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#ifndef __PPC_MMU_CONTEXT_H
#define __PPC_MMU_CONTEXT_H
/* the way contexts are handled on the ppc they are vsid's and
don't need any special treatment right now.
perhaps I can defer flushing the tlb by keeping a list of
zombie vsid/context's and handling that through destroy_context
later -- Cort
*/
#define NO_CONTEXT 0
#define LAST_CONTEXT 0xfffff
extern int next_mmu_context;
extern void mmu_context_overflow(void);
extern void set_context(int context);
/*
* Allocating context numbers this way tends to spread out
* the entries in the hash table better than a simple linear
* allocation.
*/
#define MUNGE_CONTEXT(n) (((n) * 897) & LAST_CONTEXT)
/*
* Get a new mmu context for task tsk if necessary.
*/
#define get_mmu_context(tsk) \
do { \
struct mm_struct *mm = (tsk)->mm; \
if (mm->context == NO_CONTEXT) { \
if (next_mmu_context == LAST_CONTEXT) \
mmu_context_overflow(); \
mm->context = MUNGE_CONTEXT(++next_mmu_context);\
if ( tsk == current ) \
set_context(mm->context); \
} \
} while (0)
/*
* Set up the context for a new address space.
*/
#define init_new_context(mm) ((mm)->context = NO_CONTEXT)
/*
* We're finished using the context for an address space.
*/
#define destroy_context(mm) do { } while (0)
/*
* compute the vsid from the context and segment
* segments > 7 are kernel segments and their
* vsid is the segment -- Cort
*/
#define VSID_FROM_CONTEXT(segment,context) \
((segment < 8) ? ((segment) | (context)<<4) : (segment))
#endif
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