Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1# SPDX-License-Identifier: GPL-2.0
2
3config TRACE_IRQFLAGS_SUPPORT
4 def_bool y
5
6config EARLY_PRINTK_USB
7 bool
8
9config X86_VERBOSE_BOOTUP
10 bool "Enable verbose x86 bootup info messages"
11 default y
12 help
13 Enables the informational output from the decompression stage
14 (e.g. bzImage) of the boot. If you disable this you will still
15 see errors. Disable this if you want silent bootup.
16
17config EARLY_PRINTK
18 bool "Early printk" if EXPERT
19 default y
20 help
21 Write kernel log output directly into the VGA buffer or to a serial
22 port.
23
24 This is useful for kernel debugging when your machine crashes very
25 early before the console code is initialized. For normal operation
26 it is not recommended because it looks ugly and doesn't cooperate
27 with klogd/syslogd or the X server. You should normally say N here,
28 unless you want to debug such a crash.
29
30config EARLY_PRINTK_DBGP
31 bool "Early printk via EHCI debug port"
32 depends on EARLY_PRINTK && PCI
33 select EARLY_PRINTK_USB
34 help
35 Write kernel log output directly into the EHCI debug port.
36
37 This is useful for kernel debugging when your machine crashes very
38 early before the console code is initialized. For normal operation
39 it is not recommended because it looks ugly and doesn't cooperate
40 with klogd/syslogd or the X server. You should normally say N here,
41 unless you want to debug such a crash. You need usb debug device.
42
43config EARLY_PRINTK_USB_XDBC
44 bool "Early printk via the xHCI debug port"
45 depends on EARLY_PRINTK && PCI
46 select EARLY_PRINTK_USB
47 help
48 Write kernel log output directly into the xHCI debug port.
49
50 One use for this feature is kernel debugging, for example when your
51 machine crashes very early before the regular console code is
52 initialized. Other uses include simpler, lockless logging instead of
53 a full-blown printk console driver + klogd.
54
55 For normal production environments this is normally not recommended,
56 because it doesn't feed events into klogd/syslogd and doesn't try to
57 print anything on the screen.
58
59 You should normally say N here, unless you want to debug early
60 crashes or need a very simple printk logging facility.
61
62config MCSAFE_TEST
63 def_bool n
64
65config EFI_PGT_DUMP
66 bool "Dump the EFI pagetable"
67 depends on EFI
68 select PTDUMP_CORE
69 help
70 Enable this if you want to dump the EFI page table before
71 enabling virtual mode. This can be used to debug miscellaneous
72 issues with the mapping of the EFI runtime regions into that
73 table.
74
75config DEBUG_TLBFLUSH
76 bool "Set upper limit of TLB entries to flush one-by-one"
77 depends on DEBUG_KERNEL
78 help
79
80 X86-only for now.
81
82 This option allows the user to tune the amount of TLB entries the
83 kernel flushes one-by-one instead of doing a full TLB flush. In
84 certain situations, the former is cheaper. This is controlled by the
85 tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
86 to -1, the code flushes the whole TLB unconditionally. Otherwise,
87 for positive values of it, the kernel will use single TLB entry
88 invalidating instructions according to the following formula:
89
90 flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
91
92 If in doubt, say "N".
93
94config IOMMU_DEBUG
95 bool "Enable IOMMU debugging"
96 depends on GART_IOMMU && DEBUG_KERNEL
97 depends on X86_64
98 help
99 Force the IOMMU to on even when you have less than 4GB of
100 memory and add debugging code. On overflow always panic. And
101 allow to enable IOMMU leak tracing. Can be disabled at boot
102 time with iommu=noforce. This will also enable scatter gather
103 list merging. Currently not recommended for production
104 code. When you use it make sure you have a big enough
105 IOMMU/AGP aperture. Most of the options enabled by this can
106 be set more finegrained using the iommu= command line
107 options. See Documentation/x86/x86_64/boot-options.rst for more
108 details.
109
110config IOMMU_LEAK
111 bool "IOMMU leak tracing"
112 depends on IOMMU_DEBUG && DMA_API_DEBUG
113 help
114 Add a simple leak tracer to the IOMMU code. This is useful when you
115 are debugging a buggy device driver that leaks IOMMU mappings.
116
117config HAVE_MMIOTRACE_SUPPORT
118 def_bool y
119
120config X86_DECODER_SELFTEST
121 bool "x86 instruction decoder selftest"
122 depends on DEBUG_KERNEL && INSTRUCTION_DECODER
123 depends on !COMPILE_TEST
124 help
125 Perform x86 instruction decoder selftests at build time.
126 This option is useful for checking the sanity of x86 instruction
127 decoder code.
128 If unsure, say "N".
129
130choice
131 prompt "IO delay type"
132 default IO_DELAY_0X80
133
134config IO_DELAY_0X80
135 bool "port 0x80 based port-IO delay [recommended]"
136 help
137 This is the traditional Linux IO delay used for in/out_p.
138 It is the most tested hence safest selection here.
139
140config IO_DELAY_0XED
141 bool "port 0xed based port-IO delay"
142 help
143 Use port 0xed as the IO delay. This frees up port 0x80 which is
144 often used as a hardware-debug port.
