diff options
Diffstat (limited to 'arch/sh/include/asm/mmu_context.h')
| -rw-r--r-- | arch/sh/include/asm/mmu_context.h | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/arch/sh/include/asm/mmu_context.h b/arch/sh/include/asm/mmu_context.h new file mode 100644 index 000000000..2d0965009 --- /dev/null +++ b/arch/sh/include/asm/mmu_context.h @@ -0,0 +1,193 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 1999 Niibe Yutaka + * Copyright (C) 2003 - 2007 Paul Mundt + * + * ASID handling idea taken from MIPS implementation. + */ +#ifndef __ASM_SH_MMU_CONTEXT_H +#define __ASM_SH_MMU_CONTEXT_H + +#ifdef __KERNEL__ +#include <cpu/mmu_context.h> +#include <asm/tlbflush.h> +#include <linux/uaccess.h> +#include <linux/mm_types.h> + +#include <asm/io.h> +#include <asm-generic/mm_hooks.h> + +/* + * The MMU "context" consists of two things: + * (a) TLB cache version (or round, cycle whatever expression you like) + * (b) ASID (Address Space IDentifier) + */ +#ifdef CONFIG_CPU_HAS_PTEAEX +#define MMU_CONTEXT_ASID_MASK 0x0000ffff +#else +#define MMU_CONTEXT_ASID_MASK 0x000000ff +#endif + +#define MMU_CONTEXT_VERSION_MASK (~0UL & ~MMU_CONTEXT_ASID_MASK) +#define MMU_CONTEXT_FIRST_VERSION (MMU_CONTEXT_ASID_MASK + 1) + +/* Impossible ASID value, to differentiate from NO_CONTEXT. */ +#define MMU_NO_ASID MMU_CONTEXT_FIRST_VERSION +#define NO_CONTEXT 0UL + +#define asid_cache(cpu) (cpu_data[cpu].asid_cache) + +#ifdef CONFIG_MMU +#define cpu_context(cpu, mm) ((mm)->context.id[cpu]) + +#define cpu_asid(cpu, mm) \ + (cpu_context((cpu), (mm)) & MMU_CONTEXT_ASID_MASK) + +/* + * Virtual Page Number mask + */ +#define MMU_VPN_MASK 0xfffff000 + +#if defined(CONFIG_SUPERH32) +#include <asm/mmu_context_32.h> +#else +#include <asm/mmu_context_64.h> +#endif + +/* + * Get MMU context if needed. + */ +static inline void get_mmu_context(struct mm_struct *mm, unsigned int cpu) +{ + unsigned long asid = asid_cache(cpu); + + /* Check if we have old version of context. */ + if (((cpu_context(cpu, mm) ^ asid) & MMU_CONTEXT_VERSION_MASK) == 0) + /* It's up to date, do nothing */ + return; + + /* It's old, we need to get new context with new version. */ + if (!(++asid & MMU_CONTEXT_ASID_MASK)) { + /* + * We exhaust ASID of this version. + * Flush all TLB and start new cycle. + */ + local_flush_tlb_all(); + +#ifdef CONFIG_SUPERH64 + /* + * The SH-5 cache uses the ASIDs, requiring both the I and D + * cache to be flushed when the ASID is exhausted. Weak. + */ + flush_cache_all(); +#endif + + /* + * Fix version; Note that we avoid version #0 + * to distinguish NO_CONTEXT. + */ + if (!asid) + asid = MMU_CONTEXT_FIRST_VERSION; + } + + 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_online_cpu(i) + cpu_context(i, mm) = NO_CONTEXT; + + return 0; +} + +/* + * After we have set current->mm to a new value, this activates + * the context for the new mm so we see the new mappings. + */ +static inline void activate_context(struct mm_struct *mm, unsigned int cpu) +{ + get_mmu_context(mm, cpu); + set_asid(cpu_asid(cpu, mm)); +} + +static inline void switch_mm(struct mm_struct *prev, + struct mm_struct *next, + struct task_struct *tsk) +{ + unsigned int cpu = smp_processor_id(); + + if (likely(prev != next)) { + cpumask_set_cpu(cpu, mm_cpumask(next)); + set_TTB(next->pgd); + activate_context(next, cpu); + } else + if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next))) + activate_context(next, cpu); +} + +#define activate_mm(prev, next) switch_mm((prev),(next),NULL) +#define deactivate_mm(tsk,mm) do { } while (0) +#define enter_lazy_tlb(mm,tsk) do { } while (0) + +#else + +#define set_asid(asid) do { } while (0) +#define get_asid() (0) +#define cpu_asid(cpu, mm) ({ (void)cpu; NO_CONTEXT; }) +#define switch_and_save_asid(asid) (0) +#define set_TTB(pgd) do { } while (0) +#define get_TTB() (0) + +#include <asm-generic/mmu_context.h> + +#endif /* CONFIG_MMU */ + +#if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH4) +/* + * If this processor has an MMU, we need methods to turn it off/on .. + * paging_init() will also have to be updated for the processor in + * question. + */ +static inline void enable_mmu(void) +{ + unsigned int cpu = smp_processor_id(); + + /* Enable MMU */ + __raw_writel(MMU_CONTROL_INIT, MMUCR); + ctrl_barrier(); + + if (asid_cache(cpu) == NO_CONTEXT) + asid_cache(cpu) = MMU_CONTEXT_FIRST_VERSION; + + set_asid(asid_cache(cpu) & MMU_CONTEXT_ASID_MASK); +} + +static inline void disable_mmu(void) +{ + unsigned long cr; + + cr = __raw_readl(MMUCR); + cr &= ~MMU_CONTROL_INIT; + __raw_writel(cr, MMUCR); + + ctrl_barrier(); +} +#else +/* + * MMU control handlers for processors lacking memory + * management hardware. + */ +#define enable_mmu() do { } while (0) +#define disable_mmu() do { } while (0) +#endif + +#endif /* __KERNEL__ */ +#endif /* __ASM_SH_MMU_CONTEXT_H */ |