[PATCH] x86_64: fix crash on get_user_pages of ia32 vsyscall page before it's faulted in

God invented symbolic names to help you.  Repeating magic constants by hand
is begging to lose, especially when you get them wrong.  Don't be a loser.

[ Editor's hint: 0xfffe000 vs 0xffffe000 ]
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/mm/fault.c

@@ -462,7 +462,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code)
 #ifdef CONFIG_IA32_EMULATION
 	/* 32bit vsyscall. map on demand. */
 	if (test_thread_flag(TIF_IA32) &&
-	    address >= 0xffffe000 && address < 0xffffe000 + PAGE_SIZE) { 
+	    address >= VSYSCALL32_BASE && address < VSYSCALL32_END) {
 		if (map_syscall32(mm, address) < 0)
 			goto out_of_memory2;
 		return;

arch/x86_64/mm/init.c

@@ -605,7 +605,7 @@ struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
 	if (test_tsk_thread_flag(tsk, TIF_IA32)) {
 		/* lookup code assumes the pages are present. set them up
 		   now */
-		if (__map_syscall32(tsk->mm, 0xfffe000) < 0)
+		if (__map_syscall32(tsk->mm, VSYSCALL32_BASE) < 0)
 			return NULL;
 		return &gate32_vma;
 	}