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- /* SPDX-License-Identifier: GPL-2.0 */
- /*
- * Userland implementation of gettimeofday() for 64 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
- aghi %r15,-16
- larl %r5,_vdso_data
- 0: ltgr %r3,%r3 /* check if tz is NULL */
- je 1f
- mvc 0(8,%r3),__VDSO_TIMEZONE(%r5)
- 1: ltgr %r2,%r2 /* check if tv is NULL */
- je 4f
- lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
- tmll %r4,0x0001 /* pending update ? loop */
- jnz 0b
- stcke 0(%r15) /* Store TOD clock */
- lg %r1,1(%r15)
- lg %r0,__VDSO_TS_END(%r5) /* TOD steering end time */
- slgr %r0,%r1 /* now - ts_steering_end */
- ltgr %r0,%r0 /* past end of steering ? */
- jm 6f
- srlg %r0,%r0,15 /* 1 per 2^16 */
- tm __VDSO_TS_DIR+3(%r5),0x01 /* steering direction? */
- jz 7f
- lcgr %r0,%r0 /* negative TOD offset */
- 7: algr %r1,%r0 /* add steering offset */
- 6: sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
- msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
- alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */
- lg %r0,__VDSO_XTIME_SEC(%r5) /* tk->xtime_sec */
- clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
- jne 0b
- lgf %r5,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
- srlg %r1,%r1,0(%r5) /* >> tk->shift */
- larl %r5,5f
- 2: clg %r1,0(%r5)
- jl 3f
- slg %r1,0(%r5)
- aghi %r0,1
- j 2b
- 3: stg %r0,0(%r2) /* store tv->tv_sec */
- slgr %r0,%r0 /* tv_nsec -> tv_usec */
- ml %r0,8(%r5)
- srlg %r0,%r0,6
- stg %r0,8(%r2) /* store tv->tv_usec */
- 4: lghi %r2,0
- aghi %r15,16
- br %r14
- 5: .quad 1000000000
- .long 274877907
- .cfi_endproc
- .size __kernel_gettimeofday,.-__kernel_gettimeofday
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