3 config TRACE_IRQFLAGS_SUPPORT
6 source "lib/Kconfig.debug"
8 config NONPROMISC_DEVMEM
9 bool "Disable promiscuous /dev/mem"
12 The /dev/mem file by default only allows userspace access to PCI
13 space and the BIOS code and data regions. This is sufficient for
14 dosemu and X and all common users of /dev/mem. With this config
15 option, you allow userspace access to all of memory, including
16 kernel and userspace memory. Accidental access to this is
17 obviously disasterous, but specific access can be used by people
21 bool "Early printk" if EMBEDDED
24 Write kernel log output directly into the VGA buffer or to a serial
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 N here,
31 unless you want to debug such a crash.
33 config DEBUG_STACKOVERFLOW
34 bool "Check for stack overflows"
35 depends on DEBUG_KERNEL
37 This option will cause messages to be printed if free stack space
38 drops below a certain limit.
40 config DEBUG_STACK_USAGE
41 bool "Stack utilization instrumentation"
42 depends on DEBUG_KERNEL
44 Enables the display of the minimum amount of free stack which each
45 task has ever had available in the sysrq-T and sysrq-P debug output.
47 This option will slow down process creation somewhat.
49 config DEBUG_PAGEALLOC
50 bool "Debug page memory allocations"
51 depends on DEBUG_KERNEL
53 Unmap pages from the kernel linear mapping after free_pages().
54 This results in a large slowdown, but helps to find certain types
55 of memory corruptions.
57 config DEBUG_PER_CPU_MAPS
58 bool "Debug access to per_cpu maps"
59 depends on DEBUG_KERNEL
63 Say Y to verify that the per_cpu map being accessed has
64 been setup. Adds a fair amount of code to kernel memory
65 and decreases performance.
70 bool "Export kernel pagetable layout to userspace via debugfs"
71 depends on DEBUG_KERNEL
74 Say Y here if you want to show the kernel pagetable layout in a
75 debugfs file. This information is only useful for kernel developers
76 who are working in architecture specific areas of the kernel.
77 It is probably not a good idea to enable this feature in a production
82 bool "Write protect kernel read-only data structures"
84 depends on DEBUG_KERNEL
86 Mark the kernel read-only data as write-protected in the pagetables,
87 in order to catch accidental (and incorrect) writes to such const
88 data. This is recommended so that we can catch kernel bugs sooner.
92 bool "Enable gbpages-mapped kernel pagetables"
93 depends on DEBUG_KERNEL && EXPERIMENTAL && X86_64
95 Enable gigabyte pages support (if the CPU supports it). This can
96 improve the kernel's performance a tiny bit by reducing TLB
99 This is experimental code.
101 If in doubt, say "N".
103 config DEBUG_RODATA_TEST
104 bool "Testcase for the DEBUG_RODATA feature"
105 depends on DEBUG_RODATA
107 This option enables a testcase for the DEBUG_RODATA
108 feature as well as for the change_page_attr() infrastructure.
112 tristate "Testcase for the NX non-executable stack feature"
113 depends on DEBUG_KERNEL && m
115 This option enables a testcase for the CPU NX capability
116 and the software setup of this feature.
120 bool "Use 4Kb for kernel stacks instead of 8Kb"
124 If you say Y here the kernel will use a 4Kb stacksize for the
125 kernel stack attached to each process/thread. This facilitates
126 running more threads on a system and also reduces the pressure
127 on the VM subsystem for higher order allocations. This option
128 will also use IRQ stacks to compensate for the reduced stackspace.
130 config X86_FIND_SMP_CONFIG
132 depends on X86_LOCAL_APIC || X86_VOYAGER
137 depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) || X86_64
141 bool "Enable doublefault exception handler" if EMBEDDED
144 This option allows trapping of rare doublefault exceptions that
145 would otherwise cause a system to silently reboot. Disabling this
146 option saves about 4k and might cause you much additional grey
150 bool "Enable IOMMU debugging"
151 depends on GART_IOMMU && DEBUG_KERNEL
154 Force the IOMMU to on even when you have less than 4GB of
155 memory and add debugging code. On overflow always panic. And
156 allow to enable IOMMU leak tracing. Can be disabled at boot
157 time with iommu=noforce. This will also enable scatter gather
158 list merging. Currently not recommended for production
159 code. When you use it make sure you have a big enough
160 IOMMU/AGP aperture. Most of the options enabled by this can
161 be set more finegrained using the iommu= command line
162 options. See Documentation/x86_64/boot-options.txt for more
166 bool "IOMMU leak tracing"
167 depends on DEBUG_KERNEL
168 depends on IOMMU_DEBUG
170 Add a simple leak tracer to the IOMMU code. This is useful when you
171 are debugging a buggy device driver that leaks IOMMU mappings.
177 config IO_DELAY_TYPE_0X80
181 config IO_DELAY_TYPE_0XED
185 config IO_DELAY_TYPE_UDELAY
189 config IO_DELAY_TYPE_NONE
194 prompt "IO delay type"
195 default IO_DELAY_0X80
198 bool "port 0x80 based port-IO delay [recommended]"
200 This is the traditional Linux IO delay used for in/out_p.
201 It is the most tested hence safest selection here.
204 bool "port 0xed based port-IO delay"
206 Use port 0xed as the IO delay. This frees up port 0x80 which is
207 often used as a hardware-debug port.
209 config IO_DELAY_UDELAY
210 bool "udelay based port-IO delay"
212 Use udelay(2) as the IO delay method. This provides the delay
213 while not having any side-effect on the IO port space.
216 bool "no port-IO delay"
218 No port-IO delay. Will break on old boxes that require port-IO
219 delay for certain operations. Should work on most new machines.
224 config DEFAULT_IO_DELAY_TYPE
226 default IO_DELAY_TYPE_0X80
230 config DEFAULT_IO_DELAY_TYPE
232 default IO_DELAY_TYPE_0XED
236 config DEFAULT_IO_DELAY_TYPE
238 default IO_DELAY_TYPE_UDELAY
242 config DEFAULT_IO_DELAY_TYPE
244 default IO_DELAY_TYPE_NONE
247 config DEBUG_BOOT_PARAMS
248 bool "Debug boot parameters"
249 depends on DEBUG_KERNEL
252 This option will cause struct boot_params to be exported via debugfs.
255 bool "CPA self-test code"
256 depends on DEBUG_KERNEL
258 Do change_page_attr() self-tests every 30 seconds.