Merge branch 'topic/cs35l41' into for-next

Pull CS35L41 codec updates

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 100 insertions, 0 deletions

diff --git a/include/linux/rethook.h b/include/linux/rethook.h
new file mode 100644
index 000000000000..c8ac1e5afcd1
--- /dev/null
+++ b/include/linux/rethook.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Return hooking with list-based shadow stack.
+ */
+#ifndef _LINUX_RETHOOK_H
+#define _LINUX_RETHOOK_H
+
+#include <linux/compiler.h>
+#include <linux/freelist.h>
+#include <linux/kallsyms.h>
+#include <linux/llist.h>
+#include <linux/rcupdate.h>
+#include <linux/refcount.h>
+
+struct rethook_node;
+
+typedef void (*rethook_handler_t) (struct rethook_node *, void *, struct pt_regs *);
+
+/**
+ * struct rethook - The rethook management data structure.
+ * @data: The user-defined data storage.
+ * @handler: The user-defined return hook handler.
+ * @pool: The pool of struct rethook_node.
+ * @ref: The reference counter.
+ * @rcu: The rcu_head for deferred freeing.
+ *
+ * Don't embed to another data structure, because this is a self-destructive
+ * data structure when all rethook_node are freed.
+ */
+struct rethook {
+	void			*data;
+	rethook_handler_t	handler;
+	struct freelist_head	pool;
+	refcount_t		ref;
+	struct rcu_head		rcu;
+};
+
+/**
+ * struct rethook_node - The rethook shadow-stack entry node.
+ * @freelist: The freelist, linked to struct rethook::pool.
+ * @rcu: The rcu_head for deferred freeing.
+ * @llist: The llist, linked to a struct task_struct::rethooks.
+ * @rethook: The pointer to the struct rethook.
+ * @ret_addr: The storage for the real return address.
+ * @frame: The storage for the frame pointer.
+ *
+ * You can embed this to your extended data structure to store any data
+ * on each entry of the shadow stack.
+ */
+struct rethook_node {
+	union {
+		struct freelist_node freelist;
+		struct rcu_head      rcu;
+	};
+	struct llist_node	llist;
+	struct rethook		*rethook;
+	unsigned long		ret_addr;
+	unsigned long		frame;
+};
+
+struct rethook *rethook_alloc(void *data, rethook_handler_t handler);
+void rethook_free(struct rethook *rh);
+void rethook_add_node(struct rethook *rh, struct rethook_node *node);
+struct rethook_node *rethook_try_get(struct rethook *rh);
+void rethook_recycle(struct rethook_node *node);
+void rethook_hook(struct rethook_node *node, struct pt_regs *regs, bool mcount);
+unsigned long rethook_find_ret_addr(struct task_struct *tsk, unsigned long frame,
+				    struct llist_node **cur);
+
+/* Arch dependent code must implement arch_* and trampoline code */
+void arch_rethook_prepare(struct rethook_node *node, struct pt_regs *regs, bool mcount);
+void arch_rethook_trampoline(void);
+
+/**
+ * is_rethook_trampoline() - Check whether the address is rethook trampoline
+ * @addr: The address to be checked
+ *
+ * Return true if the @addr is the rethook trampoline address.
+ */
+static inline bool is_rethook_trampoline(unsigned long addr)
+{
+	return addr == (unsigned long)dereference_symbol_descriptor(arch_rethook_trampoline);
+}
+
+/* If the architecture needs to fixup the return address, implement it. */
+void arch_rethook_fixup_return(struct pt_regs *regs,
+			       unsigned long correct_ret_addr);
+
+/* Generic trampoline handler, arch code must prepare asm stub */
+unsigned long rethook_trampoline_handler(struct pt_regs *regs,
+					 unsigned long frame);
+
+#ifdef CONFIG_RETHOOK
+void rethook_flush_task(struct task_struct *tk);
+#else
+#define rethook_flush_task(tsk)	do { } while (0)
+#endif
+
+#endif
+