1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Common implementation of switch_mm_irqs_off
5 * Copyright IBM Corp. 2017
10 #include <linux/sched/mm.h>
12 #include <asm/mmu_context.h>
13 #include <asm/pgalloc.h>
15 #if defined(CONFIG_PPC32)
16 static inline void switch_mm_pgdir(struct task_struct *tsk,
19 /* 32-bit keeps track of the current PGDIR in the thread struct */
20 tsk->thread.pgdir = mm->pgd;
22 #elif defined(CONFIG_PPC_BOOK3E_64)
23 static inline void switch_mm_pgdir(struct task_struct *tsk,
26 /* 64-bit Book3E keeps track of current PGD in the PACA */
27 get_paca()->pgd = mm->pgd;
30 static inline void switch_mm_pgdir(struct task_struct *tsk,
31 struct mm_struct *mm) { }
34 void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
35 struct task_struct *tsk)
37 bool new_on_cpu = false;
39 /* Mark this context has been used on the new CPU */
40 if (!cpumask_test_cpu(smp_processor_id(), mm_cpumask(next))) {
41 cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
42 inc_mm_active_cpus(next);
45 * This full barrier orders the store to the cpumask above vs
46 * a subsequent load which allows this CPU/MMU to begin loading
47 * translations for 'next' from page table PTEs into the TLB.
49 * When using the radix MMU, that operation is the load of the
50 * MMU context id, which is then moved to SPRN_PID.
52 * For the hash MMU it is either the first load from slb_cache
53 * in switch_slb() to preload the SLBs, or the load of
54 * get_user_context which loads the context for the VSID hash
55 * to insert a new SLB, in the SLB fault handler.
57 * On the other side, the barrier is in mm/tlb-radix.c for
58 * radix which orders earlier stores to clear the PTEs before
59 * the load of mm_cpumask to check which CPU TLBs should be
60 * flushed. For hash, pte_xchg to clear the PTE includes the
63 * This full barrier is also needed by membarrier when
64 * switching between processes after store to rq->curr, before
65 * user-space memory accesses.
72 /* Some subarchs need to track the PGD elsewhere */
73 switch_mm_pgdir(tsk, next);
75 /* Nothing else to do if we aren't actually switching */
80 * We must stop all altivec streams before changing the HW
83 if (cpu_has_feature(CPU_FTR_ALTIVEC))
84 asm volatile (PPC_DSSALL);
87 membarrier_arch_switch_mm(prev, next, tsk);
90 * The actual HW switching method differs between the various
91 * sub architectures. Out of line for now
93 switch_mmu_context(prev, next, tsk);
96 #ifndef CONFIG_PPC_BOOK3S_64
97 void arch_exit_mmap(struct mm_struct *mm)
99 void *frag = pte_frag_get(&mm->context);
102 pte_frag_destroy(frag);