From 141efad7d7fa4f4abb3a1b19f6a968d1b1f21903 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Tue, 6 Jun 2017 14:31:29 +0300 Subject: [PATCH] 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: Kirill A. Shutemov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner 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: Ingo Molnar --- arch/x86/mm/init_64.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 95651dc..7a9497a 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -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 -- 2.7.4