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