3 config TRACE_IRQFLAGS_SUPPORT
6 source "lib/Kconfig.debug"
8 config X86_VERBOSE_BOOTUP
9 bool "Enable verbose x86 bootup info messages"
12 Enables the informational output from the decompression stage
13 (e.g. bzImage) of the boot. If you disable this you will still
14 see errors. Disable this if you want silent bootup.
17 bool "Early printk" if EXPERT
20 Write kernel log output directly into the VGA buffer or to a serial
23 This is useful for kernel debugging when your machine crashes very
24 early before the console code is initialized. For normal operation
25 it is not recommended because it looks ugly and doesn't cooperate
26 with klogd/syslogd or the X server. You should normally N here,
27 unless you want to debug such a crash.
29 config EARLY_PRINTK_DBGP
30 bool "Early printk via EHCI debug port"
31 depends on EARLY_PRINTK && PCI
33 Write kernel log output directly into the EHCI debug port.
35 This is useful for kernel debugging when your machine crashes very
36 early before the console code is initialized. For normal operation
37 it is not recommended because it looks ugly and doesn't cooperate
38 with klogd/syslogd or the X server. You should normally N here,
39 unless you want to debug such a crash. You need usb debug device.
41 config EARLY_PRINTK_EFI
42 bool "Early printk via the EFI framebuffer"
43 depends on EFI && EARLY_PRINTK
46 Write kernel log output directly into the EFI framebuffer.
48 This is useful for kernel debugging when your machine crashes very
49 early before the console code is initialized.
51 config X86_PTDUMP_CORE
55 tristate "Export kernel pagetable layout to userspace via debugfs"
56 depends on DEBUG_KERNEL
58 select X86_PTDUMP_CORE
60 Say Y here if you want to show the kernel pagetable layout in a
61 debugfs file. This information is only useful for kernel developers
62 who are working in architecture specific areas of the kernel.
63 It is probably not a good idea to enable this feature in a production
68 bool "Dump the EFI pagetable"
70 select X86_PTDUMP_CORE
72 Enable this if you want to dump the EFI page table before
73 enabling virtual mode. This can be used to debug miscellaneous
74 issues with the mapping of the EFI runtime regions into that
77 config DEBUG_RODATA_TEST
78 bool "Testcase for the marking rodata read-only"
81 This option enables a testcase for the setting rodata read-only
82 as well as for the change_page_attr() infrastructure.
86 bool "Warn on W+X mappings at boot"
87 select X86_PTDUMP_CORE
89 Generate a warning if any W+X mappings are found at boot.
91 This is useful for discovering cases where the kernel is leaving
92 W+X mappings after applying NX, as such mappings are a security risk.
94 Look for a message in dmesg output like this:
96 x86/mm: Checked W+X mappings: passed, no W+X pages found.
98 or like this, if the check failed:
100 x86/mm: Checked W+X mappings: FAILED, <N> W+X pages found.
102 Note that even if the check fails, your kernel is possibly
103 still fine, as W+X mappings are not a security hole in
104 themselves, what they do is that they make the exploitation
105 of other unfixed kernel bugs easier.
107 There is no runtime or memory usage effect of this option
108 once the kernel has booted up - it's a one time check.
110 If in doubt, say "Y".
113 tristate "Testcase for the NX non-executable stack feature"
114 depends on DEBUG_KERNEL && m
116 This option enables a testcase for the CPU NX capability
117 and the software setup of this feature.
122 bool "Enable doublefault exception handler" if EXPERT
124 This option allows trapping of rare doublefault exceptions that
125 would otherwise cause a system to silently reboot. Disabling this
126 option saves about 4k and might cause you much additional grey
129 config DEBUG_TLBFLUSH
130 bool "Set upper limit of TLB entries to flush one-by-one"
131 depends on DEBUG_KERNEL
136 This option allows the user to tune the amount of TLB entries the
137 kernel flushes one-by-one instead of doing a full TLB flush. In
138 certain situations, the former is cheaper. This is controlled by the
139 tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
140 to -1, the code flushes the whole TLB unconditionally. Otherwise,
141 for positive values of it, the kernel will use single TLB entry
142 invalidating instructions according to the following formula:
144 flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
146 If in doubt, say "N".
149 bool "Enable IOMMU debugging"
150 depends on GART_IOMMU && DEBUG_KERNEL
153 Force the IOMMU to on even when you have less than 4GB of
154 memory and add debugging code. On overflow always panic. And
155 allow to enable IOMMU leak tracing. Can be disabled at boot
156 time with iommu=noforce. This will also enable scatter gather
157 list merging. Currently not recommended for production
158 code. When you use it make sure you have a big enough
159 IOMMU/AGP aperture. Most of the options enabled by this can
160 be set more finegrained using the iommu= command line
161 options. See Documentation/x86/x86_64/boot-options.txt for more
165 bool "Enable IOMMU stress-test mode"
167 This option disables various optimizations in IOMMU related
168 code to do real stress testing of the IOMMU code. This option
169 will cause a performance drop and should only be enabled for
173 bool "IOMMU leak tracing"
174 depends on IOMMU_DEBUG && DMA_API_DEBUG
176 Add a simple leak tracer to the IOMMU code. This is useful when you
177 are debugging a buggy device driver that leaks IOMMU mappings.
