 blr /* * CLOCK_MONOTONIC */ 50: bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */ lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */ ori r7,r7,16960 rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */ rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */ subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */ mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) / * XSEC_PER_SEC */ rldicl r6,r0,44,20 mulli r6,r6,1000 /* nsec = usec * 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, r5,r6 contain our sec/nsec values. * can be used */ lwa r4,WTOM_CLOCK_SEC(r3) lwa r7,WTOM_CLOCK_NSEC(r3) /* We now have our result in r4,r7. We create a fake dependency * on that result and re-check the counter */ or r9,r4,r7 xor r0,r9,r9 add r3,r3,r0 ld r0,CFG_TB_UPDATE_COUNT(r3) cmpld cr0,r0,r8 /* 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 r4,r4,r5 add r7,r7,r6 lis r9,NSEC_PER_SEC@h ori r9,r9,NSEC_PER_SEC@l cmpl cr0,r7,r9 cmpli cr1,r7,0 blt 1f subf r7,r9,r7 addi r4,r4,1 1: bge cr1,1f addi r4,r4,-1 add r7,r7,r9 1: std r4,TSPC64_TV_SEC(r11) std r7,TSPC64_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 std r3,TSPC64_TV_SEC(r4) std r5,TSPC64_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(), it returns the xsec * value in r4 and expects the datapage ptr (non clobbered) * in r3. clobbers r0,r4,r5,r6,r7,r8 * When returning, r8 contains the counter value that can be reused */ V_FUNCTION_BEGIN(__do_get_xsec) .cfi_startproc /* check for update count & load values */ 1: ld r8,CFG_TB_UPDATE_COUNT(r3) andi. r0,r8,1 /* pending update ? loop */ bne- 1b xor r0,r8,r8 /* create dependency */ add r3,r3,r0 /* Get TB & offset it */ mftb r7 ld r9,CFG_TB_ORIG_STAMP(r3) subf r7,r9,r7 /* Scale result */ ld r5,CFG_TB_TO_XS(r3) mulhdu r7,r7,r5 /* Add stamp since epoch */ ld r6,CFG_STAMP_XSEC(r3) add r4,r6,r7 xor r0,r4,r4 add r3,r3,r0 ld r0,CFG_TB_UPDATE_COUNT(r3) cmpld cr0,r0,r8 /* check if updated */ bne- 1b blr .cfi_endproc V_FUNCTION_END(__do_get_xsec)