1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __PARISC_MMU_CONTEXT_H 3 #define __PARISC_MMU_CONTEXT_H 4 5 #include <linux/mm.h> 6 #include <linux/sched.h> 7 #include <linux/atomic.h> 8 #include <asm/pgalloc.h> 9 #include <asm-generic/mm_hooks.h> 10 11 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) 12 { 13 } 14 15 /* on PA-RISC, we actually have enough contexts to justify an allocator 16 * for them. prumpf */ 17 18 extern unsigned long alloc_sid(void); 19 extern void free_sid(unsigned long); 20 21 static inline int 22 init_new_context(struct task_struct *tsk, struct mm_struct *mm) 23 { 24 BUG_ON(atomic_read(&mm->mm_users) != 1); 25 26 mm->context = alloc_sid(); 27 return 0; 28 } 29 30 static inline void 31 destroy_context(struct mm_struct *mm) 32 { 33 free_sid(mm->context); 34 mm->context = 0; 35 } 36 37 static inline unsigned long __space_to_prot(mm_context_t context) 38 { 39 #if SPACEID_SHIFT == 0 40 return context << 1; 41 #else 42 return context >> (SPACEID_SHIFT - 1); 43 #endif 44 } 45 46 static inline void load_context(mm_context_t context) 47 { 48 mtsp(context, 3); 49 mtctl(__space_to_prot(context), 8); 50 } 51 52 static inline void switch_mm_irqs_off(struct mm_struct *prev, 53 struct mm_struct *next, struct task_struct *tsk) 54 { 55 if (prev != next) { 56 mtctl(__pa(next->pgd), 25); 57 load_context(next->context); 58 } 59 } 60 61 static inline void switch_mm(struct mm_struct *prev, 62 struct mm_struct *next, struct task_struct *tsk) 63 { 64 unsigned long flags; 65 66 if (prev == next) 67 return; 68 69 local_irq_save(flags); 70 switch_mm_irqs_off(prev, next, tsk); 71 local_irq_restore(flags); 72 } 73 #define switch_mm_irqs_off switch_mm_irqs_off 74 75 #define deactivate_mm(tsk,mm) do { } while (0) 76 77 static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next) 78 { 79 /* 80 * Activate_mm is our one chance to allocate a space id 81 * for a new mm created in the exec path. There's also 82 * some lazy tlb stuff, which is currently dead code, but 83 * we only allocate a space id if one hasn't been allocated 84 * already, so we should be OK. 85 */ 86 87 BUG_ON(next == &init_mm); /* Should never happen */ 88 89 if (next->context == 0) 90 next->context = alloc_sid(); 91 92 switch_mm(prev,next,current); 93 } 94 #endif 95