179 config HAVE_MMIOTRACE_SUPPORT
182 config X86_DECODER_SELFTEST
183 bool "x86 instruction decoder selftest"
184 depends on DEBUG_KERNEL && KPROBES
185 depends on !COMPILE_TEST
187 Perform x86 instruction decoder selftests at build time.
188 This option is useful for checking the sanity of x86 instruction
196 config IO_DELAY_TYPE_0X80
200 config IO_DELAY_TYPE_0XED
204 config IO_DELAY_TYPE_UDELAY
208 config IO_DELAY_TYPE_NONE
213 prompt "IO delay type"
214 default IO_DELAY_0X80
217 bool "port 0x80 based port-IO delay [recommended]"
219 This is the traditional Linux IO delay used for in/out_p.
220 It is the most tested hence safest selection here.
223 bool "port 0xed based port-IO delay"
225 Use port 0xed as the IO delay. This frees up port 0x80 which is
226 often used as a hardware-debug port.
228 config IO_DELAY_UDELAY
229 bool "udelay based port-IO delay"
231 Use udelay(2) as the IO delay method. This provides the delay
232 while not having any side-effect on the IO port space.
235 bool "no port-IO delay"
237 No port-IO delay. Will break on old boxes that require port-IO
238 delay for certain operations. Should work on most new machines.
243 config DEFAULT_IO_DELAY_TYPE
245 default IO_DELAY_TYPE_0X80
249 config DEFAULT_IO_DELAY_TYPE
251 default IO_DELAY_TYPE_0XED
255 config DEFAULT_IO_DELAY_TYPE
257 default IO_DELAY_TYPE_UDELAY
261 config DEFAULT_IO_DELAY_TYPE
263 default IO_DELAY_TYPE_NONE
266 config DEBUG_BOOT_PARAMS
267 bool "Debug boot parameters"
268 depends on DEBUG_KERNEL
271 This option will cause struct boot_params to be exported via debugfs.
274 bool "CPA self-test code"
275 depends on DEBUG_KERNEL
277 Do change_page_attr() self-tests every 30 seconds.
279 config OPTIMIZE_INLINING
280 bool "Allow gcc to uninline functions marked 'inline'"
282 This option determines if the kernel forces gcc to inline the functions
283 developers have marked 'inline'. Doing so takes away freedom from gcc to
284 do what it thinks is best, which is desirable for the gcc 3.x series of
285 compilers. The gcc 4.x series have a rewritten inlining algorithm and
286 enabling this option will generate a smaller kernel there. Hopefully
287 this algorithm is so good that allowing gcc 4.x and above to make the
288 decision will become the default in the future. Until then this option
289 is there to test gcc for this.
294 bool "Debug low-level entry code"
295 depends on DEBUG_KERNEL
297 This option enables sanity checks in x86's low-level entry code.
298 Some of these sanity checks may slow down kernel entries and
299 exits or otherwise impact performance.
301 This is currently used to help test NMI code.
305 config DEBUG_NMI_SELFTEST
307 depends on DEBUG_KERNEL && X86_LOCAL_APIC
309 Enabling this option turns on a quick NMI selftest to verify
310 that the NMI behaves correctly.
312 This might help diagnose strange hangs that rely on NMI to
317 config DEBUG_IMR_SELFTEST
318 bool "Isolated Memory Region self test"
322 This option enables automated sanity testing of the IMR code.
323 Some simple tests are run to verify IMR bounds checking, alignment
324 and overlapping. This option is really only useful if you are
325 debugging an IMR memory map or are modifying the IMR code and want to
328 If unsure say N here.
331 bool "Debug the x86 FPU code"
332 depends on DEBUG_KERNEL
335 If this option is enabled then there will be extra sanity
336 checks and (boot time) debug printouts added to the kernel.
337 This debugging adds some small amount of runtime overhead
342 config PUNIT_ATOM_DEBUG
343 tristate "ATOM Punit debug driver"
347 This is a debug driver, which gets the power states
348 of all Punit North Complex devices. The power states of
349 each device is exposed as part of the debugfs interface.
350 The current power state can be read from
351 /sys/kernel/debug/punit_atom/dev_power_state