| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Userland implementation of gettimeofday() for 64 bits processes in a |
| 3 | * ppc64 kernel for use in the vDSO |
| 4 | * |
| 5 | * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org), |
| 6 | * IBM Corp. |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU General Public License |
| 10 | * as published by the Free Software Foundation; either version |
| 11 | * 2 of the License, or (at your option) any later version. |
| 12 | */ |
| 13 | #include <linux/config.h> |
| 14 | #include <asm/processor.h> |
| 15 | #include <asm/ppc_asm.h> |
| 16 | #include <asm/vdso.h> |
| 17 | #include <asm/offsets.h> |
| 18 | |
| 19 | .text |
| 20 | /* |
| 21 | * Exact prototype of gettimeofday |
| 22 | * |
| 23 | * int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); |
| 24 | * |
| 25 | */ |
| 26 | V_FUNCTION_BEGIN(__kernel_gettimeofday) |
| 27 | .cfi_startproc |
| 28 | mflr r12 |
| 29 | .cfi_register lr,r12 |
| 30 | |
| 31 | mr r11,r3 /* r11 holds tv */ |
| 32 | mr r10,r4 /* r10 holds tz */ |
| 33 | bl V_LOCAL_FUNC(__get_datapage) /* get data page */ |
| 34 | bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */ |
| 35 | lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */ |
| 36 | ori r7,r7,16960 |
| 37 | rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */ |
| 38 | rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */ |
| 39 | std r5,TVAL64_TV_SEC(r11) /* store sec in tv */ |
| 40 | subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */ |
| 41 | mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) / XSEC_PER_SEC */ |
| 42 | rldicl r0,r0,44,20 |
| 43 | cmpldi cr0,r10,0 /* check if tz is NULL */ |
| 44 | std r0,TVAL64_TV_USEC(r11) /* store usec in tv */ |
| 45 | beq 1f |
| 46 | lwz r4,CFG_TZ_MINUTEWEST(r3)/* fill tz */ |
| 47 | lwz r5,CFG_TZ_DSTTIME(r3) |
| 48 | stw r4,TZONE_TZ_MINWEST(r10) |
| 49 | stw r5,TZONE_TZ_DSTTIME(r10) |
| 50 | 1: mtlr r12 |
| 51 | li r3,0 /* always success */ |
| 52 | blr |
| 53 | .cfi_endproc |
| 54 | V_FUNCTION_END(__kernel_gettimeofday) |
| 55 | |
| 56 | |
| 57 | /* |
| 58 | * This is the core of gettimeofday(), it returns the xsec |
| 59 | * value in r4 and expects the datapage ptr (non clobbered) |
| 60 | * in r3. clobbers r0,r4,r5,r6,r7,r8 |
| 61 | */ |
| 62 | V_FUNCTION_BEGIN(__do_get_xsec) |
| 63 | .cfi_startproc |
| 64 | /* check for update count & load values */ |
| 65 | 1: ld r7,CFG_TB_UPDATE_COUNT(r3) |
| 66 | andi. r0,r4,1 /* pending update ? loop */ |
| 67 | bne- 1b |
| 68 | xor r0,r4,r4 /* create dependency */ |
| 69 | add r3,r3,r0 |
| 70 | |
| 71 | /* Get TB & offset it */ |
| 72 | mftb r8 |
| 73 | ld r9,CFG_TB_ORIG_STAMP(r3) |
| 74 | subf r8,r9,r8 |
| 75 | |
| 76 | /* Scale result */ |
| 77 | ld r5,CFG_TB_TO_XS(r3) |
| 78 | mulhdu r8,r8,r5 |
| 79 | |
| 80 | /* Add stamp since epoch */ |
| 81 | ld r6,CFG_STAMP_XSEC(r3) |
| 82 | add r4,r6,r8 |
| 83 | |
| 84 | xor r0,r4,r4 |
| 85 | add r3,r3,r0 |
| 86 | ld r0,CFG_TB_UPDATE_COUNT(r3) |
| 87 | cmpld cr0,r0,r7 /* check if updated */ |
| 88 | bne- 1b |
| 89 | blr |
| 90 | .cfi_endproc |
| 91 | V_FUNCTION_END(__do_get_xsec) |