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1# SPDX-License-Identifier: GPL-2.0
2
3config TRACE_IRQFLAGS_SUPPORT
4 def_bool y
5
6config TRACE_IRQFLAGS_NMI_SUPPORT
7 def_bool y
8
9config EARLY_PRINTK_USB
10 bool
11
12config X86_VERBOSE_BOOTUP
13 bool "Enable verbose x86 bootup info messages"
14 default y
15 help
16 Enables the informational output from the decompression stage
17 (e.g. bzImage) of the boot. If you disable this you will still
18 see errors. Disable this if you want silent bootup.
19
20config EARLY_PRINTK
21 bool "Early printk" if EXPERT
22 default y
23 help
24 Write kernel log output directly into the VGA buffer or to a serial
25 port.
26
27 This is useful for kernel debugging when your machine crashes very
28 early before the console code is initialized. For normal operation
29 it is not recommended because it looks ugly and doesn't cooperate
30 with klogd/syslogd or the X server. You should normally say N here,
31 unless you want to debug such a crash.
32
33config EARLY_PRINTK_DBGP
34 bool "Early printk via EHCI debug port"
35 depends on EARLY_PRINTK && PCI
36 select EARLY_PRINTK_USB
37 help
38 Write kernel log output directly into the EHCI debug port.
39
40 This is useful for kernel debugging when your machine crashes very
41 early before the console code is initialized. For normal operation
42 it is not recommended because it looks ugly and doesn't cooperate
43 with klogd/syslogd or the X server. You should normally say N here,
44 unless you want to debug such a crash. You need usb debug device.
45
46config EARLY_PRINTK_USB_XDBC
47 bool "Early printk via the xHCI debug port"
48 depends on EARLY_PRINTK && PCI
49 select EARLY_PRINTK_USB
50 help
51 Write kernel log output directly into the xHCI debug port.
52
53 One use for this feature is kernel debugging, for example when your
54 machine crashes very early before the regular console code is
55 initialized. Other uses include simpler, lockless logging instead of
56 a full-blown printk console driver + klogd.
57
58 For normal production environments this is normally not recommended,
59 because it doesn't feed events into klogd/syslogd and doesn't try to
60 print anything on the screen.
61
62 You should normally say N here, unless you want to debug early
63 crashes or need a very simple printk logging facility.
64
65config MCSAFE_TEST
66 def_bool n
67
68config EFI_PGT_DUMP
69 bool "Dump the EFI pagetable"
70 depends on EFI
71 select PTDUMP_CORE
72 help
73 Enable this if you want to dump the EFI page table before
74 enabling virtual mode. This can be used to debug miscellaneous
75 issues with the mapping of the EFI runtime regions into that
76 table.
77
78config DEBUG_TLBFLUSH
79 bool "Set upper limit of TLB entries to flush one-by-one"
80 depends on DEBUG_KERNEL
81 help
82
83 X86-only for now.
84
85 This option allows the user to tune the amount of TLB entries the
86 kernel flushes one-by-one instead of doing a full TLB flush. In
87 certain situations, the former is cheaper. This is controlled by the
88 tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
89 to -1, the code flushes the whole TLB unconditionally. Otherwise,
90 for positive values of it, the kernel will use single TLB entry
91 invalidating instructions according to the following formula:
92
93 flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
94
95 If in doubt, say "N".
96
97config IOMMU_DEBUG
98 bool "Enable IOMMU debugging"
99 depends on GART_IOMMU && DEBUG_KERNEL
100 depends on X86_64
101 help
102 Force the IOMMU to on even when you have less than 4GB of
103 memory and add debugging code. On overflow always panic. And
104 allow to enable IOMMU leak tracing. Can be disabled at boot
105 time with iommu=noforce. This will also enable scatter gather
106 list merging. Currently not recommended for production
107 code. When you use it make sure you have a big enough
108 IOMMU/AGP aperture. Most of the options enabled by this can
109 be set more finegrained using the iommu= command line
110 options. See Documentation/x86/x86_64/boot-options.rst for more
111 details.
