1 # SPDX-License-Identifier: GPL-2.0
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
16 select CLONE_BACKWARDS
17 select HAVE_DEBUG_STACKOVERFLOW
18 select MODULES_USE_ELF_REL
20 select GENERIC_VDSO_32
21 select ARCH_SPLIT_ARG64
26 # Options that are inherently 64-bit kernel only:
27 select ARCH_HAS_GIGANTIC_PAGE
28 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
29 select ARCH_USE_CMPXCHG_LOCKREF
30 select HAVE_ARCH_SOFT_DIRTY
31 select MODULES_USE_ELF_RELA
32 select NEED_DMA_MAP_STATE
35 config FORCE_DYNAMIC_FTRACE
38 depends on FUNCTION_TRACER
41 We keep the static function tracing (!DYNAMIC_FTRACE) around
42 in order to test the non static function tracing in the
43 generic code, as other architectures still use it. But we
44 only need to keep it around for x86_64. No need to keep it
45 for x86_32. For x86_32, force DYNAMIC_FTRACE.
49 # ( Note that options that are marked 'if X86_64' could in principle be
50 # ported to 32-bit as well. )
55 # Note: keep this list sorted alphabetically
57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
59 select ARCH_32BIT_OFF_T if X86_32
60 select ARCH_CLOCKSOURCE_INIT
61 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
62 select ARCH_HAS_CPU_FINALIZE_INIT
63 select ARCH_HAS_DEBUG_VIRTUAL
64 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
65 select ARCH_HAS_DEVMEM_IS_ALLOWED
66 select ARCH_HAS_EARLY_DEBUG if KGDB
67 select ARCH_HAS_ELF_RANDOMIZE
68 select ARCH_HAS_FAST_MULTIPLIER
69 select ARCH_HAS_FILTER_PGPROT
70 select ARCH_HAS_FORTIFY_SOURCE
71 select ARCH_HAS_GCOV_PROFILE_ALL
72 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
73 select ARCH_HAS_MEM_ENCRYPT
74 select ARCH_HAS_MEMBARRIER_SYNC_CORE
75 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
76 select ARCH_HAS_PMEM_API if X86_64
77 select ARCH_HAS_PTE_DEVMAP if X86_64
78 select ARCH_HAS_PTE_SPECIAL
79 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
80 select ARCH_HAS_COPY_MC if X86_64
81 select ARCH_HAS_SET_MEMORY
82 select ARCH_HAS_SET_DIRECT_MAP
83 select ARCH_HAS_STRICT_KERNEL_RWX
84 select ARCH_HAS_STRICT_MODULE_RWX
85 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
86 select ARCH_HAS_SYSCALL_WRAPPER
87 select ARCH_HAS_UBSAN_SANITIZE_ALL
88 select ARCH_HAS_DEBUG_WX
89 select ARCH_HAVE_NMI_SAFE_CMPXCHG
90 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
91 select ARCH_MIGHT_HAVE_PC_PARPORT
92 select ARCH_MIGHT_HAVE_PC_SERIO
94 select ARCH_SUPPORTS_ACPI
95 select ARCH_SUPPORTS_ATOMIC_RMW
96 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
97 select ARCH_USE_BUILTIN_BSWAP
98 select ARCH_USE_QUEUED_RWLOCKS
99 select ARCH_USE_QUEUED_SPINLOCKS
100 select ARCH_USE_SYM_ANNOTATIONS
101 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
102 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
103 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
104 select ARCH_WANT_HUGE_PMD_SHARE
105 select ARCH_WANT_LD_ORPHAN_WARN
106 select ARCH_WANTS_THP_SWAP if X86_64
107 select BUILDTIME_TABLE_SORT
109 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
110 select CLOCKSOURCE_WATCHDOG
111 select DCACHE_WORD_ACCESS
112 select EDAC_ATOMIC_SCRUB
114 select GENERIC_CLOCKEVENTS
115 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
116 select GENERIC_CLOCKEVENTS_MIN_ADJUST
117 select GENERIC_CMOS_UPDATE
118 select GENERIC_CPU_AUTOPROBE
119 select GENERIC_CPU_VULNERABILITIES
120 select GENERIC_EARLY_IOREMAP
122 select GENERIC_FIND_FIRST_BIT
124 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
125 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
126 select GENERIC_IRQ_MIGRATION if SMP
127 select GENERIC_IRQ_PROBE
128 select GENERIC_IRQ_RESERVATION_MODE
