linux-kernel - [PATCH] x86: Allow 1GB pages to be SPECIAL similar to 2MB

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Date:	Wed, 24 Sep 2014 12:19:03 -0500
From:	James Custer <jcuster@....com>
To:	x86@...nel.org, linux-kernel@...r.kernel.org, tglx@...utronix.de,
	mingo@...hat.com, hpa@...or.com
Cc:	James Custer <jcuster@....com>
Subject: [PATCH] x86: Allow 1GB pages to be SPECIAL similar to 2MB


Signed-off-by: James Custer <jcuster@....com>
---
 arch/x86/mm/gup.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index dd74e46..12ca9cf 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -121,7 +121,6 @@ static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr,
 		mask |= _PAGE_RW;
 	if ((pte_flags(pte) & mask) != mask)
 		return 0;
-	/* hugepages are never "special" */
 	VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
 	VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
 
@@ -191,7 +190,6 @@ static noinline int gup_huge_pud(pud_t pud, unsigned long addr,
 		mask |= _PAGE_RW;
 	if ((pte_flags(pte) & mask) != mask)
 		return 0;
-	/* hugepages are never "special" */
 	VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
 	VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
 
@@ -223,7 +221,7 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
 		pud_t pud = *pudp;
 
 		next = pud_addr_end(addr, end);
-		if (pud_none(pud))
+		if (pud_none(pud) || (pud_val(pud) & _PAGE_SPECIAL))
 			return 0;
 		if (unlikely(pud_large(pud))) {
 			if (!gup_huge_pud(pud, addr, next, write, pages, nr))
-- 
1.8.2.1

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