diff options
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 61 |
1 files changed, 55 insertions, 6 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 89386f6f3ab6..fb95fad81c79 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -874,6 +874,11 @@ can be useful when debugging issues that require an SLB miss to occur. + stress_slb [PPC] + Limits the number of kernel SLB entries, and flushes + them frequently to increase the rate of SLB faults + on kernel addresses. + disable= [IPV6] See Documentation/networking/ipv6.rst. @@ -1440,7 +1445,7 @@ hardlockup_all_cpu_backtrace= [KNL] Should the hard-lockup detector generate backtraces on all cpus. - Format: <integer> + Format: 0 | 1 hashdist= [KNL,NUMA] Large hashes allocated during boot are distributed across NUMA nodes. Defaults on @@ -1508,9 +1513,9 @@ hung_task_panic= [KNL] Should the hung task detector generate panics. - Format: <integer> + Format: 0 | 1 - A nonzero value instructs the kernel to panic when a + A value of 1 instructs the kernel to panic when a hung task is detected. The default value is controlled by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value selected by this boot parameter can @@ -3442,6 +3447,19 @@ bit 4: print ftrace buffer bit 5: print all printk messages in buffer + panic_on_taint= Bitmask for conditionally calling panic() in add_taint() + Format: <hex>[,nousertaint] + Hexadecimal bitmask representing the set of TAINT flags + that will cause the kernel to panic when add_taint() is + called with any of the flags in this set. + The optional switch "nousertaint" can be utilized to + prevent userspace forced crashes by writing to sysctl + /proc/sys/kernel/tainted any flagset matching with the + bitmask set on panic_on_taint. + See Documentation/admin-guide/tainted-kernels.rst for + extra details on the taint flags that users can pick + to compose the bitmask to assign to panic_on_taint. + panic_on_warn panic() instead of WARN(). Useful to cause kdump on a WARN(). @@ -3710,6 +3728,8 @@ may put more devices in an IOMMU group. force_floating [S390] Force usage of floating interrupts. nomio [S390] Do not use MIO instructions. + norid [S390] ignore the RID field and force use of + one PCI domain per PCI function pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power Management. @@ -4647,9 +4667,9 @@ softlockup_panic= [KNL] Should the soft-lockup detector generate panics. - Format: <integer> + Format: 0 | 1 - A nonzero value instructs the soft-lockup detector + A value of 1 instructs the soft-lockup detector to panic the machine when a soft-lockup occurs. It is also controlled by the kernel.softlockup_panic sysctl and CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC, which is the @@ -4658,7 +4678,7 @@ softlockup_all_cpu_backtrace= [KNL] Should the soft-lockup detector generate backtraces on all cpus. - Format: <integer> + Format: 0 | 1 sonypi.*= [HW] Sony Programmable I/O Control Device driver See Documentation/admin-guide/laptops/sonypi.rst @@ -4817,6 +4837,26 @@ the kernel will oops in either "warn" or "fatal" mode. + srbds= [X86,INTEL] + Control the Special Register Buffer Data Sampling + (SRBDS) mitigation. + + Certain CPUs are vulnerable to an MDS-like + exploit which can leak bits from the random + number generator. + + By default, this issue is mitigated by + microcode. However, the microcode fix can cause + the RDRAND and RDSEED instructions to become + much slower. Among other effects, this will + result in reduced throughput from /dev/urandom. + + The microcode mitigation can be disabled with + the following option: + + off: Disable mitigation and remove + performance impact to RDRAND and RDSEED + srcutree.counter_wrap_check [KNL] Specifies how frequently to check for grace-period sequence counter wrap for the @@ -4951,6 +4991,15 @@ switches= [HW,M68k] + sysctl.*= [KNL] + Set a sysctl parameter, right before loading the init + process, as if the value was written to the respective + /proc/sys/... file. Both '.' and '/' are recognized as + separators. Unrecognized parameters and invalid values + are reported in the kernel log. Sysctls registered + later by a loaded module cannot be set this way. + Example: sysctl.vm.swappiness=40 + sysfs.deprecated=0|1 [KNL] Enable/disable old style sysfs layout for old udev on older distributions. When this option is enabled |