2 * Copyright (C) 2012 Regents of the University of California
3 * Copyright (C) 2017 SiFive
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation, version 2.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
15 #ifndef _ASM_RISCV_MMU_CONTEXT_H
16 #define _ASM_RISCV_MMU_CONTEXT_H
18 #include <asm-generic/mm_hooks.h>
21 #include <linux/sched.h>
22 #include <asm/tlbflush.h>
23 #include <asm/cacheflush.h>
25 static inline void enter_lazy_tlb(struct mm_struct *mm,
26 struct task_struct *task)
30 /* Initialize context-related info for a new mm_struct */
31 static inline int init_new_context(struct task_struct *task,
37 static inline void destroy_context(struct mm_struct *mm)
41 static inline pgd_t *current_pgdir(void)
43 return pfn_to_virt(csr_read(sptbr) & SPTBR_PPN);
46 static inline void set_pgdir(pgd_t *pgd)
48 csr_write(sptbr, virt_to_pfn(pgd) | SPTBR_MODE);
52 * When necessary, performs a deferred icache flush for the given MM context,
53 * on the local CPU. RISC-V has no direct mechanism for instruction cache
54 * shoot downs, so instead we send an IPI that informs the remote harts they
55 * need to flush their local instruction caches. To avoid pathologically slow
56 * behavior in a common case (a bunch of single-hart processes on a many-hart
57 * machine, ie 'make -j') we avoid the IPIs for harts that are not currently
58 * executing a MM context and instead schedule a deferred local instruction
59 * cache flush to be performed before execution resumes on each hart. This
60 * actually performs that local instruction cache flush, which implicitly only
61 * refers to the current hart.
63 static inline void flush_icache_deferred(struct mm_struct *mm)
66 unsigned int cpu = smp_processor_id();
67 cpumask_t *mask = &mm->context.icache_stale_mask;
69 if (cpumask_test_cpu(cpu, mask)) {
70 cpumask_clear_cpu(cpu, mask);
72 * Ensure the remote hart's writes are visible to this hart.
73 * This pairs with a barrier in flush_icache_mm.
76 local_flush_icache_all();
81 static inline void switch_mm(struct mm_struct *prev,
82 struct mm_struct *next, struct task_struct *task)
84 if (likely(prev != next)) {
86 * Mark the current MM context as inactive, and the next as
87 * active. This is at least used by the icache flushing
88 * routines in order to determine who should
90 unsigned int cpu = smp_processor_id();
92 cpumask_clear_cpu(cpu, mm_cpumask(prev));
93 cpumask_set_cpu(cpu, mm_cpumask(next));
96 local_flush_tlb_all();
98 flush_icache_deferred(next);
102 static inline void activate_mm(struct mm_struct *prev,
103 struct mm_struct *next)
105 switch_mm(prev, next, NULL);
108 static inline void deactivate_mm(struct task_struct *task,
109 struct mm_struct *mm)
113 #endif /* _ASM_RISCV_MMU_CONTEXT_H */