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