Commit 97f99fed authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86: simplify 32-bit cpa largepage splitting 



simplify 32-bit cpa largepage splitting: do a pure split and repeat
the pte lookup to get the new pte modified.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 78c94aba

arch/x86/mm/pageattr_32.c

+8 −6
Original line number Original line Diff line number Diff line
@@ -38,7 +38,7 @@ pte_t *lookup_address(unsigned long address, int *level) 
}

}





static struct page *

static struct page *

split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)

split_large_page(unsigned long address, pgprot_t ref_prot)

{

{

	unsigned long addr;

	unsigned long addr;

	struct page *base;

	struct page *base;
@@ -58,10 +58,9 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot) 
	pbase = (pte_t *)page_address(base);

	pbase = (pte_t *)page_address(base);

	paravirt_alloc_pt(&init_mm, page_to_pfn(base));

	paravirt_alloc_pt(&init_mm, page_to_pfn(base));





	for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {

	for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)

		set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT,

		set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT, ref_prot));

					   addr == address ? prot : ref_prot));



	}

	return base;

	return base;

}

}
@@ -101,6 +100,7 @@ static int __change_page_attr(struct page *page, pgprot_t prot) 
	BUG_ON(PageHighMem(page));

	BUG_ON(PageHighMem(page));

	address = (unsigned long)page_address(page);

	address = (unsigned long)page_address(page);





repeat:

	kpte = lookup_address(address, &level);

	kpte = lookup_address(address, &level);

	if (!kpte)

	if (!kpte)

		return -EINVAL;

		return -EINVAL;
@@ -128,7 +128,8 @@ static int __change_page_attr(struct page *page, pgprot_t prot) 
		set_pte_atomic(kpte, mk_pte(page, prot));

		set_pte_atomic(kpte, mk_pte(page, prot));

	} else {

	} else {

		struct page *split;

		struct page *split;

		split = split_large_page(address, prot, ref_prot);



		split = split_large_page(address, ref_prot);

		if (!split)

		if (!split)

			return -ENOMEM;

			return -ENOMEM;
@@ -136,6 +137,7 @@ static int __change_page_attr(struct page *page, pgprot_t prot) 
		 * There's a small window here to waste a bit of RAM:

		 * There's a small window here to waste a bit of RAM:

		 */

		 */

		set_pmd_pte(kpte, address, mk_pte(split, ref_prot));

		set_pmd_pte(kpte, address, mk_pte(split, ref_prot));

		goto repeat;

	}

	}

	return 0;

	return 0;

}

}