[mirror_ubuntu-artful-kernel.git] / arch / s390 / mm / pgalloc.c

/*
 *  Page table allocation functions
 *
 *    Copyright IBM Corp. 2016
 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/mm.h>
#include <linux/sysctl.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>
#include <asm/gmap.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>

#ifdef CONFIG_PGSTE

static int page_table_allocate_pgste_min = 0;
static int page_table_allocate_pgste_max = 1;
int page_table_allocate_pgste = 0;
EXPORT_SYMBOL(page_table_allocate_pgste);

static struct ctl_table page_table_sysctl[] = {
	{
		.procname	= "allocate_pgste",
		.data		= &page_table_allocate_pgste,
		.maxlen		= sizeof(int),
		.mode		= S_IRUGO | S_IWUSR,
		.proc_handler	= proc_dointvec,
		.extra1		= &page_table_allocate_pgste_min,
		.extra2		= &page_table_allocate_pgste_max,
	},
	{ }
};

static struct ctl_table page_table_sysctl_dir[] = {
	{
		.procname	= "vm",
		.maxlen		= 0,
		.mode		= 0555,
		.child		= page_table_sysctl,
	},
	{ }
};

static int __init page_table_register_sysctl(void)
{
	return register_sysctl_table(page_table_sysctl_dir) ? 0 : -ENOMEM;
}
__initcall(page_table_register_sysctl);

#endif /* CONFIG_PGSTE */

unsigned long *crst_table_alloc(struct mm_struct *mm)
{
	struct page *page = alloc_pages(GFP_KERNEL, 2);

	if (!page)
		return NULL;
	return (unsigned long *) page_to_phys(page);
}

void crst_table_free(struct mm_struct *mm, unsigned long *table)
{
	free_pages((unsigned long) table, 2);
}

static void __crst_table_upgrade(void *arg)
{
	struct mm_struct *mm = arg;

	if (current->active_mm == mm) {
		clear_user_asce();
		set_user_asce(mm);
	}
	__tlb_flush_local();
}

int crst_table_upgrade(struct mm_struct *mm)
{
	unsigned long *table, *pgd;

	/* upgrade should only happen from 3 to 4 levels */
	BUG_ON(mm->context.asce_limit != (1UL << 42));

	table = crst_table_alloc(mm);
	if (!table)
		return -ENOMEM;

	spin_lock_bh(&mm->page_table_lock);
	pgd = (unsigned long *) mm->pgd;
	crst_table_init(table, _REGION2_ENTRY_EMPTY);
	pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd);
	mm->pgd = (pgd_t *) table;
	mm->context.asce_limit = 1UL << 53;
	mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
			   _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
	spin_unlock_bh(&mm->page_table_lock);

	on_each_cpu(__crst_table_upgrade, mm, 0);
	return 0;
}

void crst_table_downgrade(struct mm_struct *mm)
{
	pgd_t *pgd;

	/* downgrade should only happen from 3 to 2 levels (compat only) */
	BUG_ON(mm->context.asce_limit != (1UL << 42));

	if (current->active_mm == mm) {
		clear_user_asce();
		__tlb_flush_mm(mm);
	}

	pgd = mm->pgd;
	mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
	mm->context.asce_limit = 1UL << 31;
	mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
			   _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
	crst_table_free(mm, (unsigned long *) pgd);

	if (current->active_mm == mm)
		set_user_asce(mm);
}

static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
{
	unsigned int old, new;

	do {
		old = atomic_read(v);
		new = old ^ bits;
	} while (atomic_cmpxchg(v, old, new) != old);
	return new;
}

#ifdef CONFIG_PGSTE

struct page *page_table_alloc_pgste(struct mm_struct *mm)
{
	struct page *page;
	unsigned long *table;

	page = alloc_page(GFP_KERNEL);
	if (page) {
		table = (unsigned long *) page_to_phys(page);
		clear_table(table, _PAGE_INVALID, PAGE_SIZE/2);
		clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
	}
	return page;
}

void page_table_free_pgste(struct page *page)
{
	__free_page(page);
}

#endif /* CONFIG_PGSTE */

/*
 * page table entry allocation/free routines.
 */
unsigned long *page_table_alloc(struct mm_struct *mm)
{
	unsigned long *table;
	struct page *page;
	unsigned int mask, bit;

