Commit 5d51bee7 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

clocksource: Add common vdso clock mode storage 



All architectures which use the generic VDSO code have their own storage
for the VDSO clock mode. That's pointless and just requires duplicate code.

Provide generic storage for it. The new Kconfig symbol is intermediate and
will be removed once all architectures are converted over.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.028046322@linutronix.de
parent eec399dd

include/linux/clocksource.h

+11 −1
Original line number Diff line number Diff line
@@ -23,10 +23,19 @@ 
struct clocksource;

struct module;



#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA

#if defined(CONFIG_ARCH_CLOCKSOURCE_DATA) || \

    defined(CONFIG_GENERIC_VDSO_CLOCK_MODE)

#include <asm/clocksource.h>

#endif



enum vdso_clock_mode {

	VDSO_CLOCKMODE_NONE,

#ifdef CONFIG_GENERIC_VDSO_CLOCK_MODE

	VDSO_ARCH_CLOCKMODES,

#endif

	VDSO_CLOCKMODE_MAX,

};



/**

 * struct clocksource - hardware abstraction for a free running counter

 *	Provides mostly state-free accessors to the underlying hardware.
@@ -97,6 +106,7 @@ struct clocksource { 
	const char		*name;

	struct list_head	list;

	int			rating;

	enum vdso_clock_mode	vdso_clock_mode;

	unsigned long		flags;



	int			(*enable)(struct clocksource *cs);

kernel/time/clocksource.c

+9 −0
Original line number Diff line number Diff line
@@ -928,6 +928,15 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) 


	clocksource_arch_init(cs);



#ifdef CONFIG_GENERIC_VDSO_CLOCK_MODE

	if (cs->vdso_clock_mode < 0 ||

	    cs->vdso_clock_mode >= VDSO_CLOCKMODE_MAX) {

		pr_warn("clocksource %s registered with invalid VDSO mode %d. Disabling VDSO support.\n",

			cs->name, cs->vdso_clock_mode);

		cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE;

	}

#endif



	/* Initialize mult/shift and max_idle_ns */

	__clocksource_update_freq_scale(cs, scale, freq);

kernel/time/vsyscall.c

+8 −2
Original line number Diff line number Diff line
@@ -71,13 +71,19 @@ void update_vsyscall(struct timekeeper *tk) 
{

	struct vdso_data *vdata = __arch_get_k_vdso_data();

	struct vdso_timestamp *vdso_ts;

	s32 clock_mode;

	u64 nsec;



	/* copy vsyscall data */

	vdso_write_begin(vdata);



	vdata[CS_HRES_COARSE].clock_mode	= __arch_get_clock_mode(tk);

	vdata[CS_RAW].clock_mode		= __arch_get_clock_mode(tk);

#ifdef CONFIG_GENERIC_VDSO_CLOCK_MODE

	clock_mode = tk->tkr_mono.clock->vdso_clock_mode;

#else

	clock_mode = __arch_get_clock_mode(tk);

#endif

	vdata[CS_HRES_COARSE].clock_mode	= clock_mode;

	vdata[CS_RAW].clock_mode		= clock_mode;



	/* CLOCK_REALTIME also required for time() */

	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];

lib/vdso/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -30,4 +30,7 @@ config GENERIC_VDSO_TIME_NS 
	  Selected by architectures which support time namespaces in the

	  VDSO



config GENERIC_VDSO_CLOCK_MODE

	bool



endif

lib/vdso/gettimeofday.c

+11 −2
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/time.h>

#include <linux/kernel.h>

#include <linux/hrtimer_defs.h>

#include <linux/clocksource.h>

#include <vdso/datapage.h>

#include <vdso/helpers.h>
@@ -64,10 +65,14 @@ static int do_hres_timens(const struct vdso_data *vdns, clockid_t clk, 


	do {

		seq = vdso_read_begin(vd);

		if (IS_ENABLED(CONFIG_GENERIC_VDSO_CLOCK_MODE) &&

		    vd->clock_mode == VDSO_CLOCKMODE_NONE)

			return -1;

		cycles = __arch_get_hw_counter(vd->clock_mode);

		ns = vdso_ts->nsec;

		last = vd->cycle_last;

		if (unlikely((s64)cycles < 0))

		if (!IS_ENABLED(CONFIG_GENERIC_VDSO_CLOCK_MODE) &&

		    unlikely((s64)cycles < 0))

			return -1;



		ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
@@ -132,10 +137,14 @@ static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk, 
		}

		smp_rmb();



		if (IS_ENABLED(CONFIG_GENERIC_VDSO_CLOCK_MODE) &&

		    vd->clock_mode == VDSO_CLOCKMODE_NONE)

			return -1;

		cycles = __arch_get_hw_counter(vd->clock_mode);

		ns = vdso_ts->nsec;

		last = vd->cycle_last;

		if (unlikely((s64)cycles < 0))

		if (!IS_ENABLED(CONFIG_GENERIC_VDSO_CLOCK_MODE) &&

		    unlikely((s64)cycles < 0))

			return -1;



		ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);

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