112
113config IOMMU_LEAK
114 bool "IOMMU leak tracing"
115 depends on IOMMU_DEBUG && DMA_API_DEBUG
116 help
117 Add a simple leak tracer to the IOMMU code. This is useful when you
118 are debugging a buggy device driver that leaks IOMMU mappings.
119
120config HAVE_MMIOTRACE_SUPPORT
121 def_bool y
122
123config X86_DECODER_SELFTEST
124 bool "x86 instruction decoder selftest"
125 depends on DEBUG_KERNEL && INSTRUCTION_DECODER
126 depends on !COMPILE_TEST
127 help
128 Perform x86 instruction decoder selftests at build time.
129 This option is useful for checking the sanity of x86 instruction
130 decoder code.
131 If unsure, say "N".
132
133choice
134 prompt "IO delay type"
135 default IO_DELAY_0X80
136
137config IO_DELAY_0X80
138 bool "port 0x80 based port-IO delay [recommended]"
139 help
140 This is the traditional Linux IO delay used for in/out_p.
141 It is the most tested hence safest selection here.
142
143config IO_DELAY_0XED
144 bool "port 0xed based port-IO delay"
145 help
146 Use port 0xed as the IO delay. This frees up port 0x80 which is
147 often used as a hardware-debug port.
148
149config IO_DELAY_UDELAY
150 bool "udelay based port-IO delay"
151 help
152 Use udelay(2) as the IO delay method. This provides the delay
153 while not having any side-effect on the IO port space.
154
155config IO_DELAY_NONE
156 bool "no port-IO delay"
157 help
158 No port-IO delay. Will break on old boxes that require port-IO
159 delay for certain operations. Should work on most new machines.
160
161endchoice
162
163config DEBUG_BOOT_PARAMS
164 bool "Debug boot parameters"
165 depends on DEBUG_KERNEL
166 depends on DEBUG_FS
167 help
168 This option will cause struct boot_params to be exported via debugfs.
169
170config CPA_DEBUG
171 bool "CPA self-test code"
172 depends on DEBUG_KERNEL
173 help
174 Do change_page_attr() self-tests every 30 seconds.
175
176config DEBUG_ENTRY
177 bool "Debug low-level entry code"
178 depends on DEBUG_KERNEL
179 help
180 This option enables sanity checks in x86's low-level entry code.
181 Some of these sanity checks may slow down kernel entries and
182 exits or otherwise impact performance.
183
184 If unsure, say N.
185
186config DEBUG_NMI_SELFTEST
187 bool "NMI Selftest"
188 depends on DEBUG_KERNEL && X86_LOCAL_APIC
189 help
190 Enabling this option turns on a quick NMI selftest to verify
191 that the NMI behaves correctly.
192
193 This might help diagnose strange hangs that rely on NMI to
194 function properly.
195
196 If unsure, say N.
197
198config DEBUG_IMR_SELFTEST
199 bool "Isolated Memory Region self test"
200 depends on INTEL_IMR
201 help
202 This option enables automated sanity testing of the IMR code.
203 Some simple tests are run to verify IMR bounds checking, alignment
204 and overlapping. This option is really only useful if you are
205 debugging an IMR memory map or are modifying the IMR code and want to
206 test your changes.
207
208 If unsure say N here.
209
210config X86_DEBUG_FPU
211 bool "Debug the x86 FPU code"
212 depends on DEBUG_KERNEL
213 default y
214 help
215 If this option is enabled then there will be extra sanity
216 checks and (boot time) debug printouts added to the kernel.
217 This debugging adds some small amount of runtime overhead
218 to the kernel.
219
220 If unsure, say N.
221
222config PUNIT_ATOM_DEBUG
223 tristate "ATOM Punit debug driver"
224 depends on PCI
225 select DEBUG_FS
226 select IOSF_MBI
227 help
228 This is a debug driver, which gets the power states
229 of all Punit North Complex devices. The power states of
230 each device is exposed as part of the debugfs interface.
