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Commit ea3b5e60 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ingo Molnar
Browse files

x86/mm/ident_map: Add 5-level paging support 



Add additional page table level handing. It's mostly mechanical.

The only quirk is that with p4d folded, 'pgd' is equal to 'p4d' in
kernel_ident_mapping_init(). The pgd entry has to point to the pud
page table in this case.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170313143309.16020-5-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 0318e5ab

arch/x86/mm/ident_map.c

+44 −7
Original line number Diff line number Diff line
@@ -45,6 +45,34 @@ static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page, 
	return 0;

}



static int ident_p4d_init(struct x86_mapping_info *info, p4d_t *p4d_page,

			  unsigned long addr, unsigned long end)

{

	unsigned long next;



	for (; addr < end; addr = next) {

		p4d_t *p4d = p4d_page + p4d_index(addr);

		pud_t *pud;



		next = (addr & P4D_MASK) + P4D_SIZE;

		if (next > end)

			next = end;



		if (p4d_present(*p4d)) {

			pud = pud_offset(p4d, 0);

			ident_pud_init(info, pud, addr, next);

			continue;

		}

		pud = (pud_t *)info->alloc_pgt_page(info->context);

		if (!pud)

			return -ENOMEM;

		ident_pud_init(info, pud, addr, next);

		set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE));

	}



	return 0;

}



int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,

			      unsigned long pstart, unsigned long pend)

{
@@ -55,28 +83,37 @@ int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page, 


	for (; addr < end; addr = next) {

		pgd_t *pgd = pgd_page + pgd_index(addr);

		pud_t *pud;

		p4d_t *p4d;



		next = (addr & PGDIR_MASK) + PGDIR_SIZE;

		if (next > end)

			next = end;



		if (pgd_present(*pgd)) {

			pud = pud_offset(pgd, 0);

			result = ident_pud_init(info, pud, addr, next);

			p4d = p4d_offset(pgd, 0);

			result = ident_p4d_init(info, p4d, addr, next);

			if (result)

				return result;

			continue;

		}



		pud = (pud_t *)info->alloc_pgt_page(info->context);

		if (!pud)

		p4d = (p4d_t *)info->alloc_pgt_page(info->context);

		if (!p4d)

			return -ENOMEM;

		result = ident_pud_init(info, pud, addr, next);

		result = ident_p4d_init(info, p4d, addr, next);

		if (result)

			return result;

		if (IS_ENABLED(CONFIG_X86_5LEVEL)) {

			set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE));

		} else {

			/*

			 * With p4d folded, pgd is equal to p4d.

			 * The pgd entry has to point to the pud page table in this case.

			 */

			pud_t *pud = pud_offset(p4d, 0);

			set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));

		}

	}



	return 0;

}