	/* Try to get a fragment of a 4K page as a 2K page table */
	if (!mm_alloc_pgste(mm)) {
		table = NULL;
		spin_lock_bh(&mm->context.pgtable_lock);
		if (!list_empty(&mm->context.pgtable_list)) {
			page = list_first_entry(&mm->context.pgtable_list,
						struct page, lru);
			mask = atomic_read(&page->_mapcount);
			mask = (mask | (mask >> 4)) & 3;
			if (mask != 3) {
				table = (unsigned long *) page_to_phys(page);
				bit = mask & 1;		/* =1 -> second 2K */
				if (bit)
					table += PTRS_PER_PTE;
				atomic_xor_bits(&page->_mapcount, 1U << bit);
				list_del(&page->lru);
			}
		}
		spin_unlock_bh(&mm->context.pgtable_lock);
		if (table)
			return table;
	}
	/* Allocate a fresh page */
	page = alloc_page(GFP_KERNEL);
	if (!page)
		return NULL;
	if (!pgtable_page_ctor(page)) {
		__free_page(page);
		return NULL;
	}
	/* Initialize page table */
	table = (unsigned long *) page_to_phys(page);
	if (mm_alloc_pgste(mm)) {
		/* Return 4K page table with PGSTEs */
		atomic_set(&page->_mapcount, 3);
		clear_table(table, _PAGE_INVALID, PAGE_SIZE/2);
		clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
	} else {
		/* Return the first 2K fragment of the page */
		atomic_set(&page->_mapcount, 1);
		clear_table(table, _PAGE_INVALID, PAGE_SIZE);
		spin_lock_bh(&mm->context.pgtable_lock);
		list_add(&page->lru, &mm->context.pgtable_list);
		spin_unlock_bh(&mm->context.pgtable_lock);
	}
	return table;
}

void page_table_free(struct mm_struct *mm, unsigned long *table)
{
	struct page *page;
	unsigned int bit, mask;

	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
	if (!mm_alloc_pgste(mm)) {
		/* Free 2K page table fragment of a 4K page */
		bit = (__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
		spin_lock_bh(&mm->context.pgtable_lock);
		mask = atomic_xor_bits(&page->_mapcount, 1U << bit);
		if (mask & 3)
			list_add(&page->lru, &mm->context.pgtable_list);
		else
			list_del(&page->lru);
		spin_unlock_bh(&mm->context.pgtable_lock);
		if (mask != 0)
			return;
	}

	pgtable_page_dtor(page);
	atomic_set(&page->_mapcount, -1);
	__free_page(page);
}

void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
			 unsigned long vmaddr)
{
	struct mm_struct *mm;
	struct page *page;
	unsigned int bit, mask;

	mm = tlb->mm;
	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
	if (mm_alloc_pgste(mm)) {
		gmap_unlink(mm, table, vmaddr);
		table = (unsigned long *) (__pa(table) | 3);
		tlb_remove_table(tlb, table);
		return;
	}
	bit = (__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
	spin_lock_bh(&mm->context.pgtable_lock);
	mask = atomic_xor_bits(&page->_mapcount, 0x11U << bit);
	if (mask & 3)
		list_add_tail(&page->lru, &mm->context.pgtable_list);
	else
		list_del(&page->lru);
	spin_unlock_bh(&mm->context.pgtable_lock);
	table = (unsigned long *) (__pa(table) | (1U << bit));
	tlb_remove_table(tlb, table);
}

static void __tlb_remove_table(void *_table)
{
	unsigned int mask = (unsigned long) _table & 3;
	void *table = (void *)((unsigned long) _table ^ mask);
	struct page *page = pfn_to_page(__pa(table) >> PAGE_SHIFT);

