3 config TRACE_IRQFLAGS_SUPPORT
6 source "lib/Kconfig.debug"
8 config NONPROMISC_DEVMEM
9 bool "Filter access to /dev/mem"
11 If this option is left off, you allow userspace access to all
12 of memory, including kernel and userspace memory. Accidental
13 access to this is obviously disastrous, but specific access can
14 be used by people debugging the kernel.
16 If this option is switched on, the /dev/mem file only allows
17 userspace access to PCI space and the BIOS code and data regions.
18 This is sufficient for dosemu and X and all common users of
24 bool "Early printk" if EMBEDDED
27 Write kernel log output directly into the VGA buffer or to a serial
30 This is useful for kernel debugging when your machine crashes very
31 early before the console code is initialized. For normal operation
32 it is not recommended because it looks ugly and doesn't cooperate
33 with klogd/syslogd or the X server. You should normally N here,
34 unless you want to debug such a crash.
36 config DEBUG_STACKOVERFLOW
37 bool "Check for stack overflows"
38 depends on DEBUG_KERNEL
40 This option will cause messages to be printed if free stack space
41 drops below a certain limit.
43 config DEBUG_STACK_USAGE
44 bool "Stack utilization instrumentation"
45 depends on DEBUG_KERNEL
47 Enables the display of the minimum amount of free stack which each
48 task has ever had available in the sysrq-T and sysrq-P debug output.
50 This option will slow down process creation somewhat.
52 config DEBUG_PAGEALLOC
53 bool "Debug page memory allocations"
54 depends on DEBUG_KERNEL
56 Unmap pages from the kernel linear mapping after free_pages().
57 This results in a large slowdown, but helps to find certain types
58 of memory corruptions.
60 config DEBUG_PER_CPU_MAPS
61 bool "Debug access to per_cpu maps"
62 depends on DEBUG_KERNEL
66 Say Y to verify that the per_cpu map being accessed has
67 been setup. Adds a fair amount of code to kernel memory
68 and decreases performance.
73 bool "Export kernel pagetable layout to userspace via debugfs"
74 depends on DEBUG_KERNEL
77 Say Y here if you want to show the kernel pagetable layout in a
78 debugfs file. This information is only useful for kernel developers
79 who are working in architecture specific areas of the kernel.
80 It is probably not a good idea to enable this feature in a production
85 bool "Write protect kernel read-only data structures"
87 depends on DEBUG_KERNEL
89 Mark the kernel read-only data as write-protected in the pagetables,
90 in order to catch accidental (and incorrect) writes to such const
91 data. This is recommended so that we can catch kernel bugs sooner.
95 bool "Enable gbpages-mapped kernel pagetables"
96 depends on DEBUG_KERNEL && EXPERIMENTAL && X86_64
98 Enable gigabyte pages support (if the CPU supports it). This can
99 improve the kernel's performance a tiny bit by reducing TLB
102 This is experimental code.
104 If in doubt, say "N".
106 config DEBUG_RODATA_TEST
107 bool "Testcase for the DEBUG_RODATA feature"
108 depends on DEBUG_RODATA
110 This option enables a testcase for the DEBUG_RODATA
111 feature as well as for the change_page_attr() infrastructure.
115 tristate "Testcase for the NX non-executable stack feature"
116 depends on DEBUG_KERNEL && m
118 This option enables a testcase for the CPU NX capability
119 and the software setup of this feature.
123 bool "Use 4Kb for kernel stacks instead of 8Kb"
126 If you say Y here the kernel will use a 4Kb stacksize for the
127 kernel stack attached to each process/thread. This facilitates
128 running more threads on a system and also reduces the pressure
129 on the VM subsystem for higher order allocations. This option
130 will also use IRQ stacks to compensate for the reduced stackspace.
134 bool "Enable doublefault exception handler" if EMBEDDED
137 This option allows trapping of rare doublefault exceptions that
138 would otherwise cause a system to silently reboot. Disabling this
139 option saves about 4k and might cause you much additional grey
143 bool "Enable IOMMU debugging"
144 depends on GART_IOMMU && DEBUG_KERNEL
147 Force the IOMMU to on even when you have less than 4GB of
148 memory and add debugging code. On overflow always panic. And
149 allow to enable IOMMU leak tracing. Can be disabled at boot
150 time with iommu=noforce. This will also enable scatter gather
151 list merging. Currently not recommended for production
152 code. When you use it make sure you have a big enough
153 IOMMU/AGP aperture. Most of the options enabled by this can
154 be set more finegrained using the iommu= command line
155 options. See Documentation/x86_64/boot-options.txt for more
159 bool "IOMMU leak tracing"
160 depends on DEBUG_KERNEL
161 depends on IOMMU_DEBUG
163 Add a simple leak tracer to the IOMMU code. This is useful when you
164 are debugging a buggy device driver that leaks IOMMU mappings.
170 config IO_DELAY_TYPE_0X80
174 config IO_DELAY_TYPE_0XED
178 config IO_DELAY_TYPE_UDELAY
182 config IO_DELAY_TYPE_NONE
187 prompt "IO delay type"
188 default IO_DELAY_0X80
191 bool "port 0x80 based port-IO delay [recommended]"
193 This is the traditional Linux IO delay used for in/out_p.
194 It is the most tested hence safest selection here.
197 bool "port 0xed based port-IO delay"
199 Use port 0xed as the IO delay. This frees up port 0x80 which is
200 often used as a hardware-debug port.
202 config IO_DELAY_UDELAY
203 bool "udelay based port-IO delay"
205 Use udelay(2) as the IO delay method. This provides the delay
206 while not having any side-effect on the IO port space.
209 bool "no port-IO delay"
211 No port-IO delay. Will break on old boxes that require port-IO
212 delay for certain operations. Should work on most new machines.
217 config DEFAULT_IO_DELAY_TYPE
219 default IO_DELAY_TYPE_0X80
223 config DEFAULT_IO_DELAY_TYPE
225 default IO_DELAY_TYPE_0XED
229 config DEFAULT_IO_DELAY_TYPE
231 default IO_DELAY_TYPE_UDELAY
235 config DEFAULT_IO_DELAY_TYPE
237 default IO_DELAY_TYPE_NONE
240 config DEBUG_BOOT_PARAMS
241 bool "Debug boot parameters"
242 depends on DEBUG_KERNEL
245 This option will cause struct boot_params to be exported via debugfs.
248 bool "CPA self-test code"
249 depends on DEBUG_KERNEL
251 Do change_page_attr() self-tests every 30 seconds.
253 config OPTIMIZE_INLINING
254 bool "Allow gcc to uninline functions marked 'inline'"
257 This option determines if the kernel forces gcc to inline the functions
258 developers have marked 'inline'. Doing so takes away freedom from gcc to
259 do what it thinks is best, which is desirable for the gcc 3.x series of
260 compilers. The gcc 4.x series have a rewritten inlining algorithm and
261 disabling this option will generate a smaller kernel there. Hopefully
262 this algorithm is so good that allowing gcc4 to make the decision can
263 become the default in the future, until then this option is there to