/*
* Userland implementation of gettimeofday() for 32 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>
/* Offset for the low 32-bit part of a field of long type */
#ifdef CONFIG_PPC64
#define LOPART 4
#else
#define LOPART 0
#endif
.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 r10,r3 /* r10 saves tv */
mr r11,r4 /* r11 saves tz */
bl __get_datapage@local /* get data page */
mr r9, r3 /* datapage ptr in r9 */
cmplwi r10,0 /* check if tv is NULL */
beq 3f
bl __do_get_xsec@local /* get xsec from tb & kernel */
bne- 2f /* out of line -> do syscall */
/* seconds are xsec >> 20 */
rlwinm r5,r4,12,20,31
rlwimi r5,r3,12,0,19
stw r5,TVAL32_TV_SEC(r10)
/* get remaining xsec and convert to usec. we scale
* up remaining xsec by 12 bits and get the top 32 bits
* of the multiplication
*/
rlwinm r5,r4,12,0,19
lis r6,1000000@h
ori r6,r6,1000000@l
mulhwu r5,r5,r6
stw r5,TVAL32_TV_USEC(r10)
3: cmplwi r11,0 /* check if tz is NULL */
beq 1f
lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
lwz r5,CFG_TZ_DSTTIME(r9)
stw r4,TZONE_TZ_MINWEST(r11)
stw r5,TZONE_TZ_DSTTIME(r11)
1: mtlr r12
crclr cr0*4+so
li r3,0
blr
2:
mtlr r12
mr r3,r10
mr r4,r11
li r0,__NR_gettimeofday
sc
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 */
cmpli cr0,r3,CLOCK_REALTIME
cmpli 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 __get_datapage@local /* get data page */
mr r9,r3 /* datapage ptr in r9 */
50: bl __do_get_tspec@local /* get sec/nsec from tb & kernel */
bne cr1,80f /* 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_xsec.
* At this point, r3,r4 contain our sec/nsec values, r5 and r6
* can be used, r7 contains NSEC_PER_SEC.
*/
lwz r5,WTOM_CLOCK_SEC(r9)
lwz r6,WTOM_CLOCK_NSEC(r9)
/* We now have our offset in r5,r6. We create a fake dependency
* on that value and re-check the counter
*/
or r0,r6,r5
xor r0,r0,r0
add r9,r9,r0
lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
cmpl cr0,r8,r0 /* check if updated */
bne- 50b
/* Calculate and store result. Note that this mimics the C code,
* which may cause funny results if nsec goes negative... is that
* possible at all ?
*/
add r3,r3,r5
add r4,r4,r6
cmpw cr0,r4,r7
cmpwi cr1,r4,0
blt 1f
subf r4,r7,r4
addi r3,r3,1
1: bge cr1,80f
addi r3,r3,-1
add r4,r4,r7
80: stw r3,TSPC32_TV_SEC(r11)
stw r4,TSPC32_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
stw r3,TSPC32_TV_SEC(r4)
stw r5,TSPC32_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() & friends, it returns the xsec
* value in r3 & r4 and expects the datapage ptr (non clobbered)
* in r9. clobbers r0,r4,r5,r6,r7,r8.
* When returning, r8 contains the counter value that can be reused
* by the monotonic clock implementation
*/
__do_get_xsec:
.cfi_startproc
/* Check for update count & load values. We use the low
* order 32 bits of the update count
*/
1: lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
andi. r0,r8,1 /* pending update ? loop */
bne- 1b
xor r0,r8,r8 /* create dependency */
add r9,r9,r0
/* Load orig stamp (offset to TB) */
lwz r5,CFG_TB_ORIG_STAMP(r9)
lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
/* Get a stable TB value */
2: mftbu r3
mftbl r4
mftbu r0
cmpl cr0,r3,r0
bne- 2b
/* Substract tb orig stamp. If the high part is non-zero, we jump to
* the slow path which call the syscall.
