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authorDave Hansen <dave.hansen@linux.intel.com>2018-01-05 09:44:36 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-17 09:35:32 +0100
commitd013f41d0cc509513beb61bea7e5aebfef8521f7 (patch)
tree593942826450ca3c0ec2546ab786cbd4bb39bd2b /Documentation/kernel-parameters.txt
parentcf9f240627b4b732c9aedfcdcf54ffcdcda911ad (diff)
x86/Documentation: Add PTI description
commit 01c9b17bf673b05bb401b76ec763e9730ccf1376 upstream. Add some details about how PTI works, what some of the downsides are, and how to debug it when things go wrong. Also document the kernel parameter: 'pti/nopti'. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Moritz Lipp <moritz.lipp@iaik.tugraz.at> Cc: Daniel Gruss <daniel.gruss@iaik.tugraz.at> Cc: Michael Schwarz <michael.schwarz@iaik.tugraz.at> Cc: Richard Fellner <richard.fellner@student.tugraz.at> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Andi Lutomirsky <luto@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180105174436.1BC6FA2B@viggo.jf.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r--Documentation/kernel-parameters.txt21
1 files changed, 14 insertions, 7 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 5977c4d71356..39280b72f27a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2523,8 +2523,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nojitter [IA-64] Disables jitter checking for ITC timers.
- nopti [X86-64] Disable KAISER isolation of kernel from user.
-
no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
@@ -3056,11 +3054,20 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
pt. [PARIDE]
See Documentation/blockdev/paride.txt.
- pti= [X86_64]
- Control KAISER user/kernel address space isolation:
- on - enable
- off - disable
- auto - default setting
+ pti= [X86_64] Control Page Table Isolation of user and
+ kernel address spaces. Disabling this feature
+ removes hardening, but improves performance of
+ system calls and interrupts.
+
+ on - unconditionally enable
+ off - unconditionally disable
+ auto - kernel detects whether your CPU model is
+ vulnerable to issues that PTI mitigates
+
+ Not specifying this option is equivalent to pti=auto.
+
+ nopti [X86_64]
+ Equivalent to pti=off
pty.legacy_count=
[KNL] Number of legacy pty's. Overwrites compiled-in