Commit 4b23538d authored by Borislav Petkov's avatar Borislav Petkov Committed by Matt Fleming
Browse files

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



Add the next level of the pagetable populating function, we handle
chunks around a 1G boundary by mapping them with the lower level
functions - otherwise we use 1G pages for the mappings, thus using as
less amount of pagetable pages as possible.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent f3f72966

arch/x86/mm/pageattr.c

+86 −1
Original line number Diff line number Diff line
@@ -666,7 +666,92 @@ static int split_large_page(pte_t *kpte, unsigned long address) 
	return 0;

}



#define populate_pud(cpa, addr, pgd, pgprot)	(-1)

static int alloc_pmd_page(pud_t *pud)

{

	pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);

	if (!pmd)

		return -1;



	set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));

	return 0;

}



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



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

			pgprot_t pgprot)

{

	pud_t *pud;

	unsigned long end;

	int cur_pages = 0;



	end = start + (cpa->numpages << PAGE_SHIFT);



	/*

	 * Not on a Gb page boundary? => map everything up to it with

	 * smaller pages.

	 */

	if (start & (PUD_SIZE - 1)) {

		unsigned long pre_end;

		unsigned long next_page = (start + PUD_SIZE) & PUD_MASK;



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

		cur_pages = (pre_end - start) >> PAGE_SHIFT;

		cur_pages = min_t(int, (int)cpa->numpages, cur_pages);



		pud = pud_offset(pgd, start);



		/*

		 * Need a PMD page?

		 */

		if (pud_none(*pud))

			if (alloc_pmd_page(pud))

				return -1;



		cur_pages = populate_pmd(cpa, start, pre_end, cur_pages,

					 pud, pgprot);

		if (cur_pages < 0)

			return cur_pages;



		start = pre_end;

	}



	/* We mapped them all? */

	if (cpa->numpages == cur_pages)

		return cur_pages;



	pud = pud_offset(pgd, start);



	/*

	 * Map everything starting from the Gb boundary, possibly with 1G pages

	 */

	while (end - start >= PUD_SIZE) {

		set_pud(pud, __pud(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot)));



		start	  += PUD_SIZE;

		cpa->pfn  += PUD_SIZE;

		cur_pages += PUD_SIZE >> PAGE_SHIFT;

		pud++;

	}



	/* Map trailing leftover */

	if (start < end) {

		int tmp;



		pud = pud_offset(pgd, start);

		if (pud_none(*pud))

			if (alloc_pmd_page(pud))

				return -1;



		tmp = populate_pmd(cpa, start, end, cpa->numpages - cur_pages,

				   pud, pgprot);

		if (tmp < 0)

			return cur_pages;



		cur_pages += tmp;

	}

	return cur_pages;

}



/*

 * Restrictions for kernel page table do not necessarily apply when mapping in

CRA Git | Maintained and supported by SUSTech CRA and CCSE