pgalloc.h

嵌入式系统设计与实验教材二源码linux内核移植与编译

#ifndef _ALPHA_PGALLOC_H
#define _ALPHA_PGALLOC_H

#include <linux/config.h>

#ifndef __EXTERN_INLINE
#define __EXTERN_INLINE extern inline
#define __MMU_EXTERN_INLINE
#endif

extern void __load_new_mm_context(struct mm_struct *);


/* Caches aren't brain-dead on the Alpha. */
#define flush_cache_all()			do { } while (0)
#define flush_cache_mm(mm)			do { } while (0)
#define flush_cache_range(mm, start, end)	do { } while (0)
#define flush_cache_page(vma, vmaddr)		do { } while (0)
#define flush_page_to_ram(page)			do { } while (0)
#define flush_dcache_page(page)			do { } while (0)

/* Note that the following two definitions are _highly_ dependent
   on the contexts in which they are used in the kernel.  I personally
   think it is criminal how loosely defined these macros are.  */

/* We need to flush the kernel's icache after loading modules.  The
   only other use of this macro is in load_aout_interp which is not
   used on Alpha. 

   Note that this definition should *not* be used for userspace
   icache flushing.  While functional, it is _way_ overkill.  The
   icache is tagged with ASNs and it suffices to allocate a new ASN
   for the process.  */
#ifndef CONFIG_SMP
#define flush_icache_range(start, end)		imb()
#else
#define flush_icache_range(start, end)		smp_imb()
extern void smp_imb(void);
#endif


/*
 * Use a few helper functions to hide the ugly broken ASN
 * numbers on early Alphas (ev4 and ev45)
 */

__EXTERN_INLINE void
ev4_flush_tlb_current(struct mm_struct *mm)
{
	__load_new_mm_context(mm);
	tbiap();
}

__EXTERN_INLINE void
ev5_flush_tlb_current(struct mm_struct *mm)
{
	__load_new_mm_context(mm);
}

static inline void
flush_tlb_other(struct mm_struct *mm)
{
	long * mmc = &mm->context[smp_processor_id()];
	/*
	 * Check it's not zero first to avoid cacheline ping pong when
	 * possible.
	 */
	if (*mmc)
		*mmc = 0;
}

/* We need to flush the userspace icache after setting breakpoints in
   ptrace.  I don't think it's needed in do_swap_page, or do_no_page,
   but I don't know how to get rid of it either.

   Instead of indiscriminately using imb, take advantage of the fact
   that icache entries are tagged with the ASN and load a new mm context.  */
/* ??? Ought to use this in arch/alpha/kernel/signal.c too.  */

#ifndef CONFIG_SMP
static inline void
flush_icache_page(struct vm_area_struct *vma, struct page *page)
{
	if (vma->vm_flags & VM_EXEC) {
		struct mm_struct *mm = vma->vm_mm;
		if (current->active_mm == mm)
			__load_new_mm_context(mm);
		else
			mm->context[smp_processor_id()] = 0;
	}
}
#else
extern void flush_icache_page(struct vm_area_struct *vma, struct page *page);
#endif

/*
 * Flush just one page in the current TLB set.
 * We need to be very careful about the icache here, there
 * is no way to invalidate a specific icache page..
 */

__EXTERN_INLINE void
ev4_flush_tlb_current_page(struct mm_struct * mm,
			   struct vm_area_struct *vma,
			   unsigned long addr)
{
	int tbi_flag = 2;
	if (vma->vm_flags & VM_EXEC) {
		__load_new_mm_context(mm);
		tbi_flag = 3;
	}
	tbi(tbi_flag, addr);
}

__EXTERN_INLINE void
ev5_flush_tlb_current_page(struct mm_struct * mm,
			   struct vm_area_struct *vma,
			   unsigned long addr)
{
	if (vma->vm_flags & VM_EXEC)
		__load_new_mm_context(mm);
	else
		tbi(2, addr);
}


#ifdef CONFIG_ALPHA_GENERIC
# define flush_tlb_current		alpha_mv.mv_flush_tlb_current
# define flush_tlb_current_page		alpha_mv.mv_flush_tlb_current_page
#else
# ifdef CONFIG_ALPHA_EV4
#  define flush_tlb_current		ev4_flush_tlb_current
#  define flush_tlb_current_page	ev4_flush_tlb_current_page
# else
#  define flush_tlb_current		ev5_flush_tlb_current
#  define flush_tlb_current_page	ev5_flush_tlb_current_page
# endif
#endif

#ifdef __MMU_EXTERN_INLINE
#undef __EXTERN_INLINE
#undef __MMU_EXTERN_INLINE
#endif

/*
 * Flush current user mapping.
 */
static inline void flush_tlb(void)
{
	flush_tlb_current(current->active_mm);
}

/*
 * Flush a specified range of user mapping page tables
 * from TLB.
 * Although Alpha uses VPTE caches, this can be a nop, as Alpha does
 * not have finegrained tlb flushing, so it will flush VPTE stuff
 * during next flush_tlb_range.
 */
static inline void flush_tlb_pgtables(struct mm_struct *mm,
	unsigned long start, unsigned long end)
{
}

