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/*
* 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, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
* 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>
#include <asm/fpu.h>
struct task_struct;
/**
* resume - resume execution of a task
* @prev: The task previously executed.
* @next: The task to begin executing.
* @next_ti: task_thread_info(next).
*
* This function is used whilst scheduling to save the context of prev & load
* the context of next. Returns prev.
*/
extern asmlinkage struct task_struct *resume(struct task_struct *prev,
struct task_struct *next, struct thread_info *next_ti);
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
/*
* Clear LLBit during context switches on MIPSr6 such that eretnc can be used
* unconditionally when returning to userland in entry.S.
*/
#define __clear_r6_hw_ll_bit() do { \
if (cpu_has_mips_r6) \
write_c0_lladdr(0); \
} while (0)
#define __clear_software_ll_bit() do { \
if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc) \
ll_bit = 0; \
} while (0)
/*
* Check FCSR for any unmasked exceptions pending set with `ptrace',
* clear them and send a signal.
*/
#ifdef CONFIG_MIPS_FP_SUPPORT
# define __sanitize_fcr31(next) \
do { \
unsigned long fcr31 = mask_fcr31_x(next->thread.fpu.fcr31); \
void __user *pc; \
\
if (unlikely(fcr31)) { \
pc = (void __user *)task_pt_regs(next)->cp0_epc; \
next->thread.fpu.fcr31 &= ~fcr31; \
force_fcr31_sig(fcr31, pc, next); \
} \
} while (0)
#else
# define __sanitize_fcr31(next)
#endif
/*
* For newly created kernel threads switch_to() will return to
* ret_from_kernel_thread, newly created user threads to ret_from_fork.
* That is, everything following resume() will be skipped for new threads.
* So everything that matters to new threads should be placed before resume().
*/
#define switch_to(prev, next, last) \
do { \
__mips_mt_fpaff_switch_to(prev); \
lose_fpu_inatomic(1, prev); \
if (tsk_used_math(next)) \
__sanitize_fcr31(next); \
if (cpu_has_dsp) { \
__save_dsp(prev); \
__restore_dsp(next); \
} \
if (cop2_present) { \
set_c0_status(ST0_CU2); \
if ((KSTK_STATUS(prev) & ST0_CU2)) { \
if (cop2_lazy_restore) \
KSTK_STATUS(prev) &= ~ST0_CU2; \
cop2_save(prev); \
} \
if (KSTK_STATUS(next) & ST0_CU2 && \
!cop2_lazy_restore) { \
cop2_restore(next); \
} \
clear_c0_status(ST0_CU2); \
} \
__clear_r6_hw_ll_bit(); \
__clear_software_ll_bit(); \
if (cpu_has_userlocal) \
write_c0_userlocal(task_thread_info(next)->tp_value); \
__restore_watch(next); \
(last) = resume(prev, next, task_thread_info(next)); \
} while (0)
#endif /* _ASM_SWITCH_TO_H */
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