190 lines
4.4 KiB
C
190 lines
4.4 KiB
C
/*
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* Copyright (C) 1999 Niibe Yutaka
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* Copyright (C) 2003 - 2007 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 <cpu/mmu_context.h>
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#include <asm/tlbflush.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#include <asm-generic/mm_hooks.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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#ifdef CONFIG_CPU_HAS_PTEAEX
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#define MMU_CONTEXT_ASID_MASK 0x0000ffff
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#else
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#define MMU_CONTEXT_ASID_MASK 0x000000ff
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#endif
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#define MMU_CONTEXT_VERSION_MASK (~0UL & ~MMU_CONTEXT_ASID_MASK)
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#define MMU_CONTEXT_FIRST_VERSION (MMU_CONTEXT_ASID_MASK + 1)
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/* Impossible ASID value, to differentiate from NO_CONTEXT. */
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#define MMU_NO_ASID MMU_CONTEXT_FIRST_VERSION
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#define NO_CONTEXT 0UL
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#define asid_cache(cpu) (cpu_data[cpu].asid_cache)
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#ifdef CONFIG_MMU
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#define cpu_context(cpu, mm) ((mm)->context.id[cpu])
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#define cpu_asid(cpu, mm) \
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(cpu_context((cpu), (mm)) & MMU_CONTEXT_ASID_MASK)
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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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#if defined(CONFIG_SUPERH32)
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#include <asm/mmu_context_32.h>
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#else
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#include <asm/mmu_context_64.h>
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#endif
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/*
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* Get MMU context if needed.
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*/
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static inline void get_mmu_context(struct mm_struct *mm, unsigned int cpu)
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{
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unsigned long asid = asid_cache(cpu);
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/* Check if we have old version of context. */
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if (((cpu_context(cpu, mm) ^ asid) & 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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if (!(++asid & 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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local_flush_tlb_all();
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#ifdef CONFIG_SUPERH64
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/*
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* The SH-5 cache uses the ASIDs, requiring both the I and D
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* cache to be flushed when the ASID is exhausted. Weak.
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*/
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flush_cache_all();
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#endif
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/*
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* Fix version; Note that we avoid version #0
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* to distinguish NO_CONTEXT.
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*/
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if (!asid)
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asid = MMU_CONTEXT_FIRST_VERSION;
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}
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cpu_context(cpu, mm) = asid_cache(cpu) = asid;
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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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int i;
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for (i = 0; i < num_online_cpus(); i++)
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cpu_context(i, mm) = NO_CONTEXT;
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return 0;
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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, unsigned int cpu)
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{
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get_mmu_context(mm, cpu);
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set_asid(cpu_asid(cpu, mm));
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}
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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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unsigned int cpu = smp_processor_id();
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if (likely(prev != next)) {
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cpumask_set_cpu(cpu, mm_cpumask(next));
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set_TTB(next->pgd);
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activate_context(next, cpu);
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} else
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if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)))
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activate_context(next, cpu);
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}
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#define activate_mm(prev, next) switch_mm((prev),(next),NULL)
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#define deactivate_mm(tsk,mm) do { } while (0)
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#define enter_lazy_tlb(mm,tsk) do { } while (0)
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#else
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#define set_asid(asid) do { } while (0)
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#define get_asid() (0)
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#define cpu_asid(cpu, mm) ({ (void)cpu; NO_CONTEXT; })
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#define switch_and_save_asid(asid) (0)
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#define set_TTB(pgd) do { } while (0)
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#define get_TTB() (0)
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#include <asm-generic/mmu_context.h>
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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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unsigned int cpu = smp_processor_id();
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/* Enable MMU */
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__raw_writel(MMU_CONTROL_INIT, MMUCR);
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ctrl_barrier();
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if (asid_cache(cpu) == NO_CONTEXT)
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asid_cache(cpu) = MMU_CONTEXT_FIRST_VERSION;
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set_asid(asid_cache(cpu) & 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 = __raw_readl(MMUCR);
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cr &= ~MMU_CONTROL_INIT;
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__raw_writel(cr, MMUCR);
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ctrl_barrier();
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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 { } while (0)
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#define disable_mmu() do { } 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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