x86/mm/dump_pagetables: Define INIT_PGD

CVE-2017-5754

Define INIT_PGD to point to the correct initial page-table for 32 and 64
bit and use it where needed. This fixes the build on 32 bit with
CONFIG_PAGE_TABLE_ISOLATION enabled.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-32-git-send-email-joro@8bytes.org
(backported from commit 4e8537e4a7a15402b87c424b22c25c9e59681d16)
[juergh: Adjusted context.]
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index c9b50a5b79423c649c3128f0c2a0f6fcaec45e9e..7aa996bb057b22802dbd4cce41de0113b392af08 100644 (file)
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -107,6 +107,8 @@ static struct addr_marker address_markers[] = {
        [END_OF_SPACE_NR]       = { -1,                 NULL }
 };
 
+#define INIT_PGD       ((pgd_t *) &init_top_pgt)
+
 #else /* CONFIG_X86_64 */
 
 enum address_markers_idx {
@@ -135,6 +137,8 @@ static struct addr_marker address_markers[] = {
        [END_OF_SPACE_NR]       = { -1,                 NULL }
 };
 
+#define INIT_PGD       (swapper_pg_dir)
+
 #endif /* !CONFIG_X86_64 */
 
 /* Multipliers for offsets within the PTEs */
@@ -497,11 +501,7 @@ static inline bool is_hypervisor_range(int idx)
 static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
                                       bool checkwx, bool dmesg)
 {
-#ifdef CONFIG_X86_64
-       pgd_t *start = (pgd_t *) &init_top_pgt;
-#else
-       pgd_t *start = swapper_pg_dir;
-#endif
+       pgd_t *start = INIT_PGD;
        pgprotval_t prot;
        int i;
        struct pg_state st = {};
@@ -562,7 +562,7 @@ EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs);
 static void ptdump_walk_user_pgd_level_checkwx(void)
 {
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
-       pgd_t *pgd = (pgd_t *) &init_top_pgt;
+       pgd_t *pgd = INIT_PGD;
 
        if (!static_cpu_has(X86_FEATURE_PTI))
                return;