diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 071b2a6fff85..33051436c864 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -967,7 +967,7 @@ static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
 }
 
 extern unsigned long arch_align_stack(unsigned long sp);
-extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
+void free_init_pages(const char *what, unsigned long begin, unsigned long end);
 extern void free_kernel_image_pages(void *begin, void *end);
 
 void default_idle(void);
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 427a955a2cf2..f905a2371080 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -742,7 +742,7 @@ int devmem_is_allowed(unsigned long pagenr)
 	return 1;
 }
 
-void free_init_pages(char *what, unsigned long begin, unsigned long end)
+void free_init_pages(const char *what, unsigned long begin, unsigned long end)
 {
 	unsigned long begin_aligned, end_aligned;
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 031b2ce983f9..9963f77f1101 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2108,7 +2108,7 @@ extern void free_initmem(void);
  * Return pages freed into the buddy system.
  */
 extern unsigned long free_reserved_area(void *start, void *end,
-					int poison, char *s);
+					int poison, const char *s);
 
 #ifdef	CONFIG_HIGHMEM
 /*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4115d7f20223..e97ebaf5ba26 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7193,7 +7193,7 @@ void adjust_managed_page_count(struct page *page, long count)
 }
 EXPORT_SYMBOL(adjust_managed_page_count);
 
-unsigned long free_reserved_area(void *start, void *end, int poison, char *s)
+unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
 {
 	void *pos;
 	unsigned long pages = 0;