| /* |
| * 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/offsets.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) |
| |
| |
| /* |
| * 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 |
| */ |
| V_FUNCTION_BEGIN(__do_get_xsec) |
| .cfi_startproc |
| /* check for update count & load values */ |
| 1: ld r7,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 r8 |
| ld r9,CFG_TB_ORIG_STAMP(r3) |
| subf r8,r9,r8 |
| |
| /* Scale result */ |
| ld r5,CFG_TB_TO_XS(r3) |
| mulhdu r8,r8,r5 |
| |
| /* Add stamp since epoch */ |
| ld r6,CFG_STAMP_XSEC(r3) |
| add r4,r6,r8 |
| |
| xor r0,r4,r4 |
| add r3,r3,r0 |
| ld r0,CFG_TB_UPDATE_COUNT(r3) |
| cmpld cr0,r0,r7 /* check if updated */ |
| bne- 1b |
| blr |
| .cfi_endproc |
| V_FUNCTION_END(__do_get_xsec) |