	switch (mask) {
	case 0:		/* pmd or pud */
		free_pages((unsigned long) table, 2);
		break;
	case 1:		/* lower 2K of a 4K page table */
	case 2:		/* higher 2K of a 4K page table */
		if (atomic_xor_bits(&page->_mapcount, mask << 4) != 0)
			break;
		/* fallthrough */
	case 3:		/* 4K page table with pgstes */
		pgtable_page_dtor(page);
		atomic_set(&page->_mapcount, -1);
		__free_page(page);
		break;
	}
}

static void tlb_remove_table_smp_sync(void *arg)
{
	/* Simply deliver the interrupt */
}

static void tlb_remove_table_one(void *table)
{
	/*
	 * This isn't an RCU grace period and hence the page-tables cannot be
	 * assumed to be actually RCU-freed.
	 *
	 * It is however sufficient for software page-table walkers that rely
	 * on IRQ disabling. See the comment near struct mmu_table_batch.
	 */
	smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
	__tlb_remove_table(table);
}

static void tlb_remove_table_rcu(struct rcu_head *head)
{
	struct mmu_table_batch *batch;
	int i;

	batch = container_of(head, struct mmu_table_batch, rcu);

	for (i = 0; i < batch->nr; i++)
		__tlb_remove_table(batch->tables[i]);

	free_page((unsigned long)batch);
}

void tlb_table_flush(struct mmu_gather *tlb)
{
	struct mmu_table_batch **batch = &tlb->batch;

	if (*batch) {
		call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
		*batch = NULL;
	}
}

void tlb_remove_table(struct mmu_gather *tlb, void *table)
{
	struct mmu_table_batch **batch = &tlb->batch;

