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Commit 0fb1d9bc authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

[S390] make page table upgrade work again 



After TASK_SIZE now gives the current size of the address space the
upgrade of a 64 bit process from 3 to 4 levels of page table  needs
to use the arch_mmap_check hook to catch large mmap lengths. The
get_unmapped_area* functions need to check for -ENOMEM from the
arch_get_unmapped_area*, upgrade the page table and retry.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f481bfaf

arch/s390/include/asm/mman.h

+5 −0
Original line number Diff line number Diff line
@@ -22,4 +22,9 @@ 
#define MCL_CURRENT	1		/* lock all current mappings */

#define MCL_FUTURE	2		/* lock all future mappings */



#if defined(__KERNEL__) && !defined(__ASSEMBLY__) && defined(CONFIG_64BIT)

int s390_mmap_check(unsigned long addr, unsigned long len);

#define arch_mmap_check(addr,len,flags)	s390_mmap_check(addr,len)

#endif



#endif /* __S390_MMAN_H__ */

arch/s390/mm/mmap.c

+30 −14
Original line number Diff line number Diff line
@@ -89,42 +89,58 @@ EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); 


#else



int s390_mmap_check(unsigned long addr, unsigned long len)

{

	if (!test_thread_flag(TIF_31BIT) &&

	    len >= TASK_SIZE && TASK_SIZE < (1UL << 53))

		return crst_table_upgrade(current->mm, 1UL << 53);

	return 0;

}



static unsigned long

s390_get_unmapped_area(struct file *filp, unsigned long addr,

		unsigned long len, unsigned long pgoff, unsigned long flags)

{

	struct mm_struct *mm = current->mm;

	unsigned long area;

	int rc;



	addr = arch_get_unmapped_area(filp, addr, len, pgoff, flags);

	if (addr & ~PAGE_MASK)

		return addr;

	if (unlikely(mm->context.asce_limit < addr + len)) {

		rc = crst_table_upgrade(mm, addr + len);

	area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);

	if (!(area & ~PAGE_MASK))

		return area;

	if (area == -ENOMEM &&

	    !test_thread_flag(TIF_31BIT) && TASK_SIZE < (1UL << 53)) {

		/* Upgrade the page table to 4 levels and retry. */

		rc = crst_table_upgrade(mm, 1UL << 53);

		if (rc)

			return (unsigned long) rc;

		area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);

	}

	return addr;

	return area;

}



static unsigned long

s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,

s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,

			  const unsigned long len, const unsigned long pgoff,

			  const unsigned long flags)

{

	struct mm_struct *mm = current->mm;

	unsigned long addr = addr0;

	unsigned long area;

	int rc;



	addr = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);

	if (addr & ~PAGE_MASK)

		return addr;

	if (unlikely(mm->context.asce_limit < addr + len)) {

		rc = crst_table_upgrade(mm, addr + len);

	area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);

	if (!(area & ~PAGE_MASK))

		return area;

	if (area == -ENOMEM &&

	    !test_thread_flag(TIF_31BIT) && TASK_SIZE < (1UL << 53)) {

		/* Upgrade the page table to 4 levels and retry. */

		rc = crst_table_upgrade(mm, 1UL << 53);

		if (rc)

			return (unsigned long) rc;

		area = arch_get_unmapped_area_topdown(filp, addr, len,

						      pgoff, flags);

	}

	return addr;

	return area;

}

/*

 * This function, called very early during the creation of a new