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Diffstat (limited to 'arch/x86/Kconfig.debug')
| -rw-r--r-- | arch/x86/Kconfig.debug | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug new file mode 100644 index 000000000..687cd1a21 --- /dev/null +++ b/arch/x86/Kconfig.debug @@ -0,0 +1,409 @@ +# SPDX-License-Identifier: GPL-2.0 + +config TRACE_IRQFLAGS_SUPPORT + def_bool y + +config EARLY_PRINTK_USB + bool + +config X86_VERBOSE_BOOTUP + bool "Enable verbose x86 bootup info messages" + default y + ---help--- + Enables the informational output from the decompression stage + (e.g. bzImage) of the boot. If you disable this you will still + see errors. Disable this if you want silent bootup. + +config EARLY_PRINTK + bool "Early printk" if EXPERT + default y + ---help--- + Write kernel log output directly into the VGA buffer or to a serial + port. + + This is useful for kernel debugging when your machine crashes very + early before the console code is initialized. For normal operation + it is not recommended because it looks ugly and doesn't cooperate + with klogd/syslogd or the X server. You should normally say N here, + unless you want to debug such a crash. + +config EARLY_PRINTK_DBGP + bool "Early printk via EHCI debug port" + depends on EARLY_PRINTK && PCI + select EARLY_PRINTK_USB + ---help--- + Write kernel log output directly into the EHCI debug port. + + This is useful for kernel debugging when your machine crashes very + early before the console code is initialized. For normal operation + it is not recommended because it looks ugly and doesn't cooperate + with klogd/syslogd or the X server. You should normally say N here, + unless you want to debug such a crash. You need usb debug device. + +config EARLY_PRINTK_EFI + bool "Early printk via the EFI framebuffer" + depends on EFI && EARLY_PRINTK + select FONT_SUPPORT + ---help--- + Write kernel log output directly into the EFI framebuffer. + + This is useful for kernel debugging when your machine crashes very + early before the console code is initialized. + +config EARLY_PRINTK_USB_XDBC + bool "Early printk via the xHCI debug port" + depends on EARLY_PRINTK && PCI + select EARLY_PRINTK_USB + ---help--- + Write kernel log output directly into the xHCI debug port. + + One use for this feature is kernel debugging, for example when your + machine crashes very early before the regular console code is + initialized. Other uses include simpler, lockless logging instead of + a full-blown printk console driver + klogd. + + For normal production environments this is normally not recommended, + because it doesn't feed events into klogd/syslogd and doesn't try to + print anything on the screen. + + You should normally say N here, unless you want to debug early + crashes or need a very simple printk logging facility. + +config MCSAFE_TEST + def_bool n + +config X86_PTDUMP_CORE + def_bool n + +config X86_PTDUMP + tristate "Export kernel pagetable layout to userspace via debugfs" + depends on DEBUG_KERNEL + select DEBUG_FS + select X86_PTDUMP_CORE + ---help--- + Say Y here if you want to show the kernel pagetable layout in a + debugfs file. This information is only useful for kernel developers + who are working in architecture specific areas of the kernel. + It is probably not a good idea to enable this feature in a production + kernel. + If in doubt, say "N" + +config EFI_PGT_DUMP + bool "Dump the EFI pagetable" + depends on EFI + select X86_PTDUMP_CORE + ---help--- + Enable this if you want to dump the EFI page table before + enabling virtual mode. This can be used to debug miscellaneous + issues with the mapping of the EFI runtime regions into that + table. + +config DEBUG_WX + bool "Warn on W+X mappings at boot" + select X86_PTDUMP_CORE + ---help--- + Generate a warning if any W+X mappings are found at boot. + + This is useful for discovering cases where the kernel is leaving + W+X mappings after applying NX, as such mappings are a security risk. + + Look for a message in dmesg output like this: + + x86/mm: Checked W+X mappings: passed, no W+X pages found. + + or like this, if the check failed: + + x86/mm: Checked W+X mappings: FAILED, <N> W+X pages found. + + Note that even if the check fails, your kernel is possibly + still fine, as W+X mappings are not a security hole in + themselves, what they do is that they make the exploitation + of other unfixed kernel bugs easier. + + There is no runtime or memory usage effect of this option + once the kernel has booted up - it's a one time check. + + If in doubt, say "Y". + +config DOUBLEFAULT + default y + bool "Enable doublefault exception handler" if EXPERT + ---help--- + This option allows trapping of rare doublefault exceptions that + would otherwise cause a system to silently reboot. Disabling this + option saves about 4k and might cause you much additional grey + hair. + +config DEBUG_TLBFLUSH + bool "Set upper limit of TLB entries to flush one-by-one" + depends on DEBUG_KERNEL + ---help--- + + X86-only for now. + + This option allows the user to tune the amount of TLB entries the + kernel flushes one-by-one instead of doing a full TLB flush. In + certain situations, the former is cheaper. This is controlled by the + tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it + to -1, the code flushes the whole TLB unconditionally. Otherwise, + for positive values of it, the kernel will use single TLB entry + invalidating instructions according to the following formula: + + flush_entries <= active_tlb_entries / 2^tlb_flushall_shift + + If in doubt, say "N". + +config IOMMU_DEBUG + bool "Enable IOMMU debugging" + depends on GART_IOMMU && DEBUG_KERNEL + depends on X86_64 + ---help--- + Force the IOMMU to on even when you have less than 4GB of + memory and add debugging code. On overflow always panic. And + allow to enable IOMMU leak tracing. Can be disabled at boot + time with iommu=noforce. This will also enable scatter gather + list merging. Currently not recommended for production + code. When you use it make sure you have a big enough + IOMMU/AGP aperture. Most of the options enabled by this can + be set more finegrained using the iommu= command line + options. See Documentation/x86/x86_64/boot-options.txt for more + details. + +config IOMMU_LEAK + bool "IOMMU leak tracing" + depends on IOMMU_DEBUG && DMA_API_DEBUG + ---help--- + Add a simple leak tracer to the IOMMU code. This is useful when you + are debugging a buggy device driver that leaks IOMMU mappings. + +config HAVE_MMIOTRACE_SUPPORT + def_bool y + +config X86_DECODER_SELFTEST + bool "x86 instruction decoder selftest" + depends on DEBUG_KERNEL && INSTRUCTION_DECODER + depends on !COMPILE_TEST + ---help--- + Perform x86 instruction decoder selftests at build time. + This option is useful for checking the sanity of x86 instruction + decoder code. + If unsure, say "N". + +# +# IO delay types: +# + +config IO_DELAY_TYPE_0X80 + int + default "0" + +config IO_DELAY_TYPE_0XED + int + default "1" + +config IO_DELAY_TYPE_UDELAY + int + default "2" + +config IO_DELAY_TYPE_NONE + int + default "3" + +choice + prompt "IO delay type" + default IO_DELAY_0X80 + +config IO_DELAY_0X80 + bool "port 0x80 based port-IO delay [recommended]" + ---help--- + This is the traditional Linux IO delay used for in/out_p. + It is the most tested hence safest selection here. + +config IO_DELAY_0XED + bool "port 0xed based port-IO delay" + ---help--- + Use port 0xed as the IO delay. This frees up port 0x80 which is + often used as a hardware-debug port. + +config IO_DELAY_UDELAY + bool "udelay based port-IO delay" + ---help--- + Use udelay(2) as the IO delay method. This provides the delay + while not having any side-effect on the IO port space. + +config IO_DELAY_NONE + bool "no port-IO delay" + ---help--- + No port-IO delay. Will break on old boxes that require port-IO + delay for certain operations. Should work on most new machines. + +endchoice + +if IO_DELAY_0X80 +config DEFAULT_IO_DELAY_TYPE + int + default IO_DELAY_TYPE_0X80 +endif + +if IO_DELAY_0XED +config DEFAULT_IO_DELAY_TYPE + int + default IO_DELAY_TYPE_0XED +endif + +if IO_DELAY_UDELAY +config DEFAULT_IO_DELAY_TYPE + int + default IO_DELAY_TYPE_UDELAY +endif + +if IO_DELAY_NONE +config DEFAULT_IO_DELAY_TYPE + int + default IO_DELAY_TYPE_NONE +endif + +config DEBUG_BOOT_PARAMS + bool "Debug boot parameters" + depends on DEBUG_KERNEL + depends on DEBUG_FS + ---help--- + This option will cause struct boot_params to be exported via debugfs. + +config CPA_DEBUG + bool "CPA self-test code" + depends on DEBUG_KERNEL + ---help--- + Do change_page_attr() self-tests every 30 seconds. + +config OPTIMIZE_INLINING + bool "Allow gcc to uninline functions marked 'inline'" + ---help--- + This option determines if the kernel forces gcc to inline the functions + developers have marked 'inline'. Doing so takes away freedom from gcc to + do what it thinks is best, which is desirable for the gcc 3.x series of + compilers. The gcc 4.x series have a rewritten inlining algorithm and + enabling this option will generate a smaller kernel there. Hopefully + this algorithm is so good that allowing gcc 4.x and above to make the + decision will become the default in the future. Until then this option + is there to test gcc for this. + + If unsure, say N. + +config DEBUG_ENTRY + bool "Debug low-level entry code" + depends on DEBUG_KERNEL + ---help--- + This option enables sanity checks in x86's low-level entry code. + Some of these sanity checks may slow down kernel entries and + exits or otherwise impact performance. + + If unsure, say N. + +config DEBUG_NMI_SELFTEST + bool "NMI Selftest" + depends on DEBUG_KERNEL && X86_LOCAL_APIC + ---help--- + Enabling this option turns on a quick NMI selftest to verify + that the NMI behaves correctly. + + This might help diagnose strange hangs that rely on NMI to + function properly. + + If unsure, say N. + +config DEBUG_IMR_SELFTEST + bool "Isolated Memory Region self test" + default n + depends on INTEL_IMR + ---help--- + This option enables automated sanity testing of the IMR code. + Some simple tests are run to verify IMR bounds checking, alignment + and overlapping. This option is really only useful if you are + debugging an IMR memory map or are modifying the IMR code and want to + test your changes. + + If unsure say N here. + +config X86_DEBUG_FPU + bool "Debug the x86 FPU code" + depends on DEBUG_KERNEL + default y + ---help--- + If this option is enabled then there will be extra sanity + checks and (boot time) debug printouts added to the kernel. + This debugging adds some small amount of runtime overhead + to the kernel. + + If unsure, say N. + +config PUNIT_ATOM_DEBUG + tristate "ATOM Punit debug driver" + depends on PCI + select DEBUG_FS + select IOSF_MBI + ---help--- + This is a debug driver, which gets the power states + of all Punit North Complex devices. The power states of + each device is exposed as part of the debugfs interface. + The current power state can be read from + /sys/kernel/debug/punit_atom/dev_power_state + +choice + prompt "Choose kernel unwinder" + default UNWINDER_ORC if X86_64 + default UNWINDER_FRAME_POINTER if X86_32 + ---help--- + This determines which method will be used for unwinding kernel stack + traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack, + livepatch, lockdep, and more. + +config UNWINDER_ORC + bool "ORC unwinder" + depends on X86_64 + select STACK_VALIDATION + ---help--- + This option enables the ORC (Oops Rewind Capability) unwinder for + unwinding kernel stack traces. It uses a custom data format which is + a simplified version of the DWARF Call Frame Information standard. + + This unwinder is more accurate across interrupt entry frames than the + frame pointer unwinder. It also enables a 5-10% performance + improvement across the entire kernel compared to frame pointers. + + Enabling this option will increase the kernel's runtime memory usage + by roughly 2-4MB, depending on your kernel config. + +config UNWINDER_FRAME_POINTER + bool "Frame pointer unwinder" + select FRAME_POINTER + ---help--- + This option enables the frame pointer unwinder for unwinding kernel + stack traces. + + The unwinder itself is fast and it uses less RAM than the ORC + unwinder, but the kernel text size will grow by ~3% and the kernel's + overall performance will degrade by roughly 5-10%. + + This option is recommended if you want to use the livepatch + consistency model, as this is currently the only way to get a + reliable stack trace (CONFIG_HAVE_RELIABLE_STACKTRACE). + +config UNWINDER_GUESS + bool "Guess unwinder" + depends on EXPERT + depends on !STACKDEPOT + ---help--- + This option enables the "guess" unwinder for unwinding kernel stack + traces. It scans the stack and reports every kernel text address it + finds. Some of the addresses it reports may be incorrect. + + While this option often produces false positives, it can still be + useful in many cases. Unlike the other unwinders, it has no runtime + overhead. + +endchoice + +config FRAME_POINTER + depends on !UNWINDER_ORC && !UNWINDER_GUESS + bool |