Commit b7eacb59 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390/vdso: add vdso support for coarse clocks 



Add CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE optimization to
the 64-bit and 31-bit vdso.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 070b7be6

arch/s390/include/asm/vdso.h

+11 −7
Original line number Diff line number Diff line
@@ -22,13 +22,17 @@ struct vdso_data { 
	__u64 xtime_tod_stamp;		/* TOD clock for xtime		0x08 */

	__u64 xtime_clock_sec;		/* Kernel time			0x10 */

	__u64 xtime_clock_nsec;		/*				0x18 */

	__u64 wtom_clock_sec;		/* Wall to monotonic clock	0x20 */

	__u64 wtom_clock_nsec;		/*				0x28 */

	__u32 tz_minuteswest;		/* Minutes west of Greenwich	0x30 */

	__u32 tz_dsttime;		/* Type of dst correction	0x34 */

	__u32 ectg_available;		/* ECTG instruction present	0x38 */

	__u32 tk_mult;			/* Mult. used for xtime_nsec	0x3c */

	__u32 tk_shift;			/* Shift used for xtime_nsec	0x40 */

	__u64 xtime_coarse_sec;		/* Coarse kernel time		0x20 */

	__u64 xtime_coarse_nsec;	/*				0x28 */

	__u64 wtom_clock_sec;		/* Wall to monotonic clock	0x30 */

	__u64 wtom_clock_nsec;		/*				0x38 */

	__u64 wtom_coarse_sec;		/* Coarse wall to monotonic	0x40 */

	__u64 wtom_coarse_nsec;		/*				0x48 */

	__u32 tz_minuteswest;		/* Minutes west of Greenwich	0x50 */

	__u32 tz_dsttime;		/* Type of dst correction	0x54 */

	__u32 ectg_available;		/* ECTG instruction present	0x58 */

	__u32 tk_mult;			/* Mult. used for xtime_nsec	0x5c */

	__u32 tk_shift;			/* Shift used for xtime_nsec	0x60 */

};



struct vdso_per_cpu_data {

arch/s390/kernel/asm-offsets.c

+7 −0
Original line number Diff line number Diff line
@@ -62,8 +62,12 @@ int main(void) 
	DEFINE(__VDSO_XTIME_STAMP, offsetof(struct vdso_data, xtime_tod_stamp));

	DEFINE(__VDSO_XTIME_SEC, offsetof(struct vdso_data, xtime_clock_sec));

	DEFINE(__VDSO_XTIME_NSEC, offsetof(struct vdso_data, xtime_clock_nsec));

	DEFINE(__VDSO_XTIME_CRS_SEC, offsetof(struct vdso_data, xtime_coarse_sec));

	DEFINE(__VDSO_XTIME_CRS_NSEC, offsetof(struct vdso_data, xtime_coarse_nsec));

	DEFINE(__VDSO_WTOM_SEC, offsetof(struct vdso_data, wtom_clock_sec));

	DEFINE(__VDSO_WTOM_NSEC, offsetof(struct vdso_data, wtom_clock_nsec));

	DEFINE(__VDSO_WTOM_CRS_SEC, offsetof(struct vdso_data, wtom_coarse_sec));

	DEFINE(__VDSO_WTOM_CRS_NSEC, offsetof(struct vdso_data, wtom_coarse_nsec));

	DEFINE(__VDSO_TIMEZONE, offsetof(struct vdso_data, tz_minuteswest));

	DEFINE(__VDSO_ECTG_OK, offsetof(struct vdso_data, ectg_available));

	DEFINE(__VDSO_TK_MULT, offsetof(struct vdso_data, tk_mult));
@@ -73,8 +77,11 @@ int main(void) 
	/* constants used by the vdso */

	DEFINE(__CLOCK_REALTIME, CLOCK_REALTIME);

	DEFINE(__CLOCK_MONOTONIC, CLOCK_MONOTONIC);

	DEFINE(__CLOCK_REALTIME_COARSE, CLOCK_REALTIME_COARSE);

	DEFINE(__CLOCK_MONOTONIC_COARSE, CLOCK_MONOTONIC_COARSE);

	DEFINE(__CLOCK_THREAD_CPUTIME_ID, CLOCK_THREAD_CPUTIME_ID);

	DEFINE(__CLOCK_REALTIME_RES, MONOTONIC_RES_NSEC);

