[PATCH] x86: tighten kernel image page access rights

[pandora-kernel.git] / arch / x86_64 / mm / init.c

diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 69e22d3..e3134bc 100644 (file)
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -22,6 +22,7 @@
 #include <linux/bootmem.h>
 #include <linux/proc_fs.h>
 #include <linux/pci.h>
+#include <linux/pfn.h>
 #include <linux/poison.h>
 #include <linux/dma-mapping.h>
 #include <linux/module.h>
@@ -563,21 +564,23 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
        if (begin >= end)
                return;
 
-       printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
+       printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
        for (addr = begin; addr < end; addr += PAGE_SIZE) {
                struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
                ClearPageReserved(page);
                init_page_count(page);
                memset(page_address(page), POISON_FREE_INITMEM, PAGE_SIZE);
+               if (addr >= __START_KERNEL_map)
+                       change_page_attr_addr(addr, 1, __pgprot(0));
                __free_page(page);
                totalram_pages++;
        }
+       if (addr > __START_KERNEL_map)
+               global_flush_tlb();
 }
 
 void free_initmem(void)
 {
-       memset(__initdata_begin, POISON_FREE_INITDATA,
-               __initdata_end - __initdata_begin);
        free_init_pages("unused kernel memory",
                        __pa_symbol(&__init_begin),
                        __pa_symbol(&__init_end));
@@ -587,14 +590,18 @@ void free_initmem(void)
 
 void mark_rodata_ro(void)
 {
-       unsigned long addr = (unsigned long)__va(__pa_symbol(&__start_rodata));
-       unsigned long end  = (unsigned long)__va(__pa_symbol(&__end_rodata));
+       unsigned long start = PFN_ALIGN(__va(__pa_symbol(&_stext))), size;
 
-       for (; addr < end; addr += PAGE_SIZE)
-               change_page_attr_addr(addr, 1, PAGE_KERNEL_RO);
+#ifdef CONFIG_HOTPLUG_CPU
+       /* It must still be possible to apply SMP alternatives. */
+       if (num_possible_cpus() > 1)
+               start = PFN_ALIGN(__va(__pa_symbol(&_etext)));
+#endif
+       size = (unsigned long)__va(__pa_symbol(&__end_rodata)) - start;
+       change_page_attr_addr(start, size >> PAGE_SHIFT, PAGE_KERNEL_RO);
 
-       printk ("Write protecting the kernel read-only data: %luk\n",
-                       (__end_rodata - __start_rodata) >> 10);
+       printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
+              size >> 10);
 
        /*
         * change_page_attr_addr() requires a global_flush_tlb() call after it.