1# SPDX-License-Identifier: GPL-2.0 2 3config TRACE_IRQFLAGS_SUPPORT 4 def_bool y 5 6config TRACE_IRQFLAGS_NMI_SUPPORT 7 def_bool y 8 9config EARLY_PRINTK_USB 10 bool 11 12config X86_VERBOSE_BOOTUP 13 bool "Enable verbose x86 bootup info messages" 14 default y 15 help 16 Enables the informational output from the decompression stage 17 (e.g. bzImage) of the boot. If you disable this you will still 18 see errors. Disable this if you want silent bootup. 19 20config EARLY_PRINTK 21 bool "Early printk" if EXPERT 22 default y 23 help 24 Write kernel log output directly into the VGA buffer or to a serial 25 port. 26 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 say N here, 31 unless you want to debug such a crash. 32 33config EARLY_PRINTK_DBGP 34 bool "Early printk via EHCI debug port" 35 depends on EARLY_PRINTK && PCI 36 select EARLY_PRINTK_USB 37 help 38 Write kernel log output directly into the EHCI debug port. 39 40 This is useful for kernel debugging when your machine crashes very 41 early before the console code is initialized. For normal operation 42 it is not recommended because it looks ugly and doesn't cooperate 43 with klogd/syslogd or the X server. You should normally say N here, 44 unless you want to debug such a crash. You need usb debug device. 45 46config EARLY_PRINTK_USB_XDBC 47 bool "Early printk via the xHCI debug port" 48 depends on EARLY_PRINTK && PCI 49 select EARLY_PRINTK_USB 50 help 51 Write kernel log output directly into the xHCI debug port. 52 53 One use for this feature is kernel debugging, for example when your 54 machine crashes very early before the regular console code is 55 initialized. Other uses include simpler, lockless logging instead of 56 a full-blown printk console driver + klogd. 57 58 For normal production environments this is normally not recommended, 59 because it doesn't feed events into klogd/syslogd and doesn't try to 60 print anything on the screen. 61 62 You should normally say N here, unless you want to debug early 63 crashes or need a very simple printk logging facility. 64 65config MCSAFE_TEST 66 def_bool n 67 68config EFI_PGT_DUMP 69 bool "Dump the EFI pagetable" 70 depends on EFI 71 select PTDUMP_CORE 72 help 73 Enable this if you want to dump the EFI page table before 74 enabling virtual mode. This can be used to debug miscellaneous 75 issues with the mapping of the EFI runtime regions into that 76 table. 77 78config DEBUG_TLBFLUSH 79 bool "Set upper limit of TLB entries to flush one-by-one" 80 depends on DEBUG_KERNEL 81 help 82 83 X86-only for now. 84 85 This option allows the user to tune the amount of TLB entries the 86 kernel flushes one-by-one instead of doing a full TLB flush. In 87 certain situations, the former is cheaper. This is controlled by the 88 tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it 89 to -1, the code flushes the whole TLB unconditionally. Otherwise, 90 for positive values of it, the kernel will use single TLB entry 91 invalidating instructions according to the following formula: 92 93 flush_entries <= active_tlb_entries / 2^tlb_flushall_shift 94 95 If in doubt, say "N". 96 97config IOMMU_DEBUG 98 bool "Enable IOMMU debugging" 99 depends on GART_IOMMU && DEBUG_KERNEL 100 depends on X86_64 101 help 102 Force the IOMMU to on even when you have less than 4GB of 103 memory and add debugging code. On overflow always panic. And 104 allow to enable IOMMU leak tracing. Can be disabled at boot 105 time with iommu=noforce. This will also enable scatter gather 106 list merging. Currently not recommended for production 107 code. When you use it make sure you have a big enough 108 IOMMU/AGP aperture. Most of the options enabled by this can 109 be set more finegrained using the iommu= command line 110 options. See Documentation/x86/x86_64/boot-options.rst for more 111 details. 112 113config IOMMU_LEAK 114 bool "IOMMU leak tracing" 115 depends on IOMMU_DEBUG && DMA_API_DEBUG 116 help 117 Add a simple leak tracer to the IOMMU code. This is useful when you 118 are debugging a buggy device driver that leaks IOMMU mappings. 119 120config HAVE_MMIOTRACE_SUPPORT 121 def_bool y 122 123config X86_DECODER_SELFTEST 124 bool "x86 instruction decoder selftest" 125 depends on DEBUG_KERNEL && INSTRUCTION_DECODER 126 depends on !COMPILE_TEST 127 help 128 Perform x86 instruction decoder selftests at build time. 129 This option is useful for checking the sanity of x86 instruction 130 decoder code. 131 If unsure, say "N". 