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Commit 146e4b3c authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

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



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

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 0c1f1dcd

arch/s390/mm/init.c

+1 −1
Original line number Diff line number Diff line
@@ -184,7 +184,7 @@ void kernel_map_pages(struct page *page, int numpages, int enable) 
		pmd = pmd_offset(pud, address);

		pte = pte_offset_kernel(pmd, address);

		if (!enable) {

			ptep_invalidate(address, pte);

			ptep_invalidate(&init_mm, address, pte);

			continue;

		}

		*pte = mk_pte_phys(address, __pgprot(_PAGE_TYPE_RW));

arch/s390/mm/pgtable.c

+81 −21
Original line number Diff line number Diff line
@@ -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;



	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;

	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;

	}

		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);

	}

	table = (unsigned long *) page_to_phys(page);

	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);

	struct page *page;

	unsigned long bits;



	pgtable_page_dtor(virt_to_page(table));

	if (shadow)

		free_page((unsigned long) shadow);

	free_page((unsigned long) table);

	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);

}

arch/s390/mm/vmem.c

+11 −3
Original line number Diff line number Diff line
@@ -84,13 +84,18 @@ static inline pmd_t *vmem_pmd_alloc(void) 
	return pmd;

}



static inline pte_t *vmem_pte_alloc(void)

static pte_t __init_refok *vmem_pte_alloc(void)

{

	pte_t *pte = vmem_alloc_pages(0);

	pte_t *pte;



	if (slab_is_available())

		pte = (pte_t *) page_table_alloc(&init_mm);

	else

		pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));

	if (!pte)

		return NULL;

	clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY, PAGE_SIZE);

	clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,

		    PTRS_PER_PTE * sizeof(pte_t));

	return pte;

}
@@ -360,6 +365,9 @@ void __init vmem_map_init(void) 
{

	int i;



	INIT_LIST_HEAD(&init_mm.context.crst_list);

	INIT_LIST_HEAD(&init_mm.context.pgtable_list);

	init_mm.context.noexec = 0;

	NODE_DATA(0)->node_mem_map = VMEM_MAP;

	for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++)

		vmem_add_mem(memory_chunk[i].addr, memory_chunk[i].size);

include/asm-s390/elf.h

+13 −0
Original line number Diff line number Diff line
@@ -115,6 +115,7 @@ typedef s390_regs elf_gregset_t; 


#include <linux/sched.h>	/* for task_struct */

#include <asm/system.h>		/* for save_access_regs */

#include <asm/mmu_context.h>



/*

 * This is used to ensure we don't load something for the wrong architecture.
@@ -214,4 +215,16 @@ do { \ 
} while (0)

#endif /* __s390x__ */



/*

 * An executable for which elf_read_implies_exec() returns TRUE will

 * have the READ_IMPLIES_EXEC personality flag set automatically.

 */

#define elf_read_implies_exec(ex, executable_stack)	\

({							\

	if (current->mm->context.noexec &&		\

	    executable_stack != EXSTACK_DISABLE_X)	\

		disable_noexec(current->mm, current);	\

	current->mm->context.noexec == 0;		\

})



#endif

include/asm-s390/mmu.h

+6 −2
Original line number Diff line number Diff line 
#ifndef __MMU_H

#define __MMU_H



/* Default "unsigned long" context */

typedef unsigned long mm_context_t;

typedef struct {

	struct list_head crst_list;

	struct list_head pgtable_list;

	unsigned long asce_bits;

	int noexec;

} mm_context_t;



#endif