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kernel/linux-rt-4.4.41/arch/sh/mm/kmap.c 1.66 KB
5113f6f70   김현기   kernel add
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  /*
   * arch/sh/mm/kmap.c
   *
   * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
   * Copyright (C) 2002 - 2009  Paul Mundt
   *
   * Released under the terms of the GNU GPL v2.0.
   */
  #include <linux/mm.h>
  #include <linux/init.h>
  #include <linux/mutex.h>
  #include <linux/fs.h>
  #include <linux/highmem.h>
  #include <linux/module.h>
  #include <asm/mmu_context.h>
  #include <asm/cacheflush.h>
  
  #define kmap_get_fixmap_pte(vaddr)                                     \
  	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
  
  static pte_t *kmap_coherent_pte;
  
  void __init kmap_coherent_init(void)
  {
  	unsigned long vaddr;
  
  	/* cache the first coherent kmap pte */
  	vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
  	kmap_coherent_pte = kmap_get_fixmap_pte(vaddr);
  }
  
  void *kmap_coherent(struct page *page, unsigned long addr)
  {
  	enum fixed_addresses idx;
  	unsigned long vaddr;
  
  	BUG_ON(!test_bit(PG_dcache_clean, &page->flags));
  
  	preempt_disable();
  	pagefault_disable();
  
  	idx = FIX_CMAP_END -
  		(((addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1)) +
  		 (FIX_N_COLOURS * smp_processor_id()));
  
  	vaddr = __fix_to_virt(idx);
  
  	BUG_ON(!pte_none(*(kmap_coherent_pte - idx)));
  	set_pte(kmap_coherent_pte - idx, mk_pte(page, PAGE_KERNEL));
  
  	return (void *)vaddr;
  }
  
  void kunmap_coherent(void *kvaddr)
  {
  	if (kvaddr >= (void *)FIXADDR_START) {
  		unsigned long vaddr = (unsigned long)kvaddr & PAGE_MASK;
  		enum fixed_addresses idx = __virt_to_fix(vaddr);
  
  		/* XXX.. Kill this later, here for sanity at the moment.. */
  		__flush_purge_region((void *)vaddr, PAGE_SIZE);
  
  		pte_clear(&init_mm, vaddr, kmap_coherent_pte - idx);
  		local_flush_tlb_one(get_asid(), vaddr);
  	}
  
  	pagefault_enable();
  	preempt_enable();
  }