[linux-2.6-block.git] / arch / s390 / mm / hugetlbpage.c

/*
 *  IBM System z Huge TLB Page Support for Kernel.
 *
 *    Copyright IBM Corp. 2007
 *    Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
 */

#include <linux/mm.h>
#include <linux/hugetlb.h>


void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
				   pte_t *pteptr, pte_t pteval)
{
	pmd_t *pmdp = (pmd_t *) pteptr;
	unsigned long mask;

	if (!MACHINE_HAS_HPAGE) {
		pteptr = (pte_t *) pte_page(pteval)[1].index;
		mask = pte_val(pteval) &
				(_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
		pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) | mask;
	}

	pmd_val(*pmdp) = pte_val(pteval);
}

int arch_prepare_hugepage(struct page *page)
{
	unsigned long addr = page_to_phys(page);
	pte_t pte;
	pte_t *ptep;
	int i;

	if (MACHINE_HAS_HPAGE)
		return 0;

	ptep = (pte_t *) pte_alloc_one(&init_mm, addr);
	if (!ptep)
		return -ENOMEM;

	pte_val(pte) = addr;
	for (i = 0; i < PTRS_PER_PTE; i++) {
		set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte);
		pte_val(pte) += PAGE_SIZE;
	}
	page[1].index = (unsigned long) ptep;
	return 0;
}

void arch_release_hugepage(struct page *page)
{
	pte_t *ptep;

	if (MACHINE_HAS_HPAGE)
		return;

	ptep = (pte_t *) page[1].index;
	if (!ptep)
		return;
	clear_table((unsigned long *) ptep, _PAGE_TYPE_EMPTY,
		    PTRS_PER_PTE * sizeof(pte_t));
	page_table_free(&init_mm, (unsigned long *) ptep);
	page[1].index = 0;
}

pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgdp;
	pud_t *pudp;
	pmd_t *pmdp = NULL;

	pgdp = pgd_offset(mm, addr);
	pudp = pud_alloc(mm, pgdp, addr);
	if (pudp)
		pmdp = pmd_alloc(mm, pudp, addr);
	return (pte_t *) pmdp;
}

pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgdp;
	pud_t *pudp;
	pmd_t *pmdp = NULL;

	pgdp = pgd_offset(mm, addr);
	if (pgd_present(*pgdp)) {
		pudp = pud_offset(pgdp, addr);
		if (pud_present(*pudp))
			pmdp = pmd_offset(pudp, addr);
	}
	return (pte_t *) pmdp;
}

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	return 0;
}

struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
			      int write)
{
	return ERR_PTR(-EINVAL);
}

int pmd_huge(pmd_t pmd)
{
	if (!MACHINE_HAS_HPAGE)
		return 0;

	return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE);
}

int pud_huge(pud_t pud)
{
	return 0;
}

struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
			     pmd_t *pmdp, int write)
{
	struct page *page;

	if (!MACHINE_HAS_HPAGE)
		return NULL;

	page = pmd_page(*pmdp);
	if (page)
		page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
	return page;
}
Commit	Line	Data
53492b1d GS	1	/*
	2	* IBM System z Huge TLB Page Support for Kernel.
	3	*
a53c8fab	4	* Copyright IBM Corp. 2007
53492b1d GS	5	* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
	6	*/
	7
	8	#include <linux/mm.h>
	9	#include <linux/hugetlb.h>
	10
	11
	12	void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
	13	pte_t *pteptr, pte_t pteval)
	14	{
	15	pmd_t pmdp = (pmd_t ) pteptr;
53492b1d GS	16	unsigned long mask;
	17
	18	if (!MACHINE_HAS_HPAGE) {
	19	pteptr = (pte_t *) pte_page(pteval)[1].index;
	20	mask = pte_val(pteval) &
	21	(_SEGMENT_ENTRY_INV \| _SEGMENT_ENTRY_RO);
	22	pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) \| mask;
53492b1d GS	23	}
	24
	25	pmd_val(*pmdp) = pte_val(pteval);
53492b1d GS	26	}
	27
	28	int arch_prepare_hugepage(struct page *page)
	29	{
	30	unsigned long addr = page_to_phys(page);
	31	pte_t pte;
	32	pte_t *ptep;
	33	int i;
	34
	35	if (MACHINE_HAS_HPAGE)
	36	return 0;
	37
e5992f2e	38	ptep = (pte_t *) pte_alloc_one(&init_mm, addr);
53492b1d GS	39	if (!ptep)
	40	return -ENOMEM;
	41
106c992a	42	pte_val(pte) = addr;
53492b1d GS	43	for (i = 0; i < PTRS_PER_PTE; i++) {
	44	set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte);
	45	pte_val(pte) += PAGE_SIZE;
	46	}
	47	page[1].index = (unsigned long) ptep;
	48	return 0;
	49	}
	50
	51	void arch_release_hugepage(struct page *page)
	52	{
	53	pte_t *ptep;
	54
	55	if (MACHINE_HAS_HPAGE)
	56	return;
	57
	58	ptep = (pte_t *) page[1].index;
	59	if (!ptep)
	60	return;
a686425b GS	61	clear_table((unsigned long *) ptep, _PAGE_TYPE_EMPTY,
a686425b GS	62	PTRS_PER_PTE * sizeof(pte_t));
80217147	63	page_table_free(&init_mm, (unsigned long *) ptep);
53492b1d GS	64	page[1].index = 0;
	65	}
	66
a5516438 AK	67	pte_t huge_pte_alloc(struct mm_struct mm,
a5516438 AK	68	unsigned long addr, unsigned long sz)
53492b1d GS	69	{
	70	pgd_t *pgdp;
	71	pud_t *pudp;
	72	pmd_t *pmdp = NULL;
	73
	74	pgdp = pgd_offset(mm, addr);
	75	pudp = pud_alloc(mm, pgdp, addr);
	76	if (pudp)
	77	pmdp = pmd_alloc(mm, pudp, addr);
	78	return (pte_t *) pmdp;
	79	}
	80
	81	pte_t huge_pte_offset(struct mm_struct mm, unsigned long addr)
	82	{
	83	pgd_t *pgdp;
	84	pud_t *pudp;
	85	pmd_t *pmdp = NULL;
	86
	87	pgdp = pgd_offset(mm, addr);
	88	if (pgd_present(*pgdp)) {
	89	pudp = pud_offset(pgdp, addr);
	90	if (pud_present(*pudp))
	91	pmdp = pmd_offset(pudp, addr);
	92	}
	93	return (pte_t *) pmdp;
	94	}
	95
	96	int huge_pmd_unshare(struct mm_struct mm, unsigned long addr, pte_t *ptep)
	97	{
	98	return 0;
	99	}
	100
	101	struct page follow_huge_addr(struct mm_struct mm, unsigned long address,
	102	int write)
	103	{
	104	return ERR_PTR(-EINVAL);
	105	}
	106
	107	int pmd_huge(pmd_t pmd)
	108	{
	109	if (!MACHINE_HAS_HPAGE)
	110	return 0;
	111
	112	return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE);
	113	}
	114
ceb86879 AK	115	int pud_huge(pud_t pud)
	116	{
	117	return 0;
	118	}
	119
53492b1d GS	120	struct page follow_huge_pmd(struct mm_struct mm, unsigned long address,
	121	pmd_t *pmdp, int write)
	122	{
	123	struct page *page;
	124
	125	if (!MACHINE_HAS_HPAGE)
	126	return NULL;
	127
	128	page = pmd_page(*pmdp);
	129	if (page)
	130	page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
	131	return page;
	132	}