2 files changed, 15 insertions, 3 deletions

diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index ffe1c062088b..e566affeed7f 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -7,10 +7,12 @@ Machine check
 
    mce=off disable machine check
    mce=bootlog Enable logging of machine checks left over from booting.
-               Disabled by default because some BIOS leave bogus ones.
+               Disabled by default on AMD because some BIOS leave bogus ones.
                If your BIOS doesn't do that it's a good idea to enable though
                to make sure you log even machine check events that result
-               in a reboot.
+               in a reboot. On Intel systems it is enabled by default.
+   mce=nobootlog
+                Disable boot machine check logging.
    mce=tolerancelevel (number)
                 0: always panic, 1: panic if deadlock possible,
                 2: try to avoid panic, 3: never panic or exit (for testing)
@@ -122,6 +124,9 @@ SMP
 
   cpumask=MASK   only use cpus with bits set in mask
 
+  additional_cpus=NUM Allow NUM more CPUs for hotplug
+                 (defaults are specified by the BIOS or half the available CPUs)
+
 NUMA
 
   numa=off      Only set up a single NUMA node spanning all memory.
@@ -188,6 +193,9 @@ Debugging
 
   kstack=N   Print that many words from the kernel stack in oops dumps.
 
+  pagefaulttrace Dump all page faults. Only useful for extreme debugging
+                and will create a lot of output.
+
 Misc
 
   noreplacement  Don't replace instructions with more appropiate ones
diff --git a/Documentation/x86_64/mm.txt b/Documentation/x86_64/mm.txt
index 662b73971a67..133561b9cb0c 100644
--- a/Documentation/x86_64/mm.txt
+++ b/Documentation/x86_64/mm.txt
@@ -6,7 +6,7 @@ Virtual memory map with 4 level page tables:
 0000000000000000 - 00007fffffffffff (=47bits) user space, different per mm
 hole caused by [48:63] sign extension
 ffff800000000000 - ffff80ffffffffff (=40bits) guard hole
-ffff810000000000 - ffffc0ffffffffff (=46bits) direct mapping of phys. memory
+ffff810000000000 - ffffc0ffffffffff (=46bits) direct mapping of all phys. memory
 ffffc10000000000 - ffffc1ffffffffff (=40bits) hole
 ffffc20000000000 - ffffe1ffffffffff (=45bits) vmalloc/ioremap space
 ... unused hole ...
@@ -14,6 +14,10 @@ ffffffff80000000 - ffffffff82800000 (=40MB)   kernel text mapping, from phys 0
 ... unused hole ...
 ffffffff88000000 - fffffffffff00000 (=1919MB) module mapping space
 
+The direct mapping covers all memory in the system upto the highest
+memory address (this means in some cases it can also include PCI memory
+holes)
+
 vmalloc space is lazily synchronized into the different PML4 pages of
 the processes using the page fault handler, with init_level4_pgt as
 reference.