Merge branch 'linus' into timers/urgent

Get upstream changes so dependent patches can be applied.

1 files changed, 14 insertions, 4 deletions

diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 4d17bacf4030..1c1eae961340 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -13,6 +13,7 @@
 #include <linux/string.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
+#include <linux/syscalls.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/uaccess.h>
@@ -102,7 +103,7 @@ static void finalize_ldt_struct(struct ldt_struct *ldt)
 static void install_ldt(struct mm_struct *current_mm,
 			struct ldt_struct *ldt)
 {
-	/* Synchronizes with lockless_dereference in load_mm_ldt. */
+	/* Synchronizes with READ_ONCE in load_mm_ldt. */
 	smp_store_release(&current_mm->context.ldt, ldt);
 
 	/* Activate the LDT for all CPUs using current_mm. */
@@ -295,8 +296,8 @@ out:
 	return error;
 }
 
-asmlinkage int sys_modify_ldt(int func, void __user *ptr,
-			      unsigned long bytecount)
+SYSCALL_DEFINE3(modify_ldt, int , func , void __user * , ptr ,
+		unsigned long , bytecount)
 {
 	int ret = -ENOSYS;
 
@@ -314,5 +315,14 @@ asmlinkage int sys_modify_ldt(int func, void __user *ptr,
 		ret = write_ldt(ptr, bytecount, 0);
 		break;
 	}
-	return ret;
+	/*
+	 * The SYSCALL_DEFINE() macros give us an 'unsigned long'
+	 * return type, but tht ABI for sys_modify_ldt() expects
+	 * 'int'.  This cast gives us an int-sized value in %rax
+	 * for the return code.  The 'unsigned' is necessary so
+	 * the compiler does not try to sign-extend the negative
+	 * return codes into the high half of the register when
+	 * taking the value from int->long.
+	 */
+	return (unsigned int)ret;
 }