x86/speculation/l1tf: Fix up pte->pfn conversion for PAE

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@suse.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 38b679d..4e06358 100644 (file)
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -171,21 +171,21 @@ 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 & pmd_pfn_mask(pmd)) >> 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 & pud_pfn_mask(pud)) >> PAGE_SHIFT;
 }
@@ -404,7 +404,7 @@ static inline pgprotval_t massage_pgprot(pgprot_t 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));
@@ -412,7 +412,7 @@ static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
 
 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 &= PHYSICAL_PMD_PAGE_MASK;
        return __pmd(pfn | massage_pgprot(pgprot));