1 files changed, 91 insertions, 0 deletions

diff --git a/arch/ppc64/kernel/vdso64/gettimeofday.S b/arch/ppc64/kernel/vdso64/gettimeofday.S
new file mode 100644
index 000000000000..ed3f970ff05e
--- /dev/null
+++ b/arch/ppc64/kernel/vdso64/gettimeofday.S
@@ -0,0 +1,91 @@
+/*
+ * 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/offsets.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)
+
+
+/*
+ * 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
+*/
+V_FUNCTION_BEGIN(__do_get_xsec)
+  .cfi_startproc
+        /* check for update count & load values */
+1:      ld      r7,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    r8
+        ld      r9,CFG_TB_ORIG_STAMP(r3)
+        subf    r8,r9,r8
+
+        /* Scale result */
+        ld      r5,CFG_TB_TO_XS(r3)
+        mulhdu  r8,r8,r5
+
+        /* Add stamp since epoch */
+        ld      r6,CFG_STAMP_XSEC(r3)
+        add     r4,r6,r8
+
+        xor     r0,r4,r4
+        add     r3,r3,r0
+        ld      r0,CFG_TB_UPDATE_COUNT(r3)
+        cmpld   cr0,r0,r7               /* check if updated */
+        bne-    1b
+        blr
+  .cfi_endproc
+V_FUNCTION_END(__do_get_xsec)