linux/arch/mips/lib/delay.c
Ralf Baechle abe5b417fb MIPS: delay: Fix use of current_cpu_data in preemptable code.
This may lead to warnings like:

BUG: using smp_processor_id() in preemptible [00000000] code: reboot/1989
caller is __udelay+0x14/0x70
Call Trace:
[<ffffffff8110ad28>] dump_stack+0x8/0x34
[<ffffffff812dde04>] debug_smp_processor_id+0xf4/0x110
[<ffffffff812d90bc>] __udelay+0x14/0x70
[<ffffffff81378274>] md_notify_reboot+0x12c/0x148
[<ffffffff81161054>] notifier_call_chain+0x64/0xc8
[<ffffffff811614dc>] __blocking_notifier_call_chain+0x64/0xc0
[<ffffffff8115566c>] kernel_restart_prepare+0x1c/0x38
[<ffffffff811556cc>] kernel_restart+0x14/0x50
[<ffffffff8115581c>] SyS_reboot+0x10c/0x1f0
[<ffffffff81103684>] handle_sysn32+0x44/0x84

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-04-12 17:26:09 +01:00

56 lines
1.4 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 by Waldorf Electronics
* Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2007 Maciej W. Rozycki
*/
#include <linux/module.h>
#include <linux/param.h>
#include <linux/smp.h>
#include <asm/compiler.h>
#include <asm/war.h>
inline void __delay(unsigned int loops)
{
__asm__ __volatile__ (
" .set noreorder \n"
" .align 3 \n"
"1: bnez %0, 1b \n"
" subu %0, 1 \n"
" .set reorder \n"
: "=r" (loops)
: "0" (loops));
}
EXPORT_SYMBOL(__delay);
/*
* Division by multiplication: you don't have to worry about
* loss of precision.
*
* Use only for very small delays ( < 1 msec). Should probably use a
* lookup table, really, as the multiplications take much too long with
* short delays. This is a "reasonable" implementation, though (and the
* first constant multiplications gets optimized away if the delay is
* a constant)
*/
void __udelay(unsigned long us)
{
unsigned int lpj = raw_current_cpu_data.udelay_val;
__delay((us * 0x000010c7ull * HZ * lpj) >> 32);
}
EXPORT_SYMBOL(__udelay);
void __ndelay(unsigned long ns)
{
unsigned int lpj = raw_current_cpu_data.udelay_val;
__delay((ns * 0x00000005ull * HZ * lpj) >> 32);
}
EXPORT_SYMBOL(__ndelay);