[PATCH] ppc64: fix compat cpu affinity on big endian 64bit

Add compat sched affinity code.  We can argue about how
USE_COMPAT_ULONG_CPUMASK works now that the non compat interface has
changed.

The old non compat behaviour was to require a bitmap long enough in both
setaffinity and getaffinity, now its only required in getaffinity.  I could
do the same for the 32bit interfaces.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/compat.c

@@ -412,16 +412,43 @@ compat_sys_wait4(compat_pid_t pid, compat_uint_t __user *stat_addr, int options,
 	}
 }
 
+/*
+ * for maximum compatability, we allow programs to use a single (compat)
+ * unsigned long bitmask if all cpus will fit. If not, you have to have
+ * at least the kernel size available.
+ */
+#define USE_COMPAT_ULONG_CPUMASK (NR_CPUS <= BITS_PER_COMPAT_LONG)
+
 asmlinkage long compat_sys_sched_setaffinity(compat_pid_t pid, 
 					     unsigned int len,
 					     compat_ulong_t __user *user_mask_ptr)
 {
-	unsigned long kern_mask;
+	cpumask_t kern_mask;
 	mm_segment_t old_fs;
 	int ret;
 
-	if (get_user(kern_mask, user_mask_ptr))
-		return -EFAULT;
+	if (USE_COMPAT_ULONG_CPUMASK) {
+		compat_ulong_t user_mask;
+
+		if (len < sizeof(user_mask))
+			return -EINVAL;
+
+		if (get_user(user_mask, user_mask_ptr))
+			return -EFAULT;
+
+		cpus_addr(kern_mask)[0] = user_mask;
+	} else {
+		unsigned long *k;
+
+		if (len < sizeof(kern_mask))
+			return -EINVAL;
+
+		k = cpus_addr(kern_mask);
+		ret = compat_get_bitmap(k, user_mask_ptr,
+					sizeof(kern_mask) * BITS_PER_LONG);
+		if (ret)
+			return ret;
+	}
 
 	old_fs = get_fs();
 	set_fs(KERNEL_DS);
@@ -436,10 +463,14 @@ asmlinkage long compat_sys_sched_setaffinity(compat_pid_t pid,
 asmlinkage long compat_sys_sched_getaffinity(compat_pid_t pid, unsigned int len,
 					     compat_ulong_t __user *user_mask_ptr)
 {
-	unsigned long kern_mask;
+	cpumask_t kern_mask;
 	mm_segment_t old_fs;
 	int ret;
 
+	if (len < (USE_COMPAT_ULONG_CPUMASK ? sizeof(compat_ulong_t)
+				: sizeof(kern_mask)))
+		return -EINVAL;
+
 	old_fs = get_fs();
 	set_fs(KERNEL_DS);
 	ret = sys_sched_getaffinity(pid,
@@ -447,10 +478,23 @@ asmlinkage long compat_sys_sched_getaffinity(compat_pid_t pid, unsigned int len,
 				    (unsigned long __user *) &kern_mask);
 	set_fs(old_fs);
 
-	if (ret > 0) {
-		ret = sizeof(compat_ulong_t);
-		if (put_user(kern_mask, user_mask_ptr))
+	if (ret < 0)
+		return ret;
+
+	if (USE_COMPAT_ULONG_CPUMASK) {
+		if (put_user(&cpus_addr(kern_mask)[0], user_mask_ptr))
 			return -EFAULT;
+		ret = sizeof(compat_ulong_t);
+	} else {
+		unsigned long *k;
+
+		k = cpus_addr(kern_mask);
+		ret = compat_put_bitmap(user_mask_ptr, k,
+					sizeof(kern_mask) * BITS_PER_LONG);
+		if (ret)
+			return ret;
+
+		ret = sizeof(kern_mask);
 	}
 
 	return ret;