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Commit 141efad7 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ingo Molnar
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x86/mm: Add sync_global_pgds() for configuration with 5-level paging 



This basically restores slightly modified version of original
sync_global_pgds() which we had before folded p4d was introduced.

The only modification is protection against 'addr' overflow.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
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: 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/20170606113133.22974-11-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 032370b9

arch/x86/mm/init_64.c

+39 −0
Original line number Diff line number Diff line
@@ -92,6 +92,44 @@ __setup("noexec32=", nonx32_setup); 
 * When memory was added make sure all the processes MM have

 * suitable PGD entries in the local PGD level page.

 */

#ifdef CONFIG_X86_5LEVEL

void sync_global_pgds(unsigned long start, unsigned long end)

{

	unsigned long addr;



	for (addr = start; addr <= end; addr = ALIGN(addr + 1, PGDIR_SIZE)) {

		const pgd_t *pgd_ref = pgd_offset_k(addr);

		struct page *page;



		/* Check for overflow */

		if (addr < start)

			break;



		if (pgd_none(*pgd_ref))

			continue;



		spin_lock(&pgd_lock);

		list_for_each_entry(page, &pgd_list, lru) {

			pgd_t *pgd;

			spinlock_t *pgt_lock;



			pgd = (pgd_t *)page_address(page) + pgd_index(addr);

			/* the pgt_lock only for Xen */

			pgt_lock = &pgd_page_get_mm(page)->page_table_lock;

			spin_lock(pgt_lock);



			if (!pgd_none(*pgd_ref) && !pgd_none(*pgd))

				BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));



			if (pgd_none(*pgd))

				set_pgd(pgd, *pgd_ref);



			spin_unlock(pgt_lock);

		}

		spin_unlock(&pgd_lock);

	}

}

#else

void sync_global_pgds(unsigned long start, unsigned long end)

{

	unsigned long addr;
@@ -135,6 +173,7 @@ void sync_global_pgds(unsigned long start, unsigned long end) 
		spin_unlock(&pgd_lock);

	}

}

#endif



/*

 * NOTE: This function is marked __ref because it calls __init function