[deliverable/linux.git] / include / asm-generic / tlb.h

/* asm-generic/tlb.h
 *
 *	Generic TLB shootdown code
 *
 * Copyright 2001 Red Hat, Inc.
 * Based on code from mm/memory.c Copyright Linus Torvalds and others.
 *
 * 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.
 */
#ifndef _ASM_GENERIC__TLB_H
#define _ASM_GENERIC__TLB_H

#include <linux/config.h>
#include <linux/swap.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>

/*
 * For UP we don't need to worry about TLB flush
 * and page free order so much..
 */
#ifdef CONFIG_SMP
  #ifdef ARCH_FREE_PTR_NR
    #define FREE_PTR_NR   ARCH_FREE_PTR_NR
  #else
    #define FREE_PTE_NR	506
  #endif
  #define tlb_fast_mode(tlb) ((tlb)->nr == ~0U)
#else
  #define FREE_PTE_NR	1
  #define tlb_fast_mode(tlb) 1
#endif

/* struct mmu_gather is an opaque type used by the mm code for passing around
 * any data needed by arch specific code for tlb_remove_page.  This structure
 * can be per-CPU or per-MM as the page table lock is held for the duration of
 * TLB shootdown.
 */
struct mmu_gather {
	struct mm_struct	*mm;
	unsigned int		nr;	/* set to ~0U means fast mode */
	unsigned int		need_flush;/* Really unmapped some ptes? */
	unsigned int		fullmm; /* non-zero means full mm flush */
	unsigned long		freed;
	struct page *		pages[FREE_PTE_NR];
};

/* Users of the generic TLB shootdown code must declare this storage space. */
DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);

/* tlb_gather_mmu
 *	Return a pointer to an initialized struct mmu_gather.
 */
static inline struct mmu_gather *
tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
{
	struct mmu_gather *tlb = &per_cpu(mmu_gathers, smp_processor_id());

	tlb->mm = mm;

	/* Use fast mode if only one CPU is online */
	tlb->nr = num_online_cpus() > 1 ? 0U : ~0U;

	tlb->fullmm = full_mm_flush;
	tlb->freed = 0;

	return tlb;
}

static inline void
tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
	if (!tlb->need_flush)
		return;
	tlb->need_flush = 0;
	tlb_flush(tlb);
	if (!tlb_fast_mode(tlb)) {
		free_pages_and_swap_cache(tlb->pages, tlb->nr);
		tlb->nr = 0;
	}
}

/* tlb_finish_mmu
 *	Called at the end of the shootdown operation to free up any resources
 *	that were required.  The page table lock is still held at this point.
 */
static inline void
tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
	int freed = tlb->freed;
	struct mm_struct *mm = tlb->mm;
	int rss = get_mm_counter(mm, rss);

	if (rss < freed)
		freed = rss;
	add_mm_counter(mm, rss, -freed);
	tlb_flush_mmu(tlb, start, end);

	/* keep the page table cache within bounds */
	check_pgt_cache();
}

static inline unsigned int
tlb_is_full_mm(struct mmu_gather *tlb)
{
	return tlb->fullmm;
}

/* tlb_remove_page
 *	Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
 *	handling the additional races in SMP caused by other CPUs caching valid
 *	mappings in their TLBs.
 */
static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
	tlb->need_flush = 1;
	if (tlb_fast_mode(tlb)) {
		free_page_and_swap_cache(page);
		return;
	}
	tlb->pages[tlb->nr++] = page;
	if (tlb->nr >= FREE_PTE_NR)
		tlb_flush_mmu(tlb, 0, 0);
}

/**
 * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
 *
 * Record the fact that pte's were really umapped in ->need_flush, so we can
 * later optimise away the tlb invalidate.   This helps when userspace is
 * unmapping already-unmapped pages, which happens quite a lot.
 */
#define tlb_remove_tlb_entry(tlb, ptep, address)		\
	do {							\
		tlb->need_flush = 1;				\
		__tlb_remove_tlb_entry(tlb, ptep, address);	\
	} while (0)

#define pte_free_tlb(tlb, ptep)					\
	do {							\
		tlb->need_flush = 1;				\
		__pte_free_tlb(tlb, ptep);			\
	} while (0)

#ifndef __ARCH_HAS_4LEVEL_HACK
#define pud_free_tlb(tlb, pudp)					\
	do {							\
		tlb->need_flush = 1;				\
		__pud_free_tlb(tlb, pudp);			\
	} while (0)
#endif

#define pmd_free_tlb(tlb, pmdp)					\
	do {							\
		tlb->need_flush = 1;				\
		__pmd_free_tlb(tlb, pmdp);			\
	} while (0)

#define tlb_migrate_finish(mm) do {} while (0)

