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

Browse Source 
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: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo 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
This commit is contained in:
Christophe Leroy 2020-02-07 13:39:04 +01:00 committed by Thomas Gleixner
parent 8345228ccf
commit e876f0b69d
1 changed files with 57 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
lib/vdso/gettimeofday.c
View File

@ -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;
}
#ifdef VDSO_HAS_TIME
static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time)
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_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 */