mm: move free_reserved_area() to mm/memblock.c

free_reserved_area() is related to memblock as it frees reserved memory
back to the buddy allocator, similar to what memblock_free_late() does.

Move free_reserved_area() to mm/memblock.c to prepare for further
consolidation of the functions that free reserved memory.

No functional changes.

Link: https://patch.msgid.link/20260323074836.3653702-5-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>

Author: rppt

mm/memblock.c

@@ -894,6 +894,42 @@ int __init_memblock memblock_remove(phys_addr_t base, phys_addr_t size)
 	return memblock_remove_range(&memblock.memory, base, size);
 }
 
+unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
+{
+	void *pos;
+	unsigned long pages = 0;
+
+	start = (void *)PAGE_ALIGN((unsigned long)start);
+	end = (void *)((unsigned long)end & PAGE_MASK);
+	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
+		struct page *page = virt_to_page(pos);
+		void *direct_map_addr;
+
+		/*
+		 * 'direct_map_addr' might be different from 'pos'
+		 * because some architectures' virt_to_page()
+		 * work with aliases.  Getting the direct map
+		 * address ensures that we get a _writeable_
+		 * alias for the memset().
+		 */
+		direct_map_addr = page_address(page);
+		/*
+		 * Perform a kasan-unchecked memset() since this memory
+		 * has not been initialized.
+		 */
+		direct_map_addr = kasan_reset_tag(direct_map_addr);
+		if ((unsigned int)poison <= 0xFF)
+			memset(direct_map_addr, poison, PAGE_SIZE);
+
+		free_reserved_page(page);
+	}
+
+	if (pages && s)
+		pr_info("Freeing %s memory: %ldK\n", s, K(pages));
+
+	return pages;
+}
+
 /**
  * memblock_free - free boot memory allocation
  * @ptr: starting address of the  boot memory allocation
@@ -1777,7 +1813,6 @@ void __init memblock_free_late(phys_addr_t base, phys_addr_t size)
 		totalram_pages_inc();
 	}
 }
-
 /*
  * Remaining API functions
  */

mm/page_alloc.c

@@ -6234,42 +6234,6 @@ 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, const char *s)
-{
-	void *pos;
-	unsigned long pages = 0;
-
-	start = (void *)PAGE_ALIGN((unsigned long)start);
-	end = (void *)((unsigned long)end & PAGE_MASK);
-	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
-		struct page *page = virt_to_page(pos);
-		void *direct_map_addr;
-
-		/*
-		 * 'direct_map_addr' might be different from 'pos'
-		 * because some architectures' virt_to_page()
-		 * work with aliases.  Getting the direct map
-		 * address ensures that we get a _writeable_
-		 * alias for the memset().
-		 */
-		direct_map_addr = page_address(page);
-		/*
-		 * Perform a kasan-unchecked memset() since this memory
-		 * has not been initialized.
-		 */
-		direct_map_addr = kasan_reset_tag(direct_map_addr);
-		if ((unsigned int)poison <= 0xFF)
-			memset(direct_map_addr, poison, PAGE_SIZE);
-
-		free_reserved_page(page);
-	}
-
-	if (pages && s)
-		pr_info("Freeing %s memory: %ldK\n", s, K(pages));
-
-	return pages;
-}
-
 void free_reserved_page(struct page *page)
 {
 	clear_page_tag_ref(page);

tools/include/linux/mm.h

@@ -17,6 +17,7 @@
 
 #define __va(x) ((void *)((unsigned long)(x)))
 #define __pa(x) ((unsigned long)(x))
+#define __pa_symbol(x) ((unsigned long)(x))
 
 #define pfn_to_page(pfn) ((void *)((pfn) * PAGE_SIZE))
 

tools/testing/memblock/internal.h

@@ -11,9 +11,22 @@ static int memblock_debug = 1;
 
 #define pr_warn_ratelimited(fmt, ...)    printf(fmt, ##__VA_ARGS__)
 
+#define K(x) ((x) << (PAGE_SHIFT-10))
+
 bool mirrored_kernelcore = false;
 
 struct page {};
+static inline void *page_address(struct page *page)
+{
+	BUG();
+	return page;
+}
+
+static inline struct page *virt_to_page(void *virt)
+{
+	BUG();
+	return virt;
+}
 
 void memblock_free_pages(unsigned long pfn, unsigned int order)
 {
@@ -23,10 +36,25 @@ static inline void accept_memory(phys_addr_t start, unsigned long size)
 {
 }
 
-static inline unsigned long free_reserved_area(void *start, void *end,
-					       int poison, const char *s)
+unsigned long free_reserved_area(void *start, void *end, int poison, const char *s);
+void free_reserved_page(struct page *page);
+
+static inline bool deferred_pages_enabled(void)
+{
+	return false;
+}
+
+#define for_each_valid_pfn(pfn, start_pfn, end_pfn)			 \
+	for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++)
+
+static inline void *kasan_reset_tag(const void *addr)
+{
+	return (void *)addr;
+}
+
+static inline bool __is_kernel(unsigned long addr)
 {
-	return 0;
+	return false;
 }
 
 #define for_each_valid_pfn(pfn, start_pfn, end_pfn)                     \