/* * Userland implementation of gettimeofday() for 32 bits processes in a * s390 kernel for use in the vDSO * * Copyright IBM Corp. 2008 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License (version 2 only) * as published by the Free Software Foundation. */ #include <asm/vdso.h> #include <asm/asm-offsets.h> #include <asm/unistd.h> .text .align 4 .globl __kernel_gettimeofday .type __kernel_gettimeofday,@function __kernel_gettimeofday: .cfi_startproc ahi %r15,-16 basr %r5,0 0: al %r5,13f-0b(%r5) /* get &_vdso_data */ 1: ltr %r3,%r3 /* check if tz is NULL */ je 2f mvc 0(8,%r3),__VDSO_TIMEZONE(%r5) 2: ltr %r2,%r2 /* check if tv is NULL */ je 10f l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */ tml %r4,0x0001 /* pending update ? loop */ jnz 1b stcke 0(%r15) /* Store TOD clock */ lm %r0,%r1,__VDSO_TS_END(%r5) /* TOD steering end time */ s %r0,1(%r15) sl %r1,5(%r15) brc 3,14f ahi %r0,-1 14: ltr %r0,%r0 /* past end of steering? */ jm 16f srdl %r0,15 /* 1 per 2^16 */ tm __VDSO_TS_DIR+3(%r5),0x01 /* steering direction? */ jz 15f lcr %r0,%r0 /* negative TOD offset */ lcr %r1,%r1 je 15f ahi %r0,-1 15: a %r0,1(%r15) /* add TOD timestamp */ al %r1,5(%r15) brc 12,17f ahi %r0,1 j 17f 16: lm %r0,%r1,1(%r15) /* load TOD timestamp */ 17: s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ sl %r1,__VDSO_XTIME_STAMP+4(%r5) brc 3,3f ahi %r0,-1 3: ms %r0,__VDSO_TK_MULT(%r5) /* * tk->mult */ st %r0,0(%r15) l %r0,__VDSO_TK_MULT(%r5) ltr %r1,%r1 mr %r0,%r0 jnm 4f a %r0,__VDSO_TK_MULT(%r5) 4: al %r0,0(%r15) al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */ al %r1,__VDSO_XTIME_NSEC+4(%r5) brc 12,5f ahi %r0,1 5: mvc 0(4,%r15),__VDSO_XTIME_SEC+4(%r5) cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */ jne 1b l %r4,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */ srdl %r0,0(%r4) /* >> tk->shift */ l %r4,0(%r15) /* get tv_sec from stack */ basr %r5,0 6: ltr %r0,%r0 jnz 7f cl %r1,11f-6b(%r5) jl 8f 7: ahi %r4,1 sl %r1,11f-6b(%r5) brc 3,6b ahi %r0,-1 j 6b 8: st %r4,0(%r2) /* store tv->tv_sec */ ltr %r1,%r1 m %r0,12f-6b(%r5) jnm 9f al %r0,12f-6b(%r5) 9: srl %r0,6 st %r0,4(%r2) /* store tv->tv_usec */ 10: slr %r2,%r2 ahi %r15,16 br %r14 11: .long 1000000000 12: .long 274877907 13: .long _vdso_data - 0b .cfi_endproc .size __kernel_gettimeofday,.-__kernel_gettimeofday |