129 select GENERIC_IRQ_SHOW
130 select GENERIC_PENDING_IRQ if SMP
131 select GENERIC_PTDUMP
132 select GENERIC_SMP_IDLE_THREAD
133 select GENERIC_STRNCPY_FROM_USER
134 select GENERIC_STRNLEN_USER
135 select GENERIC_TIME_VSYSCALL
136 select GENERIC_GETTIMEOFDAY
137 select GENERIC_VDSO_TIME_NS
138 select GUP_GET_PTE_LOW_HIGH if X86_PAE
139 select HARDIRQS_SW_RESEND
140 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
141 select HAVE_ACPI_APEI if ACPI
142 select HAVE_ACPI_APEI_NMI if ACPI
143 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
144 select HAVE_ARCH_AUDITSYSCALL
145 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
146 select HAVE_ARCH_JUMP_LABEL
147 select HAVE_ARCH_JUMP_LABEL_RELATIVE
148 select HAVE_ARCH_KASAN if X86_64
149 select HAVE_ARCH_KASAN_VMALLOC if X86_64
150 select HAVE_ARCH_KGDB
151 select HAVE_ARCH_MMAP_RND_BITS if MMU
152 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
153 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
154 select HAVE_ARCH_PREL32_RELOCATIONS
155 select HAVE_ARCH_SECCOMP_FILTER
156 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
157 select HAVE_ARCH_STACKLEAK
158 select HAVE_ARCH_TRACEHOOK
159 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
160 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
161 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
162 select HAVE_ARCH_VMAP_STACK if X86_64
163 select HAVE_ARCH_WITHIN_STACK_FRAMES
164 select HAVE_ASM_MODVERSIONS
165 select HAVE_CMPXCHG_DOUBLE
166 select HAVE_CMPXCHG_LOCAL
167 select HAVE_CONTEXT_TRACKING if X86_64
168 select HAVE_C_RECORDMCOUNT
169 select HAVE_DEBUG_KMEMLEAK
170 select HAVE_DMA_CONTIGUOUS
171 select HAVE_DYNAMIC_FTRACE
172 select HAVE_DYNAMIC_FTRACE_WITH_REGS
173 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
175 select HAVE_EFFICIENT_UNALIGNED_ACCESS
177 select HAVE_EXIT_THREAD
179 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
180 select HAVE_FTRACE_MCOUNT_RECORD
181 select HAVE_FUNCTION_GRAPH_TRACER
182 select HAVE_FUNCTION_TRACER
183 select HAVE_GCC_PLUGINS
184 select HAVE_HW_BREAKPOINT
186 select HAVE_IOREMAP_PROT
187 select HAVE_IRQ_TIME_ACCOUNTING
188 select HAVE_KERNEL_BZIP2
189 select HAVE_KERNEL_GZIP
190 select HAVE_KERNEL_LZ4
191 select HAVE_KERNEL_LZMA
192 select HAVE_KERNEL_LZO
193 select HAVE_KERNEL_XZ
194 select HAVE_KERNEL_ZSTD
196 select HAVE_KPROBES_ON_FTRACE
197 select HAVE_FUNCTION_ERROR_INJECTION
198 select HAVE_KRETPROBES
200 select HAVE_LIVEPATCH if X86_64
201 select HAVE_MIXED_BREAKPOINTS_REGS
202 select HAVE_MOD_ARCH_SPECIFIC
206 select HAVE_OPTPROBES
207 select HAVE_PCSPKR_PLATFORM
208 select HAVE_PERF_EVENTS
209 select HAVE_PERF_EVENTS_NMI
210 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
212 select HAVE_PERF_REGS
213 select HAVE_PERF_USER_STACK_DUMP
214 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
215 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
216 select HAVE_REGS_AND_STACK_ACCESS_API
217 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
218 select HAVE_FUNCTION_ARG_ACCESS_API
219 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
220 select HAVE_STACK_VALIDATION if X86_64
221 select HAVE_STATIC_CALL
222 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
224 select HAVE_SYSCALL_TRACEPOINTS
225 select HAVE_UNSTABLE_SCHED_CLOCK
226 select HAVE_USER_RETURN_NOTIFIER
227 select HAVE_GENERIC_VDSO
228 select HOTPLUG_SMT if SMP
229 select IRQ_FORCED_THREADING
230 select NEED_SG_DMA_LENGTH
231 select PCI_DOMAINS if PCI
232 select PCI_LOCKLESS_CONFIG if PCI
235 select RTC_MC146818_LIB
238 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
239 select SYSCTL_EXCEPTION_TRACE
240 select THREAD_INFO_IN_TASK
