--- /dev/null
+/*
+ * 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 <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 */
+ cmpldi r11,0 /* check if tv is NULL */
+ beq 2f
+ lis r7,1000000@ha /* load up USEC_PER_SEC */
+ addi r7,r7,1000000@l
+ bl V_LOCAL_FUNC(__do_get_tspec) /* get sec/us from tb & kernel */
+ std r4,TVAL64_TV_SEC(r11) /* store sec in tv */
+ std r5,TVAL64_TV_USEC(r11) /* store usec in tv */
+2: cmpldi r10,0 /* check if tz is NULL */
+ 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
+ crclr cr0*4+so
+ 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*4+eq,cr0*4+eq,cr1*4+eq
+ bne cr0,99f
+
+ mflr r12 /* r12 saves lr */
+ .cfi_register lr,r12
+ mr r11,r4 /* r11 saves tp */
+ bl V_LOCAL_FUNC(__get_datapage) /* get data page */
+ lis r7,NSEC_PER_SEC@h /* want nanoseconds */
+ ori r7,r7,NSEC_PER_SEC@l
+50: bl V_LOCAL_FUNC(__do_get_tspec) /* get time from tb & kernel */
+ bne cr1,80f /* if not monotonic, all done */
+
+ /*
+ * CLOCK_MONOTONIC
+ */
+
+ /* 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_tspec.
+ * At this point, r4,r5 contain our sec/nsec values.
+ */
+
+ lwa r6,WTOM_CLOCK_SEC(r3)
+ lwa r9,WTOM_CLOCK_NSEC(r3)
+
+ /* We now have our result in r6,r9. We create a fake dependency
+ * on that result and re-check the counter
+ */
+ or r0,r6,r9
+ xor r0,r0,r0
+ add r3,r3,r0
+ ld r0,CFG_TB_UPDATE_COUNT(r3)
+ cmpld cr0,r0,r8 /* check if updated */
+ bne- 50b
+
+ /* Add wall->monotonic offset and check for overflow or underflow.
+ */
+ add r4,r4,r6
+ add r5,r5,r9
+ cmpd cr0,r5,r7
+ cmpdi cr1,r5,0
+ blt 1f
+ subf r5,r7,r5
+ addi r4,r4,1
+1: bge cr1,80f
+ addi r4,r4,-1
+ add r5,r5,r7
+
+80: std r4,TSPC64_TV_SEC(r11)
+ std r5,TSPC64_TV_NSEC(r11)
+
+ mtlr r12
+ crclr cr0*4+so
+ li r3,0
+ blr
+
+ /*
+ * syscall fallback
+ */
+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*4+eq,cr0*4+eq,cr1*4+eq
+ bne cr0,99f
+
+ li r3,0
+ cmpli cr0,r4,0
+ crclr cr0*4+so
+ 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)
+
+/*
+ * Exact prototype of time()
+ *
+ * time_t time(time *t);
+ *
+ */
+V_FUNCTION_BEGIN(__kernel_time)
+ .cfi_startproc
+ mflr r12
+ .cfi_register lr,r12
+
+ mr r11,r3 /* r11 holds t */
+ bl V_LOCAL_FUNC(__get_datapage)
+
+ ld r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
+
+ cmpldi r11,0 /* check if t is NULL */
+ beq 2f
+ std r4,0(r11) /* store result at *t */
+2: mtlr r12
+ crclr cr0*4+so
+ mr r3,r4
+ blr
+ .cfi_endproc
+V_FUNCTION_END(__kernel_time)
+
+
+/*
+ * This is the core of clock_gettime() and gettimeofday(),
+ * it returns the current time in r4 (seconds) and r5.
+ * On entry, r7 gives the resolution of r5, either USEC_PER_SEC
+ * or NSEC_PER_SEC, giving r5 in microseconds or nanoseconds.
+ * It expects the datapage ptr in r3 and doesn't clobber it.
+ * It clobbers r0, r6 and r9.
+ * On return, r8 contains the counter value that can be reused.
+ * This clobbers cr0 but not any other cr field.
+ */
+V_FUNCTION_BEGIN(__do_get_tspec)
+ .cfi_startproc
+ /* check for update count & load values */
+1: ld r8,CFG_TB_UPDATE_COUNT(r3)
+ andi. r0,r8,1 /* pending update ? loop */
+ bne- 1b
+ xor r0,r8,r8 /* create dependency */
+ add r3,r3,r0
+
+ /* Get TB & offset it. We use the MFTB macro which will generate
+ * workaround code for Cell.
+ */
+ MFTB(r6)
+ ld r9,CFG_TB_ORIG_STAMP(r3)
+ subf r6,r9,r6
+
+ /* Scale result */
+ ld r5,CFG_TB_TO_XS(r3)
+ sldi r6,r6,12 /* compute time since stamp_xtime */
+ mulhdu r6,r6,r5 /* in units of 2^-32 seconds */
+
+ /* Add stamp since epoch */
+ ld r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
+ lwz r5,STAMP_SEC_FRAC(r3)
+ or r0,r4,r5
+ or r0,r0,r6
+ xor r0,r0,r0
+ add r3,r3,r0
+ ld r0,CFG_TB_UPDATE_COUNT(r3)
+ cmpld r0,r8 /* check if updated */
+ bne- 1b /* reload if so */
+
+ /* convert to seconds & nanoseconds and add to stamp */
+ add r6,r6,r5 /* add on fractional seconds of xtime */
+ mulhwu r5,r6,r7 /* compute micro or nanoseconds and */
+ srdi r6,r6,32 /* seconds since stamp_xtime */
+ clrldi r5,r5,32
+ add r4,r4,r6
+ blr
+ .cfi_endproc
+V_FUNCTION_END(__do_get_tspec)
Code Review / kvmfornfv.git / blobdiff