	DEFINE(__CLOCK_COARSE_RES, LOW_RES_NSEC);

	BLANK();

	/* idle data offsets */

	DEFINE(__CLOCK_IDLE_ENTER, offsetof(struct s390_idle_data, clock_idle_enter));

arch/s390/kernel/time.c

+13 −0
Original line number Diff line number Diff line
@@ -232,6 +232,19 @@ void update_vsyscall(struct timekeeper *tk) 
		vdso_data->wtom_clock_nsec -= nsecps;

		vdso_data->wtom_clock_sec++;

	}



	vdso_data->xtime_coarse_sec = tk->xtime_sec;

	vdso_data->xtime_coarse_nsec =

		(long)(tk->tkr.xtime_nsec >> tk->tkr.shift);

	vdso_data->wtom_coarse_sec =

		vdso_data->xtime_coarse_sec + tk->wall_to_monotonic.tv_sec;

	vdso_data->wtom_coarse_nsec =

		vdso_data->xtime_coarse_nsec + tk->wall_to_monotonic.tv_nsec;

	while (vdso_data->wtom_coarse_nsec >= NSEC_PER_SEC) {

		vdso_data->wtom_coarse_nsec -= NSEC_PER_SEC;

		vdso_data->wtom_coarse_sec++;

	}



	vdso_data->tk_mult = tk->tkr.mult;

	vdso_data->tk_shift = tk->tkr.shift;

	smp_wmb();

arch/s390/kernel/vdso32/clock_getres.S

+9 −2
Original line number Diff line number Diff line
@@ -19,14 +19,20 @@ 
	.type  __kernel_clock_getres,@function

__kernel_clock_getres:

	.cfi_startproc

	basr	%r1,0

	la	%r1,4f-.(%r1)

	chi	%r2,__CLOCK_REALTIME

	je	0f

	chi	%r2,__CLOCK_MONOTONIC

	je	0f

	la	%r1,5f-4f(%r1)

	chi	%r2,__CLOCK_REALTIME_COARSE

	je	0f

	chi	%r2,__CLOCK_MONOTONIC_COARSE

	jne	3f

0:	ltr	%r3,%r3

	jz	2f				/* res == NULL */

	basr	%r1,0

1:	l	%r0,4f-1b(%r1)

1:	l	%r0,0(%r1)

	xc	0(4,%r3),0(%r3)			/* set tp->tv_sec to zero */

	st	%r0,4(%r3)			/* store tp->tv_usec */

2:	lhi	%r2,0
@@ -35,5 +41,6 @@ __kernel_clock_getres: 
	svc	0

	br	%r14

4:	.long	__CLOCK_REALTIME_RES

5:	.long	__CLOCK_COARSE_RES

	.cfi_endproc

	.size	__kernel_clock_getres,.-__kernel_clock_getres

arch/s390/kernel/vdso32/clock_gettime.S

+24 −0
Original line number Diff line number Diff line
@@ -21,8 +21,12 @@ __kernel_clock_gettime: 
	.cfi_startproc

	basr	%r5,0

0:	al	%r5,21f-0b(%r5)			/* get &_vdso_data */

	chi	%r2,__CLOCK_REALTIME_COARSE

	je	10f

	chi	%r2,__CLOCK_REALTIME

	je	11f

	chi	%r2,__CLOCK_MONOTONIC_COARSE

	je	9f

	chi	%r2,__CLOCK_MONOTONIC

	jne	19f
@@ -68,6 +72,26 @@ __kernel_clock_gettime: 
	lhi	%r2,0

	br	%r14



	/* CLOCK_MONOTONIC_COARSE */

9:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */

	tml	%r4,0x0001			/* pending update ? loop */

	jnz	9b

	l	%r2,__VDSO_WTOM_CRS_SEC+4(%r5)

	l	%r1,__VDSO_WTOM_CRS_NSEC+4(%r5)

	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */

	jne	9b

	j	8b



	/* CLOCK_REALTIME_COARSE */

10:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */

	tml	%r4,0x0001			/* pending update ? loop */

	jnz	10b

	l	%r2,__VDSO_XTIME_CRS_SEC+4(%r5)

	l	%r1,__VDSO_XTIME_CRS_NSEC+4(%r5)

	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */

	jne	10b

	j	17f



	/* CLOCK_REALTIME */

11:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */

	tml	%r4,0x0001			/* pending update ? loop */