[PATCH] prctl() patch

This is the patch to add support for PR_SET_FPEMU/PR_GET_FPEMU to give
per-process control over fp-emulation handling.  It also cleans up the
way PR_SET_UNALIGN_CTL/PR_GET_UNALIGN_CTL are implemented.

include/linux/prctl.h

@@ -20,4 +20,10 @@
 #define PR_GET_KEEPCAPS   7
 #define PR_SET_KEEPCAPS   8
 
+/* Get/set floating-point emulation control bits (if meaningful) */
+#define PR_GET_FPEMU  9
+#define PR_SET_FPEMU 10
+# define PR_FPEMU_NOPRINT	1	/* silently emulate fp operations accesses */
+# define PR_FPEMU_SIGFPE	2	/* don't emulate fp operations, send SIGFPE instead */
+
 #endif /* _LINUX_PRCTL_H */

kernel/sys.c

@@ -21,6 +21,19 @@
 #include <asm/io.h>
 #include <asm/unistd.h>
 
+#ifndef SET_UNALIGN_CTL
+# define SET_UNALIGN_CTL(a,b)	(-EINVAL)
+#endif
+#ifndef GET_UNALIGN_CTL
+# define GET_UNALIGN_CTL(a,b)	(-EINVAL)
+#endif
+#ifndef SET_FPEMU_CTL
+# define SET_FPEMU_CTL(a,b)	(-EINVAL)
+#endif
+#ifndef GET_FPEMU_CTL
+# define GET_FPEMU_CTL(a,b)	(-EINVAL)
+#endif
+
 /*
  * this is where the system-wide overflow UID and GID are defined, for
  * architectures that now have 32-bit UID/GID but didn't in the past
@@ -1240,20 +1253,18 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
 			}
 			current->mm->dumpable = arg2;
 			break;
-	        case PR_SET_UNALIGN:
-#ifdef SET_UNALIGN_CTL
+
+		case PR_SET_UNALIGN:
 			error = SET_UNALIGN_CTL(current, arg2);
-#else
-			error = -EINVAL;
-#endif
 			break;
-
-	        case PR_GET_UNALIGN:
-#ifdef GET_UNALIGN_CTL
+		case PR_GET_UNALIGN:
 			error = GET_UNALIGN_CTL(current, arg2);
-#else
-			error = -EINVAL;
-#endif
+			break;
+		case PR_SET_FPEMU:
+			error = SET_FPEMU_CTL(current, arg2);
+			break;
+		case PR_GET_FPEMU:
+			error = GET_FPEMU_CTL(current, arg2);
 			break;
 
 		case PR_GET_KEEPCAPS: