[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / asm-generic / tlb.h

/* include/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.
 *
 * Copyright 2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
 *
 * 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/swap.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>

#ifdef CONFIG_HAVE_RCU_TABLE_FREE
/*
 * Semi RCU freeing of the page directories.
 *
 * This is needed by some architectures to implement software pagetable walkers.
 *
 * gup_fast() and other software pagetable walkers do a lockless page-table
 * walk and therefore needs some synchronization with the freeing of the page
 * directories. The chosen means to accomplish that is by disabling IRQs over
 * the walk.
 *
 * Architectures that use IPIs to flush TLBs will then automagically DTRT,
 * since we unlink the page, flush TLBs, free the page. Since the disabling of
 * IRQs delays the completion of the TLB flush we can never observe an already
 * freed page.
 *
 * Architectures that do not have this (PPC) need to delay the freeing by some
 * other means, this is that means.
 *
 * What we do is batch the freed directory pages (tables) and RCU free them.
 * We use the sched RCU variant, as that guarantees that IRQ/preempt disabling
 * holds off grace periods.
 *
 * However, in order to batch these pages we need to allocate storage, this
 * allocation is deep inside the MM code and can thus easily fail on memory
 * pressure. To guarantee progress we fall back to single table freeing, see
 * the implementation of tlb_remove_table_one().
 *
 */
struct mmu_table_batch {
	struct rcu_head		rcu;
	unsigned int		nr;
	void			*tables[0];
};

#define MAX_TABLE_BATCH		\
	((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))

extern void tlb_table_flush(struct mmu_gather *tlb);
extern void tlb_remove_table(struct mmu_gather *tlb, void *table);

#endif

/*
 * If we can't allocate a page to make a big batch of page pointers
 * to work on, then just handle a few from the on-stack structure.
 */
#define MMU_GATHER_BUNDLE	8

struct mmu_gather_batch {
	struct mmu_gather_batch	*next;
	unsigned int		nr;
	unsigned int		max;
	struct page		*pages[0];
};

#define MAX_GATHER_BATCH	\
	((PAGE_SIZE - sizeof(struct mmu_gather_batch)) / sizeof(void *))

/* 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.
 */
struct mmu_gather {
	struct mm_struct	*mm;
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
	struct mmu_table_batch	*batch;
#endif
	unsigned long		start;
	unsigned long		end;
	unsigned int		need_flush : 1,	/* Did free PTEs */
				fast_mode  : 1; /* No batching   */

	unsigned int		fullmm;

	struct mmu_gather_batch *active;
	struct mmu_gather_batch	local;
	struct page		*__pages[MMU_GATHER_BUNDLE];
};

#define HAVE_GENERIC_MMU_GATHER

static inline int tlb_fast_mode(struct mmu_gather *tlb)
{
#ifdef CONFIG_SMP
	return tlb->fast_mode;
#else
	/*
	 * For UP we don't need to worry about TLB flush
	 * and page free order so much..
	 */
	return 1;
#endif
}

void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm);
void tlb_flush_mmu(struct mmu_gather *tlb);
void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start,
							unsigned long end);
int __tlb_remove_page(struct mmu_gather *tlb, struct page *page);

/* tlb_remove_page
 *	Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
 *	required.
 */
static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
	if (!__tlb_remove_page(tlb, page))
		tlb_flush_mmu(tlb);
}

/**
 * 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)

/**
 * tlb_remove_pmd_tlb_entry - remember a pmd mapping for later tlb invalidation
 * This is a nop so far, because only x86 needs it.
 */
#ifndef __tlb_remove_pmd_tlb_entry
#define __tlb_remove_pmd_tlb_entry(tlb, pmdp, address) do {} while (0)
#endif

#define tlb_remove_pmd_tlb_entry(tlb, pmdp, address)		\
	do {							\
		tlb->need_flush = 1;				\
		__tlb_remove_pmd_tlb_entry(tlb, pmdp, address);	\
	} while (0)

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

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

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

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

#endif /* _ASM_GENERIC__TLB_H */
Commit	Line	Data
f30c2269	1	/* include/asm-generic/tlb.h
1da177e4 LT	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	*
d16dfc55 PZ	8	* Copyright 2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
d16dfc55 PZ	9	*
1da177e4 LT	10	* This program is free software; you can redistribute it and/or
	11	* modify it under the terms of the GNU General Public License
	12	* as published by the Free Software Foundation; either version
	13	* 2 of the License, or (at your option) any later version.
	14	*/
	15	#ifndef _ASM_GENERIC__TLB_H
	16	#define _ASM_GENERIC__TLB_H
	17
1da177e4	18	#include <linux/swap.h>
62152d0e	19	#include <asm/pgalloc.h>
1da177e4 LT	20	#include <asm/tlbflush.h>
1da177e4 LT	21
26723911 PZ	22	#ifdef CONFIG_HAVE_RCU_TABLE_FREE
	23	/*
	24	* Semi RCU freeing of the page directories.
	25	*
	26	* This is needed by some architectures to implement software pagetable walkers.
	27	*
	28	* gup_fast() and other software pagetable walkers do a lockless page-table
	29	* walk and therefore needs some synchronization with the freeing of the page
	30	* directories. The chosen means to accomplish that is by disabling IRQs over
	31	* the walk.
	32	*
	33	* Architectures that use IPIs to flush TLBs will then automagically DTRT,
	34	* since we unlink the page, flush TLBs, free the page. Since the disabling of
	35	* IRQs delays the completion of the TLB flush we can never observe an already
	36	* freed page.
	37	*
	38	* Architectures that do not have this (PPC) need to delay the freeing by some
	39	* other means, this is that means.
	40	*
	41	* What we do is batch the freed directory pages (tables) and RCU free them.
	42	* We use the sched RCU variant, as that guarantees that IRQ/preempt disabling
	43	* holds off grace periods.
	44	*
	45	* However, in order to batch these pages we need to allocate storage, this
	46	* allocation is deep inside the MM code and can thus easily fail on memory
	47	* pressure. To guarantee progress we fall back to single table freeing, see
	48	* the implementation of tlb_remove_table_one().
	49	*
	50	*/
	51	struct mmu_table_batch {
	52	struct rcu_head rcu;
	53	unsigned int nr;
	54	void *tables[0];
	55	};
	56
	57	#define MAX_TABLE_BATCH \
	58	((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
	59
	60	extern void tlb_table_flush(struct mmu_gather *tlb);
	61	extern void tlb_remove_table(struct mmu_gather tlb, void table);
	62
	63	#endif
	64
d16dfc55 PZ	65	/*
	66	* If we can't allocate a page to make a big batch of page pointers
	67	* to work on, then just handle a few from the on-stack structure.
	68	*/
	69	#define MMU_GATHER_BUNDLE 8
	70
e303297e PZ	71	struct mmu_gather_batch {
	72	struct mmu_gather_batch *next;
	73	unsigned int nr;
	74	unsigned int max;
	75	struct page *pages[0];
	76	};
	77
	78	#define MAX_GATHER_BATCH \
	79	((PAGE_SIZE - sizeof(struct mmu_gather_batch)) / sizeof(void *))
	80
1da177e4	81	/* struct mmu_gather is an opaque type used by the mm code for passing around
15a23ffa	82	* any data needed by arch specific code for tlb_remove_page.
1da177e4 LT	83	*/
	84	struct mmu_gather {
	85	struct mm_struct *mm;
26723911 PZ	86	#ifdef CONFIG_HAVE_RCU_TABLE_FREE
	87	struct mmu_table_batch *batch;
	88	#endif
597e1c35 AS	89	unsigned long start;
597e1c35 AS	90	unsigned long end;
e303297e PZ	91	unsigned int need_flush : 1, /* Did free PTEs */
	92	fast_mode : 1; /* No batching */
	93
	94	unsigned int fullmm;
	95
	96	struct mmu_gather_batch *active;
	97	struct mmu_gather_batch local;
	98	struct page *__pages[MMU_GATHER_BUNDLE];
1da177e4 LT	99	};
1da177e4 LT	100
9547d01b	101	#define HAVE_GENERIC_MMU_GATHER
e303297e	102
9547d01b	103	static inline int tlb_fast_mode(struct mmu_gather *tlb)
d16dfc55	104	{
9547d01b PZ	105	#ifdef CONFIG_SMP
	106	return tlb->fast_mode;
	107	#else
	108	/*
	109	* For UP we don't need to worry about TLB flush
	110	* and page free order so much..
	111	*/
e303297e	112	return 1;
d16dfc55	113	#endif
1da177e4 LT	114	}
1da177e4 LT	115
9547d01b PZ	116	void tlb_gather_mmu(struct mmu_gather tlb, struct mm_struct mm, bool fullmm);
9547d01b PZ	117	void tlb_flush_mmu(struct mmu_gather *tlb);
c4211f42 AS	118	void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start,
c4211f42 AS	119	unsigned long end);
9547d01b	120	int __tlb_remove_page(struct mmu_gather tlb, struct page page);
d16dfc55 PZ	121
	122	/* tlb_remove_page
	123	* Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
	124	* required.
	125	*/
	126	static inline void tlb_remove_page(struct mmu_gather tlb, struct page page)
	127	{
	128	if (!__tlb_remove_page(tlb, page))
	129	tlb_flush_mmu(tlb);
1da177e4 LT	130	}
	131
	132	/**
	133	* tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
	134	*
	135	* Record the fact that pte's were really umapped in ->need_flush, so we can
	136	* later optimise away the tlb invalidate. This helps when userspace is
	137	* unmapping already-unmapped pages, which happens quite a lot.
	138	*/
	139	#define tlb_remove_tlb_entry(tlb, ptep, address) \
	140	do { \
	141	tlb->need_flush = 1; \
	142	__tlb_remove_tlb_entry(tlb, ptep, address); \
	143	} while (0)
	144
f21760b1 SL	145	/**
	146	* tlb_remove_pmd_tlb_entry - remember a pmd mapping for later tlb invalidation
	147	* This is a nop so far, because only x86 needs it.
	148	*/
	149	#ifndef __tlb_remove_pmd_tlb_entry
	150	#define __tlb_remove_pmd_tlb_entry(tlb, pmdp, address) do {} while (0)
	151	#endif
	152
	153	#define tlb_remove_pmd_tlb_entry(tlb, pmdp, address) \
	154	do { \
	155	tlb->need_flush = 1; \
	156	__tlb_remove_pmd_tlb_entry(tlb, pmdp, address); \
	157	} while (0)
	158
9e1b32ca	159	#define pte_free_tlb(tlb, ptep, address) \
1da177e4 LT	160	do { \
1da177e4 LT	161	tlb->need_flush = 1; \
9e1b32ca	162	__pte_free_tlb(tlb, ptep, address); \
1da177e4 LT	163	} while (0)
	164
	165	#ifndef __ARCH_HAS_4LEVEL_HACK
9e1b32ca	166	#define pud_free_tlb(tlb, pudp, address) \
1da177e4 LT	167	do { \
1da177e4 LT	168	tlb->need_flush = 1; \
9e1b32ca	169	__pud_free_tlb(tlb, pudp, address); \
1da177e4 LT	170	} while (0)
	171	#endif
	172
9e1b32ca	173	#define pmd_free_tlb(tlb, pmdp, address) \
1da177e4 LT	174	do { \
1da177e4 LT	175	tlb->need_flush = 1; \
9e1b32ca	176	__pmd_free_tlb(tlb, pmdp, address); \
1da177e4 LT	177	} while (0)
	178
	179	#define tlb_migrate_finish(mm) do {} while (0)
	180
	181	#endif /* _ASM_GENERIC__TLB_H */