---

yaml
---
r: 204689
b: refs/heads/master
c: 8fd63a9
h: refs/heads/master
i:
  204687: 150712a
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5f07aa7524e98d6f68f2bec54f155ef6012e2c9a
+refs/heads/master: 8fd63a9ea7528463211a6c88d500c51851d960c8

trunk/arch/powerpc/include/asm/vdso_datapage.h

@@ -85,6 +85,7 @@ struct vdso_data {
 	__s32 wtom_clock_sec;			/* Wall to monotonic clock */
 	__s32 wtom_clock_nsec;
 	struct timespec stamp_xtime;	/* xtime as at tb_orig_stamp */
+	__u32 stamp_sec_fraction;	/* fractional seconds of stamp_xtime */
    	__u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls  */
    	__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
 };
@@ -105,6 +106,7 @@ struct vdso_data {
 	__s32 wtom_clock_sec;			/* Wall to monotonic clock */
 	__s32 wtom_clock_nsec;
 	struct timespec stamp_xtime;	/* xtime as at tb_orig_stamp */
+	__u32 stamp_sec_fraction;	/* fractional seconds of stamp_xtime */
    	__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
 	__u32 dcache_block_size;	/* L1 d-cache block size     */
 	__u32 icache_block_size;	/* L1 i-cache block size     */

trunk/arch/powerpc/kernel/asm-offsets.c

@@ -342,6 +342,7 @@ int main(void)
 	DEFINE(WTOM_CLOCK_SEC, offsetof(struct vdso_data, wtom_clock_sec));
 	DEFINE(WTOM_CLOCK_NSEC, offsetof(struct vdso_data, wtom_clock_nsec));
 	DEFINE(STAMP_XTIME, offsetof(struct vdso_data, stamp_xtime));
+	DEFINE(STAMP_SEC_FRAC, offsetof(struct vdso_data, stamp_sec_fraction));
 	DEFINE(CFG_ICACHE_BLOCKSZ, offsetof(struct vdso_data, icache_block_size));
 	DEFINE(CFG_DCACHE_BLOCKSZ, offsetof(struct vdso_data, dcache_block_size));
 	DEFINE(CFG_ICACHE_LOGBLOCKSZ, offsetof(struct vdso_data, icache_log_block_size));

trunk/arch/powerpc/kernel/time.c

@@ -423,30 +423,6 @@ void udelay(unsigned long usecs)
 }
 EXPORT_SYMBOL(udelay);
 
-static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
-			       u64 new_tb_to_xs)
-{
-	/*
-	 * tb_update_count is used to allow the userspace gettimeofday code
-	 * to assure itself that it sees a consistent view of the tb_to_xs and
-	 * stamp_xsec variables.  It reads the tb_update_count, then reads
-	 * tb_to_xs and stamp_xsec and then reads tb_update_count again.  If
-	 * the two values of tb_update_count match and are even then the
-	 * tb_to_xs and stamp_xsec values are consistent.  If not, then it
-	 * loops back and reads them again until this criteria is met.
-	 * We expect the caller to have done the first increment of
-	 * vdso_data->tb_update_count already.
-	 */
-	vdso_data->tb_orig_stamp = new_tb_stamp;
-	vdso_data->stamp_xsec = new_stamp_xsec;
-	vdso_data->tb_to_xs = new_tb_to_xs;
-	vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
-	vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
-	vdso_data->stamp_xtime = xtime;
-	smp_wmb();
-	++(vdso_data->tb_update_count);
-}
-
 #ifdef CONFIG_SMP
 unsigned long profile_pc(struct pt_regs *regs)
 {
@@ -873,10 +849,37 @@ static cycle_t timebase_read(struct clocksource *cs)
 	return (cycle_t)get_tb();
 }
 
