1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle 7 * Copyright (C) 1996 by Paul M. Antoine 8 * Copyright (C) 1999 Silicon Graphics 9 * Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com 10 * Copyright (C) 2000 MIPS Technologies, Inc. 11 */ 12 #ifndef _ASM_SWITCH_TO_H 13 #define _ASM_SWITCH_TO_H 14 15 #include <asm/cpu-features.h> 16 #include <asm/watch.h> 17 #include <asm/dsp.h> 18 19 struct task_struct; 20 21 /* 22 * switch_to(n) should switch tasks to task nr n, first 23 * checking that n isn't the current task, in which case it does nothing. 24 */ 25 extern asmlinkage void *resume(void *last, void *next, void *next_ti, u32 __usedfpu); 26 27 extern unsigned int ll_bit; 28 extern struct task_struct *ll_task; 29 30 #ifdef CONFIG_MIPS_MT_FPAFF 31 32 /* 33 * Handle the scheduler resume end of FPU affinity management. We do this 34 * inline to try to keep the overhead down. If we have been forced to run on 35 * a "CPU" with an FPU because of a previous high level of FP computation, 36 * but did not actually use the FPU during the most recent time-slice (CU1 37 * isn't set), we undo the restriction on cpus_allowed. 38 * 39 * We're not calling set_cpus_allowed() here, because we have no need to 40 * force prompt migration - we're already switching the current CPU to a 41 * different thread. 42 */ 43 44 #define __mips_mt_fpaff_switch_to(prev) \ 45 do { \ 46 struct thread_info *__prev_ti = task_thread_info(prev); \ 47 \ 48 if (cpu_has_fpu && \ 49 test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) && \ 50 (!(KSTK_STATUS(prev) & ST0_CU1))) { \ 51 clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND); \ 52 prev->cpus_allowed = prev->thread.user_cpus_allowed; \ 53 } \ 54 next->thread.emulated_fp = 0; \ 55 } while(0) 56 57 #else 58 #define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0) 59 #endif 60 61 #define __clear_software_ll_bit() \ 62 do { \ 63 if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc) \ 64 ll_bit = 0; \ 65 } while (0) 66 67 #define switch_to(prev, next, last) \ 68 do { \ 69 u32 __usedfpu; \ 70 __mips_mt_fpaff_switch_to(prev); \ 71 if (cpu_has_dsp) \ 72 __save_dsp(prev); \ 73 __clear_software_ll_bit(); \ 74 __usedfpu = test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU); \ 75 (last) = resume(prev, next, task_thread_info(next), __usedfpu); \ 76 } while (0) 77 78 #define finish_arch_switch(prev) \ 79 do { \ 80 if (cpu_has_dsp) \ 81 __restore_dsp(current); \ 82 if (cpu_has_userlocal) \ 83 write_c0_userlocal(current_thread_info()->tp_value); \ 84 __restore_watch(); \ 85 } while (0) 86 87 #endif /* _ASM_SWITCH_TO_H */ 88