/* * 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 <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 r11,r3 /* r11 holds tv */ mr r10,r4 /* r10 holds tz */ bl V_LOCAL_FUNC(__get_datapage) /* get data page */ cmpldi r11,0 /* check if tv is NULL */ beq 2f lis r7,1000000@ha /* load up USEC_PER_SEC */ addi r7,r7,1000000@l bl V_LOCAL_FUNC(__do_get_tspec) /* get sec/us from tb & kernel */ std r4,TVAL64_TV_SEC(r11) /* store sec in tv */ std r5,TVAL64_TV_USEC(r11) /* store usec in tv */ 2: cmpldi r10,0 /* check if tz is NULL */ 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 r11,r4 /* r11 saves tp */ bl V_LOCAL_FUNC(__get_datapage) /* get data page */ lis r7,NSEC_PER_SEC@h /* want nanoseconds */ ori r7,r7,NSEC_PER_SEC@l 50: bl V_LOCAL_FUNC(__do_get_tspec) /* get time from tb & kernel */ bne cr1,80f /* if not monotonic, all done */ /* * CLOCK_MONOTONIC */ /* 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_tspec. * At this point, r4,r5 contain our sec/nsec values. */ lwa r6,WTOM_CLOCK_SEC(r3) lwa r9,WTOM_CLOCK_NSEC(r3) /* We now have our result in r6,r9. We create a fake dependency * on that result and re-check the counter */ or r0,r6,r9 xor r0,r0,r0 add r3,r3,r0 ld r0,CFG_TB_UPDATE_COUNT(r3) cmpld cr0,r0,r8 /* check if updated */ bne- 50b /* Add wall->monotonic offset and check for overflow or underflow. */ add r4,r4,r6 add r5,r5,r9 cmpd cr0,r5,r7 cmpdi cr1,r5,0 blt 1f subf r5,r7,r5 addi r4,r4,1 1: bge cr1,80f addi r4,r4,-1 add r5,r5,r7 80: std r4,TSPC64_TV_SEC(r11) std r5,TSPC64_TV_NSEC(r11) mtlr r12 crclr cr0*4+so li r3,0 blr /* * syscall fallback */ 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 clock_gettime() and gettimeofday(), * it returns the current time in r4 (seconds) and r5. * On entry, r7 gives the resolution of r5, either USEC_PER_SEC * or NSEC_PER_SEC, giving r5 in microseconds or nanoseconds. * It expects the datapage ptr in r3 and doesn't clobber it. * It clobbers r0, r6 and r9. * On return, r8 contains the counter value that can be reused. * This clobbers cr0 but not any other cr field. */ V_FUNCTION_BEGIN(__do_get_tspec) .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. We use the MFTB macro which will generate * workaround code for Cell. */ MFTB(r6) ld r9,CFG_TB_ORIG_STAMP(r3) subf r6,r9,r6 /* Scale result */ ld r5,CFG_TB_TO_XS(r3) sldi r6,r6,12 /* compute time since stamp_xtime */ mulhdu r6,r6,r5 /* in units of 2^-32 seconds */ /* Add stamp since epoch */ ld r4,STAMP_XTIME+TSPC64_TV_SEC(r3) lwz r5,STAMP_SEC_FRAC(r3) or r0,r4,r5 or r0,r0,r6 xor r0,r0,r0 add r3,r3,r0 ld r0,CFG_TB_UPDATE_COUNT(r3) cmpld r0,r8 /* check if updated */ bne- 1b /* reload if so */ /* convert to seconds & nanoseconds and add to stamp */ add r6,r6,r5 /* add on fractional seconds of xtime */ mulhwu r5,r6,r7 /* compute micro or nanoseconds and */ srdi r6,r6,32 /* seconds since stamp_xtime */ clrldi r5,r5,32 add r4,r4,r6 blr .cfi_endproc V_FUNCTION_END(__do_get_tspec)