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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt62
1 files changed, 56 insertions, 6 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6571fbfdb2a1..46b26bfee27b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -328,11 +328,15 @@
not play well with APC CPU idle - disable it if you have
APC and your system crashes randomly.
- apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
+ apic= [APIC,X86] Advanced Programmable Interrupt Controller
Change the output verbosity whilst booting
Format: { quiet (default) | verbose | debug }
Change the amount of debugging information output
when initialising the APIC and IO-APIC components.
+ For X86-32, this can also be used to specify an APIC
+ driver name.
+ Format: apic=driver_name
+ Examples: apic=bigsmp
apic_extnmi= [APIC,X86] External NMI delivery setting
Format: { bsp (default) | all | none }
@@ -709,9 +713,6 @@
It will be ignored when crashkernel=X,high is not used
or memory reserved is below 4G.
- crossrelease_fullstack
- [KNL] Allow to record full stack trace in cross-release
-
cryptomgr.notests
[KNL] Disable crypto self-tests
@@ -1737,7 +1738,7 @@
isapnp= [ISAPNP]
Format: <RDP>,<reset>,<pci_scan>,<verbosity>
- isolcpus= [KNL,SMP] Isolate a given set of CPUs from disturbance.
+ isolcpus= [KNL,SMP,ISOL] Isolate a given set of CPUs from disturbance.
[Deprecated - use cpusets instead]
Format: [flag-list,]<cpu-list>
@@ -2622,6 +2623,11 @@
nosmt [KNL,S390] Disable symmetric multithreading (SMT).
Equivalent to smt=1.
+ nospectre_v2 [X86] Disable all mitigations for the Spectre variant 2
+ (indirect branch prediction) vulnerability. System may
+ allow data leaks with this option, which is equivalent
+ to spectre_v2=off.
+
noxsave [BUGS=X86] Disables x86 extended register state save
and restore using xsave. The kernel will fallback to
enabling legacy floating-point and sse state.
@@ -2662,7 +2668,7 @@
Valid arguments: on, off
Default: on
- nohz_full= [KNL,BOOT]
+ nohz_full= [KNL,BOOT,SMP,ISOL]
The argument is a cpu list, as described above.
In kernels built with CONFIG_NO_HZ_FULL=y, set
the specified list of CPUs whose tick will be stopped
@@ -3094,6 +3100,12 @@
pcie_scan_all Scan all possible PCIe devices. Otherwise we
only look for one device below a PCIe downstream
port.
+ big_root_window Try to add a big 64bit memory window to the PCIe
+ root complex on AMD CPUs. Some GFX hardware
+ can resize a BAR to allow access to all VRAM.
+ Adding the window is slightly risky (it may
+ conflict with unreported devices), so this
+ taints the kernel.
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.
@@ -3282,6 +3294,21 @@
pt. [PARIDE]
See Documentation/blockdev/paride.txt.
+ 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
default number.
@@ -3931,6 +3958,29 @@
sonypi.*= [HW] Sony Programmable I/O Control Device driver
See Documentation/laptops/sonypi.txt
+ spectre_v2= [X86] Control mitigation of Spectre variant 2
+ (indirect branch speculation) vulnerability.
+
+ on - unconditionally enable
+ off - unconditionally disable
+ auto - kernel detects whether your CPU model is
+ vulnerable
+
+ Selecting 'on' will, and 'auto' may, choose a
+ mitigation method at run time according to the
+ CPU, the available microcode, the setting of the
+ CONFIG_RETPOLINE configuration option, and the
+ compiler with which the kernel was built.
+
+ Specific mitigations can also be selected manually:
+
+ retpoline - replace indirect branches
+ retpoline,generic - google's original retpoline
+ retpoline,amd - AMD-specific minimal thunk
+
+ Not specifying this option is equivalent to
+ spectre_v2=auto.
+
spia_io_base= [HW,MTD]
spia_fio_base=
spia_pedr=