	tlb->mm->context.flush_mm = 1;
	if (*batch == NULL) {
		*batch = (struct mmu_table_batch *)
			__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
		if (*batch == NULL) {
			__tlb_flush_mm_lazy(tlb->mm);
			tlb_remove_table_one(table);
			return;
		}
		(*batch)->nr = 0;
	}
	(*batch)->tables[(*batch)->nr++] = table;
	if ((*batch)->nr == MAX_TABLE_BATCH)
		tlb_flush_mmu(tlb);
}
Commit	Line	Data
1e133ab2 MS	1	/*
	2	* Page table allocation functions
	3	*
	4	* Copyright IBM Corp. 2016
	5	* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
	6	*/
	7
	8	#include <linux/mm.h>
	9	#include <linux/sysctl.h>
	10	#include <asm/mmu_context.h>
	11	#include <asm/pgalloc.h>
	12	#include <asm/gmap.h>
	13	#include <asm/tlb.h>
	14	#include <asm/tlbflush.h>
	15
	16	#ifdef CONFIG_PGSTE
	17
	18	static int page_table_allocate_pgste_min = 0;
	19	static int page_table_allocate_pgste_max = 1;
	20	int page_table_allocate_pgste = 0;
	21	EXPORT_SYMBOL(page_table_allocate_pgste);
	22
	23	static struct ctl_table page_table_sysctl[] = {
	24	{
	25	.procname = "allocate_pgste",
	26	.data = &page_table_allocate_pgste,
	27	.maxlen = sizeof(int),
	28	.mode = S_IRUGO \| S_IWUSR,
	29	.proc_handler = proc_dointvec,
	30	.extra1 = &page_table_allocate_pgste_min,
	31	.extra2 = &page_table_allocate_pgste_max,
	32	},
	33	{ }
	34	};
	35
	36	static struct ctl_table page_table_sysctl_dir[] = {
	37	{
	38	.procname = "vm",
	39	.maxlen = 0,
	40	.mode = 0555,
	41	.child = page_table_sysctl,
	42	},
	43	{ }
	44	};
	45
	46	static int __init page_table_register_sysctl(void)
	47	{
	48	return register_sysctl_table(page_table_sysctl_dir) ? 0 : -ENOMEM;
	49	}
	50	__initcall(page_table_register_sysctl);
	51
	52	#endif /* CONFIG_PGSTE */
	53
	54	unsigned long crst_table_alloc(struct mm_struct mm)
	55	{
	56	struct page *page = alloc_pages(GFP_KERNEL, 2);
	57
	58	if (!page)
	59	return NULL;
	60	return (unsigned long *) page_to_phys(page);
	61	}
	62
	63	void crst_table_free(struct mm_struct mm, unsigned long table)
	64	{
65	free_pages((unsigned long) table, 2);
66	}
67
68	static void __crst_table_upgrade(void *arg)
69	{
70	struct mm_struct *mm = arg;
71
72	if (current->active_mm == mm) {
73	clear_user_asce();
74	set_user_asce(mm);
75	}
76	__tlb_flush_local();
77	}
78
723cacbd	79	int crst_table_upgrade(struct mm_struct *mm)
1e133ab2 MS	80	{
1e133ab2 MS	81	unsigned long table, pgd;
1e133ab2	82
723cacbd GS	83	/* upgrade should only happen from 3 to 4 levels */
	84	BUG_ON(mm->context.asce_limit != (1UL << 42));
	85
1e133ab2 MS	86	table = crst_table_alloc(mm);
	87	if (!table)
	88	return -ENOMEM;
723cacbd	89
1e133ab2	90	spin_lock_bh(&mm->page_table_lock);
723cacbd GS	91	pgd = (unsigned long *) mm->pgd;
	92	crst_table_init(table, _REGION2_ENTRY_EMPTY);
	93	pgd_populate(mm, (pgd_t ) table, (pud_t ) pgd);
	94	mm->pgd = (pgd_t *) table;
	95	mm->context.asce_limit = 1UL << 53;
	96	mm->context.asce = __pa(mm->pgd) \| _ASCE_TABLE_LENGTH \|
	97	_ASCE_USER_BITS \| _ASCE_TYPE_REGION2;
1e133ab2	98	spin_unlock_bh(&mm->page_table_lock);
723cacbd GS	99
723cacbd GS	100	on_each_cpu(__crst_table_upgrade, mm, 0);
1e133ab2 MS	101	return 0;
	102	}
	103
723cacbd	104	void crst_table_downgrade(struct mm_struct *mm)
1e133ab2 MS	105	{
	106	pgd_t *pgd;
	107
723cacbd GS	108	/* downgrade should only happen from 3 to 2 levels (compat only) */
	109	BUG_ON(mm->context.asce_limit != (1UL << 42));
	110
1e133ab2 MS	111	if (current->active_mm == mm) {
	112	clear_user_asce();
	113	__tlb_flush_mm(mm);
	114	}
723cacbd GS	115
	116	pgd = mm->pgd;
	117	mm->pgd = (pgd_t ) (pgd_val(pgd) & _REGION_ENTRY_ORIGIN);
