Commit e876f0b6 authored by Christophe Leroy's avatar Christophe Leroy Committed by Thomas Gleixner
Browse files

lib/vdso: Allow architectures to provide the vdso data pointer 



On powerpc, __arch_get_vdso_data() clobbers the link register, requiring
the caller to save it.

As the parent function already has to set a stack frame and saves the link
register before calling the C vdso function, retrieving the vdso data
pointer there is less overhead.

Split out the functional code from the __cvdso.*() interfaces into new
static functions which can either be called from the existing interfaces
with the vdso data pointer supplied via __arch_get_vdso_data() or directly
from ASM code.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
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://lore.kernel.org/r/abf97996602ef07223fec30c005df78e5ed41b2e.1580399657.git.christophe.leroy@c-s.fr
Link: https://lkml.kernel.org/r/20200207124403.965789141@linutronix.de
parent 8345228c

lib/vdso/gettimeofday.c

+56 −16
Original line number Diff line number Diff line
@@ -233,9 +233,9 @@ static __always_inline int do_coarse(const struct vdso_data *vd, clockid_t clk, 
}



static __maybe_unused int

__cvdso_clock_gettime_common(clockid_t clock, struct __kernel_timespec *ts)

__cvdso_clock_gettime_common(const struct vdso_data *vd, clockid_t clock,

			     struct __kernel_timespec *ts)

{

	const struct vdso_data *vd = __arch_get_vdso_data();

	u32 msk;



	/* Check for negative values or invalid clocks */
@@ -260,23 +260,31 @@ __cvdso_clock_gettime_common(clockid_t clock, struct __kernel_timespec *ts) 
}



static __maybe_unused int

__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)

__cvdso_clock_gettime_data(const struct vdso_data *vd, clockid_t clock,

			   struct __kernel_timespec *ts)

{

	int ret = __cvdso_clock_gettime_common(clock, ts);

	int ret = __cvdso_clock_gettime_common(vd, clock, ts);



	if (unlikely(ret))

		return clock_gettime_fallback(clock, ts);

	return 0;

}



static __maybe_unused int

__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)

{

	return __cvdso_clock_gettime_data(__arch_get_vdso_data(), clock, ts);

}



#ifdef BUILD_VDSO32

static __maybe_unused int

__cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)

__cvdso_clock_gettime32_data(const struct vdso_data *vd, clockid_t clock,

			     struct old_timespec32 *res)

{

	struct __kernel_timespec ts;

	int ret;



	ret = __cvdso_clock_gettime_common(clock, &ts);

	ret = __cvdso_clock_gettime_common(vd, clock, &ts);



	if (unlikely(ret))

		return clock_gettime32_fallback(clock, res);
@@ -287,12 +295,18 @@ __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res) 


	return ret;

}



static __maybe_unused int

__cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)

{

	return __cvdso_clock_gettime32_data(__arch_get_vdso_data(), clock, res);

}

#endif /* BUILD_VDSO32 */



static __maybe_unused int

__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)

__cvdso_gettimeofday_data(const struct vdso_data *vd,

			  struct __kernel_old_timeval *tv, struct timezone *tz)

{

	const struct vdso_data *vd = __arch_get_vdso_data();



	if (likely(tv != NULL)) {

		struct __kernel_timespec ts;
@@ -316,10 +330,16 @@ __cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) 
	return 0;

}



static __maybe_unused int

__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)

{

	return __cvdso_gettimeofday_data(__arch_get_vdso_data(), tv, tz);

}



#ifdef VDSO_HAS_TIME

static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time)

static __maybe_unused __kernel_old_time_t

__cvdso_time_data(const struct vdso_data *vd, __kernel_old_time_t *time)

{

	const struct vdso_data *vd = __arch_get_vdso_data();

	__kernel_old_time_t t;



	if (IS_ENABLED(CONFIG_TIME_NS) &&
@@ -333,13 +353,18 @@ static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time 


	return t;

}



static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time)

{

	return __cvdso_time_data(__arch_get_vdso_data(), time);

}

#endif /* VDSO_HAS_TIME */



#ifdef VDSO_HAS_CLOCK_GETRES

static __maybe_unused

int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res)

int __cvdso_clock_getres_common(const struct vdso_data *vd, clockid_t clock,

				struct __kernel_timespec *res)

{

	const struct vdso_data *vd = __arch_get_vdso_data();

	u32 msk;

	u64 ns;
@@ -378,23 +403,31 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) 
}



static __maybe_unused

int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)

int __cvdso_clock_getres_data(const struct vdso_data *vd, clockid_t clock,

			      struct __kernel_timespec *res)

{

	int ret = __cvdso_clock_getres_common(clock, res);

	int ret = __cvdso_clock_getres_common(vd, clock, res);



	if (unlikely(ret))

		return clock_getres_fallback(clock, res);

	return 0;

}



static __maybe_unused

int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)

{

	return __cvdso_clock_getres_data(__arch_get_vdso_data(), clock, res);

}



#ifdef BUILD_VDSO32

static __maybe_unused int

__cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)

__cvdso_clock_getres_time32_data(const struct vdso_data *vd, clockid_t clock,

				 struct old_timespec32 *res)

{

	struct __kernel_timespec ts;

	int ret;



	ret = __cvdso_clock_getres_common(clock, &ts);

	ret = __cvdso_clock_getres_common(vd, clock, &ts);



	if (unlikely(ret))

		return clock_getres32_fallback(clock, res);
@@ -405,5 +438,12 @@ __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res) 
	}

	return ret;

}



static __maybe_unused int

__cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)

{

	return __cvdso_clock_getres_time32_data(__arch_get_vdso_data(),

						clock, res);

}

#endif /* BUILD_VDSO32 */

#endif /* VDSO_HAS_CLOCK_GETRES */

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