diff options
Diffstat (limited to 'include/asm-sh/mmu_context.h')
| -rw-r--r-- | include/asm-sh/mmu_context.h | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/include/asm-sh/mmu_context.h b/include/asm-sh/mmu_context.h new file mode 100644 index 000000000000..6760d064bd02 --- /dev/null +++ b/include/asm-sh/mmu_context.h @@ -0,0 +1,206 @@ +/* + * 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 ^ 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 = 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 = 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 & 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); + + /* The manual suggests doing some nops after turning on the MMU */ + __asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop\n\t"); + + 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); + __asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop\n\t"); +} +#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 */ |