/*
* 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, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle
* Copyright (C) 1996 by Paul M. Antoine
* Copyright (C) 1999 Silicon Graphics
* Kevin D. Kissell, [email protected] and Carsten Langgaard, [email protected]
* Copyright (C) 2000 MIPS Technologies, Inc.
*/
#ifndef _ASM_SWITCH_TO_H
#define _ASM_SWITCH_TO_H

#include <asm/cpu-features.h>
#include <asm/watch.h>
#include <asm/dsp.h>
#include <asm/cop2.h>

struct task_struct;

/*
* switch_to(n) should switch tasks to task nr n, first
* checking that n isn't the current task, in which case it does nothing.
*/
extern asmlinkage void *resume(void *last, void *next, void *next_ti, u32 __usedfpu);

extern unsigned int ll_bit;
extern struct task_struct *ll_task;

#ifdef CONFIG_MIPS_MT_FPAFF

/*
* Handle the scheduler resume end of FPU affinity management. We do this
* inline to try to keep the overhead down. If we have been forced to run on
* a "CPU" with an FPU because of a previous high level of FP computation,
* but did not actually use the FPU during the most recent time-slice (CU1
* isn't set), we undo the restriction on cpus_allowed.
*
* We're not calling set_cpus_allowed() here, because we have no need to
* force prompt migration - we're already switching the current CPU to a
* different thread.
*/

#define __mips_mt_fpaff_switch_to(prev) \
do { \
struct thread_info *__prev_ti = task_thread_info(prev); \
\
if (cpu_has_fpu && \
test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) && \
(!(KSTK_STATUS(prev) & ST0_CU1))) { \
clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND); \
prev->cpus_allowed = prev->thread.user_cpus_allowed; \
} \
next->thread.emulated_fp = 0; \
} while(0)

#else
#define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0)
#endif

#define __clear_software_ll_bit() \
do { \
if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc) \
ll_bit = 0; \
} while (0)

#define switch_to(prev, next, last) \
do { \
u32 __usedfpu, __c0_stat; \
__mips_mt_fpaff_switch_to(prev); \
if (cpu_has_dsp) \
__save_dsp(prev); \
if (cop2_present && (KSTK_STATUS(prev) & ST0_CU2)) { \
if (cop2_lazy_restore) \
KSTK_STATUS(prev) &= ~ST0_CU2; \
__c0_stat = read_c0_status(); \
write_c0_status(__c0_stat | ST0_CU2); \
cop2_save(&prev->thread.cp2); \
write_c0_status(__c0_stat & ~ST0_CU2); \
} \
__clear_software_ll_bit(); \
__usedfpu = test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU); \
(last) = resume(prev, next, task_thread_info(next), __usedfpu); \
} while (0)

#define finish_arch_switch(prev) \
do { \
u32 __c0_stat; \
if (cop2_present && !cop2_lazy_restore && \
(KSTK_STATUS(current) & ST0_CU2)) { \
__c0_stat = read_c0_status(); \
write_c0_status(__c0_stat | ST0_CU2); \
cop2_restore(&current->thread.cp2); \
write_c0_status(__c0_stat & ~ST0_CU2); \
} \
if (cpu_has_dsp) \
__restore_dsp(current); \
if (cpu_has_userlocal) \
write_c0_userlocal(current_thread_info()->tp_value); \
__restore_watch(); \
} while (0)

#endif /* _ASM_SWITCH_TO_H */