/* * Copyright (C) 1999 Niibe Yutaka * Copyright (C) 2003 Paul Mundt * * ASID handling idea taken from MIPS implementation. */ #ifndef __ASM_SH_MMU_CONTEXT_H #define __ASM_SH_MMU_CONTEXT_H #ifdef __KERNEL__ #include <asm/cpu/mmu_context.h> #include <asm/tlbflush.h> #include <asm/pgalloc.h> #include <asm/uaccess.h> #include <asm/io.h> /* * The MMU "context" consists of two things: * (a) TLB cache version (or round, cycle whatever expression you like) * (b) ASID (Address Space IDentifier) */ /* * Cache of MMU context last used. */ extern unsigned long mmu_context_cache; #define MMU_CONTEXT_ASID_MASK 0x000000ff #define MMU_CONTEXT_VERSION_MASK 0xffffff00 #define MMU_CONTEXT_FIRST_VERSION 0x00000100 #define NO_CONTEXT 0 /* ASID is 8-bit value, so it can't be 0x100 */ #define MMU_NO_ASID 0x100 /* * Virtual Page Number mask */ #define MMU_VPN_MASK 0xfffff000 #ifdef CONFIG_MMU /* * Get MMU context if needed. */ static __inline__ void get_mmu_context(struct mm_struct *mm) { extern void flush_tlb_all(void); unsigned long mc = mmu_context_cache; /* Check if we have old version of context. */ if (((mm->context.id ^ mc) & 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. */ mc = ++mmu_context_cache; if (!(mc & MMU_CONTEXT_ASID_MASK)) { /* * We exhaust ASID of this version. * Flush all TLB and start new cycle. */ flush_tlb_all(); /* * Fix version; Note that we avoid version #0 * to distingush NO_CONTEXT. */ if (!mc) mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION; } mm->context.id = mc; } /* * 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) { mm->context.id = NO_CONTEXT; return 0; } /* * 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) { /* Do nothing */ } static __inline__ void set_asid(unsigned long asid) { unsigned long __dummy; __asm__ __volatile__ ("mov.l %2, %0\n\t" "and %3, %0\n\t" "or %1, %0\n\t" "mov.l %0, %2" : "=&r" (__dummy) : "r" (asid), "m" (__m(MMU_PTEH)), "r" (0xffffff00)); } static __inline__ unsigned long get_asid(void) { unsigned long asid; __asm__ __volatile__ ("mov.l %1, %0" : "=r" (asid) : "m" (__m(MMU_PTEH))); asid &= MMU_CONTEXT_ASID_MASK; return asid; } /* * 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) { get_mmu_context(mm); set_asid(mm->context.id & MMU_CONTEXT_ASID_MASK); } /* MMU_TTB can be used for optimizing the fault handling. (Currently not used) */ static __inline__ void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) { if (likely(prev != next)) { unsigned long __pgdir = (unsigned long)next->pgd; __asm__ __volatile__("mov.l %0, %1" : /* no output */ : "r" (__pgdir), "m" (__m(MMU_TTB))); activate_context(next); } } #define deactivate_mm(tsk,mm) do { } while (0) #define activate_mm(prev, next) \ switch_mm((prev),(next),NULL) static __inline__ void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) { } #else /* !CONFIG_MMU */ #define get_mmu_context(mm) do { } while (0) #define init_new_context(tsk,mm) (0) #define destroy_context(mm) do { } while (0) #define set_asid(asid) do { } while (0) #define get_asid() (0) #define activate_context(mm) do { } while (0) #define switch_mm(prev,next,tsk) do { } while (0) #define deactivate_mm(tsk,mm) do { } while (0) #define activate_mm(prev,next) do { } while (0) #define enter_lazy_tlb(mm,tsk) do { } while (0) #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) { /* Enable MMU */ ctrl_outl(MMU_CONTROL_INIT, MMUCR); ctrl_barrier(); if (mmu_context_cache == NO_CONTEXT) mmu_context_cache = MMU_CONTEXT_FIRST_VERSION; set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK); } static inline void disable_mmu(void) { unsigned long cr; cr = ctrl_inl(MMUCR); cr &= ~MMU_CONTROL_INIT; ctrl_outl(cr, MMUCR); ctrl_barrier(); } #else /* * MMU control handlers for processors lacking memory * management hardware. */ #define enable_mmu() do { BUG(); } while (0) #define disable_mmu() do { BUG(); } while (0) #endif #endif /* __KERNEL__ */ #endif /* __ASM_SH_MMU_CONTEXT_H */