231 The current power state can be read from
232 /sys/kernel/debug/punit_atom/dev_power_state
233
234choice
235 prompt "Choose kernel unwinder"
236 default UNWINDER_ORC if X86_64
237 default UNWINDER_FRAME_POINTER if X86_32
238 help
239 This determines which method will be used for unwinding kernel stack
240 traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack,
241 livepatch, lockdep, and more.
242
243config UNWINDER_ORC
244 bool "ORC unwinder"
245 depends on X86_64
246 select STACK_VALIDATION
247 help
248 This option enables the ORC (Oops Rewind Capability) unwinder for
249 unwinding kernel stack traces. It uses a custom data format which is
250 a simplified version of the DWARF Call Frame Information standard.
251
252 This unwinder is more accurate across interrupt entry frames than the
253 frame pointer unwinder. It also enables a 5-10% performance
254 improvement across the entire kernel compared to frame pointers.
255
256 Enabling this option will increase the kernel's runtime memory usage
257 by roughly 2-4MB, depending on your kernel config.
258
259config UNWINDER_FRAME_POINTER
260 bool "Frame pointer unwinder"
261 select FRAME_POINTER
262 help
263 This option enables the frame pointer unwinder for unwinding kernel
264 stack traces.
265
266 The unwinder itself is fast and it uses less RAM than the ORC
267 unwinder, but the kernel text size will grow by ~3% and the kernel's
268 overall performance will degrade by roughly 5-10%.
269
270config UNWINDER_GUESS
271 bool "Guess unwinder"
272 depends on EXPERT
273 depends on !STACKDEPOT
274 help
275 This option enables the "guess" unwinder for unwinding kernel stack
276 traces. It scans the stack and reports every kernel text address it
277 finds. Some of the addresses it reports may be incorrect.
278
279 While this option often produces false positives, it can still be
280 useful in many cases. Unlike the other unwinders, it has no runtime
281 overhead.
282
283endchoice
284
285config FRAME_POINTER
286 depends on !UNWINDER_ORC && !UNWINDER_GUESS
287 bool
1# SPDX-License-Identifier: GPL-2.0
2
3config EARLY_PRINTK_USB
4 bool
5
6config X86_VERBOSE_BOOTUP
7 bool "Enable verbose x86 bootup info messages"
8 default y
9 help
10 Enables the informational output from the decompression stage
11 (e.g. bzImage) of the boot. If you disable this you will still
12 see errors. Disable this if you want silent bootup.
13
14config EARLY_PRINTK
15 bool "Early printk" if EXPERT
16 default y
17 help
18 Write kernel log output directly into the VGA buffer or to a serial
19 port.
20
21 This is useful for kernel debugging when your machine crashes very
22 early before the console code is initialized. For normal operation
23 it is not recommended because it looks ugly and doesn't cooperate
24 with klogd/syslogd or the X server. You should normally say N here,
25 unless you want to debug such a crash.
26
27config EARLY_PRINTK_DBGP
28 bool "Early printk via EHCI debug port"
29 depends on EARLY_PRINTK && PCI
30 select EARLY_PRINTK_USB
31 help
32 Write kernel log output directly into the EHCI debug port.
33
34 This is useful for kernel debugging when your machine crashes very
35 early before the console code is initialized. For normal operation
36 it is not recommended because it looks ugly and doesn't cooperate
37 with klogd/syslogd or the X server. You should normally say N here,
38 unless you want to debug such a crash. You need usb debug device.
39
40config EARLY_PRINTK_USB_XDBC
41 bool "Early printk via the xHCI debug port"
42 depends on EARLY_PRINTK && PCI
43 select EARLY_PRINTK_USB
44 help
45 Write kernel log output directly into the xHCI debug port.
46
47 One use for this feature is kernel debugging, for example when your
48 machine crashes very early before the regular console code is
49 initialized. Other uses include simpler, lockless logging instead of
50 a full-blown printk console driver + klogd.
