[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel

This patch moves the vdso's to arch/powerpc, adds support for the 32
bits vdso to the 32 bits kernel, rename systemcfg (finally !), and adds
some new (still untested) routines to both vdso's: clock_gettime() with
support for CLOCK_REALTIME and CLOCK_MONOTONIC, clock_getres() (same
clocks) and get_tbfreq() for glibc to retreive the timebase frequency.

Tom,Steve: The implementation of get_tbfreq() I've done for 32 bits
returns a long long (r3, r4) not a long. This is such that if we ever
add support for >4Ghz timebases on ppc32, the userland interface won't
have to change.

I have tested gettimeofday() using some glibc patches in both ppc32 and
ppc64 kernels using 32 bits userland (I haven't had a chance to test a
64 bits userland yet, but the implementation didn't change and was
tested earlier). I haven't tested yet the new functions.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 242 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S
new file mode 100644
index 00000000000..d371c02a8c0
--- /dev/null
+++ b/arch/powerpc/kernel/vdso64/gettimeofday.S
@@ -0,0 +1,242 @@
+/*
+ * 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)