/*
* 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
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
std r0,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 */
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 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. We use the MFTB macro which will generate
* workaround code for Cell.
*/
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)
/*
* This is the core of clock_gettime(), it returns the current
* time in seconds and nanoseconds in r4 and r5.
* It expects the datapage ptr in r3 and doesn't clobber it.
* It clobbers r0 and r6 and returns NSEC_PER_SEC in r7.
* 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(r7)
ld r9,CFG_TB_ORIG_STAMP(r3)
subf r7,r9,r7
/* Scale result */
ld r5,CFG_TB_TO_XS(r3)
sldi r7,r7,12 /* compute time since stamp_xtime */
mulhdu r6,r7,r5 /* in units of 2^-32 seconds */
/* Add stamp since epoch */
ld r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
ld r5,STAMP_XTIME+TSPC64_TV_NSEC(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 */
lis r7,NSEC_PER_SEC@h
ori r7,r7,NSEC_PER_SEC@l
mulhwu r0,r6,r7 /* compute nanoseconds and */
srdi r6,r6,32 /* seconds since stamp_xtime */
clrldi r0,r0,32
add r5,r5,r0 /* add nanoseconds together */
cmpd r5,r7 /* overflow? */
add r4,r4,r6
bltlr /* all done if no overflow */
subf r5,r7,r5 /* if overflow, adjust */
addi r4,r4,1
blr
.cfi_endproc
V_FUNCTION_END(__do_get_tspec)
