Merge tag 'please-pull-ia64_for_5.4' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-microblaze.git] / Documentation / admin-guide / kernel-parameters.txt

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4ace5af..0d2a67e 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1732,6 +1732,11 @@
                        Note that using this option lowers the security
                        provided by tboot because it makes the system
                        vulnerable to DMA attacks.
                        Note that using this option lowers the security
                        provided by tboot because it makes the system
                        vulnerable to DMA attacks.

+               nobounce [Default off]
+                       Disable bounce buffer for unstrusted devices such as
+                       the Thunderbolt devices. This will treat the untrusted
+                       devices as the trusted ones, hence might expose security
+                       risks of DMA attacks.

 
        intel_idle.max_cstate=  [KNL,HW,ACPI,X86]
                        0       disables intel_idle and fall back on acpi_idle.
 
        intel_idle.max_cstate=  [KNL,HW,ACPI,X86]
                        0       disables intel_idle and fall back on acpi_idle.


@@ -1811,7 +1816,7 @@
                          synchronously.
 
        iommu.passthrough=
                          synchronously.
 
        iommu.passthrough=

-                       [ARM64] Configure DMA to bypass the IOMMU by default.
+                       [ARM64, X86] Configure DMA to bypass the IOMMU by default.

                        Format: { "0" | "1" }
                        0 - Use IOMMU translation for DMA.
                        1 - Bypass the IOMMU for DMA.
                        Format: { "0" | "1" }
                        0 - Use IOMMU translation for DMA.
                        1 - Bypass the IOMMU for DMA.


@@ -2604,7 +2609,7 @@
                                expose users to several CPU vulnerabilities.
                                Equivalent to: nopti [X86,PPC]
                                               kpti=0 [ARM64]
                                expose users to several CPU vulnerabilities.
                                Equivalent to: nopti [X86,PPC]
                                               kpti=0 [ARM64]

-                                              nospectre_v1 [PPC]
+                                              nospectre_v1 [X86,PPC]

                                               nobp=0 [S390]
                                               nospectre_v2 [X86,PPC,S390,ARM64]
                                               spectre_v2_user=off [X86]
                                               nobp=0 [S390]
                                               nospectre_v2 [X86,PPC,S390,ARM64]
                                               spectre_v2_user=off [X86]


@@ -2965,9 +2970,9 @@
                        nosmt=force: Force disable SMT, cannot be undone
                                     via the sysfs control file.
 
                        nosmt=force: Force disable SMT, cannot be undone
                                     via the sysfs control file.
 

-       nospectre_v1    [PPC] Disable mitigations for Spectre Variant 1 (bounds
-                       check bypass). With this option data leaks are possible
-                       in the system.
+       nospectre_v1    [X86,PPC] Disable mitigations for Spectre Variant 1
+                       (bounds check bypass). With this option data leaks are
+                       possible in the system.

 
        nospectre_v2    [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for
                        the Spectre variant 2 (indirect branch prediction)
 
        nospectre_v2    [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for
                        the Spectre variant 2 (indirect branch prediction)


@@ -4090,6 +4095,13 @@
                        Run specified binary instead of /init from the ramdisk,
                        used for early userspace startup. See initrd.
 
                        Run specified binary instead of /init from the ramdisk,
                        used for early userspace startup. See initrd.
 

+       rdrand=         [X86]
+                       force - Override the decision by the kernel to hide the
+                               advertisement of RDRAND support (this affects
+                               certain AMD processors because of buggy BIOS
+                               support, specifically around the suspend/resume
+                               path).
+

        rdt=            [HW,X86,RDT]
                        Turn on/off individual RDT features. List is:
                        cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp,
        rdt=            [HW,X86,RDT]
                        Turn on/off individual RDT features. List is:
                        cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp,