b9a8d94a47
Port two patches from i386 to x86_64 delay.c to make sure all rounding is done upward instead of downward. There is no sign in commit messages that the mismatch was done on purpose, and "delay() guarantees sleeping at least for the specified time" is still a valid rule IMHO. The original x86 patches are both from pre-GIT era, i.e.: "[PATCH] round up in __udelay()" in commit 54c7e1f5cc6771ff644d7bc21a2b829308bd126f "[PATCH] add 1 in __const_udelay()" in commit 42c77a9801b8877d8b90f65f75db758822a0bccc (both commits are from converted BK repository to x86_64). AK: fixed gcc warning linux/arch/x86_64/lib/delay.c:43: warning: suggest parentheses around + or - inside shift (did this actually work?) Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andi Kleen <ak@suse.de>
58 lines
1.1 KiB
C
58 lines
1.1 KiB
C
/*
|
|
* Precise Delay Loops for x86-64
|
|
*
|
|
* Copyright (C) 1993 Linus Torvalds
|
|
* Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
|
|
*
|
|
* The __delay function must _NOT_ be inlined as its execution time
|
|
* depends wildly on alignment on many x86 processors.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/delay.h>
|
|
#include <asm/delay.h>
|
|
#include <asm/msr.h>
|
|
|
|
#ifdef CONFIG_SMP
|
|
#include <asm/smp.h>
|
|
#endif
|
|
|
|
int read_current_timer(unsigned long *timer_value)
|
|
{
|
|
rdtscll(*timer_value);
|
|
return 0;
|
|
}
|
|
|
|
void __delay(unsigned long loops)
|
|
{
|
|
unsigned bclock, now;
|
|
|
|
rdtscl(bclock);
|
|
do
|
|
{
|
|
rep_nop();
|
|
rdtscl(now);
|
|
}
|
|
while((now-bclock) < loops);
|
|
}
|
|
EXPORT_SYMBOL(__delay);
|
|
|
|
inline void __const_udelay(unsigned long xloops)
|
|
{
|
|
__delay(((xloops * HZ * cpu_data[raw_smp_processor_id()].loops_per_jiffy) >> 32) + 1);
|
|
}
|
|
EXPORT_SYMBOL(__const_udelay);
|
|
|
|
void __udelay(unsigned long usecs)
|
|
{
|
|
__const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
|
|
}
|
|
EXPORT_SYMBOL(__udelay);
|
|
|
|
void __ndelay(unsigned long nsecs)
|
|
{
|
|
__const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
|
|
}
|
|
EXPORT_SYMBOL(__ndelay);
|