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Commit 0a4d8a47 authored by Glauber Costa's avatar Glauber Costa Committed by Ingo Molnar
Browse files

x86: provide delay loop for x86_64. 



This is for consistency with i386. We call use_tsc_delay()
at tsc initialization for x86_64, so we'll be always using it.

Signed-off-by: default avatarGlauber Costa <gcosta@redhat.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ff1b15b6

arch/x86/kernel/tsc.c

+1 −0
Original line number Diff line number Diff line
@@ -513,6 +513,7 @@ void __init tsc_init(void) 
	 */

	for_each_possible_cpu(cpu)

		set_cyc2ns_scale(cpu_khz, cpu);

	use_tsc_delay();



	if (tsc_disabled > 0)

		return;

arch/x86/lib/delay_64.c

+40 −4
Original line number Diff line number Diff line
@@ -22,13 +22,28 @@ 
#include <asm/smp.h>

#endif



int __devinit read_current_timer(unsigned long *timer_value)

/* simple loop based delay: */

static void delay_loop(unsigned long loops)

{

	rdtscll(*timer_value);

	return 0;

	asm volatile(

		"	test %0,%0	\n"

		"	jz 3f		\n"

		"	jmp 1f		\n"



		".align 16		\n"

		"1:	jmp 2f		\n"



		".align 16		\n"

		"2:	dec %0		\n"

		"	jnz 2b		\n"

		"3:	dec %0		\n"



		: /* we don't need output */

		:"a" (loops)

	);

}



void __delay(unsigned long loops)

static void delay_tsc(unsigned long loops)

{

	unsigned bclock, now;

	int cpu;
@@ -63,6 +78,27 @@ void __delay(unsigned long loops) 
	}

	preempt_enable();

}



static void (*delay_fn)(unsigned long) = delay_loop;



void use_tsc_delay(void)

{

	delay_fn = delay_tsc;

}



int __devinit read_current_timer(unsigned long *timer_value)

{

	if (delay_fn == delay_tsc) {

		rdtscll(*timer_value);

		return 0;

	}

	return -1;

}



void __delay(unsigned long loops)

{

	delay_fn(loops);

}

EXPORT_SYMBOL(__delay);



inline void __const_udelay(unsigned long xloops)