+static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
+			       u64 new_tb_to_xs, struct timespec *now,
+			       u32 frac_sec)
+{
+	/*
+	 * tb_update_count is used to allow the userspace gettimeofday code
+	 * to assure itself that it sees a consistent view of the tb_to_xs and
+	 * stamp_xsec variables.  It reads the tb_update_count, then reads
+	 * tb_to_xs and stamp_xsec and then reads tb_update_count again.  If
+	 * the two values of tb_update_count match and are even then the
+	 * tb_to_xs and stamp_xsec values are consistent.  If not, then it
+	 * loops back and reads them again until this criteria is met.
+	 * We expect the caller to have done the first increment of
+	 * vdso_data->tb_update_count already.
+	 */
+	vdso_data->tb_orig_stamp = new_tb_stamp;
+	vdso_data->stamp_xsec = new_stamp_xsec;
+	vdso_data->tb_to_xs = new_tb_to_xs;
+	vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
+	vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
+	vdso_data->stamp_xtime = *now;
+	vdso_data->stamp_sec_fraction = frac_sec;
+	smp_wmb();
+	++(vdso_data->tb_update_count);
+}
+
 void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
 		     u32 mult)
 {
 	u64 t2x, stamp_xsec;
+	u32 frac_sec;
 
 	if (clock != &clocksource_timebase)
 		return;
@@ -888,10 +891,14 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
 	/* XXX this assumes clock->shift == 22 */
 	/* 4611686018 ~= 2^(20+64-22) / 1e9 */
 	t2x = (u64) mult * 4611686018ULL;
-	stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
+	stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
 	do_div(stamp_xsec, 1000000000);
-	stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
-	update_gtod(clock->cycle_last, stamp_xsec, t2x);
+	stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
+
+	BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
+	/* this is tv_nsec / 1e9 as a 0.32 fraction */
+	frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
+	update_gtod(clock->cycle_last, stamp_xsec, t2x, wall_time, frac_sec);
 }
 
 void update_vsyscall_tz(void)

trunk/arch/powerpc/kernel/vdso32/gettimeofday.S

@@ -19,8 +19,10 @@
 /* Offset for the low 32-bit part of a field of long type */
 #ifdef CONFIG_PPC64
 #define LOPART	4
+#define TSPEC_TV_SEC	TSPC64_TV_SEC+LOPART
 #else
 #define LOPART	0
+#define TSPEC_TV_SEC	TSPC32_TV_SEC
 #endif
 
 	.text
@@ -41,23 +43,11 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
 	mr	r9, r3			/* datapage ptr in r9 */
 	cmplwi	r10,0			/* check if tv is NULL */
 	beq	3f
-	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)
+	lis	r7,1000000@ha		/* load up USEC_PER_SEC */
+	addi	r7,r7,1000000@l		/* so we get microseconds in r4 */
+	bl	__do_get_tspec@local	/* get sec/usec from tb & kernel */
+	stw	r3,TVAL32_TV_SEC(r10)
+	stw	r4,TVAL32_TV_USEC(r10)
 
 3:	cmplwi	r11,0			/* check if tz is NULL */
 	beq	1f
@@ -70,14 +60,6 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
 	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)
 
@@ -100,7 +82,8 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime)
 	mr	r11,r4			/* r11 saves tp */
 	bl	__get_datapage@local	/* get data page */
 	mr	r9,r3			/* datapage ptr in r9 */
-
+	lis	r7,NSEC_PER_SEC@h	/* want nanoseconds */
+	ori	r7,r7,NSEC_PER_SEC@l
 50:	bl	__do_get_tspec@local	/* get sec/nsec from tb & kernel */
 	bne	cr1,80f			/* not monotonic -> all done */
 
@@ -198,83 +181,12 @@ 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
-	 */
-1:	lwz	r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
-	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
-	lwz	r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
-        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
-
-/*
- * This is the core of clock_gettime(), it returns the current
- * time in seconds and nanoseconds in r3 and r4.
+ * This is the core of clock_gettime() and gettimeofday(),
+ * it returns the current time in r3 (seconds) and r4.
+ * On entry, r7 gives the resolution of r4, either USEC_PER_SEC
+ * or NSEC_PER_SEC, giving r4 in microseconds or nanoseconds.
  * It expects the datapage ptr in r9 and doesn't clobber it.
- * It clobbers r0, r5, r6, r10 and returns NSEC_PER_SEC in r7.
+ * It clobbers r0, r5 and r6.
  * On return, r8 contains the counter value that can be reused.
  * This clobbers cr0 but not any other cr field.
  */
@@ -297,70 +209,58 @@ __do_get_tspec:
 2:	mftbu	r3
 	mftbl	r4
 	mftbu	r0
-	cmpl	cr0,r3,r0
+	cmplw	cr0,r3,r0
 	bne-	2b
 
