1 files changed, 49 insertions, 0 deletions

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
new file mode 100644
index 000000000000..ce6a722587d8
--- /dev/null
+++ b/arch/x86/mm/init.c
@@ -0,0 +1,49 @@
+#include <linux/swap.h>
+#include <asm/cacheflush.h>
+#include <asm/page.h>
+#include <asm/sections.h>
+#include <asm/system.h>
+
+void free_init_pages(char *what, unsigned long begin, unsigned long end)
+{
+        unsigned long addr = begin;
+
+        if (addr >= end)
+                return;
+
+        /*
+         * If debugging page accesses then do not free this memory but
+         * mark them not present - any buggy init-section access will
+         * create a kernel page fault:
+         */
+#ifdef CONFIG_DEBUG_PAGEALLOC
+        printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
+                begin, PAGE_ALIGN(end));
+        set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
+#else
+        /*
+         * We just marked the kernel text read only above, now that
+         * we are going to free part of that, we need to make that
+         * writeable first.
+         */
+        set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
+
+        printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
+
+        for (; addr < end; addr += PAGE_SIZE) {
+                ClearPageReserved(virt_to_page(addr));
+                init_page_count(virt_to_page(addr));
+                memset((void *)(addr & ~(PAGE_SIZE-1)),
+                        POISON_FREE_INITMEM, PAGE_SIZE);
+                free_page(addr);
+                totalram_pages++;
+        }
+#endif
+}
+
+void free_initmem(void)
+{
+        free_init_pages("unused kernel memory",
+                        (unsigned long)(&__init_begin),
+                        (unsigned long)(&__init_end));
+}