	118	mm->context.asce_limit = 1UL << 31;
	119	mm->context.asce = __pa(mm->pgd) \| _ASCE_TABLE_LENGTH \|
	120	_ASCE_USER_BITS \| _ASCE_TYPE_SEGMENT;
723cacbd GS	121	crst_table_free(mm, (unsigned long *) pgd);
723cacbd GS	122
1e133ab2 MS	123	if (current->active_mm == mm)
	124	set_user_asce(mm);
	125	}
	126
	127	static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
	128	{
	129	unsigned int old, new;
	130
	131	do {
	132	old = atomic_read(v);
	133	new = old ^ bits;
	134	} while (atomic_cmpxchg(v, old, new) != old);
	135	return new;
	136	}
	137
4be130a0 MS	138	#ifdef CONFIG_PGSTE
	139
	140	struct page page_table_alloc_pgste(struct mm_struct mm)
	141	{
	142	struct page *page;
	143	unsigned long *table;
	144
faee35a5	145	page = alloc_page(GFP_KERNEL);
4be130a0 MS	146	if (page) {
	147	table = (unsigned long *) page_to_phys(page);
	148	clear_table(table, _PAGE_INVALID, PAGE_SIZE/2);
	149	clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
	150	}
	151	return page;
	152	}
	153
	154	void page_table_free_pgste(struct page *page)
	155	{
	156	__free_page(page);
	157	}
	158
	159	#endif /* CONFIG_PGSTE */
	160
1e133ab2 MS	161	/*
	162	* page table entry allocation/free routines.
	163	*/
	164	unsigned long page_table_alloc(struct mm_struct mm)
	165	{
	166	unsigned long *table;
	167	struct page *page;
	168	unsigned int mask, bit;
	169
	170	/* Try to get a fragment of a 4K page as a 2K page table */
	171	if (!mm_alloc_pgste(mm)) {
	172	table = NULL;
8ecb1a59	173	spin_lock_bh(&mm->context.pgtable_lock);
1e133ab2 MS	174	if (!list_empty(&mm->context.pgtable_list)) {
	175	page = list_first_entry(&mm->context.pgtable_list,
	176	struct page, lru);
	177	mask = atomic_read(&page->_mapcount);
	178	mask = (mask \| (mask >> 4)) & 3;
	179	if (mask != 3) {
	180	table = (unsigned long *) page_to_phys(page);
	181	bit = mask & 1; /* =1 -> second 2K */
	182	if (bit)
	183	table += PTRS_PER_PTE;
	184	atomic_xor_bits(&page->_mapcount, 1U << bit);
	185	list_del(&page->lru);
	186	}
	187	}
8ecb1a59	188	spin_unlock_bh(&mm->context.pgtable_lock);
1e133ab2 MS	189	if (table)
	190	return table;
	191	}
	192	/* Allocate a fresh page */
10d58bf2	193	page = alloc_page(GFP_KERNEL);
1e133ab2 MS	194	if (!page)
	195	return NULL;
	196	if (!pgtable_page_ctor(page)) {
	197	__free_page(page);
	198	return NULL;
	199	}
	200	/* Initialize page table */
	201	table = (unsigned long *) page_to_phys(page);
	202	if (mm_alloc_pgste(mm)) {
	203	/* Return 4K page table with PGSTEs */
	204	atomic_set(&page->_mapcount, 3);
	205	clear_table(table, _PAGE_INVALID, PAGE_SIZE/2);
	206	clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
	207	} else {
	208	/* Return the first 2K fragment of the page */
	209	atomic_set(&page->_mapcount, 1);
	210	clear_table(table, _PAGE_INVALID, PAGE_SIZE);
8ecb1a59	211	spin_lock_bh(&mm->context.pgtable_lock);
1e133ab2	212	list_add(&page->lru, &mm->context.pgtable_list);
8ecb1a59	213	spin_unlock_bh(&mm->context.pgtable_lock);
1e133ab2 MS	214	}
	215	return table;
	216	}
	217
	218	void page_table_free(struct mm_struct mm, unsigned long table)
	219	{
	220	struct page *page;
	221	unsigned int bit, mask;
	222
	223	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
	224	if (!mm_alloc_pgste(mm)) {
	225	/* Free 2K page table fragment of a 4K page */
	226	bit = (__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
8ecb1a59	227	spin_lock_bh(&mm->context.pgtable_lock);
1e133ab2 MS	228	mask = atomic_xor_bits(&page->_mapcount, 1U << bit);
	229	if (mask & 3)
	230	list_add(&page->lru, &mm->context.pgtable_list);
