Viewing file:  mmu_context.h (3.14 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
#ifndef _ASM_IA64_MMU_CONTEXT_H
#define _ASM_IA64_MMU_CONTEXT_H
/*
* Copyright (C) 1998-2001 Hewlett-Packard Co
* Copyright (C) 1998-2001 David Mosberger-Tang <davidm@hpl.hp.com>
*/
/*
* Routines to manage the allocation of task context numbers. Task context numbers are
* used to reduce or eliminate the need to perform TLB flushes due to context switches.
* Context numbers are implemented using ia-64 region ids. Since the IA-64 TLB does not
* consider the region number when performing a TLB lookup, we need to assign a unique
* region id to each region in a process. We use the least significant three bits in a
* region id for this purpose.
*
* Copyright (C) 1998-2001 David Mosberger-Tang <davidm@hpl.hp.com>
*/
#define IA64_REGION_ID_KERNEL 0 /* the kernel's region id (tlb.c depends on this being 0) */
#define ia64_rid(ctx,addr) (((ctx) << 3) | (addr >> 61))
# ifndef __ASSEMBLY__
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <asm/processor.h>
struct ia64_ctx {
spinlock_t lock;
unsigned int next; /* next context number to use */
unsigned int limit; /* next >= limit => must call wrap_mmu_context() */
unsigned int max_ctx; /* max. context value supported by all CPUs */
};
extern struct ia64_ctx ia64_ctx;
extern void wrap_mmu_context (struct mm_struct *mm);
static inline void
enter_lazy_tlb (struct mm_struct *mm, struct task_struct *tsk, unsigned cpu)
{
}
static inline void
get_new_mmu_context (struct mm_struct *mm)
{
spin_lock(&ia64_ctx.lock);
{
if (ia64_ctx.next >= ia64_ctx.limit)
wrap_mmu_context(mm);
mm->context = ia64_ctx.next++;
}
spin_unlock(&ia64_ctx.lock);
}
static inline void
get_mmu_context (struct mm_struct *mm)
{
if (mm->context == 0)
get_new_mmu_context(mm);
}
static inline int
init_new_context (struct task_struct *p, struct mm_struct *mm)
{
mm->context = 0;
return 0;
}
static inline void
destroy_context (struct mm_struct *mm)
{
/* Nothing to do. */
}
static inline void
reload_context (struct mm_struct *mm)
{
unsigned long rid;
unsigned long rid_incr = 0;
unsigned long rr0, rr1, rr2, rr3, rr4;
rid = mm->context << 3; /* make space for encoding the region number */
rid_incr = 1 << 8;
/* encode the region id, preferred page size, and VHPT enable bit: */
rr0 = (rid << 8) | (PAGE_SHIFT << 2) | 1;
rr1 = rr0 + 1*rid_incr;
rr2 = rr0 + 2*rid_incr;
rr3 = rr0 + 3*rid_incr;
rr4 = rr0 + 4*rid_incr;
ia64_set_rr(0x0000000000000000, rr0);
ia64_set_rr(0x2000000000000000, rr1);
ia64_set_rr(0x4000000000000000, rr2);
ia64_set_rr(0x6000000000000000, rr3);
ia64_set_rr(0x8000000000000000, rr4);
ia64_insn_group_barrier();
ia64_srlz_i(); /* srlz.i implies srlz.d */
ia64_insn_group_barrier();
}
/*
* Switch from address space PREV to address space NEXT.
*/
static inline void
activate_mm (struct mm_struct *prev, struct mm_struct *next)
{
/*
* We may get interrupts here, but that's OK because interrupt
* handlers cannot touch user-space.
*/
ia64_set_kr(IA64_KR_PT_BASE, __pa(next->pgd));
get_mmu_context(next);
reload_context(next);
}
#define switch_mm(prev_mm,next_mm,next_task,cpu) activate_mm(prev_mm, next_mm)
# endif /* ! __ASSEMBLY__ */
#endif /* _ASM_IA64_MMU_CONTEXT_H */
|