x86/mm/pageattr: Always dump the right page table in an oops

Now that we have EFI-specific page tables we need to lookup the pgd when
dumping those page tables, rather than assuming that swapper_pgdir is
the current pgdir.

Remove the double underscore prefix, which is usually reserved for
static functions.

Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

2 files changed, 14 insertions, 5 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 6dea040cc3a1..6055a2001b27 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -584,8 +584,13 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code,
 
         if (error_code & PF_INSTR) {
                 unsigned int level;
+                pgd_t *pgd;
+                pte_t *pte;
 
-                pte_t *pte = lookup_address(address, &level);
+                pgd = __va(read_cr3() & PHYSICAL_PAGE_MASK);
+                pgd += pgd_index(address);
+
+                pte = lookup_address_in_pgd(pgd, address, &level);
 
                 if (pte && pte_present(*pte) && !pte_exec(*pte))
                         printk(nx_warning, from_kuid(&init_user_ns, current_uid()));
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index b3b19f46c016..14c656f0483b 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -323,8 +323,12 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
         return prot;
 }
 
-static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
-                                      unsigned int *level)
+/*
+ * Lookup the page table entry for a virtual address in a specific pgd.
+ * Return a pointer to the entry and the level of the mapping.
+ */
+pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
+                             unsigned int *level)
 {
         pud_t *pud;
         pmd_t *pmd;
@@ -365,7 +369,7 @@ static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
  */
 pte_t *lookup_address(unsigned long address, unsigned int *level)
 {
-        return __lookup_address_in_pgd(pgd_offset_k(address), address, level);
+        return lookup_address_in_pgd(pgd_offset_k(address), address, level);
 }
 EXPORT_SYMBOL_GPL(lookup_address);
 
@@ -373,7 +377,7 @@ static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address,
                                   unsigned int *level)
 {
         if (cpa->pgd)
-                return __lookup_address_in_pgd(cpa->pgd + pgd_index(address),
+                return lookup_address_in_pgd(cpa->pgd + pgd_index(address),
                                                address, level);
 
         return lookup_address(address, level);