	231	else
	232	list_del(&page->lru);
8ecb1a59	233	spin_unlock_bh(&mm->context.pgtable_lock);
1e133ab2 MS	234	if (mask != 0)
	235	return;
	236	}
	237
	238	pgtable_page_dtor(page);
	239	atomic_set(&page->_mapcount, -1);
	240	__free_page(page);
	241	}
	242
	243	void page_table_free_rcu(struct mmu_gather tlb, unsigned long table,
	244	unsigned long vmaddr)
	245	{
	246	struct mm_struct *mm;
	247	struct page *page;
	248	unsigned int bit, mask;
	249
	250	mm = tlb->mm;
	251	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
	252	if (mm_alloc_pgste(mm)) {
	253	gmap_unlink(mm, table, vmaddr);
	254	table = (unsigned long *) (__pa(table) \| 3);
	255	tlb_remove_table(tlb, table);
	256	return;
	257	}
	258	bit = (__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
8ecb1a59	259	spin_lock_bh(&mm->context.pgtable_lock);
1e133ab2 MS	260	mask = atomic_xor_bits(&page->_mapcount, 0x11U << bit);
	261	if (mask & 3)
	262	list_add_tail(&page->lru, &mm->context.pgtable_list);
	263	else
	264	list_del(&page->lru);
8ecb1a59	265	spin_unlock_bh(&mm->context.pgtable_lock);
1e133ab2 MS	266	table = (unsigned long *) (__pa(table) \| (1U << bit));
	267	tlb_remove_table(tlb, table);
	268	}
	269
	270	static void __tlb_remove_table(void *_table)
	271	{
	272	unsigned int mask = (unsigned long) _table & 3;
	273	void table = (void )((unsigned long) _table ^ mask);
	274	struct page *page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
	275
	276	switch (mask) {
	277	case 0: /* pmd or pud */
	278	free_pages((unsigned long) table, 2);
	279	break;
	280	case 1: /* lower 2K of a 4K page table */
	281	case 2: /* higher 2K of a 4K page table */
	282	if (atomic_xor_bits(&page->_mapcount, mask << 4) != 0)
	283	break;
	284	/* fallthrough */
	285	case 3: /* 4K page table with pgstes */
	286	pgtable_page_dtor(page);
	287	atomic_set(&page->_mapcount, -1);
	288	__free_page(page);
	289	break;
	290	}
	291	}
	292
	293	static void tlb_remove_table_smp_sync(void *arg)
	294	{
	295	/* Simply deliver the interrupt */
	296	}
	297
	298	static void tlb_remove_table_one(void *table)
	299	{
	300	/*
	301	* This isn't an RCU grace period and hence the page-tables cannot be
	302	* assumed to be actually RCU-freed.
	303	*
	304	* It is however sufficient for software page-table walkers that rely
	305	* on IRQ disabling. See the comment near struct mmu_table_batch.
	306	*/
	307	smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
	308	__tlb_remove_table(table);
	309	}
	310
	311	static void tlb_remove_table_rcu(struct rcu_head *head)
	312	{
	313	struct mmu_table_batch *batch;
	314	int i;
	315
	316	batch = container_of(head, struct mmu_table_batch, rcu);
	317
	318	for (i = 0; i < batch->nr; i++)
	319	__tlb_remove_table(batch->tables[i]);
	320
	321	free_page((unsigned long)batch);
	322	}
	323
	324	void tlb_table_flush(struct mmu_gather *tlb)
	325	{
	326	struct mmu_table_batch **batch = &tlb->batch;
	327
	328	if (*batch) {
	329	call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
330	*batch = NULL;
331	}
332	}
333
334	void tlb_remove_table(struct mmu_gather tlb, void table)
335	{
336	struct mmu_table_batch **batch = &tlb->batch;
337
338	tlb->mm->context.flush_mm = 1;
339	if (*batch == NULL) {
340	batch = (struct mmu_table_batch )
341	__get_free_page(GFP_NOWAIT \| __GFP_NOWARN);
342	if (*batch == NULL) {
343	__tlb_flush_mm_lazy(tlb->mm);
344	tlb_remove_table_one(table);
345	return;
346	}
347	(*batch)->nr = 0;
348	}
349	(batch)->tables[(batch)->nr++] = table;
350	if ((*batch)->nr == MAX_TABLE_BATCH)
351	tlb_flush_mmu(tlb);
352	}