um: fix stub location calculation

[linux-2.6-microblaze.git] / arch / x86 / um / shared / sysdep / stub_64.h

diff --git a/arch/x86/um/shared/sysdep/stub_64.h b/arch/x86/um/shared/sysdep/stub_64.h
index 6e2626b..e9c4b2b 100644 (file)
--- a/arch/x86/um/shared/sysdep/stub_64.h
+++ b/arch/x86/um/shared/sysdep/stub_64.h
@@ -108,4 +108,16 @@ static inline void remap_stack_and_trap(void)
                __syscall_clobber, "r10", "r8", "r9");
 }
 
                __syscall_clobber, "r10", "r8", "r9");
 }
 

+static __always_inline void *get_stub_page(void)
+{
+       unsigned long ret;
+
+       asm volatile (
+               "movq %%rsp,%0 ;"
+               "andq %1,%0"
+               : "=a" (ret)
+               : "g" (~(UM_KERN_PAGE_SIZE - 1)));
+
+       return (void *)ret;
+}

 #endif
 #endif