--- /dev/null
+/*
+ * Userland implementation of gettimeofday() for 32 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 r10,r3 /* r10 saves tv */
+ mr r11,r4 /* r11 saves tz */
+ bl __get_datapage@local /* get data page */
+ mr r9, r3 /* datapage ptr in r9 */
+ bl __do_get_xsec@local /* get xsec from tb & kernel */
+ bne- 2f /* out of line -> do syscall */
+
+ /* seconds are xsec >> 20 */
+ rlwinm r5,r4,12,20,31
+ rlwimi r5,r3,12,0,19
+ stw r5,TVAL32_TV_SEC(r10)
+
+ /* get remaining xsec and convert to usec. we scale
+ * up remaining xsec by 12 bits and get the top 32 bits
+ * of the multiplication
+ */
+ rlwinm r5,r4,12,0,19
+ lis r6,1000000@h
+ ori r6,r6,1000000@l
+ mulhwu r5,r5,r6
+ stw r5,TVAL32_TV_USEC(r10)
+
+ cmpli cr0,r11,0 /* check if tz is NULL */
+ beq 1f
+ lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
+ lwz r5,CFG_TZ_DSTTIME(r9)
+ stw r4,TZONE_TZ_MINWEST(r11)
+ stw r5,TZONE_TZ_DSTTIME(r11)
+
+1: mtlr r12
+ crclr cr0*4+so
+ li r3,0
+ blr
+
+2:
+ mtlr r12
+ mr r3,r10
+ mr r4,r11
+ li r0,__NR_gettimeofday
+ sc
+ 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 */
+ cmpli cr0,r3,CLOCK_REALTIME
+ cmpli 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 r10,r3 /* r10 saves id */
+ mr r11,r4 /* r11 saves tp */
+ bl __get_datapage@local /* get data page */
+ mr r9,r3 /* datapage ptr in r9 */
+ beq cr1,50f /* if monotonic -> jump there */
+
+ /*
+ * CLOCK_REALTIME
+ */
+
+ bl __do_get_xsec@local /* get xsec from tb & kernel */
+ bne- 98f /* out of line -> do syscall */
+
+ /* seconds are xsec >> 20 */
+ rlwinm r5,r4,12,20,31
+ rlwimi r5,r3,12,0,19
+ stw r5,TSPC32_TV_SEC(r11)
+
+ /* get remaining xsec and convert to nsec. we scale
+ * up remaining xsec by 12 bits and get the top 32 bits
+ * of the multiplication, then we multiply by 1000
+ */
+ rlwinm r5,r4,12,0,19
+ lis r6,1000000@h
+ ori r6,r6,1000000@l
+ mulhwu r5,r5,r6
+ mulli r5,r5,1000
+ stw r5,TSPC32_TV_NSEC(r11)
+ mtlr r12
+ crclr cr0*4+so
+ li r3,0
+ blr
+
+ /*
+ * CLOCK_MONOTONIC
+ */
+
+50: bl __do_get_xsec@local /* get xsec from tb & kernel */
+ bne- 98f /* out of line -> do syscall */
+
+ /* seconds are xsec >> 20 */
+ rlwinm r6,r4,12,20,31
+ rlwimi r6,r3,12,0,19
+
+ /* get remaining xsec and convert to nsec. we scale
+ * up remaining xsec by 12 bits and get the top 32 bits
+ * of the multiplication, then we multiply by 1000
+ */
+ rlwinm r7,r4,12,0,19
+ lis r5,1000000@h
+ ori r5,r5,1000000@l
+ mulhwu r7,r7,r5
+ mulli r7,r7,1000
+
+ /* 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, r6,r7 contain our sec/nsec values, r3,r4 and r5
+ * can be used
+ */
+
+ lwz r3,WTOM_CLOCK_SEC(r9)
+ lwz r4,WTOM_CLOCK_NSEC(r9)
+
+ /* We now have our result in r3,r4. We create a fake dependency
+ * on that result and re-check the counter
+ */
+ or r5,r4,r3
+ xor r0,r5,r5
+ add r9,r9,r0
+#ifdef CONFIG_PPC64
+ lwz r0,(CFG_TB_UPDATE_COUNT+4)(r9)
+#else
+ lwz r0,(CFG_TB_UPDATE_COUNT)(r9)
+#endif
+ cmpl cr0,r8,r0 /* 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 r3,r3,r6
+ add r4,r4,r7
+ lis r5,NSEC_PER_SEC@h
+ ori r5,r5,NSEC_PER_SEC@l
+ cmpl cr0,r4,r5
+ cmpli cr1,r4,0
+ blt 1f
+ subf r4,r5,r4
+ addi r3,r3,1
+1: bge cr1,1f
+ addi r3,r3,-1
+ add r4,r4,r5
+1: stw r3,TSPC32_TV_SEC(r11)
+ stw r4,TSPC32_TV_NSEC(r11)
+
+ mtlr r12
+ crclr cr0*4+so
+ 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*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
+ stw r3,TSPC32_TV_SEC(r4)
+ stw r5,TSPC32_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() & friends, it returns the xsec
+ * value in r3 & r4 and expects the datapage ptr (non clobbered)
+ * in r9. clobbers r0,r4,r5,r6,r7,r8.