145
146config IO_DELAY_UDELAY
147 bool "udelay based port-IO delay"
148 help
149 Use udelay(2) as the IO delay method. This provides the delay
150 while not having any side-effect on the IO port space.
151
152config IO_DELAY_NONE
153 bool "no port-IO delay"
154 help
155 No port-IO delay. Will break on old boxes that require port-IO
156 delay for certain operations. Should work on most new machines.
157
158endchoice
159
160config DEBUG_BOOT_PARAMS
161 bool "Debug boot parameters"
162 depends on DEBUG_KERNEL
163 depends on DEBUG_FS
164 help
165 This option will cause struct boot_params to be exported via debugfs.
166
167config CPA_DEBUG
168 bool "CPA self-test code"
169 depends on DEBUG_KERNEL
170 help
171 Do change_page_attr() self-tests every 30 seconds.
172
173config DEBUG_ENTRY
174 bool "Debug low-level entry code"
175 depends on DEBUG_KERNEL
176 help
177 This option enables sanity checks in x86's low-level entry code.
178 Some of these sanity checks may slow down kernel entries and
179 exits or otherwise impact performance.
180
181 If unsure, say N.
182
183config DEBUG_NMI_SELFTEST
184 bool "NMI Selftest"
185 depends on DEBUG_KERNEL && X86_LOCAL_APIC
186 help
187 Enabling this option turns on a quick NMI selftest to verify
188 that the NMI behaves correctly.
189
190 This might help diagnose strange hangs that rely on NMI to
191 function properly.
192
193 If unsure, say N.
194
195config DEBUG_IMR_SELFTEST
196 bool "Isolated Memory Region self test"
197 depends on INTEL_IMR
198 help
199 This option enables automated sanity testing of the IMR code.
200 Some simple tests are run to verify IMR bounds checking, alignment
201 and overlapping. This option is really only useful if you are
202 debugging an IMR memory map or are modifying the IMR code and want to
203 test your changes.
204
205 If unsure say N here.
206
207config X86_DEBUG_FPU
208 bool "Debug the x86 FPU code"
209 depends on DEBUG_KERNEL
210 default y
211 help
212 If this option is enabled then there will be extra sanity
213 checks and (boot time) debug printouts added to the kernel.
214 This debugging adds some small amount of runtime overhead
215 to the kernel.
216
217 If unsure, say N.
218
219config PUNIT_ATOM_DEBUG
220 tristate "ATOM Punit debug driver"
221 depends on PCI
222 select DEBUG_FS
223 select IOSF_MBI
224 help
225 This is a debug driver, which gets the power states
226 of all Punit North Complex devices. The power states of
227 each device is exposed as part of the debugfs interface.
228 The current power state can be read from
229 /sys/kernel/debug/punit_atom/dev_power_state
230
231choice
232 prompt "Choose kernel unwinder"
233 default UNWINDER_ORC if X86_64
234 default UNWINDER_FRAME_POINTER if X86_32
235 help
236 This determines which method will be used for unwinding kernel stack
237 traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack,
238 livepatch, lockdep, and more.
239
240config UNWINDER_ORC
241 bool "ORC unwinder"
242 depends on X86_64
243 select STACK_VALIDATION
244 help
245 This option enables the ORC (Oops Rewind Capability) unwinder for
246 unwinding kernel stack traces. It uses a custom data format which is
247 a simplified version of the DWARF Call Frame Information standard.
248
249 This unwinder is more accurate across interrupt entry frames than the
250 frame pointer unwinder. It also enables a 5-10% performance
251 improvement across the entire kernel compared to frame pointers.
252
253 Enabling this option will increase the kernel's runtime memory usage
254 by roughly 2-4MB, depending on your kernel config.
255
256config UNWINDER_FRAME_POINTER
257 bool "Frame pointer unwinder"
258 select FRAME_POINTER
259 help
260 This option enables the frame pointer unwinder for unwinding kernel
261 stack traces.
262
263 The unwinder itself is fast and it uses less RAM than the ORC
264 unwinder, but the kernel text size will grow by ~3% and the kernel's
265 overall performance will degrade by roughly 5-10%.
266
267config UNWINDER_GUESS
268 bool "Guess unwinder"
269 depends on EXPERT
270 depends on !STACKDEPOT
271 help
272 This option enables the "guess" unwinder for unwinding kernel stack
273 traces. It scans the stack and reports every kernel text address it
274 finds. Some of the addresses it reports may be incorrect.
275
276 While this option often produces false positives, it can still be
277 useful in many cases. Unlike the other unwinders, it has no runtime
278 overhead.
279
280endchoice
281
282config FRAME_POINTER
283 depends on !UNWINDER_ORC && !UNWINDER_GUESS
284 bool