#ifndef CONFIG_SMP
/*
 * Flush everything (kernel mapping may also have
 * changed due to vmalloc/vfree)
 */
static inline void flush_tlb_all(void)
{
	tbia();
}

/*
 * Flush a specified user mapping
 */
static inline void flush_tlb_mm(struct mm_struct *mm)
{
	if (mm == current->active_mm)
		flush_tlb_current(mm);
	else
		flush_tlb_other(mm);
}

/*
 * Page-granular tlb flush.
 *
 * do a tbisd (type = 2) normally, and a tbis (type = 3)
 * if it is an executable mapping.  We want to avoid the
 * itlb flush, because that potentially also does a
 * icache flush.
 */
static inline void flush_tlb_page(struct vm_area_struct *vma,
	unsigned long addr)
{
	struct mm_struct * mm = vma->vm_mm;

	if (mm == current->active_mm)
		flush_tlb_current_page(mm, vma, addr);
	else
		flush_tlb_other(mm);
}

/*
 * Flush a specified range of user mapping:  on the
 * Alpha we flush the whole user tlb.
 */
static inline void flush_tlb_range(struct mm_struct *mm,
	unsigned long start, unsigned long end)
{
	flush_tlb_mm(mm);
}

#else /* CONFIG_SMP */

extern void flush_tlb_all(void);
extern void flush_tlb_mm(struct mm_struct *);
extern void flush_tlb_page(struct vm_area_struct *, unsigned long);
extern void flush_tlb_range(struct mm_struct *, unsigned long, unsigned long);

#endif /* CONFIG_SMP */

/*      
 * Allocate and free page tables. The xxx_kernel() versions are
 * used to allocate a kernel page table - this turns on ASN bits
 * if any.
 */
#ifndef CONFIG_SMP
extern struct pgtable_cache_struct {
	unsigned long *pgd_cache;
	unsigned long *pmd_cache;
	unsigned long *pte_cache;
	unsigned long pgtable_cache_sz;
} quicklists;
#else
#include <asm/smp.h>
#define quicklists cpu_data[smp_processor_id()]
#endif
#define pgd_quicklist (quicklists.pgd_cache)
#define pmd_quicklist (quicklists.pmd_cache)
#define pte_quicklist (quicklists.pte_cache)
#define pgtable_cache_size (quicklists.pgtable_cache_sz)

#define pmd_populate(mm, pmd, pte)	pmd_set(pmd, pte)
#define pgd_populate(mm, pgd, pmd)	pgd_set(pgd, pmd)

extern pgd_t *get_pgd_slow(void);

static inline pgd_t *get_pgd_fast(void)
{
	unsigned long *ret;

	if ((ret = pgd_quicklist) != NULL) {
		pgd_quicklist = (unsigned long *)(*ret);
		ret[0] = 0;
		pgtable_cache_size--;
	} else
		ret = (unsigned long *)get_pgd_slow();
	return (pgd_t *)ret;
}

static inline void free_pgd_fast(pgd_t *pgd)
{
	*(unsigned long *)pgd = (unsigned long) pgd_quicklist;
	pgd_quicklist = (unsigned long *) pgd;
	pgtable_cache_size++;
}

static inline void free_pgd_slow(pgd_t *pgd)
{
	free_page((unsigned long)pgd);
}

static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
{
	pmd_t *ret = (pmd_t *)__get_free_page(GFP_KERNEL);
	if (ret)
		clear_page(ret);
	return ret;
}

static inline pmd_t *pmd_alloc_one_fast(struct mm_struct *mm, unsigned long address)
{
	unsigned long *ret;

	if ((ret = (unsigned long *)pte_quicklist) != NULL) {
		pte_quicklist = (unsigned long *)(*ret);
		ret[0] = 0;
		pgtable_cache_size--;
	}
	return (pmd_t *)ret;
}

static inline void pmd_free_fast(pmd_t *pmd)
{
	*(unsigned long *)pmd = (unsigned long) pte_quicklist;
	pte_quicklist = (unsigned long *) pmd;
	pgtable_cache_size++;
}

static inline void pmd_free_slow(pmd_t *pmd)
{
	free_page((unsigned long)pmd);
}

static inline pte_t *pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
	pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL);
	if (pte)
		clear_page(pte);
	return pte;
}

static inline pte_t *pte_alloc_one_fast(struct mm_struct *mm, unsigned long address)
{
	unsigned long *ret;

	if ((ret = (unsigned long *)pte_quicklist) != NULL) {
		pte_quicklist = (unsigned long *)(*ret);
		ret[0] = 0;
		pgtable_cache_size--;
	}
	return (pte_t *)ret;
}

static inline void pte_free_fast(pte_t *pte)
{
	*(unsigned long *)pte = (unsigned long) pte_quicklist;
	pte_quicklist = (unsigned long *) pte;
	pgtable_cache_size++;
}

static inline void pte_free_slow(pte_t *pte)
{
	free_page((unsigned long)pte);
}

#define pte_free(pte)		pte_free_fast(pte)
#define pmd_free(pmd)		pmd_free_fast(pmd)
#define pgd_free(pgd)		free_pgd_fast(pgd)
#define pgd_alloc(mm)		get_pgd_fast()

extern int do_check_pgt_cache(int, int);

#endif /* _ALPHA_PGALLOC_H */