diff options
Diffstat (limited to 'arch/s390/include/asm/switch_to.h')
| -rw-r--r-- | arch/s390/include/asm/switch_to.h | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/arch/s390/include/asm/switch_to.h b/arch/s390/include/asm/switch_to.h index f6c2b5814ab0..c61b2cc1a8a8 100644 --- a/arch/s390/include/asm/switch_to.h +++ b/arch/s390/include/asm/switch_to.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ /* * Copyright IBM Corp. 1999, 2009 * @@ -29,21 +30,20 @@ static inline void restore_access_regs(unsigned int *acrs) asm volatile("lam 0,15,%0" : : "Q" (*(acrstype *)acrs)); } -#define switch_to(prev,next,last) do { \ - if (prev->mm) { \ - save_fpu_regs(); \ - save_access_regs(&prev->thread.acrs[0]); \ - save_ri_cb(prev->thread.ri_cb); \ - save_gs_cb(prev->thread.gs_cb); \ - } \ - if (next->mm) { \ - update_cr_regs(next); \ - set_cpu_flag(CIF_FPU); \ - restore_access_regs(&next->thread.acrs[0]); \ - restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb); \ - restore_gs_cb(next->thread.gs_cb); \ - } \ - prev = __switch_to(prev,next); \ +#define switch_to(prev, next, last) do { \ + /* save_fpu_regs() sets the CIF_FPU flag, which enforces \ + * a restore of the floating point / vector registers as \ + * soon as the next task returns to user space \ + */ \ + save_fpu_regs(); \ + save_access_regs(&prev->thread.acrs[0]); \ + save_ri_cb(prev->thread.ri_cb); \ + save_gs_cb(prev->thread.gs_cb); \ + update_cr_regs(next); \ + restore_access_regs(&next->thread.acrs[0]); \ + restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb); \ + restore_gs_cb(next->thread.gs_cb); \ + prev = __switch_to(prev, next); \ } while (0) #endif /* __ASM_SWITCH_TO_H */ |