linux-kernel - [PATCH 2 of 8] x86_64: unmap iomapping before populating

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Date:	Tue, 01 Jul 2008 16:46:31 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
	Stephen Tweedie <sct@...hat.com>,
	Eduardo Habkost <ehabkost@...hat.com>,
	Mark McLoughlin <markmc@...hat.com>, x86@...nel.org
Subject: [PATCH 2 of 8] x86_64: unmap iomapping before populating

Xen doesn't like stray writable mappings of pagetable pages, so make
sure the ioremap mapping is removed before attaching the new page to
the pagetable.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
---
 arch/x86/mm/init_64.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -333,11 +333,11 @@
 		pmd = alloc_low_page(&pmd_phys);
 
 		spin_lock(&init_mm.page_table_lock);
+		last_map_addr = phys_pmd_init(pmd, addr, end);
+		unmap_low_page(pmd);
 		pud_populate(&init_mm, pud, __va(pmd_phys));
-		last_map_addr = phys_pmd_init(pmd, addr, end);
 		spin_unlock(&init_mm.page_table_lock);
 
-		unmap_low_page(pmd);
 	}
 	__flush_tlb_all();
 	update_page_count(PG_LEVEL_1G, pages);
@@ -534,10 +534,10 @@
 		if (next > end)
 			next = end;
 		last_map_addr = phys_pud_init(pud, __pa(start), __pa(next));
+		unmap_low_page(pud);
 		if (!after_bootmem)
 			pgd_populate(&init_mm, pgd_offset_k(start),
 				     __va(pud_phys));
-		unmap_low_page(pud);
 	}
 
 	if (!after_bootmem)


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