mirror of
https://github.com/torvalds/linux.git
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1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
207 lines
4.9 KiB
C
207 lines
4.9 KiB
C
/*
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* Copyright (C) 1999 Niibe Yutaka
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* Copyright (C) 2003 Paul Mundt
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*
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* ASID handling idea taken from MIPS implementation.
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*/
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#ifndef __ASM_SH_MMU_CONTEXT_H
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#define __ASM_SH_MMU_CONTEXT_H
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#ifdef __KERNEL__
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#include <asm/cpu/mmu_context.h>
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#include <asm/tlbflush.h>
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#include <asm/pgalloc.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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/*
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* The MMU "context" consists of two things:
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* (a) TLB cache version (or round, cycle whatever expression you like)
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* (b) ASID (Address Space IDentifier)
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*/
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/*
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* Cache of MMU context last used.
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*/
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extern unsigned long mmu_context_cache;
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#define MMU_CONTEXT_ASID_MASK 0x000000ff
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#define MMU_CONTEXT_VERSION_MASK 0xffffff00
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#define MMU_CONTEXT_FIRST_VERSION 0x00000100
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#define NO_CONTEXT 0
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/* ASID is 8-bit value, so it can't be 0x100 */
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#define MMU_NO_ASID 0x100
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/*
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* Virtual Page Number mask
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*/
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#define MMU_VPN_MASK 0xfffff000
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#ifdef CONFIG_MMU
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/*
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* Get MMU context if needed.
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*/
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static __inline__ void
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get_mmu_context(struct mm_struct *mm)
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{
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extern void flush_tlb_all(void);
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unsigned long mc = mmu_context_cache;
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/* Check if we have old version of context. */
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if (((mm->context ^ mc) & MMU_CONTEXT_VERSION_MASK) == 0)
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/* It's up to date, do nothing */
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return;
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/* It's old, we need to get new context with new version. */
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mc = ++mmu_context_cache;
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if (!(mc & MMU_CONTEXT_ASID_MASK)) {
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/*
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* We exhaust ASID of this version.
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* Flush all TLB and start new cycle.
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*/
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flush_tlb_all();
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/*
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* Fix version; Note that we avoid version #0
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* to distingush NO_CONTEXT.
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*/
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if (!mc)
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mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION;
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}
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mm->context = mc;
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}
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/*
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* Initialize the context related info for a new mm_struct
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* instance.
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*/
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static __inline__ int init_new_context(struct task_struct *tsk,
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struct mm_struct *mm)
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{
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mm->context = NO_CONTEXT;
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return 0;
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}
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/*
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* Destroy context related info for an mm_struct that is about
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* to be put to rest.
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*/
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static __inline__ void destroy_context(struct mm_struct *mm)
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{
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/* Do nothing */
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}
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static __inline__ void set_asid(unsigned long asid)
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{
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unsigned long __dummy;
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__asm__ __volatile__ ("mov.l %2, %0\n\t"
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"and %3, %0\n\t"
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"or %1, %0\n\t"
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"mov.l %0, %2"
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: "=&r" (__dummy)
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: "r" (asid), "m" (__m(MMU_PTEH)),
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"r" (0xffffff00));
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}
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static __inline__ unsigned long get_asid(void)
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{
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unsigned long asid;
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__asm__ __volatile__ ("mov.l %1, %0"
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: "=r" (asid)
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: "m" (__m(MMU_PTEH)));
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asid &= MMU_CONTEXT_ASID_MASK;
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return asid;
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}
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/*
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* After we have set current->mm to a new value, this activates
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* the context for the new mm so we see the new mappings.
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*/
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static __inline__ void activate_context(struct mm_struct *mm)
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{
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get_mmu_context(mm);
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set_asid(mm->context & MMU_CONTEXT_ASID_MASK);
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}
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/* MMU_TTB can be used for optimizing the fault handling.
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(Currently not used) */
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static __inline__ void switch_mm(struct mm_struct *prev,
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struct mm_struct *next,
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struct task_struct *tsk)
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{
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if (likely(prev != next)) {
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unsigned long __pgdir = (unsigned long)next->pgd;
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__asm__ __volatile__("mov.l %0, %1"
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: /* no output */
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: "r" (__pgdir), "m" (__m(MMU_TTB)));
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activate_context(next);
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}
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}
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#define deactivate_mm(tsk,mm) do { } while (0)
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#define activate_mm(prev, next) \
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switch_mm((prev),(next),NULL)
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static __inline__ void
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enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
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{
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}
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#else /* !CONFIG_MMU */
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#define get_mmu_context(mm) do { } while (0)
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#define init_new_context(tsk,mm) (0)
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#define destroy_context(mm) do { } while (0)
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#define set_asid(asid) do { } while (0)
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#define get_asid() (0)
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#define activate_context(mm) do { } while (0)
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#define switch_mm(prev,next,tsk) do { } while (0)
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#define deactivate_mm(tsk,mm) do { } while (0)
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#define activate_mm(prev,next) do { } while (0)
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#define enter_lazy_tlb(mm,tsk) do { } while (0)
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#endif /* CONFIG_MMU */
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#if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH4)
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/*
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* If this processor has an MMU, we need methods to turn it off/on ..
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* paging_init() will also have to be updated for the processor in
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* question.
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*/
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static inline void enable_mmu(void)
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{
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/* Enable MMU */
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ctrl_outl(MMU_CONTROL_INIT, MMUCR);
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/* The manual suggests doing some nops after turning on the MMU */
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__asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop\n\t");
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if (mmu_context_cache == NO_CONTEXT)
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mmu_context_cache = MMU_CONTEXT_FIRST_VERSION;
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set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK);
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}
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static inline void disable_mmu(void)
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{
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unsigned long cr;
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cr = ctrl_inl(MMUCR);
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cr &= ~MMU_CONTROL_INIT;
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ctrl_outl(cr, MMUCR);
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__asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop\n\t");
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}
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#else
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/*
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* MMU control handlers for processors lacking memory
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* management hardware.
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*/
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#define enable_mmu() do { BUG(); } while (0)
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#define disable_mmu() do { BUG(); } while (0)
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#endif
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#endif /* __KERNEL__ */
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#endif /* __ASM_SH_MMU_CONTEXT_H */
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