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[S390] 1K/2K page table pages.

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This patch implements 1K/2K page table pages for s390.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2008-02-09 18:24:35 +01:00
parent 0c1f1dcd8c
commit 146e4b3c8b
11 changed files with 209 additions and 185 deletions
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108
arch/s390/mm/pgtable.c
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@@ -26,8 +26,14 @@
#ifndef CONFIG_64BIT
#define ALLOC_ORDER 1
#define TABLES_PER_PAGE 4
#define FRAG_MASK 15UL
#define SECOND_HALVES 10UL
#else
#define ALLOC_ORDER 2
#define TABLES_PER_PAGE 2
#define FRAG_MASK 3UL
#define SECOND_HALVES 2UL
#endif
unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec)
@@ -45,13 +51,20 @@ unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec)
}
page->index = page_to_phys(shadow);
}
spin_lock(&mm->page_table_lock);
list_add(&page->lru, &mm->context.crst_list);
spin_unlock(&mm->page_table_lock);
return (unsigned long *) page_to_phys(page);
}
void crst_table_free(unsigned long *table)
void crst_table_free(struct mm_struct *mm, unsigned long *table)
{
unsigned long *shadow = get_shadow_table(table);
struct page *page = virt_to_page(table);
spin_lock(&mm->page_table_lock);
list_del(&page->lru);
spin_unlock(&mm->page_table_lock);
if (shadow)
free_pages((unsigned long) shadow, ALLOC_ORDER);
free_pages((unsigned long) table, ALLOC_ORDER);
@@ -60,37 +73,84 @@ void crst_table_free(unsigned long *table)
/*
* page table entry allocation/free routines.
*/
unsigned long *page_table_alloc(int noexec)
unsigned long *page_table_alloc(struct mm_struct *mm)
{
struct page *page = alloc_page(GFP_KERNEL);
struct page *page;
unsigned long *table;
unsigned long bits;
if (!page)
return NULL;
page->index = 0;
if (noexec) {
struct page *shadow = alloc_page(GFP_KERNEL);
if (!shadow) {
__free_page(page);
return NULL;
}
table = (unsigned long *) page_to_phys(shadow);
clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
page->index = (addr_t) table;
bits = mm->context.noexec ? 3UL : 1UL;
spin_lock(&mm->page_table_lock);
page = NULL;
if (!list_empty(&mm->context.pgtable_list)) {
page = list_first_entry(&mm->context.pgtable_list,
struct page, lru);
if ((page->flags & FRAG_MASK) == ((1UL << TABLES_PER_PAGE) - 1))
page = NULL;
}
if (!page) {
spin_unlock(&mm->page_table_lock);
page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
if (!page)
return NULL;
pgtable_page_ctor(page);
page->flags &= ~FRAG_MASK;
table = (unsigned long *) page_to_phys(page);
clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
spin_lock(&mm->page_table_lock);
list_add(&page->lru, &mm->context.pgtable_list);
}
pgtable_page_ctor(page);
table = (unsigned long *) page_to_phys(page);
clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
while (page->flags & bits) {
table += 256;
bits <<= 1;
}
page->flags |= bits;
if ((page->flags & FRAG_MASK) == ((1UL << TABLES_PER_PAGE) - 1))
list_move_tail(&page->lru, &mm->context.pgtable_list);
spin_unlock(&mm->page_table_lock);
return table;
}
void page_table_free(unsigned long *table)
void page_table_free(struct mm_struct *mm, unsigned long *table)
{
unsigned long *shadow = get_shadow_pte(table);
pgtable_page_dtor(virt_to_page(table));
if (shadow)
free_page((unsigned long) shadow);
free_page((unsigned long) table);
struct page *page;
unsigned long bits;
bits = mm->context.noexec ? 3UL : 1UL;
bits <<= (__pa(table) & (PAGE_SIZE - 1)) / 256 / sizeof(unsigned long);
page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
spin_lock(&mm->page_table_lock);
page->flags ^= bits;
if (page->flags & FRAG_MASK) {
/* Page now has some free pgtable fragments. */
list_move(&page->lru, &mm->context.pgtable_list);
page = NULL;
} else
/* All fragments of the 4K page have been freed. */
list_del(&page->lru);
spin_unlock(&mm->page_table_lock);
if (page) {
pgtable_page_dtor(page);
__free_page(page);
}
}
void disable_noexec(struct mm_struct *mm, struct task_struct *tsk)
{
struct page *page;
spin_lock(&mm->page_table_lock);
/* Free shadow region and segment tables. */
list_for_each_entry(page, &mm->context.crst_list, lru)
if (page->index) {
free_pages((unsigned long) page->index, ALLOC_ORDER);
page->index = 0;
}
/* "Free" second halves of page tables. */
list_for_each_entry(page, &mm->context.pgtable_list, lru)
page->flags &= ~SECOND_HALVES;
spin_unlock(&mm->page_table_lock);
mm->context.noexec = 0;
update_mm(mm, tsk);
}