Commit f66501dc authored by Vincenzo Frascino's avatar Vincenzo Frascino Committed by Thomas Gleixner
Browse files

x86/vdso: Add clock_getres() entry point 



The generic vDSO library provides an implementation of clock_getres()
that can be leveraged by each architecture.

Add the clock_getres() VDSO entry point on x86.

[ tglx: Massaged changelog and cleaned up the function signature formatting ]

Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Huw Davies <huw@codeweavers.com>
Cc: Shijith Thotton <sthotton@marvell.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Link: https://lkml.kernel.org/r/20190621095252.32307-24-vincenzo.frascino@arm.com
parent 7ac87074

arch/x86/entry/vdso/vclock_gettime.c

+17 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ time_t time(time_t *t) __attribute__((weak, alias("__vdso_time"))); 
#if defined(CONFIG_X86_64) && !defined(BUILD_VDSO32_64)

/* both 64-bit and x32 use these */

extern int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);

extern int __vdso_clock_getres(clockid_t clock, struct __kernel_timespec *res);



int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)

{
@@ -45,9 +46,18 @@ int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts) 
int clock_gettime(clockid_t, struct __kernel_timespec *)

	__attribute__((weak, alias("__vdso_clock_gettime")));



int __vdso_clock_getres(clockid_t clock,

			struct __kernel_timespec *res)

{

	return __cvdso_clock_getres(clock, res);

}

int clock_getres(clockid_t, struct __kernel_timespec *)

	__attribute__((weak, alias("__vdso_clock_getres")));



#else

/* i386 only */

extern int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts);

extern int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res);



int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts)

{
@@ -57,4 +67,11 @@ int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts) 
int clock_gettime(clockid_t, struct old_timespec32 *)

	__attribute__((weak, alias("__vdso_clock_gettime")));



int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res)

{

	return __cvdso_clock_getres_time32(clock, res);

}



int clock_getres(clockid_t, struct old_timespec32 *)

	__attribute__((weak, alias("__vdso_clock_getres")));

#endif

arch/x86/entry/vdso/vdso.lds.S

+2 −0
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ VERSION { 
		__vdso_getcpu;

		time;

		__vdso_time;

		clock_getres;

		__vdso_clock_getres;

	local: *;

	};

}

arch/x86/entry/vdso/vdso32/vdso32.lds.S

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ VERSION 
		__vdso_clock_gettime;

		__vdso_gettimeofday;

		__vdso_time;

		__vdso_clock_getres;

	};



	LINUX_2.5 {

arch/x86/include/asm/vdso/gettimeofday.h

+31 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ 


#define VDSO_HAS_TIME 1



#define VDSO_HAS_CLOCK_GETRES 1



#ifdef CONFIG_PARAVIRT_CLOCK

extern u8 pvclock_page[PAGE_SIZE]

	__attribute__((visibility("hidden")));
@@ -60,6 +62,18 @@ long gettimeofday_fallback(struct __kernel_old_timeval *_tv, 
	return ret;

}



static __always_inline

long clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)

{

	long ret;



	asm ("syscall" : "=a" (ret), "=m" (*_ts) :

	     "0" (__NR_clock_getres), "D" (_clkid), "S" (_ts) :

	     "rcx", "r11");



	return ret;

}



#else



static __always_inline
@@ -97,6 +111,23 @@ long gettimeofday_fallback(struct __kernel_old_timeval *_tv, 
	return ret;

}



static __always_inline long

clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)

{

	long ret;



	asm (

		"mov %%ebx, %%edx \n"

		"mov %[clock], %%ebx \n"

		"call __kernel_vsyscall \n"

		"mov %%edx, %%ebx \n"

		: "=a" (ret), "=m" (*_ts)

		: "0" (__NR_clock_getres_time64), [clock] "g" (_clkid), "c" (_ts)

		: "edx");



	return ret;

}



#endif



#ifdef CONFIG_PARAVIRT_CLOCK

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