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- /*
- * 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
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