[PATCH 8/8] riscv: add two hook functions of ftrace

[Zong Li]

After the text section be mask as non-writable, the ftrace have to
change the permission of text for dynamic patching the intructions.
Add ftrace_arch_code_modify_prepare and
ftrace_arch_code_modify_post_process to change permission.

Signed-off-by: Zong Li <zong.li@xxxxxxxxxx>
---
 arch/riscv/kernel/ftrace.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
index c40fdcdeb950..576df0807200 100644
--- a/arch/riscv/kernel/ftrace.c
+++ b/arch/riscv/kernel/ftrace.c
@@ -7,9 +7,27 @@
 
 #include <linux/ftrace.h>
 #include <linux/uaccess.h>
+#include <linux/memory.h>
+#include <asm/set_memory.h>
 #include <asm/cacheflush.h>
 
 #ifdef CONFIG_DYNAMIC_FTRACE
+int ftrace_arch_code_modify_prepare(void) __acquires(&text_mutex)
+{
+	mutex_lock(&text_mutex);
+	set_kernel_text_rw();
+	set_all_modules_text_rw();
+	return 0;
+}
+
+int ftrace_arch_code_modify_post_process(void) __releases(&text_mutex)
+{
+	set_all_modules_text_ro();
+	set_kernel_text_ro();
+	mutex_unlock(&text_mutex);
+	return 0;
+}
+
 static int ftrace_check_current_call(unsigned long hook_pos,
 				     unsigned int *expected)
 {
-- 
2.25.0