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-rw-r--r--Documentation/x86_64/boot-options.txt12
-rw-r--r--Documentation/x86_64/mm.txt6
2 files changed, 15 insertions, 3 deletions
diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index ffe1c062088..e566affeed7 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 662b73971a6..133561b9cb0 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.