132 133choice 134 prompt "IO delay type" 135 default IO_DELAY_0X80 136 137config IO_DELAY_0X80 138 bool "port 0x80 based port-IO delay [recommended]" 139 help 140 This is the traditional Linux IO delay used for in/out_p. 141 It is the most tested hence safest selection here. 142 143config IO_DELAY_0XED 144 bool "port 0xed based port-IO delay" 145 help 146 Use port 0xed as the IO delay. This frees up port 0x80 which is 147 often used as a hardware-debug port. 148 149config IO_DELAY_UDELAY 150 bool "udelay based port-IO delay" 151 help 152 Use udelay(2) as the IO delay method. This provides the delay 153 while not having any side-effect on the IO port space. 154 155config IO_DELAY_NONE 156 bool "no port-IO delay" 157 help 158 No port-IO delay. Will break on old boxes that require port-IO 159 delay for certain operations. Should work on most new machines. 160 161endchoice 162 163config DEBUG_BOOT_PARAMS 164 bool "Debug boot parameters" 165 depends on DEBUG_KERNEL 166 depends on DEBUG_FS 167 help 168 This option will cause struct boot_params to be exported via debugfs. 169 170config CPA_DEBUG 171 bool "CPA self-test code" 172 depends on DEBUG_KERNEL 173 help 174 Do change_page_attr() self-tests every 30 seconds. 175 176config DEBUG_ENTRY 177 bool "Debug low-level entry code" 178 depends on DEBUG_KERNEL 179 help 180 This option enables sanity checks in x86's low-level entry code. 181 Some of these sanity checks may slow down kernel entries and 182 exits or otherwise impact performance. 183 184 If unsure, say N. 185 186config DEBUG_NMI_SELFTEST 187 bool "NMI Selftest" 188 depends on DEBUG_KERNEL && X86_LOCAL_APIC 189 help 190 Enabling this option turns on a quick NMI selftest to verify 191 that the NMI behaves correctly. 192 193 This might help diagnose strange hangs that rely on NMI to 194 function properly. 195 196 If unsure, say N. 197 198config DEBUG_IMR_SELFTEST 199 bool "Isolated Memory Region self test" 200 depends on INTEL_IMR 201 help 202 This option enables automated sanity testing of the IMR code. 203 Some simple tests are run to verify IMR bounds checking, alignment 204 and overlapping. This option is really only useful if you are 205 debugging an IMR memory map or are modifying the IMR code and want to 206 test your changes. 207 208 If unsure say N here. 209 210config X86_DEBUG_FPU 211 bool "Debug the x86 FPU code" 212 depends on DEBUG_KERNEL 213 default y 214 help 215 If this option is enabled then there will be extra sanity 216 checks and (boot time) debug printouts added to the kernel. 217 This debugging adds some small amount of runtime overhead 218 to the kernel. 219 220 If unsure, say N. 221 222config PUNIT_ATOM_DEBUG 223 tristate "ATOM Punit debug driver" 224 depends on PCI 225 select DEBUG_FS 226 select IOSF_MBI 227 help 228 This is a debug driver, which gets the power states 229 of all Punit North Complex devices. The power states of 230 each device is exposed as part of the debugfs interface. 231 The current power state can be read from 232 /sys/kernel/debug/punit_atom/dev_power_state 233 234choice 235 prompt "Choose kernel unwinder" 236 default UNWINDER_ORC if X86_64 237 default UNWINDER_FRAME_POINTER if X86_32 238 help 239 This determines which method will be used for unwinding kernel stack 240 traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack, 241 livepatch, lockdep, and more. 242 243config UNWINDER_ORC 244 bool "ORC unwinder" 245 depends on X86_64 246 select STACK_VALIDATION 247 help 248 This option enables the ORC (Oops Rewind Capability) unwinder for 249 unwinding kernel stack traces. It uses a custom data format which is 250 a simplified version of the DWARF Call Frame Information standard. 251 252 This unwinder is more accurate across interrupt entry frames than the 253 frame pointer unwinder. It also enables a 5-10% performance 254 improvement across the entire kernel compared to frame pointers. 255 256 Enabling this option will increase the kernel's runtime memory usage 257 by roughly 2-4MB, depending on your kernel config. 258 259config UNWINDER_FRAME_POINTER 260 bool "Frame pointer unwinder" 261 select FRAME_POINTER 262 help 263 This option enables the frame pointer unwinder for unwinding kernel 264 stack traces. 265 266 The unwinder itself is fast and it uses less RAM than the ORC 267 unwinder, but the kernel text size will grow by ~3% and the kernel's 268 overall performance will degrade by roughly 5-10%. 269 270config UNWINDER_GUESS 271 bool "Guess unwinder" 272 depends on EXPERT 273 depends on !STACKDEPOT 274 help 275 This option enables the "guess" unwinder for unwinding kernel stack 276 traces. It scans the stack and reports every kernel text address it 277 finds. Some of the addresses it reports may be incorrect. 278 279 While this option often produces false positives, it can still be 280 useful in many cases. Unlike the other unwinders, it has no runtime 281 overhead. 282 283endchoice 284 285config FRAME_POINTER 286 depends on !UNWINDER_ORC && !UNWINDER_GUESS 287 bool 288