text: /*
   * This file contains the routines for TLB flushing.
   * On machines where the MMU uses a hash table to store virtual to
   * physical translations, these routines flush entries from the
   * hash table also.
   *  -- paulus
   *
   *  Derived from arch/ppc/mm/init.c:
   *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   *
   *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
   *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
   *    Copyright (C) 1996 Paul Mackerras
   *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
   *
   *  Derived from "arch/i386/mm/init.c"
   *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   *
   *  This program is free software; you can redistribute it and/or
   *  modify it under the terms of the GNU General Public License
   *  as published by the Free Software Foundation; either version
   *  2 of the License, or (at your option) any later version.
   *
   */
  
  #include <linux/config.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/init.h>
  #include <asm/mmu.h>
  #include "mmu_decl.h"
  
  /*
   * TLB flushing:
   *
   *  - flush_tlb_all() flushes all processes TLBs
   *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
   *  - flush_tlb_page(vma, vmaddr) flushes one page
   *  - flush_tlb_range(mm, start, end) flushes a range of pages
   *
   * since the hardware hash table functions as an extension of the
   * tlb as far as the linux tables are concerned, flush it too.
   *    -- Cort
   */
  
  /*
   * Flush all tlb/hash table entries (except perhaps for those
   * mapping RAM starting at PAGE_OFFSET, since they never change).
   */
  void
  local_flush_tlb_all(void)
  {
  	/* aargh!!! */
  	/*
  	 * Just flush the kernel part of the address space, that's
  	 * all that the current callers of this require.
  	 * Eventually I hope to persuade the powers that be that
  	 * we can and should dispense with flush_tlb_all().
  	 *  -- paulus.
  	 */
  	local_flush_tlb_range(&init_mm, TASK_SIZE, ~0UL);
  
  #ifdef CONFIG_SMP
  	smp_send_tlb_invalidate(0);
  #endif /* CONFIG_SMP */
  }
  
  /*
   * Flush all the (user) entries for the address space described
   * by mm.  We can't rely on mm->mmap describing all the entries
   * that might be in the hash table.
   */
  void
  local_flush_tlb_mm(struct mm_struct *mm)
  {
  	if (Hash == 0) {
  		_tlbia();
  		return;
  	}
  
  	if (mm->map_count) {
  		struct vm_area_struct *mp;
  		for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
  			local_flush_tlb_range(mm, mp->vm_start, mp->vm_end);
  	} else
  		local_flush_tlb_range(mm, 0, TASK_SIZE);
  
  #ifdef CONFIG_SMP
  	smp_send_tlb_invalidate(0);
  #endif
  }
  
  void
  local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
  {
  	struct mm_struct *mm;
  	pmd_t *pmd;
  	pte_t *pte;
  
  	if (Hash == 0) {
  		_tlbie(vmaddr);
  		return;
  	}
  	mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
  	pmd = pmd_offset(pgd_offset(mm, vmaddr), vmaddr);
  	if (!pmd_none(*pmd)) {
  		pte = pte_offset(pmd, vmaddr);
  		if (pte_val(*pte) & _PAGE_HASHPTE)
  			flush_hash_page(mm->context, vmaddr, pte);
  	}
  #ifdef CONFIG_SMP
  	smp_send_tlb_invalidate(0);
  #endif
  }
  
  
  /*
   * For each address in the range, find the pte for the address
   * and check _PAGE_HASHPTE bit; if it is set, find and destroy
   * the corresponding HPTE.
   */
  void
  local_flush_tlb_range(struct mm_struct *mm, unsigned long start, unsigned long end)
  {
  	pmd_t *pmd;
  	pte_t *pte;
  	unsigned long pmd_end;
  	unsigned int ctx = mm->context;
  
  	if (Hash == 0) {
  		_tlbia();
  		return;
  	}
  	start &= PAGE_MASK;
  	if (start >= end)
  		return;
  	pmd = pmd_offset(pgd_offset(mm, start), start);
  	do {
  		pmd_end = (start + PGDIR_SIZE) & PGDIR_MASK;
  		if (!pmd_none(*pmd)) {
  			if (!pmd_end || pmd_end > end)
  				pmd_end = end;
  			pte = pte_offset(pmd, start);
  			do {
  				if ((pte_val(*pte) & _PAGE_HASHPTE) != 0)
  					flush_hash_page(ctx, start, pte);
  				start += PAGE_SIZE;
  				++pte;
  			} while (start && start < pmd_end);
  		} else {
  			start = pmd_end;
  		}
  		++pmd;
  	} while (start && start < end);
  
  #ifdef CONFIG_SMP
  	smp_send_tlb_invalidate(0);
  #endif
  }
  