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

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.

Fixes: 6b28baca ("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>

CVE-2018-3620
CVE-2018-3646

[smb: Drop change to pfn_pud which does not exist]
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

arch/x86/include/asm/pgtable.h

@@ -154,21 +154,21 @@ 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;
 }
@@ -374,7 +374,7 @@ 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));
@@ -382,7 +382,7 @@ 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));