241 select USER_STACKTRACE_SUPPORT
243 select HAVE_ARCH_KCSAN if X86_64
244 select X86_FEATURE_NAMES if PROC_FS
245 select PROC_PID_ARCH_STATUS if PROC_FS
246 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
248 config INSTRUCTION_DECODER
250 depends on KPROBES || PERF_EVENTS || UPROBES
254 default "elf32-i386" if X86_32
255 default "elf64-x86-64" if X86_64
257 config LOCKDEP_SUPPORT
260 config STACKTRACE_SUPPORT
266 config ARCH_MMAP_RND_BITS_MIN
270 config ARCH_MMAP_RND_BITS_MAX
274 config ARCH_MMAP_RND_COMPAT_BITS_MIN
277 config ARCH_MMAP_RND_COMPAT_BITS_MAX
283 config GENERIC_ISA_DMA
285 depends on ISA_DMA_API
290 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
292 config GENERIC_BUG_RELATIVE_POINTERS
295 config ARCH_MAY_HAVE_PC_FDC
297 depends on ISA_DMA_API
299 config GENERIC_CALIBRATE_DELAY
302 config ARCH_HAS_CPU_RELAX
305 config ARCH_HAS_CACHE_LINE_SIZE
308 config ARCH_HAS_FILTER_PGPROT
311 config HAVE_SETUP_PER_CPU_AREA
314 config NEED_PER_CPU_EMBED_FIRST_CHUNK
317 config NEED_PER_CPU_PAGE_FIRST_CHUNK
320 config ARCH_HIBERNATION_POSSIBLE
323 config ARCH_SUSPEND_POSSIBLE
326 config ARCH_WANT_GENERAL_HUGETLB
335 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
338 config KASAN_SHADOW_OFFSET
341 default 0xdffffc0000000000
343 config HAVE_INTEL_TXT
345 depends on INTEL_IOMMU && ACPI
349 depends on X86_32 && SMP
353 depends on X86_64 && SMP
355 config ARCH_SUPPORTS_UPROBES
358 config FIX_EARLYCON_MEM
361 config DYNAMIC_PHYSICAL_MASK
364 config PGTABLE_LEVELS
366 default 5 if X86_5LEVEL
371 config CC_HAS_SANE_STACKPROTECTOR
373 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
374 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
376 We have to make sure stack protector is unconditionally disabled if
377 the compiler produces broken code or if it does not let us control
378 the segment on 32-bit kernels.
380 menu "Processor type and features"
383 bool "DMA memory allocation support" if EXPERT
386 DMA memory allocation support allows devices with less than 32-bit
387 addressing to allocate within the first 16MB of address space.
388 Disable if no such devices will be used.
393 bool "Symmetric multi-processing support"
395 This enables support for systems with more than one CPU. If you have
396 a system with only one CPU, say N. If you have a system with more
399 If you say N here, the kernel will run on uni- and multiprocessor
400 machines, but will use only one CPU of a multiprocessor machine. If
401 you say Y here, the kernel will run on many, but not all,
402 uniprocessor machines. On a uniprocessor machine, the kernel
403 will run faster if you say N here.
405 Note that if you say Y here and choose architecture "586" or
406 "Pentium" under "Processor family", the kernel will not work on 486
407 architectures. Similarly, multiprocessor kernels for the "PPro"
408 architecture may not work on all Pentium based boards.
410 People using multiprocessor machines who say Y here should also say
411 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
412 Management" code will be disabled if you say Y here.
414 See also <file:Documentation/x86/i386/IO-APIC.rst>,
415 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
416 <http://www.tldp.org/docs.html#howto>.
418 If you don't know what to do here, say N.
420 config X86_FEATURE_NAMES
421 bool "Processor feature human-readable names" if EMBEDDED
424 This option compiles in a table of x86 feature bits and corresponding
425 names. This is required to support /proc/cpuinfo and a few kernel
426 messages. You can disable this to save space, at the expense of
427 making those few kernel messages show numeric feature bits instead.
