[PATCH] uml: fix x86_64 page leak

We were leaking pmd pages when 3_LEVEL_PGTABLES was enabled.  This fixes that.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 22 insertions, 12 deletions

diff --git a/arch/um/kernel/skas/include/mmu-skas.h b/arch/um/kernel/skas/include/mmu-skas.h
index 278b72f1d9ad..09536f81ee42 100644
--- a/arch/um/kernel/skas/include/mmu-skas.h
+++ b/arch/um/kernel/skas/include/mmu-skas.h
@@ -6,11 +6,15 @@
 #ifndef __SKAS_MMU_H
 #define __SKAS_MMU_H
 
+#include "linux/config.h"
 #include "mm_id.h"
 
 struct mmu_context_skas {
         struct mm_id id;
         unsigned long last_page_table;
+#ifdef CONFIG_3_LEVEL_PGTABLES
+        unsigned long last_pmd;
+#endif
 };
 
 extern void switch_mm_skas(struct mm_id * mm_idp);
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index d837223e22af..240143b616a2 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -56,6 +56,9 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
          */
 
         mm->context.skas.last_page_table = pmd_page_kernel(*pmd);
+#ifdef CONFIG_3_LEVEL_PGTABLES
+        mm->context.skas.last_pmd = (unsigned long) __va(pud_val(*pud));
+#endif
 
         *pte = mk_pte(virt_to_page(kernel), __pgprot(_PAGE_PRESENT));
         *pte = pte_mkexec(*pte);
@@ -144,6 +147,10 @@ void destroy_context_skas(struct mm_struct *mm)
 
         if(!proc_mm || !ptrace_faultinfo){
                 free_page(mmu->id.stack);
-                free_page(mmu->last_page_table);
+                pte_free_kernel((pte_t *) mmu->last_page_table);
+                dec_page_state(nr_page_table_pages);
+#ifdef CONFIG_3_LEVEL_PGTABLES
+                pmd_free((pmd_t *) mmu->last_pmd);
+#endif
         }
 }
diff --git a/include/asm-um/pgalloc.h b/include/asm-um/pgalloc.h
index 8fcb2fc0a892..ea49411236dc 100644
--- a/include/asm-um/pgalloc.h
+++ b/include/asm-um/pgalloc.h
@@ -42,11 +42,13 @@ static inline void pte_free(struct page *pte)
 #define __pte_free_tlb(tlb,pte) tlb_remove_page((tlb),(pte))
 
 #ifdef CONFIG_3_LEVEL_PGTABLES
-/*
- * In the 3-level case we free the pmds as part of the pgd.
- */
-#define pmd_free(x)                     do { } while (0)
-#define __pmd_free_tlb(tlb,x)           do { } while (0)
+
+extern __inline__ void pmd_free(pmd_t *pmd)
+{
+        free_page((unsigned long)pmd);
+}
+
+#define __pmd_free_tlb(tlb,x)   tlb_remove_page((tlb),virt_to_page(x))
 #endif
 
 #define check_pgt_cache()       do { } while (0)
diff --git a/include/asm-um/pgtable-3level.h b/include/asm-um/pgtable-3level.h
index 32cd6236f245..786c25727289 100644
--- a/include/asm-um/pgtable-3level.h
+++ b/include/asm-um/pgtable-3level.h
@@ -69,14 +69,11 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
         return pmd;
 }
 
-static inline void pmd_free(pmd_t *pmd){
-        free_page((unsigned long) pmd);
+extern inline void pud_clear (pud_t *pud)
+{
+        set_pud(pud, __pud(0));
 }
 
-#define __pmd_free_tlb(tlb,x)   do { } while (0)
-
-static inline void pud_clear (pud_t * pud) { }
-
 #define pud_page(pud) \
         ((struct page *) __va(pud_val(pud) & PAGE_MASK))