mmu_context.h

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#ifndef __ASM_POWERPC_MMU_CONTEXT_H
#define __ASM_POWERPC_MMU_CONTEXT_H
#ifdef __KERNEL__

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <asm/mmu.h>    
#include <asm/cputable.h>
#include <asm-generic/mm_hooks.h>
#include <asm/cputhreads.h>

/*
 * Most if the context management is out of line
 */
extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
extern void destroy_context(struct mm_struct *mm);

extern void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next);
extern void switch_stab(struct task_struct *tsk, struct mm_struct *mm);
extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm);
extern void set_context(unsigned long id, pgd_t *pgd);

#ifdef CONFIG_PPC_BOOK3S_64
extern int __init_new_context(void);
extern void __destroy_context(int context_id);
static inline void mmu_context_init(void) { }
#else
extern unsigned long __init_new_context(void);
extern void __destroy_context(unsigned long context_id);
extern void mmu_context_init(void);
#endif

extern void switch_cop(struct mm_struct *next);
extern int use_cop(unsigned long acop, struct mm_struct *mm);
extern void drop_cop(unsigned long acop, struct mm_struct *mm);

/*
 * switch_mm is the entry point called from the architecture independent
 * code in kernel/sched.c
 */
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
                 struct task_struct *tsk)
{
    /* Mark this context has been used on the new CPU */
    cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));

    /* 32-bit keeps track of the current PGDIR in the thread struct */
#ifdef CONFIG_PPC32
    tsk->thread.pgdir = next->pgd;
#endif /* CONFIG_PPC32 */

    /* 64-bit Book3E keeps track of current PGD in the PACA */
#ifdef CONFIG_PPC_BOOK3E_64
    get_paca()->pgd = next->pgd;
#endif
    /* Nothing else to do if we aren't actually switching */
    if (prev == next)
        return;

#ifdef CONFIG_PPC_ICSWX
    /* Switch coprocessor context only if prev or next uses a coprocessor */
    if (prev->context.acop || next->context.acop)
        switch_cop(next);
#endif /* CONFIG_PPC_ICSWX */

    /* We must stop all altivec streams before changing the HW
     * context
     */
#ifdef CONFIG_ALTIVEC
    if (cpu_has_feature(CPU_FTR_ALTIVEC))
        asm volatile ("dssall");
#endif /* CONFIG_ALTIVEC */

    /* The actual HW switching method differs between the various
     * sub architectures.
     */
#ifdef CONFIG_PPC_STD_MMU_64
    if (mmu_has_feature(MMU_FTR_SLB))
        switch_slb(tsk, next);
    else
        switch_stab(tsk, next);
#else
    /* Out of line for now */
    switch_mmu_context(prev, next);
#endif

}

#define deactivate_mm(tsk,mm)   do { } while (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_mm(struct mm_struct *prev, struct mm_struct *next)
{
    unsigned long flags;

    local_irq_save(flags);
    switch_mm(prev, next, current);
    local_irq_restore(flags);
}

/* We don't currently use enter_lazy_tlb() for anything */
static inline void enter_lazy_tlb(struct mm_struct *mm,
                  struct task_struct *tsk)
{
    /* 64-bit Book3E keeps track of current PGD in the PACA */
#ifdef CONFIG_PPC_BOOK3E_64
    get_paca()->pgd = NULL;
#endif
}

#endif /* __KERNEL__ */
#endif /* __ASM_POWERPC_MMU_CONTEXT_H */