Commit | Line | Data |
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1da177e4 LT |
1 | AMD64 specific boot options |
2 | ||
3 | There are many others (usually documented in driver documentation), but | |
4 | only the AMD64 specific ones are listed here. | |
5 | ||
6 | Machine check | |
7 | ||
8 | mce=off disable machine check | |
d5172f26 | 9 | mce=bootlog Enable logging of machine checks left over from booting. |
e583538f | 10 | Disabled by default on AMD because some BIOS leave bogus ones. |
d5172f26 AK |
11 | If your BIOS doesn't do that it's a good idea to enable though |
12 | to make sure you log even machine check events that result | |
e583538f AK |
13 | in a reboot. On Intel systems it is enabled by default. |
14 | mce=nobootlog | |
15 | Disable boot machine check logging. | |
8c566ef5 AK |
16 | mce=tolerancelevel (number) |
17 | 0: always panic, 1: panic if deadlock possible, | |
18 | 2: try to avoid panic, 3: never panic or exit (for testing) | |
19 | default is 1 | |
20 | Can be also set using sysfs which is preferable. | |
1da177e4 LT |
21 | |
22 | nomce (for compatibility with i386): same as mce=off | |
23 | ||
24 | Everything else is in sysfs now. | |
25 | ||
26 | APICs | |
27 | ||
28 | apic Use IO-APIC. Default | |
29 | ||
30 | noapic Don't use the IO-APIC. | |
31 | ||
32 | disableapic Don't use the local APIC | |
33 | ||
34 | nolapic Don't use the local APIC (alias for i386 compatibility) | |
35 | ||
36 | pirq=... See Documentation/i386/IO-APIC.txt | |
37 | ||
38 | noapictimer Don't set up the APIC timer | |
39 | ||
14d98cad AK |
40 | no_timer_check Don't check the IO-APIC timer. This can work around |
41 | problems with incorrect timer initialization on some boards. | |
42 | ||
1da177e4 LT |
43 | Early Console |
44 | ||
45 | syntax: earlyprintk=vga | |
46 | earlyprintk=serial[,ttySn[,baudrate]] | |
47 | ||
48 | The early console is useful when the kernel crashes before the | |
49 | normal console is initialized. It is not enabled by | |
50 | default because it has some cosmetic problems. | |
51 | Append ,keep to not disable it when the real console takes over. | |
52 | Only vga or serial at a time, not both. | |
53 | Currently only ttyS0 and ttyS1 are supported. | |
54 | Interaction with the standard serial driver is not very good. | |
55 | The VGA output is eventually overwritten by the real console. | |
56 | ||
57 | Timing | |
58 | ||
59 | notsc | |
60 | Don't use the CPU time stamp counter to read the wall time. | |
61 | This can be used to work around timing problems on multiprocessor systems | |
ef4d7cbe | 62 | with not properly synchronized CPUs. |
1da177e4 LT |
63 | |
64 | report_lost_ticks | |
65 | Report when timer interrupts are lost because some code turned off | |
66 | interrupts for too long. | |
67 | ||
68 | nmi_watchdog=NUMBER[,panic] | |
69 | NUMBER can be: | |
70 | 0 don't use an NMI watchdog | |
71 | 1 use the IO-APIC timer for the NMI watchdog | |
72 | 2 use the local APIC for the NMI watchdog using a performance counter. Note | |
73 | This will use one performance counter and the local APIC's performance | |
74 | vector. | |
75 | When panic is specified panic when an NMI watchdog timeout occurs. | |
76 | This is useful when you use a panic=... timeout and need the box | |
77 | quickly up again. | |
78 | ||
79 | nohpet | |
80 | Don't use the HPET timer. | |
81 | ||
82 | Idle loop | |
83 | ||
84 | idle=poll | |
85 | Don't do power saving in the idle loop using HLT, but poll for rescheduling | |
86 | event. This will make the CPUs eat a lot more power, but may be useful | |
87 | to get slightly better performance in multiprocessor benchmarks. It also | |
88 | makes some profiling using performance counters more accurate. | |
ef4d7cbe AK |
89 | Please note that on systems with MONITOR/MWAIT support (like Intel EM64T |
90 | CPUs) this option has no performance advantage over the normal idle loop. | |
91 | It may also interact badly with hyperthreading. | |
1da177e4 LT |
92 | |
93 | Rebooting | |
94 | ||
95 | reboot=b[ios] | t[riple] | k[bd] [, [w]arm | [c]old] | |
96 | bios Use the CPU reboto vector for warm reset | |
97 | warm Don't set the cold reboot flag | |
98 | cold Set the cold reboot flag | |