* If it's ok, then we have our 32 bits tb_ticks value in r7
*/
subfc r7,r6,r4
subfe. r0,r5,r3
bne- 3f
/* Load scale factor & do multiplication */
lwz r5,CFG_TB_TO_XS(r9) /* load values */
lwz r6,(CFG_TB_TO_XS+4)(r9)
mulhwu r4,r7,r5
mulhwu r6,r7,r6
mullw r0,r7,r5
addc r6,r6,r0
/* At this point, we have the scaled xsec value in r4 + XER:CA
* we load & add the stamp since epoch
*/
lwz r5,CFG_STAMP_XSEC(r9)
lwz r6,(CFG_STAMP_XSEC+4)(r9)
adde r4,r4,r6
addze r3,r5
/* We now have our result in r3,r4. We create a fake dependency
* on that result and re-check the counter
*/
or r6,r4,r3
xor r0,r6,r6
add r9,r9,r0
lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
cmpl cr0,r8,r0 /* check if updated */
bne- 1b
/* Warning ! The caller expects CR:EQ to be set to indicate a
* successful calculation (so it won't fallback to the syscall
* method). We have overriden that CR bit in the counter check,
* but fortunately, the loop exit condition _is_ CR:EQ set, so
* we can exit safely here. If you change this code, be careful
* of that side effect.
*/
3: blr
.cfi_endproc
/*
* This is the core of clock_gettime(), it returns the current
* time in seconds and nanoseconds in r3 and r4.
* It expects the datapage ptr in r9 and doesn't clobber it.
* It clobbers r0, r5, r6, r10 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.
*/
__do_get_tspec:
.cfi_startproc
/* Check for update count & load values. We use the low
* order 32 bits of the update count
*/
1: lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
andi. r0,r8,1 /* pending update ? loop */
bne- 1b
xor r0,r8,r8 /* create dependency */
add r9,r9,r0
/* Load orig stamp (offset to TB) */
lwz r5,CFG_TB_ORIG_STAMP(r9)
lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
/* Get a stable TB value */
2: mftbu r3
mftbl r4
mftbu r0
cmpl cr0,r3,r0
bne- 2b
/* Subtract tb orig stamp and shift left 12 bits.
*/
subfc r7,r6,r4
subfe r0,r5,r3
slwi r0,r0,12
rlwimi. r0,r7,12,20,31
slwi r7,r7,12
/* Load scale factor & do multiplication */
lwz r5,CFG_TB_TO_XS(r9) /* load values */
lwz r6,(CFG_TB_TO_XS+4)(r9)
mulhwu r3,r7,r6
mullw r10,r7,r5
mulhwu r4,r7,r5
addc r10,r3,r10
li r3,0
beq+ 4f /* skip high part computation if 0 */
mulhwu r3,r0,r5
mullw r7,r0,r5
mulhwu r5,r0,r6
mullw r6,r0,r6
adde r4,r4,r7
addze r3,r3
addc r4,r4,r5
addze r3,r3
addc r10,r10,r6
4: addze r4,r4 /* add in carry */
lis r7,NSEC_PER_SEC@h
ori r7,r7,NSEC_PER_SEC@l
mulhwu r4,r4,r7 /* convert to nanoseconds */
/* At this point, we have seconds & nanoseconds since the xtime
* stamp in r3+CA and r4. Load & add the xtime stamp.
*/
#ifdef CONFIG_PPC64
lwz r5,STAMP_XTIME+TSPC64_TV_SEC+LOPART(r9)
lwz r6,STAMP_XTIME+TSPC64_TV_NSEC+LOPART(r9)
#else
lwz r5,STAMP_XTIME+TSPC32_TV_SEC(r9)
lwz r6,STAMP_XTIME+TSPC32_TV_NSEC(r9)
#endif
add r4,r4,r6
adde r3,r3,r5
/* We now have our result in r3,r4. We create a fake dependency
* on that result and re-check the counter
*/
or r6,r4,r3
xor r0,r6,r6
add r9,r9,r0
lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
cmpl cr0,r8,r0 /* check if updated */
bne- 1b
/* check for nanosecond overflow and adjust if necessary */
cmpw r4,r7
bltlr /* all done if no overflow */
subf r4,r7,r4 /* adjust if overflow */
addi r3,r3,1
blr
.cfi_endproc
