linux-kernel - [PATCH 3.16 114/131] x86/speculation/l1tf: Fix up pte->pfn conversion for PAE

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Date:   Sat, 29 Sep 2018 22:43:07 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Jan Beulich" <JBeulich@...e.com>,
        "Michal Hocko" <mhocko@...e.cz>, "Michal Hocko" <mhocko@...e.com>,
        "Guenter Roeck" <linux@...ck-us.net>,
        "David Woodhouse" <dwmw@...zon.co.uk>,
        "Vlastimil Babka" <vbabka@...e.cz>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        "Thomas Gleixner" <tglx@...utronix.de>
Subject: [PATCH 3.16 114/131] x86/speculation/l1tf: Fix up pte->pfn
 conversion for PAE

3.16.59-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Michal Hocko <mhocko@...e.cz>

commit e14d7dfb41f5807a0c1c26a13f2b8ef16af24935 upstream.

Jan has noticed that pte_pfn and co. resp. pfn_pte are incorrect for
CONFIG_PAE because phys_addr_t is wider than unsigned long and so the
pte_val reps. shift left would get truncated. Fix this up by using proper
types.

[dwmw2: Backport to 4.9]

Fixes: 6b28baca9b1f ("x86/speculation/l1tf: Protect PROT_NONE PTEs against speculation")
Reported-by: Jan Beulich <JBeulich@...e.com>
Signed-off-by: Michal Hocko <mhocko@...e.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
Signed-off-by: David Woodhouse <dwmw@...zon.co.uk>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
[bwh: Backported to 3.16: Adjust context.  Also restore the fix to pfn_pud().]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/include/asm/pgtable.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -147,21 +147,21 @@ static inline u64 protnone_mask(u64 val)
 
 static inline unsigned long pte_pfn(pte_t pte)
 {
-	unsigned long pfn = pte_val(pte);
+	phys_addr_t pfn = pte_val(pte);
 	pfn ^= protnone_mask(pfn);
 	return (pfn & PTE_PFN_MASK) >> PAGE_SHIFT;
 }
 
 static inline unsigned long pmd_pfn(pmd_t pmd)
 {
-	unsigned long pfn = pmd_val(pmd);
+	phys_addr_t pfn = pmd_val(pmd);
 	pfn ^= protnone_mask(pfn);
 	return (pfn & PTE_PFN_MASK) >> PAGE_SHIFT;
 }
 
 static inline unsigned long pud_pfn(pud_t pud)
 {
-	unsigned long pfn = pud_val(pud);
+	phys_addr_t pfn = pud_val(pud);
 	pfn ^= protnone_mask(pfn);
 	return (pfn & PTE_PFN_MASK) >> PAGE_SHIFT;
 }
@@ -371,7 +371,7 @@ static inline pgprotval_t massage_pgprot
 
 static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
 {
-	phys_addr_t pfn = page_nr << PAGE_SHIFT;
+	phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT;
 	pfn ^= protnone_mask(pgprot_val(pgprot));
 	pfn &= PTE_PFN_MASK;
 	return __pte(pfn | massage_pgprot(pgprot));
@@ -379,7 +379,7 @@ static inline pte_t pfn_pte(unsigned lon
 
 static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
 {
-	phys_addr_t pfn = page_nr << PAGE_SHIFT;
+	phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT;
 	pfn ^= protnone_mask(pgprot_val(pgprot));
 	pfn &= PTE_PFN_MASK;
 	return __pmd(pfn | massage_pgprot(pgprot));
@@ -387,7 +387,7 @@ static inline pmd_t pfn_pmd(unsigned lon
 
 static inline pud_t pfn_pud(unsigned long page_nr, pgprot_t pgprot)
 {
-	phys_addr_t pfn = page_nr << PAGE_SHIFT;
+	phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT;
 	pfn ^= protnone_mask(pgprot_val(pgprot));
 	pfn &= PTE_PFN_MASK;
 	return __pud(pfn | massage_pgprot(pgprot));