diff options
Diffstat (limited to 'arch/loongarch/include/asm/mmu_context.h')
| -rw-r--r-- | arch/loongarch/include/asm/mmu_context.h | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/mmu_context.h b/arch/loongarch/include/asm/mmu_context.h new file mode 100644 index 000000000..9f97c3453 --- /dev/null +++ b/arch/loongarch/include/asm/mmu_context.h @@ -0,0 +1,152 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Switch a MMU context. + * + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited + */ +#ifndef _ASM_MMU_CONTEXT_H +#define _ASM_MMU_CONTEXT_H + +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/mm_types.h> +#include <linux/smp.h> +#include <linux/slab.h> + +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include <asm-generic/mm_hooks.h> + +/* + * All unused by hardware upper bits will be considered + * as a software asid extension. + */ +static inline u64 asid_version_mask(unsigned int cpu) +{ + return ~(u64)(cpu_asid_mask(&cpu_data[cpu])); +} + +static inline u64 asid_first_version(unsigned int cpu) +{ + return cpu_asid_mask(&cpu_data[cpu]) + 1; +} + +#define cpu_context(cpu, mm) ((mm)->context.asid[cpu]) +#define asid_cache(cpu) (cpu_data[cpu].asid_cache) +#define cpu_asid(cpu, mm) (cpu_context((cpu), (mm)) & cpu_asid_mask(&cpu_data[cpu])) + +static inline int asid_valid(struct mm_struct *mm, unsigned int cpu) +{ + if ((cpu_context(cpu, mm) ^ asid_cache(cpu)) & asid_version_mask(cpu)) + return 0; + + return 1; +} + +static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) +{ +} + +/* Normal, classic get_new_mmu_context */ +static inline void +get_new_mmu_context(struct mm_struct *mm, unsigned long cpu) +{ + u64 asid = asid_cache(cpu); + + if (!((++asid) & cpu_asid_mask(&cpu_data[cpu]))) + local_flush_tlb_user(); /* start new asid cycle */ + + cpu_context(cpu, mm) = asid_cache(cpu) = asid; +} + +/* + * Initialize the context related info for a new mm_struct + * instance. + */ +static inline int +init_new_context(struct task_struct *tsk, struct mm_struct *mm) +{ + int i; + + for_each_possible_cpu(i) + cpu_context(i, mm) = 0; + + return 0; +} + +static inline void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, + struct task_struct *tsk) +{ + unsigned int cpu = smp_processor_id(); + + /* Check if our ASID is of an older version and thus invalid */ + if (!asid_valid(next, cpu)) + get_new_mmu_context(next, cpu); + + write_csr_asid(cpu_asid(cpu, next)); + + if (next != &init_mm) + csr_write64((unsigned long)next->pgd, LOONGARCH_CSR_PGDL); + else + csr_write64((unsigned long)invalid_pg_dir, LOONGARCH_CSR_PGDL); + + /* + * Mark current->active_mm as not "active" anymore. + * We don't want to mislead possible IPI tlb flush routines. + */ + cpumask_set_cpu(cpu, mm_cpumask(next)); +} + +#define switch_mm_irqs_off switch_mm_irqs_off + +static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, + struct task_struct *tsk) +{ + unsigned long flags; + + local_irq_save(flags); + switch_mm_irqs_off(prev, next, tsk); + local_irq_restore(flags); +} + +/* + * Destroy context related info for an mm_struct that is about + * to be put to rest. + */ +static inline void destroy_context(struct mm_struct *mm) +{ +} + +#define activate_mm(prev, next) switch_mm(prev, next, current) +#define deactivate_mm(task, mm) do { } while (0) + +/* + * If mm is currently active, we can't really drop it. + * Instead, we will get a new one for it. + */ +static inline void +drop_mmu_context(struct mm_struct *mm, unsigned int cpu) +{ + int asid; + unsigned long flags; + + local_irq_save(flags); + + asid = read_csr_asid() & cpu_asid_mask(¤t_cpu_data); + + if (asid == cpu_asid(cpu, mm)) { + if (!current->mm || (current->mm == mm)) { + get_new_mmu_context(mm, cpu); + write_csr_asid(cpu_asid(cpu, mm)); + goto out; + } + } + + /* Will get a new context next time */ + cpu_context(cpu, mm) = 0; + cpumask_clear_cpu(cpu, mm_cpumask(mm)); +out: + local_irq_restore(flags); +} + +#endif /* _ASM_MMU_CONTEXT_H */ |