Commit f900a4b8 authored by Borislav Petkov's avatar Borislav Petkov Committed by Matt Fleming
Browse files

x86/mm/pageattr: Add a PMD pagetable populating function 



Handle PMD-level mappings the same as PUD ones.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 4b23538d

arch/x86/mm/pageattr.c

+81 −1
Original line number Diff line number Diff line
@@ -666,6 +666,16 @@ static int split_large_page(pte_t *kpte, unsigned long address) 
	return 0;

}



static int alloc_pte_page(pmd_t *pmd)

{

	pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);

	if (!pte)

		return -1;



	set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));

	return 0;

}



static int alloc_pmd_page(pud_t *pud)

{

	pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
@@ -676,7 +686,77 @@ static int alloc_pmd_page(pud_t *pud) 
	return 0;

}



#define populate_pmd(cpa, start, end, pages, pud, pgprot)	(-1)

#define populate_pte(cpa, start, end, pages, pmd, pgprot)	do {} while (0)



static int populate_pmd(struct cpa_data *cpa,

			unsigned long start, unsigned long end,

			unsigned num_pages, pud_t *pud, pgprot_t pgprot)

{

	unsigned int cur_pages = 0;

	pmd_t *pmd;



	/*

	 * Not on a 2M boundary?

	 */

	if (start & (PMD_SIZE - 1)) {

		unsigned long pre_end = start + (num_pages << PAGE_SHIFT);

		unsigned long next_page = (start + PMD_SIZE) & PMD_MASK;



		pre_end   = min_t(unsigned long, pre_end, next_page);

		cur_pages = (pre_end - start) >> PAGE_SHIFT;

		cur_pages = min_t(unsigned int, num_pages, cur_pages);



		/*

		 * Need a PTE page?

		 */

		pmd = pmd_offset(pud, start);

		if (pmd_none(*pmd))

			if (alloc_pte_page(pmd))

				return -1;



		populate_pte(cpa, start, pre_end, cur_pages, pmd, pgprot);



		start = pre_end;

	}



	/*

	 * We mapped them all?

	 */

	if (num_pages == cur_pages)

		return cur_pages;



	while (end - start >= PMD_SIZE) {



		/*

		 * We cannot use a 1G page so allocate a PMD page if needed.

		 */

		if (pud_none(*pud))

			if (alloc_pmd_page(pud))

				return -1;



		pmd = pmd_offset(pud, start);



		set_pmd(pmd, __pmd(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot)));



		start	  += PMD_SIZE;

		cpa->pfn  += PMD_SIZE;

		cur_pages += PMD_SIZE >> PAGE_SHIFT;

	}



	/*

	 * Map trailing 4K pages.

	 */

	if (start < end) {

		pmd = pmd_offset(pud, start);

		if (pmd_none(*pmd))

			if (alloc_pte_page(pmd))

				return -1;



		populate_pte(cpa, start, end, num_pages - cur_pages,

			     pmd, pgprot);

	}

	return num_pages;

}



static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd,

			pgprot_t pgprot)