51
52 For normal production environments this is normally not recommended,
53 because it doesn't feed events into klogd/syslogd and doesn't try to
54 print anything on the screen.
55
56 You should normally say N here, unless you want to debug early
57 crashes or need a very simple printk logging facility.
58
59config EFI_PGT_DUMP
60 bool "Dump the EFI pagetable"
61 depends on EFI
62 select PTDUMP_CORE
63 help
64 Enable this if you want to dump the EFI page table before
65 enabling virtual mode. This can be used to debug miscellaneous
66 issues with the mapping of the EFI runtime regions into that
67 table.
68
69config DEBUG_TLBFLUSH
70 bool "Set upper limit of TLB entries to flush one-by-one"
71 depends on DEBUG_KERNEL
72 help
73 X86-only for now.
74
75 This option allows the user to tune the amount of TLB entries the
76 kernel flushes one-by-one instead of doing a full TLB flush. In
77 certain situations, the former is cheaper. This is controlled by the
78 tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
79 to -1, the code flushes the whole TLB unconditionally. Otherwise,
80 for positive values of it, the kernel will use single TLB entry
81 invalidating instructions according to the following formula:
82
83 flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
84
85 If in doubt, say "N".
86
87config IOMMU_DEBUG
88 bool "Enable IOMMU debugging"
89 depends on GART_IOMMU && DEBUG_KERNEL
90 depends on X86_64
91 help
92 Force the IOMMU to on even when you have less than 4GB of
93 memory and add debugging code. On overflow always panic. And
94 allow to enable IOMMU leak tracing. Can be disabled at boot
95 time with iommu=noforce. This will also enable scatter gather
96 list merging. Currently not recommended for production
97 code. When you use it make sure you have a big enough
98 IOMMU/AGP aperture. Most of the options enabled by this can
99 be set more finegrained using the iommu= command line
100 options. See Documentation/arch/x86/x86_64/boot-options.rst for more
101 details.
102
103config IOMMU_LEAK
104 bool "IOMMU leak tracing"
105 depends on IOMMU_DEBUG && DMA_API_DEBUG
106 help
107 Add a simple leak tracer to the IOMMU code. This is useful when you
108 are debugging a buggy device driver that leaks IOMMU mappings.
109
110config HAVE_MMIOTRACE_SUPPORT
111 def_bool y
112
113config X86_DECODER_SELFTEST
114 bool "x86 instruction decoder selftest"
115 depends on DEBUG_KERNEL && INSTRUCTION_DECODER
116 depends on !COMPILE_TEST
117 help
118 Perform x86 instruction decoder selftests at build time.
119 This option is useful for checking the sanity of x86 instruction
120 decoder code.
121 If unsure, say "N".
122
123choice
124 prompt "IO delay type"
125 default IO_DELAY_0X80
126
127config IO_DELAY_0X80
128 bool "port 0x80 based port-IO delay [recommended]"
129 help
130 This is the traditional Linux IO delay used for in/out_p.
131 It is the most tested hence safest selection here.
132
133config IO_DELAY_0XED
134 bool "port 0xed based port-IO delay"
135 help
136 Use port 0xed as the IO delay. This frees up port 0x80 which is
137 often used as a hardware-debug port.
138
139config IO_DELAY_UDELAY
140 bool "udelay based port-IO delay"
141 help
142 Use udelay(2) as the IO delay method. This provides the delay
143 while not having any side-effect on the IO port space.
144
145config IO_DELAY_NONE
146 bool "no port-IO delay"
147 help
148 No port-IO delay. Will break on old boxes that require port-IO
149 delay for certain operations. Should work on most new machines.
