--- /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 <linux/config.h>
+#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 */
+ 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)
+
+
+/*
+ * 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,cr0,cr1
+ bne cr0,99f
+
+ mflr r12 /* r12 saves lr */
+ .cfi_register lr,r12
+ mr r10,r3 /* r10 saves id */
+ mr r11,r4 /* r11 saves tp */
+ bl V_LOCAL_FUNC(__get_datapage) /* get data page */
+ beq cr1,50f /* if monotonic -> jump there */
+
+ /*
+ * CLOCK_REALTIME
+ */
+
+ bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
+
+ lis r7,0x3b9a /* r7 = 1000000000 = NSEC_PER_SEC */
+ ori r7,r7,0xca00
+ rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */
+ rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */
+ std r5,TSPC64_TV_SEC(r11) /* store sec in tv */
+ subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */
+ mulld r0,r0,r7 /* nsec = (xsec * NSEC_PER_SEC) /
+ * XSEC_PER_SEC
+ */
+ rldicl r0,r0,44,20
+ std r0,TSPC64_TV_NSEC(r11) /* store nsec in tp */
+
+ mtlr r12
+ li r3,0
+ blr
+
+ /*
+ * CLOCK_MONOTONIC
+ */
+
+50: bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
+
+ lis r7,0x3b9a /* r7 = 1000000000 = NSEC_PER_SEC */
+ ori r7,r7,0xca00
+ rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */
+ rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */
+ subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */
+ mulld r0,r0,r7 /* nsec = (xsec * NSEC_PER_SEC) /
+ * XSEC_PER_SEC
+ */
+ rldicl r6,r0,44,20
+
+ /* 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_xsec.
+ * At this point, r5,r6 contain our sec/nsec values.
+ * can be used
+ */
+
+ lwz r4,WTOM_CLOCK_SEC(r9)
+ lwz r7,WTOM_CLOCK_NSEC(r9)
+
+ /* We now have our result in r4,r7. We create a fake dependency
+ * on that result and re-check the counter
+ */
+ or r9,r4,r7
+ xor r0,r9,r9
+ add r3,r3,r0
+ ld r0,CFG_TB_UPDATE_COUNT(r3)
+ cmpld cr0,r0,r8 /* check if updated */
+ bne- 50b
+
+ /* Calculate and store result. Note that this mimmics the C code,
+ * which may cause funny results if nsec goes negative... is that
+ * possible at all ?
+ */
+ add r4,r4,r5
+ add r7,r7,r6
+ lis r9,NSEC_PER_SEC@h
+ ori r9,r9,NSEC_PER_SEC@l
+ cmpli cr0,r7,r9
+ blt 1f
+ subf r7,r9,r7
+ addi r4,r4,1
+1: std r4,TSPC64_TV_SEC(r11)
+ std r7,TSPC64_TV_NSEC(r11)
+
+ mtlr r12
+ li r3,0
+ blr
+
+ /*
+ * syscall fallback
+ */
+98:
+ mtlr r12
+ mr r3,r10
+ mr r4,r11
+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,cr0,cr1
+ bne cr0,99f
+
+ li r3,0
+ cmpli cr0,r4,0
+ 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)
+
+
+/*
+ * 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
+ * When returning, r8 contains the counter value that can be reused
+ */
+V_FUNCTION_BEGIN(__do_get_xsec)
+ .cfi_startproc
+ /* check for update count & load values */
+1: ld r8,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 r7
+ ld r9,CFG_TB_ORIG_STAMP(r3)
+ subf r7,r9,r7
+
+ /* Scale result */
+ ld r5,CFG_TB_TO_XS(r3)
+ mulhdu r7,r7,r5
+
+ /* Add stamp since epoch */
+ ld r6,CFG_STAMP_XSEC(r3)
+ add r4,r6,r7
+
+ xor r0,r4,r4
+ add r3,r3,r0
+ ld r0,CFG_TB_UPDATE_COUNT(r3)
+ cmpld cr0,r0,r8 /* check if updated */
+ bne- 1b
+ blr
+ .cfi_endproc
+V_FUNCTION_END(__do_get_xsec)
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