mmu_context.h

  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 <linux/spinlock.h>
  9#include <asm-generic/mm_hooks.h>
 10
 11/* on PA-RISC, we actually have enough contexts to justify an allocator
 12 * for them.  prumpf */
 13
 14extern unsigned long alloc_sid(void);
 15extern void free_sid(unsigned long);
 16
 17#define init_new_context init_new_context
 18static inline int
 19init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 20{
 21	BUG_ON(atomic_read(&mm->mm_users) != 1);
 22
 23	mm->context.space_id = alloc_sid();
 24	return 0;
 25}
 26
 27#define destroy_context destroy_context
 28static inline void
 29destroy_context(struct mm_struct *mm)
 30{
 31	free_sid(mm->context.space_id);
 32	mm->context.space_id = 0;
 33}
 34
 35static inline unsigned long __space_to_prot(mm_context_t context)
 36{
 37#if SPACEID_SHIFT == 0
 38	return context.space_id << 1;
 39#else
 40	return context.space_id >> (SPACEID_SHIFT - 1);
 41#endif
 42}
 43
 44static inline void load_context(mm_context_t context)
 45{
 46	mtsp(context.space_id, SR_USER);
 47	mtctl(__space_to_prot(context), 8);
 48}
 49
 50static inline void switch_mm_irqs_off(struct mm_struct *prev,
 51		struct mm_struct *next, struct task_struct *tsk)
 52{
 53	if (prev != next) {
 54#ifdef CONFIG_TLB_PTLOCK
 55		/* put physical address of page_table_lock in cr28 (tr4)
 56		   for TLB faults */
 57		spinlock_t *pgd_lock = &next->page_table_lock;
 58		mtctl(__pa(__ldcw_align(&pgd_lock->rlock.raw_lock)), 28);
 59#endif
 60		mtctl(__pa(next->pgd), 25);
 61		load_context(next->context);
 62	}
 63}
 64
 65static inline void switch_mm(struct mm_struct *prev,
 66		struct mm_struct *next, struct task_struct *tsk)
 67{
 68	unsigned long flags;
 69
 70	if (prev == next)
 71		return;
 72
 73	local_irq_save(flags);
 74	switch_mm_irqs_off(prev, next, tsk);
 75	local_irq_restore(flags);
 76}
 77#define switch_mm_irqs_off switch_mm_irqs_off
 78
 79#define activate_mm activate_mm
 80static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
 81{
 82	/*
 83	 * Activate_mm is our one chance to allocate a space id
 84	 * for a new mm created in the exec path. There's also
 85	 * some lazy tlb stuff, which is currently dead code, but
 86	 * we only allocate a space id if one hasn't been allocated
 87	 * already, so we should be OK.
 88	 */
 89
 90	BUG_ON(next == &init_mm); /* Should never happen */
 91
 92	if (next->context.space_id == 0)
 93		next->context.space_id = alloc_sid();
 94
 95	switch_mm(prev,next,current);
 96}
 97
 98#include <asm-generic/mmu_context.h>
 99
100#endif