+ * When returning, r8 contains the counter value that can be reused
+ * by the monotonic clock implementation
+ */
+__do_get_xsec:
+ .cfi_startproc
+ /* Check for update count & load values. We use the low
+ * order 32 bits of the update count
+ */
+#ifdef CONFIG_PPC64
+1: lwz r8,(CFG_TB_UPDATE_COUNT+4)(r9)
+#else
+1: lwz r8,(CFG_TB_UPDATE_COUNT)(r9)
+#endif
+ andi. r0,r8,1 /* pending update ? loop */
+ bne- 1b
+ xor r0,r8,r8 /* create dependency */
+ add r9,r9,r0
+
+ /* Load orig stamp (offset to TB) */
+ lwz r5,CFG_TB_ORIG_STAMP(r9)
+ lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
+
+ /* Get a stable TB value */
+2: mftbu r3
+ mftbl r4
+ mftbu r0
+ cmpl cr0,r3,r0
+ bne- 2b
+
+ /* Substract tb orig stamp. If the high part is non-zero, we jump to
+ * the slow path which call the syscall.
+ * If it's ok, then we have our 32 bits tb_ticks value in r7
+ */
+ subfc r7,r6,r4
+ subfe. r0,r5,r3
+ bne- 3f
+
+ /* Load scale factor & do multiplication */
+ lwz r5,CFG_TB_TO_XS(r9) /* load values */
+ lwz r6,(CFG_TB_TO_XS+4)(r9)
+ mulhwu r4,r7,r5
+ mulhwu r6,r7,r6
+ mullw r0,r7,r5
+ addc r6,r6,r0
+
+ /* At this point, we have the scaled xsec value in r4 + XER:CA
+ * we load & add the stamp since epoch
+ */
+ lwz r5,CFG_STAMP_XSEC(r9)
+ lwz r6,(CFG_STAMP_XSEC+4)(r9)
+ adde r4,r4,r6
+ addze r3,r5
+
+ /* We now have our result in r3,r4. We create a fake dependency
+ * on that result and re-check the counter
+ */
+ or r6,r4,r3
+ xor r0,r6,r6
+ add r9,r9,r0
+#ifdef CONFIG_PPC64
+ lwz r0,(CFG_TB_UPDATE_COUNT+4)(r9)
+#else
+ lwz r0,(CFG_TB_UPDATE_COUNT)(r9)
+#endif
+ cmpl cr0,r8,r0 /* check if updated */
+ bne- 1b
+
+ /* Warning ! The caller expects CR:EQ to be set to indicate a
+ * successful calculation (so it won't fallback to the syscall
+ * method). We have overriden that CR bit in the counter check,
+ * but fortunately, the loop exit condition _is_ CR:EQ set, so
+ * we can exit safely here. If you change this code, be careful
+ * of that side effect.
+ */
+3: blr
+ .cfi_endproc
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