diff options
Diffstat (limited to 'arch/powerpc/kernel/vdso64/gettimeofday.S')
| -rw-r--r-- | arch/powerpc/kernel/vdso64/gettimeofday.S | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S new file mode 100644 index 000000000..20f8be40c --- /dev/null +++ b/arch/powerpc/kernel/vdso64/gettimeofday.S @@ -0,0 +1,290 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * 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. + */ +#include <asm/processor.h> +#include <asm/ppc_asm.h> +#include <asm/vdso.h> +#include <asm/vdso_datapage.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 */ + get_datapage r3, r0 + 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 + + cmpwi cr5,r3,CLOCK_REALTIME_COARSE + cmpwi cr6,r3,CLOCK_MONOTONIC_COARSE + cror cr5*4+eq,cr5*4+eq,cr6*4+eq + + cror cr0*4+eq,cr0*4+eq,cr5*4+eq + bne cr0,99f + + mflr r12 /* r12 saves lr */ + .cfi_register lr,r12 + mr r11,r4 /* r11 saves tp */ + get_datapage r3, r0 + lis r7,NSEC_PER_SEC@h /* want nanoseconds */ + ori r7,r7,NSEC_PER_SEC@l + beq cr5,70f +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. + */ + + ld 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 + b 78f + + /* + * For coarse clocks we get data directly from the vdso data page, so + * we don't need to call __do_get_tspec, but we still need to do the + * counter trick. + */ +70: ld r8,CFG_TB_UPDATE_COUNT(r3) + andi. r0,r8,1 /* pending update ? loop */ + bne- 70b + add r3,r3,r0 /* r0 is already 0 */ + + /* + * CLOCK_REALTIME_COARSE, below values are needed for MONOTONIC_COARSE + * too + */ + ld r4,STAMP_XTIME_SEC(r3) + ld r5,STAMP_XTIME_NSEC(r3) + bne cr6,75f + + /* CLOCK_MONOTONIC_COARSE */ + ld r6,WTOM_CLOCK_SEC(r3) + lwa r9,WTOM_CLOCK_NSEC(r3) + + /* check if counter has updated */ + or r0,r6,r9 +75: or r0,r0,r4 + or r0,r0,r5 + xor r0,r0,r0 + add r3,r3,r0 + ld r0,CFG_TB_UPDATE_COUNT(r3) + cmpld cr0,r0,r8 /* check if updated */ + bne- 70b + + /* Counter has not updated, so continue calculating proper values for + * sec and nsec if monotonic coarse, or just return with the proper + * values for realtime. + */ + bne cr6,80f + + /* Add wall->monotonic offset and check for overflow or underflow */ +78: add r4,r4,r6 + add r5,r5,r9 + cmpd cr0,r5,r7 + cmpdi cr1,r5,0 + blt 79f + subf r5,r7,r5 + addi r4,r4,1 +79: 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 + .cfi_restore lr + 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 + + mflr r12 + .cfi_register lr,r12 + get_datapage r3, r0 + lwz r5, CLOCK_HRTIMER_RES(r3) + mtlr r12 + li r3,0 + cmpldi cr0,r4,0 + crclr cr0*4+so + beqlr + 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) + +/* + * Exact prototype of time() + * + * time_t time(time *t); + * + */ +V_FUNCTION_BEGIN(__kernel_time) + .cfi_startproc + mflr r12 + .cfi_register lr,r12 + + mr r11,r3 /* r11 holds t */ + get_datapage r3, r0 + + ld r4,STAMP_XTIME_SEC(r3) + + cmpldi r11,0 /* check if t is NULL */ + beq 2f + std r4,0(r11) /* store result at *t */ +2: mtlr r12 + crclr cr0*4+so + mr r3,r4 + blr + .cfi_endproc +V_FUNCTION_END(__kernel_time) + + +/* + * 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_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) |