clone3: Add padding for kABI

This commit cherry-picks the header changes from two recent
upstream clone3 changes:
49cb2fc Adrian Reber fork: extend clone3() to support setting a PID
ef2c41c Christian Brauner clone3: allow spawning processes into cgroups

Note that the actual implementations were not backported in
this commit; only the header changes that would affect the
kABI were backported.

Orabug: 30958591
Signed-off-by: Tom Hromatka <[email protected]>
Reviewed-by: chris hyser <[email protected]>

Author: drakenclimber

include/linux/sched/task.h

@@ -26,6 +26,20 @@ struct kernel_clone_args {
 	unsigned long stack;
 	unsigned long stack_size;
 	unsigned long tls;
+	/*
+	 * The following attributes were cherry-picked from commits
+	 * 49cb2fc42ce4b and ef2c41cf38a75 in Tejun Heo's "for-5.7" branch
+	 * in https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git/
+	 *
+	 * Note that these values are currently unused but are reserved for
+	 * use if/when these clone3 features are added to UEK6.
+	 */
+	pid_t *set_tid;
+	/* Number of elements in *set_tid */
+	size_t set_tid_size;
+	int cgroup;
+	struct cgroup *cgrp;
+	struct css_set *cset;
 };
 
 /*

include/uapi/linux/sched.h

@@ -59,6 +59,25 @@
  * @tls:         If CLONE_SETTLS is set, the tls descriptor
  *               is set to tls.
  *
+ * The following structure members are not yet utilized by UEK6.
+ *
+ * @set_tid:      Pointer to an array of type *pid_t. The size
+ *                of the array is defined using @set_tid_size.
+ *                This array is used to select PIDs/TIDs for
+ *                newly created processes. The first element in
+ *                this defines the PID in the most nested PID
+ *                namespace. Each additional element in the array
+ *                defines the PID in the parent PID namespace of
+ *                the original PID namespace. If the array has
+ *                less entries than the number of currently
+ *                nested PID namespaces only the PIDs in the
+ *                corresponding namespaces are set.
+ * @set_tid_size: This defines the size of the array referenced
+ *                in @set_tid. This cannot be larger than the
+ *                kernel's limit of nested PID namespaces.
+ * @cgroup:       If CLONE_INTO_CGROUP is specified set this to
+ *                a file descriptor for the cgroup.
+ *
  * The structure is versioned by size and thus extensible.
  * New struct members must go at the end of the struct and
  * must be properly 64bit aligned.
@@ -72,10 +91,23 @@ struct clone_args {
 	__aligned_u64 stack;
 	__aligned_u64 stack_size;
 	__aligned_u64 tls;
+	/*
+	 * The following attributes were cherry-picked from commits
+	 * 49cb2fc42ce4b and ef2c41cf38a75 in Tejun Heo's "for-5.7" branch
+	 * in https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git/
+	 *
+	 * Note that these values are currently unused but are reserved for
+	 * use if/when these clone3 features are added to UEK6.
+	 */
+	__aligned_u64 set_tid;
+	__aligned_u64 set_tid_size;
+	__aligned_u64 cgroup;
 };
 #endif
 
 #define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */
+#define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */
+#define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */
 
 /*
  * Scheduling policies