/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _H8300_SWITCH_TO_H #define _H8300_SWITCH_TO_H /* * switch_to(n) should switch tasks to task ptr, first checking that * ptr isn't the current task, in which case it does nothing. This * also clears the TS-flag if the task we switched to has used the * math co-processor latest. */ /* * switch_to() saves the extra registers, that are not saved * automatically by SAVE_SWITCH_STACK in resume(), ie. d0-d5 and * a0-a1. Some of these are used by schedule() and its predecessors * and so we might get see unexpected behaviors when a task returns * with unexpected register values. * * syscall stores these registers itself and none of them are used * by syscall after the function in the syscall has been called. * * Beware that resume now expects *next to be in d1 and the offset of * tss to be in a1. This saves a few instructions as we no longer have * to push them onto the stack and read them back right after. * * 02/17/96 - Jes Sorensen (jds@kom.auc.dk) * * Changed 96/09/19 by Andreas Schwab * pass prev in a0, next in a1, offset of tss in d1, and whether * the mm structures are shared in d2 (to avoid atc flushing). * * H8/300 Porting 2002/09/04 Yoshinori Sato */ asmlinkage void resume(void); #define switch_to(prev, next, last) \ do { \ void *_last; \ __asm__ __volatile__( \ "mov.l %1, er0\n\t" \ "mov.l %2, er1\n\t" \ "mov.l %3, er2\n\t" \ "jsr @_resume\n\t" \ "mov.l er2,%0\n\t" \ : "=r" (_last) \ : "r" (&(prev->thread)), \ "r" (&(next->thread)), \ "g" (prev) \ : "cc", "er0", "er1", "er2", "er3"); \ (last) = _last; \ } while (0) #endif /* _H8300_SWITCH_TO_H */