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Diffstat (limited to 'arch/mips/include/asm/switch_to.h')
| -rw-r--r-- | arch/mips/include/asm/switch_to.h | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/mips/include/asm/switch_to.h b/arch/mips/include/asm/switch_to.h new file mode 100644 index 00000000000..495c1041a2c --- /dev/null +++ b/arch/mips/include/asm/switch_to.h @@ -0,0 +1,124 @@ +/* + * 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/msa.h> + +struct task_struct; + +enum { + FP_SAVE_NONE = 0, + FP_SAVE_VECTOR = -1, + FP_SAVE_SCALAR = 1, +}; + +/** + * resume - resume execution of a task + * @prev: The task previously executed. + * @next: The task to begin executing. + * @next_ti: task_thread_info(next). + * @fp_save: Which, if any, FP context to save for prev. + * + * 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, + s32 fp_save); + +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 __c0_stat; \ + s32 __fpsave = FP_SAVE_NONE; \ + __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(); \ + if (test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU)) \ + __fpsave = FP_SAVE_SCALAR; \ + if (test_and_clear_tsk_thread_flag(prev, TIF_USEDMSA)) \ + __fpsave = FP_SAVE_VECTOR; \ + (last) = resume(prev, next, task_thread_info(next), __fpsave); \ + disable_msa(); \ +} 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(¤t->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 */ |