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![Andy Lutomirski](/assets/img/avatar_default.png)
This will allow IRQ stacks to nest inside NMIs or similar entries that can happen during IRQ stack setup or teardown. The new macros won't work correctly if they're invoked with IRQs on. Add a check under CONFIG_DEBUG_ENTRY to detect that. Signed-off-by: Andy Lutomirski <luto@kernel.org> [ Use %r10 instead of %r11 in xen_do_hypervisor_callback to make objtool and ORC unwinder's lives a little easier. ] Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/b0b2ff5fb97d2da2e1d7e1f380190c92545c8bb5.1499786555.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
358 lines
11 KiB
Text
358 lines
11 KiB
Text
menu "Kernel hacking"
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config TRACE_IRQFLAGS_SUPPORT
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def_bool y
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source "lib/Kconfig.debug"
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config EARLY_PRINTK_USB
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bool
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config X86_VERBOSE_BOOTUP
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bool "Enable verbose x86 bootup info messages"
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default y
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---help---
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Enables the informational output from the decompression stage
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(e.g. bzImage) of the boot. If you disable this you will still
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see errors. Disable this if you want silent bootup.
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config EARLY_PRINTK
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bool "Early printk" if EXPERT
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default y
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---help---
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Write kernel log output directly into the VGA buffer or to a serial
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port.
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This is useful for kernel debugging when your machine crashes very
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early before the console code is initialized. For normal operation
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it is not recommended because it looks ugly and doesn't cooperate
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with klogd/syslogd or the X server. You should normally say N here,
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unless you want to debug such a crash.
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config EARLY_PRINTK_DBGP
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bool "Early printk via EHCI debug port"
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depends on EARLY_PRINTK && PCI
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select EARLY_PRINTK_USB
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---help---
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Write kernel log output directly into the EHCI debug port.
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This is useful for kernel debugging when your machine crashes very
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early before the console code is initialized. For normal operation
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it is not recommended because it looks ugly and doesn't cooperate
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with klogd/syslogd or the X server. You should normally say N here,
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unless you want to debug such a crash. You need usb debug device.
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config EARLY_PRINTK_EFI
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bool "Early printk via the EFI framebuffer"
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depends on EFI && EARLY_PRINTK
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select FONT_SUPPORT
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---help---
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Write kernel log output directly into the EFI framebuffer.
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This is useful for kernel debugging when your machine crashes very
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early before the console code is initialized.
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config EARLY_PRINTK_USB_XDBC
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bool "Early printk via the xHCI debug port"
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depends on EARLY_PRINTK && PCI
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select EARLY_PRINTK_USB
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---help---
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Write kernel log output directly into the xHCI debug port.
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One use for this feature is kernel debugging, for example when your
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machine crashes very early before the regular console code is
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initialized. Other uses include simpler, lockless logging instead of
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a full-blown printk console driver + klogd.
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For normal production environments this is normally not recommended,
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because it doesn't feed events into klogd/syslogd and doesn't try to
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print anything on the screen.
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You should normally say N here, unless you want to debug early
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crashes or need a very simple printk logging facility.
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config X86_PTDUMP_CORE
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def_bool n
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config X86_PTDUMP
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tristate "Export kernel pagetable layout to userspace via debugfs"
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depends on DEBUG_KERNEL
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select DEBUG_FS
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select X86_PTDUMP_CORE
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---help---
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Say Y here if you want to show the kernel pagetable layout in a
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debugfs file. This information is only useful for kernel developers
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who are working in architecture specific areas of the kernel.
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It is probably not a good idea to enable this feature in a production
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kernel.
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If in doubt, say "N"
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config EFI_PGT_DUMP
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bool "Dump the EFI pagetable"
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depends on EFI
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select X86_PTDUMP_CORE
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---help---
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Enable this if you want to dump the EFI page table before
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enabling virtual mode. This can be used to debug miscellaneous
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issues with the mapping of the EFI runtime regions into that
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table.
