diff options
Diffstat (limited to 'arch/powerpc/kernel/vdso64/gettimeofday.S')
| -rw-r--r-- | arch/powerpc/kernel/vdso64/gettimeofday.S | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S new file mode 100644 index 0000000..d371c02 --- /dev/null +++ b/arch/powerpc/kernel/vdso64/gettimeofday.S @@ -0,0 +1,242 @@ +/* + * 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 <linux/config.h> +#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 */ + 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 + cmpldi cr0,r10,0 /* check if tz is NULL */ + std r0,TVAL64_TV_USEC(r11) /* store usec in tv */ + 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 + 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,cr0,cr1 + bne cr0,99f + + mflr r12 /* r12 saves lr */ + .cfi_register lr,r12 + mr r10,r3 /* r10 saves id */ + mr r11,r4 /* r11 saves tp */ + bl V_LOCAL_FUNC(__get_datapage) /* get data page */ + beq cr1,50f /* if monotonic -> jump there */ + + /* + * CLOCK_REALTIME + */ + + bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */ + + lis r7,0x3b9a /* r7 = 1000000000 = NSEC_PER_SEC */ + ori r7,r7,0xca00 + rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */ + rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */ + std r5,TSPC64_TV_SEC(r11) /* store sec in tv */ + subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */ + mulld r0,r0,r7 /* nsec = (xsec * NSEC_PER_SEC) / + * XSEC_PER_SEC + */ + rldicl r0,r0,44,20 + std r0,TSPC64_TV_NSEC(r11) /* store nsec in tp */ + + mtlr r12 + li r3,0 + blr + + /* + * CLOCK_MONOTONIC + */ + +50: bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */ + + lis r7,0x3b9a /* r7 = 1000000000 = NSEC_PER_SEC */ + ori r7,r7,0xca00 + rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */ + rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */ + subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */ + mulld r0,r0,r7 /* nsec = (xsec * NSEC_PER_SEC) / + * XSEC_PER_SEC + */ + rldicl r6,r0,44,20 + + /* 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, r5,r6 contain our sec/nsec values. + * can be used + */ + + lwz r4,WTOM_CLOCK_SEC(r9) + lwz r7,WTOM_CLOCK_NSEC(r9) + + /* We now have our result in r4,r7. We create a fake dependency + * on that result and re-check the counter + */ + or r9,r4,r7 + xor r0,r9,r9 + add r3,r3,r0 + ld r0,CFG_TB_UPDATE_COUNT(r3) + cmpld cr0,r0,r8 /* check if updated */ + bne- 50b + + /* Calculate and store result. Note that this mimmics the C code, + * which may cause funny results if nsec goes negative... is that + * possible at all ? + */ + add r4,r4,r5 + add r7,r7,r6 + lis r9,NSEC_PER_SEC@h + ori r9,r9,NSEC_PER_SEC@l + cmpli cr0,r7,r9 + blt 1f + subf r7,r9,r7 + addi r4,r4,1 +1: std r4,TSPC64_TV_SEC(r11) + std r7,TSPC64_TV_NSEC(r11) + + mtlr r12 + li r3,0 + blr + + /* + * syscall fallback + */ +98: + mtlr r12 + mr r3,r10 + mr r4,r11 +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,cr0,cr1 + bne cr0,99f + + li r3,0 + cmpli cr0,r4,0 + 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,r4,1 /* pending update ? loop */ + bne- 1b + xor r0,r4,r4 /* create dependency */ + add r3,r3,r0 + + /* Get TB & offset it */ + 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) |