150
151endchoice
152
153config DEBUG_BOOT_PARAMS
154 bool "Debug boot parameters"
155 depends on DEBUG_KERNEL
156 depends on DEBUG_FS
157 help
158 This option will cause struct boot_params to be exported via debugfs.
159
160config CPA_DEBUG
161 bool "CPA self-test code"
162 depends on DEBUG_KERNEL
163 help
164 Do change_page_attr() self-tests every 30 seconds.
165
166config DEBUG_ENTRY
167 bool "Debug low-level entry code"
168 depends on DEBUG_KERNEL
169 help
170 This option enables sanity checks in x86's low-level entry code.
171 Some of these sanity checks may slow down kernel entries and
172 exits or otherwise impact performance.
173
174 If unsure, say N.
175
176config DEBUG_NMI_SELFTEST
177 bool "NMI Selftest"
178 depends on DEBUG_KERNEL && X86_LOCAL_APIC
179 help
180 Enabling this option turns on a quick NMI selftest to verify
181 that the NMI behaves correctly.
182
183 This might help diagnose strange hangs that rely on NMI to
184 function properly.
185
186 If unsure, say N.
187
188config DEBUG_IMR_SELFTEST
189 bool "Isolated Memory Region self test"
190 depends on INTEL_IMR
191 help
192 This option enables automated sanity testing of the IMR code.
193 Some simple tests are run to verify IMR bounds checking, alignment
194 and overlapping. This option is really only useful if you are
195 debugging an IMR memory map or are modifying the IMR code and want to
196 test your changes.
197
198 If unsure say N here.
199
200config X86_DEBUG_FPU
201 bool "Debug the x86 FPU code"
202 depends on DEBUG_KERNEL
203 default y
204 help
205 If this option is enabled then there will be extra sanity
206 checks and (boot time) debug printouts added to the kernel.
207 This debugging adds some small amount of runtime overhead
208 to the kernel.
209
210 If unsure, say N.
211
212config PUNIT_ATOM_DEBUG
213 tristate "ATOM Punit debug driver"
214 depends on PCI
215 select DEBUG_FS
216 select IOSF_MBI
217 help
218 This is a debug driver, which gets the power states
219 of all Punit North Complex devices. The power states of
220 each device is exposed as part of the debugfs interface.
221 The current power state can be read from
222 /sys/kernel/debug/punit_atom/dev_power_state
223
224choice
225 prompt "Choose kernel unwinder"
226 default UNWINDER_ORC if X86_64
227 default UNWINDER_FRAME_POINTER if X86_32
228 help
229 This determines which method will be used for unwinding kernel stack
230 traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack,
231 livepatch, lockdep, and more.
232
233config UNWINDER_ORC
234 bool "ORC unwinder"
235 depends on X86_64
236 select OBJTOOL
237 help
238 This option enables the ORC (Oops Rewind Capability) unwinder for
239 unwinding kernel stack traces. It uses a custom data format which is
240 a simplified version of the DWARF Call Frame Information standard.
241
242 This unwinder is more accurate across interrupt entry frames than the
243 frame pointer unwinder. It also enables a 5-10% performance
244 improvement across the entire kernel compared to frame pointers.
245
246 Enabling this option will increase the kernel's runtime memory usage
247 by roughly 2-4MB, depending on your kernel config.
248
249config UNWINDER_FRAME_POINTER
250 bool "Frame pointer unwinder"
251 select ARCH_WANT_FRAME_POINTERS
252 select FRAME_POINTER
253 help
254 This option enables the frame pointer unwinder for unwinding kernel
255 stack traces.
256
257 The unwinder itself is fast and it uses less RAM than the ORC
258 unwinder, but the kernel text size will grow by ~3% and the kernel's
259 overall performance will degrade by roughly 5-10%.
260
261config UNWINDER_GUESS
262 bool "Guess unwinder"
263 depends on EXPERT
264 depends on !STACKDEPOT
265 help
266 This option enables the "guess" unwinder for unwinding kernel stack
267 traces. It scans the stack and reports every kernel text address it
268 finds. Some of the addresses it reports may be incorrect.
269
270 While this option often produces false positives, it can still be
271 useful in many cases. Unlike the other unwinders, it has no runtime
272 overhead.
273
274endchoice