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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt58
1 files changed, 37 insertions, 21 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index bdc1f33fd3d1..f7ac0e663976 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -577,7 +577,7 @@
loops can be debugged more effectively on production
systems.
- clearcpuid=BITNUM [X86]
+ clearcpuid=BITNUM[,BITNUM...] [X86]
Disable CPUID feature X for the kernel. See
arch/x86/include/asm/cpufeatures.h for the valid bit
numbers. Note the Linux specific bits are not necessarily
@@ -591,13 +591,24 @@
some critical bits.
cma=nn[MG]@[start[MG][-end[MG]]]
- [ARM,X86,KNL]
+ [KNL,CMA]
Sets the size of kernel global memory area for
contiguous memory allocations and optionally the
placement constraint by the physical address range of
memory allocations. A value of 0 disables CMA
altogether. For more information, see
- include/linux/dma-contiguous.h
+ kernel/dma/contiguous.c
+
+ cma_pernuma=nn[MG]
+ [ARM64,KNL]
+ Sets the size of kernel per-numa memory area for
+ contiguous memory allocations. A value of 0 disables
+ per-numa CMA altogether. And If this option is not
+ specificed, the default value is 0.
+ With per-numa CMA enabled, DMA users on node nid will
+ first try to allocate buffer from the pernuma area
+ which is located in node nid, if the allocation fails,
+ they will fallback to the global default memory area.
cmo_free_hint= [PPC] Format: { yes | no }
Specify whether pages are marked as being inactive
@@ -940,7 +951,7 @@
Arch Perfmon v4 (Skylake and newer).
disable_ddw [PPC/PSERIES]
- Disable Dynamic DMA Window support. Use this if
+ Disable Dynamic DMA Window support. Use this
to workaround buggy firmware.
disable_ipv6= [IPV6]
@@ -1019,7 +1030,7 @@
what data is available or for reverse-engineering.
dyndbg[="val"] [KNL,DYNAMIC_DEBUG]
- module.dyndbg[="val"]
+ <module>.dyndbg[="val"]
Enable debug messages at boot time. See
Documentation/admin-guide/dynamic-debug-howto.rst
for details.
@@ -1027,7 +1038,7 @@
nopku [X86] Disable Memory Protection Keys CPU feature found
in some Intel CPUs.
- module.async_probe [KNL]
+ <module>.async_probe [KNL]
Enable asynchronous probe on this module.
early_ioremap_debug [KNL]
@@ -1233,8 +1244,7 @@
efi= [EFI]
Format: { "debug", "disable_early_pci_dma",
"nochunk", "noruntime", "nosoftreserve",
- "novamap", "no_disable_early_pci_dma",
- "old_map" }
+ "novamap", "no_disable_early_pci_dma" }
debug: enable misc debug output.
disable_early_pci_dma: disable the busmaster bit on all
PCI bridges while in the EFI boot stub.
@@ -1251,8 +1261,6 @@
novamap: do not call SetVirtualAddressMap().
no_disable_early_pci_dma: Leave the busmaster bit set
on all PCI bridges while in the EFI boot stub
- old_map [X86-64]: switch to the old ioremap-based EFI
- runtime services mapping. [Needs CONFIG_X86_UV=y]
efi_no_storage_paranoia [EFI; X86]
Using this parameter you can use more than 50% of
@@ -1959,7 +1967,7 @@
1 - Bypass the IOMMU for DMA.
unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
- io7= [HW] IO7 for Marvel based alpha systems
+ io7= [HW] IO7 for Marvel-based Alpha systems
See comment before marvel_specify_io7 in
arch/alpha/kernel/core_marvel.c.
@@ -2180,7 +2188,7 @@
kgdbwait [KGDB] Stop kernel execution and enter the
kernel debugger at the earliest opportunity.
- kmac= [MIPS] korina ethernet MAC address.
+ kmac= [MIPS] Korina ethernet MAC address.
Configure the RouterBoard 532 series on-chip
Ethernet adapter MAC address.
@@ -2261,6 +2269,14 @@
[KVM,ARM] Allow use of GICv4 for direct injection of
LPIs.
+ kvm_cma_resv_ratio=n [PPC]
+ Reserves given percentage from system memory area for
+ contiguous memory allocation for KVM hash pagetable
+ allocation.
+ By default it reserves 5% of total system memory.
+ Format: <integer>
+ Default: 5
+
kvm-intel.ept= [KVM,Intel] Disable extended page tables
(virtualized MMU) support on capable Intel chips.
Default is 1 (enabled)
@@ -2370,9 +2386,10 @@
lapic [X86-32,APIC] Enable the local APIC even if BIOS
disabled it.
- lapic= [X86,APIC] "notscdeadline" Do not use TSC deadline
+ lapic= [X86,APIC] Do not use TSC deadline
value for LAPIC timer one-shot implementation. Default
back to the programmable timer unit in the LAPIC.
+ Format: notscdeadline
lapic_timer_c2_ok [X86,APIC] trust the local apic timer
in C2 power state.
@@ -2444,8 +2461,7 @@
memblock=debug [KNL] Enable memblock debug messages.
- load_ramdisk= [RAM] List of ramdisks to load from floppy
- See Documentation/admin-guide/blockdev/ramdisk.rst.
+ load_ramdisk= [RAM] [Deprecated]
lockd.nlm_grace_period=P [NFS] Assign grace period.
Format: <integer>
@@ -2582,8 +2598,8 @@
(machvec) in a generic kernel.
Example: machvec=hpzx1
- machtype= [Loongson] Share the same kernel image file between different
- yeeloong laptop.
+ machtype= [Loongson] Share the same kernel image file between
+ different yeeloong laptops.
Example: machtype=lemote-yeeloong-2f-7inch
max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
@@ -3188,7 +3204,7 @@
register save and restore. The kernel will only save
legacy floating-point registers on task switch.
- nohugeiomap [KNL,X86,PPC] Disable kernel huge I/O mappings.
+ nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
nosmt [KNL,S390] Disable symmetric multithreading (SMT).
Equivalent to smt=1.
@@ -3924,9 +3940,7 @@
Param: <number> - step/bucket size as a power of 2 for
statistical time based profiling.
- prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
- before loading.
- See Documentation/admin-guide/blockdev/ramdisk.rst.
+ prompt_ramdisk= [RAM] [Deprecated]
prot_virt= [S390] enable hosting protected virtual machines
isolated from the hypervisor (if hardware supports
@@ -3984,6 +3998,8 @@
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
See Documentation/admin-guide/blockdev/ramdisk.rst.
+ ramdisk_start= [RAM] RAM disk image start address
+
random.trust_cpu={on,off}
[KNL] Enable or disable trusting the use of the
CPU's random number generator (if available) to