mirror of https://gitee.com/openkylin/linux.git
141 lines
4.3 KiB
C
141 lines
4.3 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, 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_mask.
|
|
*
|
|
* 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_mask = 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 */
|