432 bool "Support x2apic"
433 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
435 This enables x2apic support on CPUs that have this feature.
437 This allows 32-bit apic IDs (so it can support very large systems),
438 and accesses the local apic via MSRs not via mmio.
440 If you don't know what to do here, say N.
443 bool "Enable MPS table" if ACPI || SFI
445 depends on X86_LOCAL_APIC
447 For old smp systems that do not have proper acpi support. Newer systems
448 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
452 depends on X86_GOLDFISH
454 config X86_CPU_RESCTRL
455 bool "x86 CPU resource control support"
456 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
458 select PROC_CPU_RESCTRL if PROC_FS
460 Enable x86 CPU resource control support.
462 Provide support for the allocation and monitoring of system resources
465 Intel calls this Intel Resource Director Technology
466 (Intel(R) RDT). More information about RDT can be found in the
467 Intel x86 Architecture Software Developer Manual.
469 AMD calls this AMD Platform Quality of Service (AMD QoS).
470 More information about AMD QoS can be found in the AMD64 Technology
471 Platform Quality of Service Extensions manual.
477 bool "Support for big SMP systems with more than 8 CPUs"
480 This option is needed for the systems that have more than 8 CPUs.
482 config X86_EXTENDED_PLATFORM
483 bool "Support for extended (non-PC) x86 platforms"
486 If you disable this option then the kernel will only support
487 standard PC platforms. (which covers the vast majority of
490 If you enable this option then you'll be able to select support
491 for the following (non-PC) 32 bit x86 platforms:
492 Goldfish (Android emulator)
495 SGI 320/540 (Visual Workstation)
496 STA2X11-based (e.g. Northville)
497 Moorestown MID devices
499 If you have one of these systems, or if you want to build a
500 generic distribution kernel, say Y here - otherwise say N.
504 config X86_EXTENDED_PLATFORM
505 bool "Support for extended (non-PC) x86 platforms"
508 If you disable this option then the kernel will only support
509 standard PC platforms. (which covers the vast majority of
512 If you enable this option then you'll be able to select support
513 for the following (non-PC) 64 bit x86 platforms:
518 If you have one of these systems, or if you want to build a
519 generic distribution kernel, say Y here - otherwise say N.
521 # This is an alphabetically sorted list of 64 bit extended platforms
522 # Please maintain the alphabetic order if and when there are additions
524 bool "Numascale NumaChip"
526 depends on X86_EXTENDED_PLATFORM
529 depends on X86_X2APIC
530 depends on PCI_MMCONFIG
532 Adds support for Numascale NumaChip large-SMP systems. Needed to
533 enable more than ~168 cores.
534 If you don't have one of these, you should say N here.
538 select HYPERVISOR_GUEST
540 depends on X86_64 && PCI
541 depends on X86_EXTENDED_PLATFORM
544 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
545 supposed to run on these EM64T-based machines. Only choose this option
546 if you have one of these machines.
549 bool "SGI Ultraviolet"
551 depends on X86_EXTENDED_PLATFORM
554 depends on KEXEC_CORE
555 depends on X86_X2APIC
558 This option is needed in order to support SGI Ultraviolet systems.
559 If you don't have one of these, you should say N here.
561 # Following is an alphabetically sorted list of 32 bit extended platforms
562 # Please maintain the alphabetic order if and when there are additions
565 bool "Goldfish (Virtual Platform)"
566 depends on X86_EXTENDED_PLATFORM
568 Enable support for the Goldfish virtual platform used primarily
569 for Android development. Unless you are building for the Android
570 Goldfish emulator say N here.
573 bool "CE4100 TV platform"
575 depends on PCI_GODIRECT
576 depends on X86_IO_APIC
578 depends on X86_EXTENDED_PLATFORM
579 select X86_REBOOTFIXUPS
581 select OF_EARLY_FLATTREE
583 Select for the Intel CE media processor (CE4100) SOC.
584 This option compiles in support for the CE4100 SOC for settop
585 boxes and media devices.
