Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: fix compat-vdso
  x86/mm: unify init task OOM handling
  x86/mm: do not trigger a kernel warning if user-space disables interrupts and generates a page fault

2 files changed, 23 insertions, 29 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 3f2b896..31e8730 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -640,24 +640,23 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
 	}
 
 
-#ifdef CONFIG_X86_32
-	/* It's safe to allow irq's after cr2 has been saved and the vmalloc
-	   fault has been handled. */
-	if (regs->flags & (X86_EFLAGS_IF | X86_VM_MASK))
-		local_irq_enable();
-
 	/*
-	 * If we're in an interrupt, have no user context or are running in an
-	 * atomic region then we must not take the fault.
+	 * It's safe to allow irq's after cr2 has been saved and the
+	 * vmalloc fault has been handled.
+	 *
+	 * User-mode registers count as a user access even for any
+	 * potential system fault or CPU buglet.
 	 */
-	if (in_atomic() || !mm)
-		goto bad_area_nosemaphore;
-#else /* CONFIG_X86_64 */
-	if (likely(regs->flags & X86_EFLAGS_IF))
+	if (user_mode_vm(regs)) {
+		local_irq_enable();
+		error_code |= PF_USER;
+	} else if (regs->flags & X86_EFLAGS_IF)
 		local_irq_enable();
 
+#ifdef CONFIG_X86_64
 	if (unlikely(error_code & PF_RSVD))
 		pgtable_bad(address, regs, error_code);
+#endif
 
 	/*
 	 * If we're in an interrupt, have no user context or are running in an
@@ -666,15 +665,9 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
 	if (unlikely(in_atomic() || !mm))
 		goto bad_area_nosemaphore;
 
-	/*
-	 * User-mode registers count as a user access even for any
-	 * potential system fault or CPU buglet.
-	 */
-	if (user_mode_vm(regs))
-		error_code |= PF_USER;
 again:
-#endif
-	/* When running in the kernel we expect faults to occur only to
+	/*
+	 * When running in the kernel we expect faults to occur only to
 	 * addresses in user space.  All other faults represent errors in the
 	 * kernel and should generate an OOPS.  Unfortunately, in the case of an
 	 * erroneous fault occurring in a code path which already holds mmap_sem
@@ -737,9 +730,6 @@ good_area:
 			goto bad_area;
 	}
 
-#ifdef CONFIG_X86_32
-survive:
-#endif
 	/*
 	 * If for any reason at all we couldn't handle the fault,
 	 * make sure we exit gracefully rather than endlessly redo
@@ -874,12 +864,11 @@ out_of_memory:
 	up_read(&mm->mmap_sem);
 	if (is_global_init(tsk)) {
 		yield();
-#ifdef CONFIG_X86_32
-		down_read(&mm->mmap_sem);
-		goto survive;
-#else
+		/*
+		 * Re-lookup the vma - in theory the vma tree might
+		 * have changed:
+		 */
 		goto again;
-#endif
 	}
 
 	printk("VM: killing process %s\n", tsk->comm);
diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 182f9d4..88a53b1 100644
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -148,8 +148,13 @@
 #ifdef CONFIG_X86_64
 #define __PAGE_KERNEL_IDENT_LARGE_EXEC	__PAGE_KERNEL_LARGE_EXEC
 #else
+/*
+ * For PDE_IDENT_ATTR include USER bit. As the PDE and PTE protection
+ * bits are combined, this will alow user to access the high address mapped
+ * VDSO in the presence of CONFIG_COMPAT_VDSO
+ */
 #define PTE_IDENT_ATTR	 0x003		/* PRESENT+RW */
-#define PDE_IDENT_ATTR	 0x063		/* PRESENT+RW+DIRTY+ACCESSED */
+#define PDE_IDENT_ATTR	 0x067		/* PRESENT+RW+USER+DIRTY+ACCESSED */
 #define PGD_IDENT_ATTR	 0x001		/* PRESENT (no other attributes) */
 #endif