swh:1:snp:77163734605b0ec556b01d897b7bb4a7e30d46b6
Tip revision: 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c authored by Linus Torvalds on 02 July 2017, 23:07:02 UTC
Linux 4.12
Linux 4.12
Tip revision: 6f7da29
Kconfig.debug
menu "Kernel hacking"
source "lib/Kconfig.debug"
config ARM64_PTDUMP_CORE
def_bool n
config ARM64_PTDUMP_DEBUGFS
bool "Export kernel pagetable layout to userspace via debugfs"
depends on DEBUG_KERNEL
select ARM64_PTDUMP_CORE
select DEBUG_FS
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 PID_IN_CONTEXTIDR
bool "Write the current PID to the CONTEXTIDR register"
help
Enabling this option causes the kernel to write the current PID to
the CONTEXTIDR register, at the expense of some additional
instructions during context switch. Say Y here only if you are
planning to use hardware trace tools with this kernel.
config ARM64_RANDOMIZE_TEXT_OFFSET
bool "Randomize TEXT_OFFSET at build time"
help
Say Y here if you want the image load offset (AKA TEXT_OFFSET)
of the kernel to be randomized at build-time. When selected,
this option will cause TEXT_OFFSET to be randomized upon any
build of the kernel, and the offset will be reflected in the
text_offset field of the resulting Image. This can be used to
fuzz-test bootloaders which respect text_offset.
This option is intended for bootloader and/or kernel testing
only. Bootloaders must make no assumptions regarding the value
of TEXT_OFFSET and platforms must not require a specific
value.
config DEBUG_WX
bool "Warn on W+X mappings at boot"
select ARM64_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.
This check also includes UXN, which should be set on all kernel
mappings.
Look for a message in dmesg output like this:
arm64/mm: Checked W+X mappings: passed, no W+X pages found.
or like this, if the check failed:
arm64/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 DEBUG_ALIGN_RODATA
depends on STRICT_KERNEL_RWX
bool "Align linker sections up to SECTION_SIZE"
help
If this option is enabled, sections that may potentially be marked as
read only or non-executable will be aligned up to the section size of
the kernel. This prevents sections from being split into pages and
avoids a potential TLB penalty. The downside is an increase in
alignment and potentially wasted space. Turn on this option if
performance is more important than memory pressure.
If in doubt, say N.
config DEBUG_EFI
depends on EFI && DEBUG_INFO
bool "UEFI debugging"
help
Enable this option to include EFI specific debugging features into
the kernel that are only useful when using a debug build of the
UEFI firmware
config ARM64_RELOC_TEST
depends on m
tristate "Relocation testing module"
source "drivers/hwtracing/coresight/Kconfig"
endmenu