1# SPDX-License-Identifier: GPL-2.0-only 2config PROC_FS 3 bool "/proc file system support" if EXPERT 4 default y 5 help 6 This is a virtual file system providing information about the status 7 of the system. "Virtual" means that it doesn't take up any space on 8 your hard disk: the files are created on the fly by the kernel when 9 you try to access them. Also, you cannot read the files with older 10 version of the program less: you need to use more or cat. 11 12 It's totally cool; for example, "cat /proc/interrupts" gives 13 information about what the different IRQs are used for at the moment 14 (there is a small number of Interrupt ReQuest lines in your computer 15 that are used by the attached devices to gain the CPU's attention -- 16 often a source of trouble if two devices are mistakenly configured 17 to use the same IRQ). The program procinfo to display some 18 information about your system gathered from the /proc file system. 19 20 Before you can use the /proc file system, it has to be mounted, 21 meaning it has to be given a location in the directory hierarchy. 22 That location should be /proc. A command such as "mount -t proc proc 23 /proc" or the equivalent line in /etc/fstab does the job. 24 25 The /proc file system is explained in the file 26 <file:Documentation/filesystems/proc.rst> and on the proc(5) manpage 27 ("man 5 proc"). 28 29 This option will enlarge your kernel by about 67 KB. Several 30 programs depend on this, so everyone should say Y here. 31 32config PROC_KCORE 33 bool "/proc/kcore support" if !ARM 34 depends on PROC_FS && MMU 35 select VMCORE_INFO 36 help 37 Provides a virtual ELF core file of the live kernel. This can 38 be read with gdb and other ELF tools. No modifications can be 39 made using this mechanism. 40 41config PROC_VMCORE 42 bool "/proc/vmcore support" 43 depends on PROC_FS && CRASH_DUMP 44 default y 45 help 46 Exports the dump image of crashed kernel in ELF format. 47 48config PROC_VMCORE_DEVICE_DUMP 49 bool "Device Hardware/Firmware Log Collection" 50 depends on PROC_VMCORE 51 default n 52 help 53 After kernel panic, device drivers can collect the device 54 specific snapshot of their hardware or firmware before the 55 underlying devices are initialized in crash recovery kernel. 56 Note that the device driver must be present in the crash 57 recovery kernel's initramfs to collect its underlying device 58 snapshot. 59 60 If you say Y here, the collected device dumps will be added 61 as ELF notes to /proc/vmcore. You can still disable device 62 dump using the kernel command line option 'novmcoredd'. 63 64config NEED_PROC_VMCORE_DEVICE_RAM 65 bool 66 67config PROC_VMCORE_DEVICE_RAM 68 def_bool y 69 depends on PROC_VMCORE && NEED_PROC_VMCORE_DEVICE_RAM 70 depends on VIRTIO_MEM 71 help 72 If the elfcore hdr is allocated and prepared by the dump kernel 73 ("2nd kernel") instead of the crashed kernel, RAM provided by memory 74 devices such as virtio-mem will not be included in the dump 75 image, because only the device driver can properly detect them. 76 77 With this config enabled, these RAM ranges will be queried from the 78 device drivers once the device gets probed, so they can be included 79 in the crash dump. 80 81 Relevant architectures should select NEED_PROC_VMCORE_DEVICE_RAM. 82 83config SYSCTL 84 bool "Sysctl support (/proc/sys)" if EXPERT 85 depends on PROC_FS 86 default y 87 help 88 The sysctl interface provides a means of dynamically changing 89 certain kernel parameters and variables on the fly without requiring 90 a recompile of the kernel or reboot of the system. The primary 91 interface is through /proc/sys. If you say Y here a tree of 92 modifiable sysctl entries will be generated beneath the 93 /proc/sys directory. They are explained in the files 94 in <file:Documentation/admin-guide/sysctl/>. Note that enabling this 95 option will enlarge the kernel by at least 8 KB. 96 97 As it is generally a good thing, you should say Y here unless 98 building a kernel for install/rescue disks or your system is very 99 limited in memory. 100 101config PROC_PAGE_MONITOR 102 default y 103 depends on PROC_FS && MMU 104 bool "Enable /proc page monitoring" if EXPERT 105 help 106 Various /proc files exist to monitor process memory utilization: 107 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap, 108 /proc/kpagecount, and /proc/kpageflags. Disabling these 109 interfaces will reduce the size of the kernel by approximately 4kb. 110 111config PROC_CHILDREN 112 bool "Include /proc/<pid>/task/<tid>/children file" 113 depends on PROC_FS 114 default n 115 help 116 Provides a fast way to retrieve first level children pids of a task. See 117 <file:Documentation/filesystems/proc.rst> for more information. 118 119 Say Y if you are running any user-space software which takes benefit from 120 this interface. For example, rkt is such a piece of software. 121 122config PROC_PID_ARCH_STATUS 123 def_bool n 124 depends on PROC_FS 125 126config PROC_CPU_RESCTRL 127 def_bool n 128 depends on PROC_FS 129