xref: /openbmc/linux/arch/arm64/Kconfig.debug (revision 0f4630f3)
1menu "Kernel hacking"
2
3source "lib/Kconfig.debug"
4
5config ARM64_PTDUMP
6	bool "Export kernel pagetable layout to userspace via debugfs"
7	depends on DEBUG_KERNEL
8	select DEBUG_FS
9        help
10	  Say Y here if you want to show the kernel pagetable layout in a
11	  debugfs file. This information is only useful for kernel developers
12	  who are working in architecture specific areas of the kernel.
13	  It is probably not a good idea to enable this feature in a production
14	  kernel.
15	  If in doubt, say "N"
16
17config STRICT_DEVMEM
18	bool "Filter access to /dev/mem"
19	depends on MMU
20	help
21	  If this option is disabled, you allow userspace (root) access to all
22	  of memory, including kernel and userspace memory. Accidental
23	  access to this is obviously disastrous, but specific access can
24	  be used by people debugging the kernel.
25
26	  If this option is switched on, the /dev/mem file only allows
27	  userspace access to memory mapped peripherals.
28
29	  If in doubt, say Y.
30
31config PID_IN_CONTEXTIDR
32	bool "Write the current PID to the CONTEXTIDR register"
33	help
34	  Enabling this option causes the kernel to write the current PID to
35	  the CONTEXTIDR register, at the expense of some additional
36	  instructions during context switch. Say Y here only if you are
37	  planning to use hardware trace tools with this kernel.
38
39config ARM64_RANDOMIZE_TEXT_OFFSET
40	bool "Randomize TEXT_OFFSET at build time"
41	help
42	  Say Y here if you want the image load offset (AKA TEXT_OFFSET)
43	  of the kernel to be randomized at build-time. When selected,
44	  this option will cause TEXT_OFFSET to be randomized upon any
45	  build of the kernel, and the offset will be reflected in the
46	  text_offset field of the resulting Image. This can be used to
47	  fuzz-test bootloaders which respect text_offset.
48
49	  This option is intended for bootloader and/or kernel testing
50	  only. Bootloaders must make no assumptions regarding the value
51	  of TEXT_OFFSET and platforms must not require a specific
52	  value.
53
54config DEBUG_SET_MODULE_RONX
55        bool "Set loadable kernel module data as NX and text as RO"
56        depends on MODULES
57        help
58          This option helps catch unintended modifications to loadable
59          kernel module's text and read-only data. It also prevents execution
60          of module data. Such protection may interfere with run-time code
61          patching and dynamic kernel tracing - and they might also protect
62          against certain classes of kernel exploits.
63          If in doubt, say "N".
64
65config DEBUG_RODATA
66	bool "Make kernel text and rodata read-only"
67	help
68	  If this is set, kernel text and rodata will be made read-only. This
69	  is to help catch accidental or malicious attempts to change the
70	  kernel's executable code. Additionally splits rodata from kernel
71	  text so it can be made explicitly non-executable.
72
73          If in doubt, say Y
74
75config DEBUG_ALIGN_RODATA
76	depends on DEBUG_RODATA && ARM64_4K_PAGES
77	bool "Align linker sections up to SECTION_SIZE"
78	help
79	  If this option is enabled, sections that may potentially be marked as
80	  read only or non-executable will be aligned up to the section size of
81	  the kernel. This prevents sections from being split into pages and
82	  avoids a potential TLB penalty. The downside is an increase in
83	  alignment and potentially wasted space. Turn on this option if
84	  performance is more important than memory pressure.
85
86	  If in doubt, say N
87
88source "drivers/hwtracing/coresight/Kconfig"
89
90endmenu
91