[PATCH 03/13] x86/mm/pageattr: Always dump the right page table in an oops

Matt Fleming
2014-03-04T13:14:38Z

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>
---
arch/x86/include/asm/pgtable_types.h | 2 ++
arch/x86/mm/fault.c | 7 ++++++-
arch/x86/mm/pageattr.c | 12 ++++++++----
3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 765a4f52d6cd..4384c560499e 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -381,6 +381,8 @@ static inline void update_page_count(int level, unsigned long pages) { }
* as a pte too.
*/
extern pte_t *lookup_address(unsigned long address, unsigned int *level);
+extern pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
+ unsigned int *level);
extern phys_addr_t slow_virt_to_phys(void *__address);
extern int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
unsigned numpages, unsigned long page_flags);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 9d591c895803..b8d278f66095 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 a3488689e301..1585da3b9b85 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);
--
1.8.5.3