 	/* Subtract tb orig stamp and shift left 12 bits.
 	 */
-	subfc	r7,r6,r4
+	subfc	r4,r6,r4
 	subfe	r0,r5,r3
 	slwi	r0,r0,12
-	rlwimi.	r0,r7,12,20,31
-	slwi	r7,r7,12
+	rlwimi.	r0,r4,12,20,31
+	slwi	r4,r4,12
 
-	/* Load scale factor & do multiplication */
+	/*
+	 * Load scale factor & do multiplication.
+	 * We only use the high 32 bits of the tb_to_xs value.
+	 * Even with a 1GHz timebase clock, the high 32 bits of
+	 * tb_to_xs will be at least 4 million, so the error from
+	 * ignoring the low 32 bits will be no more than 0.25ppm.
+	 * The error will just make the clock run very very slightly
+	 * slow until the next time the kernel updates the VDSO data,
+	 * at which point the clock will catch up to the kernel's value,
+	 * so there is no long-term error accumulation.
+	 */
 	lwz	r5,CFG_TB_TO_XS(r9)	/* load values */
-	lwz	r6,(CFG_TB_TO_XS+4)(r9)
-	mulhwu	r3,r7,r6
-	mullw	r10,r7,r5
-	mulhwu	r4,r7,r5
-	addc	r10,r3,r10
+	mulhwu	r4,r4,r5
 	li	r3,0
 
 	beq+	4f			/* skip high part computation if 0 */
 	mulhwu	r3,r0,r5
-	mullw	r7,r0,r5
-	mulhwu	r5,r0,r6
-	mullw	r6,r0,r6
-	adde	r4,r4,r7
-	addze	r3,r3
+	mullw	r5,r0,r5
 	addc	r4,r4,r5
 	addze	r3,r3
-	addc	r10,r10,r6
-
-4:	addze	r4,r4			/* add in carry */
-	lis	r7,NSEC_PER_SEC@h
-	ori	r7,r7,NSEC_PER_SEC@l
-	mulhwu	r4,r4,r7		/* convert to nanoseconds */
-
-	/* At this point, we have seconds & nanoseconds since the xtime
-	 * stamp in r3+CA and r4.  Load & add the xtime stamp.
+4:
+	/* At this point, we have seconds since the xtime stamp
+	 * as a 32.32 fixed-point number in r3 and r4.
+	 * Load & add the xtime stamp.
 	 */
-#ifdef CONFIG_PPC64
-	lwz	r5,STAMP_XTIME+TSPC64_TV_SEC+LOPART(r9)
-	lwz	r6,STAMP_XTIME+TSPC64_TV_NSEC+LOPART(r9)
-#else
-	lwz	r5,STAMP_XTIME+TSPC32_TV_SEC(r9)
-	lwz	r6,STAMP_XTIME+TSPC32_TV_NSEC(r9)
-#endif
-	add	r4,r4,r6
+	lwz	r5,STAMP_XTIME+TSPEC_TV_SEC(r9)
+	lwz	r6,STAMP_SEC_FRAC(r9)
+	addc	r4,r4,r6
 	adde	r3,r3,r5
 
-	/* We now have our result in r3,r4. We create a fake dependency
-	 * on that result and re-check the counter
+	/* We create a fake dependency on the result in r3/r4
+	 * and re-check the counter
 	 */
 	or	r6,r4,r3
 	xor	r0,r6,r6
 	add	r9,r9,r0
 	lwz	r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
-        cmpl    cr0,r8,r0		/* check if updated */
+        cmplw	cr0,r8,r0		/* check if updated */
 	bne-	1b
 
-	/* check for nanosecond overflow and adjust if necessary */
-	cmpw	r4,r7
-	bltlr				/* all done if no overflow */
-	subf	r4,r7,r4		/* adjust if overflow */
-	addi	r3,r3,1
+	mulhwu	r4,r4,r7		/* convert to micro or nanoseconds */
 
 	blr
   .cfi_endproc