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config DEBUG_WX
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bool "Warn on W+X mappings at boot"
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select X86_PTDUMP_CORE
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---help---
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Generate a warning if any W+X mappings are found at boot.
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This is useful for discovering cases where the kernel is leaving
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W+X mappings after applying NX, as such mappings are a security risk.
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Look for a message in dmesg output like this:
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x86/mm: Checked W+X mappings: passed, no W+X pages found.
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or like this, if the check failed:
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x86/mm: Checked W+X mappings: FAILED, <N> W+X pages found.
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Note that even if the check fails, your kernel is possibly
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still fine, as W+X mappings are not a security hole in
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themselves, what they do is that they make the exploitation
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of other unfixed kernel bugs easier.
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There is no runtime or memory usage effect of this option
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once the kernel has booted up - it's a one time check.
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If in doubt, say "Y".
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config DOUBLEFAULT
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default y
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bool "Enable doublefault exception handler" if EXPERT
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---help---
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This option allows trapping of rare doublefault exceptions that
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would otherwise cause a system to silently reboot. Disabling this
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option saves about 4k and might cause you much additional grey
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hair.
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config DEBUG_TLBFLUSH
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bool "Set upper limit of TLB entries to flush one-by-one"
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depends on DEBUG_KERNEL
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---help---
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X86-only for now.
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This option allows the user to tune the amount of TLB entries the
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kernel flushes one-by-one instead of doing a full TLB flush. In
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certain situations, the former is cheaper. This is controlled by the
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tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
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to -1, the code flushes the whole TLB unconditionally. Otherwise,
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for positive values of it, the kernel will use single TLB entry
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invalidating instructions according to the following formula:
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flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
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If in doubt, say "N".
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config IOMMU_DEBUG
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bool "Enable IOMMU debugging"
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depends on GART_IOMMU && DEBUG_KERNEL
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depends on X86_64
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---help---
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Force the IOMMU to on even when you have less than 4GB of
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memory and add debugging code. On overflow always panic. And
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allow to enable IOMMU leak tracing. Can be disabled at boot
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time with iommu=noforce. This will also enable scatter gather
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list merging. Currently not recommended for production
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code. When you use it make sure you have a big enough
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IOMMU/AGP aperture. Most of the options enabled by this can
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be set more finegrained using the iommu= command line
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options. See Documentation/x86/x86_64/boot-options.txt for more
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details.
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config IOMMU_STRESS
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bool "Enable IOMMU stress-test mode"
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---help---
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This option disables various optimizations in IOMMU related
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code to do real stress testing of the IOMMU code. This option
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will cause a performance drop and should only be enabled for
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testing.
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config IOMMU_LEAK
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bool "IOMMU leak tracing"
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depends on IOMMU_DEBUG && DMA_API_DEBUG
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---help---
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Add a simple leak tracer to the IOMMU code. This is useful when you
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are debugging a buggy device driver that leaks IOMMU mappings.
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config HAVE_MMIOTRACE_SUPPORT
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def_bool y
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config X86_DECODER_SELFTEST
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bool "x86 instruction decoder selftest"
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depends on DEBUG_KERNEL && KPROBES
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depends on !COMPILE_TEST
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---help---
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Perform x86 instruction decoder selftests at build time.
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This option is useful for checking the sanity of x86 instruction
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decoder code.
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If unsure, say "N".
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#
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# IO delay types:
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#
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config IO_DELAY_TYPE_0X80
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int
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default "0"
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config IO_DELAY_TYPE_0XED
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int
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default "1"
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config IO_DELAY_TYPE_UDELAY
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int
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default "2"
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config IO_DELAY_TYPE_NONE
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int
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default "3"
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choice
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prompt "IO delay type"
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default IO_DELAY_0X80
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config IO_DELAY_0X80
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bool "port 0x80 based port-IO delay [recommended]"
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---help---
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This is the traditional Linux IO delay used for in/out_p.
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It is the most tested hence safest selection here.