99 | triple Force a triple fault (init) | |
100 | kbd Use the keyboard controller. cold reset (default) | |
101 | ||
102 | Using warm reset will be much faster especially on big memory | |
103 | systems because the BIOS will not go through the memory check. | |
104 | Disadvantage is that not all hardware will be completely reinitialized | |
105 | on reboot so there may be boot problems on some systems. | |
106 | ||
107 | reboot=force | |
108 | ||
109 | Don't stop other CPUs on reboot. This can make reboot more reliable | |
110 | in some cases. | |
111 | ||
112 | Non Executable Mappings | |
113 | ||
114 | noexec=on|off | |
115 | ||
116 | on Enable(default) | |
117 | off Disable | |
118 | ||
119 | SMP | |
120 | ||
121 | nosmp Only use a single CPU | |
122 | ||
123 | maxcpus=NUMBER only use upto NUMBER CPUs | |
124 | ||
125 | cpumask=MASK only use cpus with bits set in mask | |
126 | ||
420f8f68 | 127 | additional_cpus=NUM Allow NUM more CPUs for hotplug |
f62a91f6 | 128 | (defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec) |
420f8f68 | 129 | |
1da177e4 LT |
130 | NUMA |
131 | ||
132 | numa=off Only set up a single NUMA node spanning all memory. | |
133 | ||
134 | numa=noacpi Don't parse the SRAT table for NUMA setup | |
135 | ||
136 | numa=fake=X Fake X nodes and ignore NUMA setup of the actual machine. | |
137 | ||
138 | ACPI | |
139 | ||
140 | acpi=off Don't enable ACPI | |
141 | acpi=ht Use ACPI boot table parsing, but don't enable ACPI | |
142 | interpreter | |
143 | acpi=force Force ACPI on (currently not needed) | |
144 | ||
145 | acpi=strict Disable out of spec ACPI workarounds. | |
146 | ||
147 | acpi_sci={edge,level,high,low} Set up ACPI SCI interrupt. | |
148 | ||
149 | acpi=noirq Don't route interrupts | |
150 | ||
151 | PCI | |
152 | ||
153 | pci=off Don't use PCI | |
154 | pci=conf1 Use conf1 access. | |
155 | pci=conf2 Use conf2 access. | |
156 | pci=rom Assign ROMs. | |
157 | pci=assign-busses Assign busses | |
158 | pci=irqmask=MASK Set PCI interrupt mask to MASK | |
159 | pci=lastbus=NUMBER Scan upto NUMBER busses, no matter what the mptable says. | |
160 | pci=noacpi Don't use ACPI to set up PCI interrupt routing. | |
161 | ||
162 | IOMMU | |
163 | ||
164 | iommu=[size][,noagp][,off][,force][,noforce][,leak][,memaper[=order]][,merge] | |
165 | [,forcesac][,fullflush][,nomerge][,noaperture] | |
166 | size set size of iommu (in bytes) | |
167 | noagp don't initialize the AGP driver and use full aperture. | |
168 | off don't use the IOMMU | |
169 | leak turn on simple iommu leak tracing (only when CONFIG_IOMMU_LEAK is on) | |
170 | memaper[=order] allocate an own aperture over RAM with size 32MB^order. | |
171 | noforce don't force IOMMU usage. Default. | |
172 | force Force IOMMU. | |
173 | merge Do SG merging. Implies force (experimental) | |
174 | nomerge Don't do SG merging. | |
175 | forcesac For SAC mode for masks <40bits (experimental) | |
176 | fullflush Flush IOMMU on each allocation (default) | |
177 | nofullflush Don't use IOMMU fullflush | |
178 | allowed overwrite iommu off workarounds for specific chipsets. | |
179 | soft Use software bounce buffering (default for Intel machines) | |
180 | noaperture Don't touch the aperture for AGP. | |
181 | ||
182 | swiotlb=pages[,force] | |
183 | ||
184 | pages Prereserve that many 128K pages for the software IO bounce buffering. | |
185 | force Force all IO through the software TLB. | |
186 | ||
187 | Debugging | |
188 | ||
189 | oops=panic Always panic on oopses. Default is to just kill the process, | |
190 | but there is a small probability of deadlocking the machine. | |
191 | This will also cause panics on machine check exceptions. | |
192 | Useful together with panic=30 to trigger a reboot. | |
193 | ||
194 | kstack=N Print that many words from the kernel stack in oops dumps. | |
195 | ||
9e43e1b7 AK |
196 | pagefaulttrace Dump all page faults. Only useful for extreme debugging |
197 | and will create a lot of output. | |
198 | ||
1da177e4 LT |
199 | Misc |
200 | ||
575c9687 | 201 | noreplacement Don't replace instructions with more appropriate ones |
ef4d7cbe AK |
202 | for the CPU. This may be useful on asymmetric MP systems |
203 | where some CPU have less capabilities than the others. |