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