1 files changed, 17 insertions, 87 deletions

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index f7ae44d3dd9e..7c253deb46e9 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -10,6 +10,7 @@
 #ifdef CONFIG_DYNAMIC_PHYSICAL_MASK
 phys_addr_t physical_mask __ro_after_init = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
 EXPORT_SYMBOL(physical_mask);
+SYM_PIC_ALIAS(physical_mask);
 #endif
 
 pgtable_t pte_alloc_one(struct mm_struct *mm)
@@ -68,12 +69,6 @@ static inline void pgd_list_del(pgd_t *pgd)
 	list_del(&ptdesc->pt_list);
 }
 
-#define UNSHARED_PTRS_PER_PGD				\
-	(SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
-#define MAX_UNSHARED_PTRS_PER_PGD			\
-	MAX_T(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD)
-
-
 static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
 {
 	virt_to_ptdesc(pgd)->pt_mm = mm;
@@ -86,29 +81,19 @@ struct mm_struct *pgd_page_get_mm(struct page *page)
 
 static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
 {
-	/* If the pgd points to a shared pagetable level (either the
-	   ptes in non-PAE, or shared PMD in PAE), then just copy the
-	   references from swapper_pg_dir. */
-	if (CONFIG_PGTABLE_LEVELS == 2 ||
-	    (CONFIG_PGTABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
-	    CONFIG_PGTABLE_LEVELS >= 4) {
+	/* PAE preallocates all its PMDs.  No cloning needed. */
+	if (!IS_ENABLED(CONFIG_X86_PAE))
 		clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
 				swapper_pg_dir + KERNEL_PGD_BOUNDARY,
 				KERNEL_PGD_PTRS);
-	}
 
-	/* list required to sync kernel mapping updates */
-	if (!SHARED_KERNEL_PMD) {
-		pgd_set_mm(pgd, mm);
-		pgd_list_add(pgd);
-	}
+	/* List used to sync kernel mapping updates */
+	pgd_set_mm(pgd, mm);
+	pgd_list_add(pgd);
 }
 
 static void pgd_dtor(pgd_t *pgd)
 {
-	if (SHARED_KERNEL_PMD)
-		return;
-
 	spin_lock(&pgd_lock);
 	pgd_list_del(pgd);
 	spin_unlock(&pgd_lock);
@@ -132,15 +117,15 @@ static void pgd_dtor(pgd_t *pgd)
  * processor notices the update.  Since this is expensive, and
  * all 4 top-level entries are used almost immediately in a
  * new process's life, we just pre-populate them here.
- *
- * Also, if we're in a paravirt environment where the kernel pmd is
- * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
- * and initialize the kernel pmds here.
  */
-#define PREALLOCATED_PMDS	UNSHARED_PTRS_PER_PGD
-#define MAX_PREALLOCATED_PMDS	MAX_UNSHARED_PTRS_PER_PGD
+#define PREALLOCATED_PMDS	PTRS_PER_PGD
 
 /*
+ * "USER_PMDS" are the PMDs for the user copy of the page tables when
+ * PTI is enabled. They do not exist when PTI is disabled.  Note that
+ * this is distinct from the user _portion_ of the kernel page tables
+ * which always exists.
+ *
  * We allocate separate PMDs for the kernel part of the user page-table
  * when PTI is enabled. We need them to map the per-process LDT into the
  * user-space page-table.
@@ -169,7 +154,6 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
 
 /* No need to prepopulate any pagetable entries in non-PAE modes. */
 #define PREALLOCATED_PMDS	0
-#define MAX_PREALLOCATED_PMDS	0
 #define PREALLOCATED_USER_PMDS	 0
 #define MAX_PREALLOCATED_USER_PMDS 0
 #endif	/* CONFIG_X86_PAE */
@@ -318,68 +302,15 @@ static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
 {
 }
 #endif
-/*
- * Xen paravirt assumes pgd table should be in one page. 64 bit kernel also
- * assumes that pgd should be in one page.
- *
- * But kernel with PAE paging that is not running as a Xen domain
- * only needs to allocate 32 bytes for pgd instead of one page.
- */
-#ifdef CONFIG_X86_PAE
-
-#include <linux/slab.h>
-
-#define PGD_SIZE	(PTRS_PER_PGD * sizeof(pgd_t))
-#define PGD_ALIGN	32
-
-static struct kmem_cache *pgd_cache;
-
-void __init pgtable_cache_init(void)
-{
-	/*
-	 * When PAE kernel is running as a Xen domain, it does not use
-	 * shared kernel pmd. And this requires a whole page for pgd.
-	 */
-	if (!SHARED_KERNEL_PMD)
-		return;
-
-	/*
-	 * when PAE kernel is not running as a Xen domain, it uses
-	 * shared kernel pmd. Shared kernel pmd does not require a whole
-	 * page for pgd. We are able to just allocate a 32-byte for pgd.
-	 * During boot time, we create a 32-byte slab for pgd table allocation.
-	 */
-	pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_ALIGN,
-				      SLAB_PANIC, NULL);
-}
 
 static inline pgd_t *_pgd_alloc(struct mm_struct *mm)
 {
 	/*
-	 * If no SHARED_KERNEL_PMD, PAE kernel is running as a Xen domain.
-	 * We allocate one page for pgd.
-	 */
-	if (!SHARED_KERNEL_PMD)
-		return __pgd_alloc(mm, pgd_allocation_order());
-
-	/*
-	 * Now PAE kernel is not running as a Xen domain. We can allocate
-	 * a 32-byte slab for pgd to save memory space.
+	 * PTI and Xen need a whole page for the PAE PGD
+	 * even though the hardware only needs 32 bytes.
+	 *
+	 * For simplicity, allocate a page for all users.
 	 */
-	return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_USER);
-}
-
-static inline void _pgd_free(struct mm_struct *mm, pgd_t *pgd)
-{
-	if (!SHARED_KERNEL_PMD)
-		__pgd_free(mm, pgd);
-	else
-		kmem_cache_free(pgd_cache, pgd);
-}
-#else
-
-static inline pgd_t *_pgd_alloc(struct mm_struct *mm)
-{
 	return __pgd_alloc(mm, pgd_allocation_order());
 }
 
@@ -387,13 +318,12 @@ static inline void _pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
 	__pgd_free(mm, pgd);
 }
-#endif /* CONFIG_X86_PAE */
 
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	pgd_t *pgd;
 	pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
-	pmd_t *pmds[MAX_PREALLOCATED_PMDS];
+	pmd_t *pmds[PREALLOCATED_PMDS];
 
 	pgd = _pgd_alloc(mm);