4 files changed, 82 insertions, 8 deletions

diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h
index 2f8466540fb5..6145063cfe0e 100644
--- a/arch/x86/include/asm/cacheflush.h
+++ b/arch/x86/include/asm/cacheflush.h
@@ -104,6 +104,11 @@ void clflush_cache_range(void *addr, unsigned int size);
 #ifdef CONFIG_DEBUG_RODATA
 void mark_rodata_ro(void);
 extern const int rodata_test_data;
+void set_kernel_text_rw(void);
+void set_kernel_text_ro(void);
+#else
+static inline void set_kernel_text_rw(void) { }
+static inline void set_kernel_text_ro(void) { }
 #endif
 
 #ifdef CONFIG_DEBUG_RODATA_TEST
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 231bdd3c5b1c..77857d4f7d0f 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -18,6 +18,7 @@
 #include <linux/init.h>
 #include <linux/list.h>
 
+#include <asm/cacheflush.h>
 #include <asm/ftrace.h>
 #include <linux/ftrace.h>
 #include <asm/nops.h>
@@ -26,6 +27,18 @@
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
+int ftrace_arch_code_modify_prepare(void)
+{
+        set_kernel_text_rw();
+        return 0;
+}
+
+int ftrace_arch_code_modify_post_process(void)
+{
+        set_kernel_text_ro();
+        return 0;
+}
+
 union ftrace_code_union {
         char code[MCOUNT_INSN_SIZE];
         struct {
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 2cef05074413..3eb2ed188a4c 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -1155,17 +1155,47 @@ static noinline int do_test_wp_bit(void)
 const int rodata_test_data = 0xC3;
 EXPORT_SYMBOL_GPL(rodata_test_data);
 
+static int kernel_set_to_readonly;
+
+void set_kernel_text_rw(void)
+{
+        unsigned long start = PFN_ALIGN(_text);
+        unsigned long size = PFN_ALIGN(_etext) - start;
+
+        if (!kernel_set_to_readonly)
+                return;
+
+        pr_debug("Set kernel text: %lx - %lx for read write\n",
+                 start, start+size);
+
+        set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
+}
+
+void set_kernel_text_ro(void)
+{
+        unsigned long start = PFN_ALIGN(_text);
+        unsigned long size = PFN_ALIGN(_etext) - start;
+
+        if (!kernel_set_to_readonly)
+                return;
+
+        pr_debug("Set kernel text: %lx - %lx for read only\n",
+                 start, start+size);
+
+        set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
+}
+
 void mark_rodata_ro(void)
 {
         unsigned long start = PFN_ALIGN(_text);
         unsigned long size = PFN_ALIGN(_etext) - start;
 
-#ifndef CONFIG_DYNAMIC_FTRACE
-        /* Dynamic tracing modifies the kernel text section */
         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
                 size >> 10);
 
+        kernel_set_to_readonly = 1;
+
 #ifdef CONFIG_CPA_DEBUG
         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
                 start, start+size);
@@ -1174,7 +1204,6 @@ void mark_rodata_ro(void)
         printk(KERN_INFO "Testing CPA: write protecting again\n");
         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
 #endif
-#endif /* CONFIG_DYNAMIC_FTRACE */
 
         start += size;
         size = (unsigned long)__end_rodata - start;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index e6d36b490250..63fdc531601d 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -986,21 +986,48 @@ void free_initmem(void)
 const int rodata_test_data = 0xC3;
 EXPORT_SYMBOL_GPL(rodata_test_data);
 
+static int kernel_set_to_readonly;
+
+void set_kernel_text_rw(void)
+{
+        unsigned long start = PFN_ALIGN(_stext);
+        unsigned long end = PFN_ALIGN(__start_rodata);
+
+        if (!kernel_set_to_readonly)
+                return;
+
+        pr_debug("Set kernel text: %lx - %lx for read write\n",
+                 start, end);
+
+        set_memory_rw(start, (end - start) >> PAGE_SHIFT);
+}
+
+void set_kernel_text_ro(void)
+{
+        unsigned long start = PFN_ALIGN(_stext);
+        unsigned long end = PFN_ALIGN(__start_rodata);
+
+        if (!kernel_set_to_readonly)
+                return;
+
+        pr_debug("Set kernel text: %lx - %lx for read only\n",
+                 start, end);
+
+        set_memory_ro(start, (end - start) >> PAGE_SHIFT);
+}
+
 void mark_rodata_ro(void)
 {
         unsigned long start = PFN_ALIGN(_stext), end = PFN_ALIGN(__end_rodata);
         unsigned long rodata_start =
                 ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
 
-#ifdef CONFIG_DYNAMIC_FTRACE
-        /* Dynamic tracing modifies the kernel text section */
-        start = rodata_start;
-#endif
-
         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
                (end - start) >> 10);
         set_memory_ro(start, (end - start) >> PAGE_SHIFT);
 
+        kernel_set_to_readonly = 1;
+
         /*
          * The rodata section (but not the kernel text!) should also be
          * not-executable.