Merge branch 'tip-x86-kaslr' of git://git.kernel.org/pub/scm/linux/kernel/git/bp...

Pull ASLR and kASLR fixes from Borislav Petkov:

  - Add a global flag announcing KASLR state so that relevant code can do
    informed decisions based on its setting. (Jiri Kosina)

  - Fix a stack randomization entropy decrease bug. (Hector Marco-Gisbert)

Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --combined arch/x86/kernel/setup.c
index c4648adadd7d4c025e82c9df4b890da1b009a79e,16b6043cb073404e3bdf14cd7d982deb4d813b1d..0d8071d7addbee19d956fcda2d929d2d16f09746
--- 1/arch/x86/kernel/setup.c
--- 2/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@@ -121,6 -121,8 +121,8 @@@
  unsigned long max_low_pfn_mapped;
  unsigned long max_pfn_mapped;
  
+ bool __read_mostly kaslr_enabled = false;
+ 
  #ifdef CONFIG_DMI
  RESERVE_BRK(dmi_alloc, 65536);
  #endif
@@@ -424,6 -426,11 +426,11 @@@ static void __init reserve_initrd(void
  }
  #endif /* CONFIG_BLK_DEV_INITRD */
  
+ static void __init parse_kaslr_setup(u64 pa_data, u32 data_len)
+ {
+       kaslr_enabled = (bool)(pa_data + sizeof(struct setup_data));
+ }
+ 
  static void __init parse_setup_data(void)
  {
        struct setup_data *data;
@@@ -431,13 -438,15 +438,13 @@@
  
        pa_data = boot_params.hdr.setup_data;
        while (pa_data) {
 -              u32 data_len, map_len, data_type;
 +              u32 data_len, data_type;
  
 -              map_len = max(PAGE_SIZE - (pa_data & ~PAGE_MASK),
 -                            (u64)sizeof(struct setup_data));
 -              data = early_memremap(pa_data, map_len);
 +              data = early_memremap(pa_data, sizeof(*data));
                data_len = data->len + sizeof(struct setup_data);
                data_type = data->type;
                pa_next = data->next;
 -              early_iounmap(data, map_len);
 +              early_iounmap(data, sizeof(*data));
  
                switch (data_type) {
                case SETUP_E820_EXT:
@@@ -449,6 -458,9 +456,9 @@@
                case SETUP_EFI:
                        parse_efi_setup(pa_data, data_len);
                        break;
+               case SETUP_KASLR:
+                       parse_kaslr_setup(pa_data, data_len);
+                       break;
                default:
                        break;
                }
@@@ -831,10 -843,14 +841,14 @@@ static void __init trim_low_memory_rang
  static int
  dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
  {
-       pr_emerg("Kernel Offset: 0x%lx from 0x%lx "
-                "(relocation range: 0x%lx-0x%lx)\n",
-                (unsigned long)&_text - __START_KERNEL, __START_KERNEL,
-                __START_KERNEL_map, MODULES_VADDR-1);
+       if (kaslr_enabled)
+               pr_emerg("Kernel Offset: 0x%lx from 0x%lx (relocation range: 0x%lx-0x%lx)\n",
+                        (unsigned long)&_text - __START_KERNEL,
+                        __START_KERNEL,
+                        __START_KERNEL_map,
+                        MODULES_VADDR-1);
+       else
+               pr_emerg("Kernel Offset: disabled\n");
  
        return 0;
  }