um: set __HAVE_ARCH_GATE_AREA for x86_64

Implement arch_vma_name() and make get_gate_vma(), in_gate_area() and
in_gate_area_no_mm() a nop.

We need arch_vma_name() to support vDSO.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/um/sys-x86_64/Makefile

@@ -4,7 +4,7 @@
 # Licensed under the GPL
 #
 
-obj-y = bug.o bugs.o delay.o fault.o ldt.o ptrace.o ptrace_user.o \
+obj-y = bug.o bugs.o delay.o fault.o ldt.o ptrace.o ptrace_user.o mem.o \
 	setjmp.o signal.o stub.o stub_segv.o syscalls.o syscall_table.o \
 	sysrq.o ksyms.o tls.o
 

arch/um/sys-x86_64/asm/elf.h

@@ -119,4 +119,14 @@ extern long elf_aux_hwcap;
 
 #define SET_PERSONALITY(ex) do ; while(0)
 
+#define __HAVE_ARCH_GATE_AREA 1
+#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
+struct linux_binprm;
+extern int arch_setup_additional_pages(struct linux_binprm *bprm,
+	int uses_interp);
+
+extern unsigned long um_vdso_addr;
+#define AT_SYSINFO_EHDR 33
+#define ARCH_DLINFO	NEW_AUX_ENT(AT_SYSINFO_EHDR, um_vdso_addr)
+
 #endif

arch/um/sys-x86_64/mem.c

+#include "linux/mm.h"
+#include "asm/page.h"
+#include "asm/mman.h"
+
+const char *arch_vma_name(struct vm_area_struct *vma)
+{
+	if (vma->vm_mm && vma->vm_start == um_vdso_addr)
+		return "[vdso]";
+
+	return NULL;
+}
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return NULL;
+}
+
+int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	return 0;
+}
+
+int in_gate_area_no_mm(unsigned long addr)
+{
+	return 0;
+}