diff options
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 43 |
1 files changed, 30 insertions, 13 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index ce3696d8256c..3e2d22eb5e59 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1736,6 +1736,11 @@ 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. @@ -1815,7 +1820,7 @@ 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. @@ -2377,7 +2382,7 @@ machvec= [IA-64] Force the use of a particular machine-vector (machvec) in a generic kernel. - Example: machvec=hpzx1_swiotlb + Example: machvec=hpzx1 machtype= [Loongson] Share the same kernel image file between different yeeloong laptop. @@ -2549,7 +2554,7 @@ mem_encrypt=on: Activate SME mem_encrypt=off: Do not activate SME - Refer to Documentation/virtual/kvm/amd-memory-encryption.rst + Refer to Documentation/virt/kvm/amd-memory-encryption.rst for details on when memory encryption can be activated. mem_sleep_default= [SUSPEND] Default system suspend mode: @@ -2608,7 +2613,7 @@ 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] @@ -2969,9 +2974,9 @@ 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) @@ -3841,12 +3846,13 @@ RCU_BOOST is not set, valid values are 0-99 and the default is zero (non-realtime operation). - rcutree.rcu_nocb_leader_stride= [KNL] - Set the number of NOCB kthread groups, which - defaults to the square root of the number of - CPUs. Larger numbers reduces the wakeup overhead - on the per-CPU grace-period kthreads, but increases - that same overhead on each group's leader. + rcutree.rcu_nocb_gp_stride= [KNL] + Set the number of NOCB callback kthreads in + each group, which defaults to the square root + of the number of CPUs. Larger numbers reduce + the wakeup overhead on the global grace-period + kthread, but increases that same overhead on + each group's NOCB grace-period kthread. rcutree.qhimark= [KNL] Set threshold of queued RCU callbacks beyond which @@ -4051,6 +4057,10 @@ rcutorture.verbose= [KNL] Enable additional printk() statements. + rcupdate.rcu_cpu_stall_ftrace_dump= [KNL] + Dump ftrace buffer after reporting RCU CPU + stall warning. + rcupdate.rcu_cpu_stall_suppress= [KNL] Suppress RCU CPU stall warning messages. @@ -4094,6 +4104,13 @@ 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, |