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config IO_DELAY_0XED
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bool "port 0xed based port-IO delay"
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---help---
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Use port 0xed as the IO delay. This frees up port 0x80 which is
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often used as a hardware-debug port.
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config IO_DELAY_UDELAY
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bool "udelay based port-IO delay"
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---help---
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Use udelay(2) as the IO delay method. This provides the delay
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while not having any side-effect on the IO port space.
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config IO_DELAY_NONE
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bool "no port-IO delay"
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---help---
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No port-IO delay. Will break on old boxes that require port-IO
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delay for certain operations. Should work on most new machines.
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endchoice
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if IO_DELAY_0X80
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config DEFAULT_IO_DELAY_TYPE
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int
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default IO_DELAY_TYPE_0X80
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endif
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if IO_DELAY_0XED
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config DEFAULT_IO_DELAY_TYPE
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int
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default IO_DELAY_TYPE_0XED
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endif
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if IO_DELAY_UDELAY
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config DEFAULT_IO_DELAY_TYPE
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int
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default IO_DELAY_TYPE_UDELAY
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endif
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if IO_DELAY_NONE
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config DEFAULT_IO_DELAY_TYPE
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int
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default IO_DELAY_TYPE_NONE
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endif
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config DEBUG_BOOT_PARAMS
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bool "Debug boot parameters"
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depends on DEBUG_KERNEL
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depends on DEBUG_FS
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---help---
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This option will cause struct boot_params to be exported via debugfs.
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config CPA_DEBUG
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bool "CPA self-test code"
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depends on DEBUG_KERNEL
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---help---
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Do change_page_attr() self-tests every 30 seconds.
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config OPTIMIZE_INLINING
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bool "Allow gcc to uninline functions marked 'inline'"
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---help---
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This option determines if the kernel forces gcc to inline the functions
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developers have marked 'inline'. Doing so takes away freedom from gcc to
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do what it thinks is best, which is desirable for the gcc 3.x series of
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compilers. The gcc 4.x series have a rewritten inlining algorithm and
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enabling this option will generate a smaller kernel there. Hopefully
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this algorithm is so good that allowing gcc 4.x and above to make the
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decision will become the default in the future. Until then this option
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is there to test gcc for this.
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If unsure, say N.
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config DEBUG_ENTRY
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bool "Debug low-level entry code"
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depends on DEBUG_KERNEL
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---help---
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This option enables sanity checks in x86's low-level entry code.
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Some of these sanity checks may slow down kernel entries and
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exits or otherwise impact performance.
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If unsure, say N.
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config DEBUG_NMI_SELFTEST
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bool "NMI Selftest"
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depends on DEBUG_KERNEL && X86_LOCAL_APIC
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---help---
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Enabling this option turns on a quick NMI selftest to verify
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that the NMI behaves correctly.
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This might help diagnose strange hangs that rely on NMI to
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function properly.
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If unsure, say N.
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config DEBUG_IMR_SELFTEST
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bool "Isolated Memory Region self test"
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default n
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depends on INTEL_IMR
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---help---
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This option enables automated sanity testing of the IMR code.
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Some simple tests are run to verify IMR bounds checking, alignment
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and overlapping. This option is really only useful if you are
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debugging an IMR memory map or are modifying the IMR code and want to
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test your changes.
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If unsure say N here.
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config X86_DEBUG_FPU
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bool "Debug the x86 FPU code"
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depends on DEBUG_KERNEL
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default y
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---help---
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If this option is enabled then there will be extra sanity
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checks and (boot time) debug printouts added to the kernel.
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This debugging adds some small amount of runtime overhead
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to the kernel.
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If unsure, say N.
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config PUNIT_ATOM_DEBUG
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tristate "ATOM Punit debug driver"
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select DEBUG_FS
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select IOSF_MBI
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---help---
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This is a debug driver, which gets the power states
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of all Punit North Complex devices. The power states of
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each device is exposed as part of the debugfs interface.
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The current power state can be read from
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/sys/kernel/debug/punit_atom/dev_power_state
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endmenu
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