3 config TRACE_IRQFLAGS_SUPPORT
6 source "lib/Kconfig.debug"
9 bool "Early printk" if EMBEDDED
12 Write kernel log output directly into the VGA buffer or to a serial
15 This is useful for kernel debugging when your machine crashes very
16 early before the console code is initialized. For normal operation
17 it is not recommended because it looks ugly and doesn't cooperate
18 with klogd/syslogd or the X server. You should normally N here,
19 unless you want to debug such a crash.
21 config DEBUG_STACKOVERFLOW
22 bool "Check for stack overflows"
23 depends on DEBUG_KERNEL
25 This option will cause messages to be printed if free stack space
26 drops below a certain limit.
28 config DEBUG_STACK_USAGE
29 bool "Stack utilization instrumentation"
30 depends on DEBUG_KERNEL
32 Enables the display of the minimum amount of free stack which each
33 task has ever had available in the sysrq-T and sysrq-P debug output.
35 This option will slow down process creation somewhat.
37 config DEBUG_PAGEALLOC
38 bool "Debug page memory allocations"
39 depends on DEBUG_KERNEL
41 Unmap pages from the kernel linear mapping after free_pages().
42 This results in a large slowdown, but helps to find certain types
43 of memory corruptions.
45 config DEBUG_PER_CPU_MAPS
46 bool "Debug access to per_cpu maps"
47 depends on DEBUG_KERNEL
51 Say Y to verify that the per_cpu map being accessed has
52 been setup. Adds a fair amount of code to kernel memory
53 and decreases performance.
58 bool "Export kernel pagetable layout to userspace via debugfs"
62 Say Y here if you want to show the kernel pagetable layout in a
63 debugfs file. This information is only useful for kernel developers
64 who are working in architecture specific areas of the kernel.
65 It is probably not a good idea to enable this feature in a production
70 bool "Write protect kernel read-only data structures"
72 depends on DEBUG_KERNEL
74 Mark the kernel read-only data as write-protected in the pagetables,
75 in order to catch accidental (and incorrect) writes to such const
76 data. This is recommended so that we can catch kernel bugs sooner.
79 config DEBUG_RODATA_TEST
80 bool "Testcase for the DEBUG_RODATA feature"
81 depends on DEBUG_RODATA
83 This option enables a testcase for the DEBUG_RODATA
84 feature as well as for the change_page_attr() infrastructure.
88 tristate "Testcase for the NX non-executable stack feature"
89 depends on DEBUG_KERNEL && m
91 This option enables a testcase for the CPU NX capability
92 and the software setup of this feature.
96 bool "Use 4Kb for kernel stacks instead of 8Kb"
97 depends on DEBUG_KERNEL
100 If you say Y here the kernel will use a 4Kb stacksize for the
101 kernel stack attached to each process/thread. This facilitates
102 running more threads on a system and also reduces the pressure
103 on the VM subsystem for higher order allocations. This option
104 will also use IRQ stacks to compensate for the reduced stackspace.
106 config X86_FIND_SMP_CONFIG
108 depends on X86_LOCAL_APIC || X86_VOYAGER
113 depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) || X86_64
117 bool "Enable doublefault exception handler" if EMBEDDED
120 This option allows trapping of rare doublefault exceptions that
121 would otherwise cause a system to silently reboot. Disabling this
122 option saves about 4k and might cause you much additional grey
126 bool "Enable IOMMU debugging"
127 depends on GART_IOMMU && DEBUG_KERNEL
130 Force the IOMMU to on even when you have less than 4GB of
131 memory and add debugging code. On overflow always panic. And
132 allow to enable IOMMU leak tracing. Can be disabled at boot
133 time with iommu=noforce. This will also enable scatter gather
134 list merging. Currently not recommended for production
135 code. When you use it make sure you have a big enough
136 IOMMU/AGP aperture. Most of the options enabled by this can
137 be set more finegrained using the iommu= command line
138 options. See Documentation/x86_64/boot-options.txt for more
142 bool "IOMMU leak tracing"
143 depends on DEBUG_KERNEL
144 depends on IOMMU_DEBUG
146 Add a simple leak tracer to the IOMMU code. This is useful when you
147 are debugging a buggy device driver that leaks IOMMU mappings.
153 config IO_DELAY_TYPE_0X80
157 config IO_DELAY_TYPE_0XED
161 config IO_DELAY_TYPE_UDELAY
165 config IO_DELAY_TYPE_NONE
170 prompt "IO delay type"
171 default IO_DELAY_0X80
174 bool "port 0x80 based port-IO delay [recommended]"
176 This is the traditional Linux IO delay used for in/out_p.
177 It is the most tested hence safest selection here.
180 bool "port 0xed based port-IO delay"
182 Use port 0xed as the IO delay. This frees up port 0x80 which is
183 often used as a hardware-debug port.
185 config IO_DELAY_UDELAY
186 bool "udelay based port-IO delay"
188 Use udelay(2) as the IO delay method. This provides the delay
189 while not having any side-effect on the IO port space.
192 bool "no port-IO delay"
194 No port-IO delay. Will break on old boxes that require port-IO
195 delay for certain operations. Should work on most new machines.
200 config DEFAULT_IO_DELAY_TYPE
202 default IO_DELAY_TYPE_0X80
206 config DEFAULT_IO_DELAY_TYPE
208 default IO_DELAY_TYPE_0XED
212 config DEFAULT_IO_DELAY_TYPE
214 default IO_DELAY_TYPE_UDELAY
218 config DEFAULT_IO_DELAY_TYPE
220 default IO_DELAY_TYPE_NONE
223 config DEBUG_BOOT_PARAMS
224 bool "Debug boot parameters"
225 depends on DEBUG_KERNEL
228 This option will cause struct boot_params to be exported via debugfs.
231 bool "CPA self-test code"
232 depends on DEBUG_KERNEL
234 Do change_page_attr() self-tests every 30 seconds.