uml: stop specially protecting kernel stacks

Map all of physical memory as executable to avoid having to change stack
protections during fork and exit.

unprotect_stack is now called only from MODE_TT code, so it is marked as such.

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

4 files changed, 7 insertions, 4 deletions

diff --git a/arch/um/include/kern_util.h b/arch/um/include/kern_util.h
index 6c2be26f1d7d..b84b5dadb958 100644
--- a/arch/um/include/kern_util.h
+++ b/arch/um/include/kern_util.h
@@ -82,7 +82,9 @@ extern void check_stack_overflow(void *ptr);
 extern void relay_signal(int sig, union uml_pt_regs *regs);
 extern int user_context(unsigned long sp);
 extern void timer_irq(union uml_pt_regs *regs);
+#ifdef CONFIG_MODE_TT
 extern void unprotect_stack(unsigned long stack);
+#endif
 extern void do_uml_exitcalls(void);
 extern int attach_debugger(int idle_pid, int pid, int stop);
 extern int config_gdb(char *str);
diff --git a/arch/um/kernel/init_task.c b/arch/um/kernel/init_task.c
index cba516e6c99a..fa90db964b28 100644
--- a/arch/um/kernel/init_task.c
+++ b/arch/um/kernel/init_task.c
@@ -47,7 +47,9 @@ union thread_union cpu0_irqstack
         __attribute__((__section__(".data.init_irqstack"))) =
                 { INIT_THREAD_INFO(init_task) };
 
+#ifdef CONFIG_MODE_TT
 void unprotect_stack(unsigned long stack)
 {
         os_protect_memory((void *) stack, THREAD_SIZE, 1, 1, 0);
 }
+#endif
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index 5ee7e851bbc1..8aeac4d93511 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -105,7 +105,7 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end,
 
         offset = uml_reserved - uml_physmem;
         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
-                            len - offset, 1, 1, 0);
+                            len - offset, 1, 1, 1);
         if(err < 0){
                 os_print_error(err, "Mapping memory");
                 exit(1);
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index bfa52f206bb6..f083787410af 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -82,9 +82,9 @@ unsigned long alloc_stack(int order, int atomic)
         if (atomic)
                 flags = GFP_ATOMIC;
         page = __get_free_pages(flags, order);
-        if(page == 0)
+        if (page == 0)
                 return 0;
-        stack_protections(page);
+
         return page;
 }
 
@@ -141,7 +141,6 @@ void release_thread(struct task_struct *task)
 
 void exit_thread(void)
 {
-        unprotect_stack((unsigned long) current_thread);
 }
 
 void *get_current(void)