#endif /* _ASM_GENERIC__TLB_H */
Commit	Line	Data
1da177e4 LT	1	/* asm-generic/tlb.h
	2	*
	3	* Generic TLB shootdown code
	4	*
	5	* Copyright 2001 Red Hat, Inc.
	6	* Based on code from mm/memory.c Copyright Linus Torvalds and others.
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*/
	13	#ifndef _ASM_GENERIC__TLB_H
	14	#define _ASM_GENERIC__TLB_H
	15
	16	#include <linux/config.h>
	17	#include <linux/swap.h>
	18	#include <asm/pgalloc.h>
	19	#include <asm/tlbflush.h>
	20
	21	/*
	22	* For UP we don't need to worry about TLB flush
	23	* and page free order so much..
	24	*/
	25	#ifdef CONFIG_SMP
2b4a0815 AK	26	#ifdef ARCH_FREE_PTR_NR
	27	#define FREE_PTR_NR ARCH_FREE_PTR_NR
	28	#else
	29	#define FREE_PTE_NR 506
	30	#endif
1da177e4 LT	31	#define tlb_fast_mode(tlb) ((tlb)->nr == ~0U)
	32	#else
	33	#define FREE_PTE_NR 1
	34	#define tlb_fast_mode(tlb) 1
	35	#endif
	36
	37	/* struct mmu_gather is an opaque type used by the mm code for passing around
	38	* any data needed by arch specific code for tlb_remove_page. This structure
	39	* can be per-CPU or per-MM as the page table lock is held for the duration of
	40	* TLB shootdown.
	41	*/
	42	struct mmu_gather {
	43	struct mm_struct *mm;
	44	unsigned int nr; /* set to ~0U means fast mode */
	45	unsigned int need_flush;/* Really unmapped some ptes? */
	46	unsigned int fullmm; /* non-zero means full mm flush */
	47	unsigned long freed;
	48	struct page * pages[FREE_PTE_NR];
	49	};
	50
	51	/* Users of the generic TLB shootdown code must declare this storage space. */
	52	DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
	53
	54	/* tlb_gather_mmu
	55	* Return a pointer to an initialized struct mmu_gather.
	56	*/
	57	static inline struct mmu_gather *
	58	tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
	59	{
	60	struct mmu_gather *tlb = &per_cpu(mmu_gathers, smp_processor_id());
	61
	62	tlb->mm = mm;
	63
	64	/* Use fast mode if only one CPU is online */
	65	tlb->nr = num_online_cpus() > 1 ? 0U : ~0U;
	66
	67	tlb->fullmm = full_mm_flush;
	68	tlb->freed = 0;
	69
	70	return tlb;
	71	}
	72
	73	static inline void
	74	tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
	75	{
	76	if (!tlb->need_flush)
	77	return;
	78	tlb->need_flush = 0;
	79	tlb_flush(tlb);
	80	if (!tlb_fast_mode(tlb)) {
	81	free_pages_and_swap_cache(tlb->pages, tlb->nr);
	82	tlb->nr = 0;
	83	}
	84	}
	85
	86	/* tlb_finish_mmu
	87	* Called at the end of the shootdown operation to free up any resources
	88	* that were required. The page table lock is still held at this point.
	89	*/
	90	static inline void
	91	tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
	92	{
	93	int freed = tlb->freed;
	94	struct mm_struct *mm = tlb->mm;
95	int rss = get_mm_counter(mm, rss);
96
97	if (rss < freed)
98	freed = rss;
99	add_mm_counter(mm, rss, -freed);
100	tlb_flush_mmu(tlb, start, end);
101
102	/* keep the page table cache within bounds */
103	check_pgt_cache();
104	}
105
106	static inline unsigned int
107	tlb_is_full_mm(struct mmu_gather *tlb)
108	{
109	return tlb->fullmm;
110	}
111
112	/* tlb_remove_page
113	* Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
114	* handling the additional races in SMP caused by other CPUs caching valid
115	* mappings in their TLBs.
116	*/
117	static inline void tlb_remove_page(struct mmu_gather tlb, struct page page)
118	{
119	tlb->need_flush = 1;
120	if (tlb_fast_mode(tlb)) {
121	free_page_and_swap_cache(page);
122	return;
123	}
124	tlb->pages[tlb->nr++] = page;
125	if (tlb->nr >= FREE_PTE_NR)
126	tlb_flush_mmu(tlb, 0, 0);
127	}
128
129	/**
130	* tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
131	*
132	* Record the fact that pte's were really umapped in ->need_flush, so we can
133	* later optimise away the tlb invalidate. This helps when userspace is
134	* unmapping already-unmapped pages, which happens quite a lot.
135	*/
136	#define tlb_remove_tlb_entry(tlb, ptep, address) \
137	do { \
138	tlb->need_flush = 1; \
139	__tlb_remove_tlb_entry(tlb, ptep, address); \
140	} while (0)
141
142	#define pte_free_tlb(tlb, ptep) \
143	do { \
144	tlb->need_flush = 1; \
145	__pte_free_tlb(tlb, ptep); \
146	} while (0)
147
148	#ifndef __ARCH_HAS_4LEVEL_HACK
149	#define pud_free_tlb(tlb, pudp) \
150	do { \
151	tlb->need_flush = 1; \
152	__pud_free_tlb(tlb, pudp); \
153	} while (0)
154	#endif
155
156	#define pmd_free_tlb(tlb, pmdp) \
157	do { \
158	tlb->need_flush = 1; \
159	__pmd_free_tlb(tlb, pmdp); \
160	} while (0)
161
162	#define tlb_migrate_finish(mm) do {} while (0)
163
164	#endif /* _ASM_GENERIC__TLB_H */