arch/x86/mm/init.c

   1 #include <linux/swap.h>
   2 #include <asm/cacheflush.h>
   3 #include <asm/page.h>
   4 #include <asm/sections.h>
   5 #include <asm/system.h>
   6
   7 void free_init_pages(char *what, unsigned long begin, unsigned long end)
   8 {
   9         unsigned long addr = begin;
  10
  11         if (addr >= end)
  12                 return;
  13
  14         /*
  15          * If debugging page accesses then do not free this memory but
  16          * mark them not present - any buggy init-section access will
  17          * create a kernel page fault:
  18          */
  19 #ifdef CONFIG_DEBUG_PAGEALLOC
  20         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
  21                 begin, PAGE_ALIGN(end));
  22         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
  23 #else
  24         /*
  25          * We just marked the kernel text read only above, now that
  26          * we are going to free part of that, we need to make that
  27          * writeable first.
  28          */
  29         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
  30
  31         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
  32
  33         for (; addr < end; addr += PAGE_SIZE) {
  34                 ClearPageReserved(virt_to_page(addr));
  35                 init_page_count(virt_to_page(addr));
  36                 memset((void *)(addr & ~(PAGE_SIZE-1)),
  37                         POISON_FREE_INITMEM, PAGE_SIZE);
  38                 free_page(addr);
  39                 totalram_pages++;
  40         }
  41 #endif
  42 }
  43
  44 void free_initmem(void)
  45 {
  46         free_init_pages("unused kernel memory",
  47                         (unsigned long)(&__init_begin),
  48                         (unsigned long)(&__init_end));
  49 }