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