s390: introduce CPU alternatives

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / Documentation / kernel-parameters.txt

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 39280b7..4df6bd7 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2402,6 +2402,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
        noalign         [KNL,ARM]
 
+       noaltinstr      [S390] Disables alternative instructions patching
+                       (CPU alternatives feature).
+
        noapic          [SMP,APIC] Tells the kernel to not make use of any
                        IOAPICs that may be present in the system.
 
@@ -2452,6 +2455,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
        nohugeiomap     [KNL,x86] Disable kernel huge I/O mappings.
 
+       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.
@@ -2560,8 +2568,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
        norandmaps      Don't use address space randomization.  Equivalent to
                        echo 0 > /proc/sys/kernel/randomize_va_space
 
-       noreplace-paravirt      [X86,IA-64,PV_OPS] Don't patch paravirt_ops
-
        noreplace-smp   [X86-32,SMP] Don't replace SMP instructions
                        with UP alternatives
 
@@ -3594,6 +3600,29 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
        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=