1menu "Kernel hacking" 2 3source "lib/Kconfig.debug" 4 5config FRAME_POINTER 6 bool 7 default y 8 9config ARM64_PTDUMP 10 bool "Export kernel pagetable layout to userspace via debugfs" 11 depends on DEBUG_KERNEL 12 select DEBUG_FS 13 help 14 Say Y here if you want to show the kernel pagetable layout in a 15 debugfs file. This information is only useful for kernel developers 16 who are working in architecture specific areas of the kernel. 17 It is probably not a good idea to enable this feature in a production 18 kernel. 19 If in doubt, say "N" 20 21config STRICT_DEVMEM 22 bool "Filter access to /dev/mem" 23 depends on MMU 24 help 25 If this option is disabled, you allow userspace (root) access to all 26 of memory, including kernel and userspace memory. Accidental 27 access to this is obviously disastrous, but specific access can 28 be used by people debugging the kernel. 29 30 If this option is switched on, the /dev/mem file only allows 31 userspace access to memory mapped peripherals. 32 33 If in doubt, say Y. 34 35config PID_IN_CONTEXTIDR 36 bool "Write the current PID to the CONTEXTIDR register" 37 help 38 Enabling this option causes the kernel to write the current PID to 39 the CONTEXTIDR register, at the expense of some additional 40 instructions during context switch. Say Y here only if you are 41 planning to use hardware trace tools with this kernel. 42 43config ARM64_RANDOMIZE_TEXT_OFFSET 44 bool "Randomize TEXT_OFFSET at build time" 45 help 46 Say Y here if you want the image load offset (AKA TEXT_OFFSET) 47 of the kernel to be randomized at build-time. When selected, 48 this option will cause TEXT_OFFSET to be randomized upon any 49 build of the kernel, and the offset will be reflected in the 50 text_offset field of the resulting Image. This can be used to 51 fuzz-test bootloaders which respect text_offset. 52 53 This option is intended for bootloader and/or kernel testing 54 only. Bootloaders must make no assumptions regarding the value 55 of TEXT_OFFSET and platforms must not require a specific 56 value. 57 58config DEBUG_SET_MODULE_RONX 59 bool "Set loadable kernel module data as NX and text as RO" 60 depends on MODULES 61 help 62 This option helps catch unintended modifications to loadable 63 kernel module's text and read-only data. It also prevents execution 64 of module data. Such protection may interfere with run-time code 65 patching and dynamic kernel tracing - and they might also protect 66 against certain classes of kernel exploits. 67 If in doubt, say "N". 68 69config DEBUG_RODATA 70 bool "Make kernel text and rodata read-only" 71 help 72 If this is set, kernel text and rodata will be made read-only. This 73 is to help catch accidental or malicious attempts to change the 74 kernel's executable code. Additionally splits rodata from kernel 75 text so it can be made explicitly non-executable. 76 77 If in doubt, say Y 78 79config DEBUG_ALIGN_RODATA 80 depends on DEBUG_RODATA && !ARM64_64K_PAGES 81 bool "Align linker sections up to SECTION_SIZE" 82 help 83 If this option is enabled, sections that may potentially be marked as 84 read only or non-executable will be aligned up to the section size of 85 the kernel. This prevents sections from being split into pages and 86 avoids a potential TLB penalty. The downside is an increase in 87 alignment and potentially wasted space. Turn on this option if 88 performance is more important than memory pressure. 89 90 If in doubt, say N 91 92source "drivers/hwtracing/coresight/Kconfig" 93 94endmenu 95