588 bool "Intel MID platform support"
589 depends on X86_EXTENDED_PLATFORM
590 depends on X86_PLATFORM_DEVICES
592 depends on X86_64 || (PCI_GOANY && X86_32)
593 depends on X86_IO_APIC
599 select MFD_INTEL_MSIC
601 Select to build a kernel capable of supporting Intel MID (Mobile
602 Internet Device) platform systems which do not have the PCI legacy
603 interfaces. If you are building for a PC class system say N here.
605 Intel MID platforms are based on an Intel processor and chipset which
606 consume less power than most of the x86 derivatives.
608 config X86_INTEL_QUARK
609 bool "Intel Quark platform support"
611 depends on X86_EXTENDED_PLATFORM
612 depends on X86_PLATFORM_DEVICES
616 depends on X86_IO_APIC
621 Select to include support for Quark X1000 SoC.
622 Say Y here if you have a Quark based system such as the Arduino
623 compatible Intel Galileo.
625 config X86_INTEL_LPSS
626 bool "Intel Low Power Subsystem Support"
627 depends on X86 && ACPI && PCI
632 Select to build support for Intel Low Power Subsystem such as
633 found on Intel Lynxpoint PCH. Selecting this option enables
634 things like clock tree (common clock framework) and pincontrol
635 which are needed by the LPSS peripheral drivers.
637 config X86_AMD_PLATFORM_DEVICE
638 bool "AMD ACPI2Platform devices support"
643 Select to interpret AMD specific ACPI device to platform device
644 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
645 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
646 implemented under PINCTRL subsystem.
649 tristate "Intel SoC IOSF Sideband support for SoC platforms"
652 This option enables sideband register access support for Intel SoC
653 platforms. On these platforms the IOSF sideband is used in lieu of
654 MSR's for some register accesses, mostly but not limited to thermal
655 and power. Drivers may query the availability of this device to
656 determine if they need the sideband in order to work on these
657 platforms. The sideband is available on the following SoC products.
658 This list is not meant to be exclusive.
663 You should say Y if you are running a kernel on one of these SoC's.
665 config IOSF_MBI_DEBUG
666 bool "Enable IOSF sideband access through debugfs"
667 depends on IOSF_MBI && DEBUG_FS
669 Select this option to expose the IOSF sideband access registers (MCR,
670 MDR, MCRX) through debugfs to write and read register information from
671 different units on the SoC. This is most useful for obtaining device
672 state information for debug and analysis. As this is a general access
673 mechanism, users of this option would have specific knowledge of the
674 device they want to access.
676 If you don't require the option or are in doubt, say N.
679 bool "RDC R-321x SoC"
681 depends on X86_EXTENDED_PLATFORM
683 select X86_REBOOTFIXUPS
685 This option is needed for RDC R-321x system-on-chip, also known
687 If you don't have one of these chips, you should say N here.
689 config X86_32_NON_STANDARD
690 bool "Support non-standard 32-bit SMP architectures"
691 depends on X86_32 && SMP
692 depends on X86_EXTENDED_PLATFORM
694 This option compiles in the bigsmp and STA2X11 default
695 subarchitectures. It is intended for a generic binary
696 kernel. If you select them all, kernel will probe it one by
697 one and will fallback to default.
699 # Alphabetically sorted list of Non standard 32 bit platforms
701 config X86_SUPPORTS_MEMORY_FAILURE
703 # MCE code calls memory_failure():
705 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
706 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
707 depends on X86_64 || !SPARSEMEM
708 select ARCH_SUPPORTS_MEMORY_FAILURE
711 bool "STA2X11 Companion Chip Support"
712 depends on X86_32_NON_STANDARD && PCI
717 This adds support for boards based on the STA2X11 IO-Hub,
718 a.k.a. "ConneXt". The chip is used in place of the standard
719 PC chipset, so all "standard" peripherals are missing. If this
720 option is selected the kernel will still be able to boot on
721 standard PC machines.
724 tristate "Eurobraille/Iris poweroff module"
727 The Iris machines from EuroBraille do not have APM or ACPI support
728 to shut themselves down properly. A special I/O sequence is
729 needed to do so, which is what this module does at
732 This is only for Iris machines from EuroBraille.
736 config SCHED_OMIT_FRAME_POINTER
738 prompt "Single-depth WCHAN output"
741 Calculate simpler /proc/<PID>/wchan values. If this option
742 is disabled then wchan values will recurse back to the
743 caller function. This provides more accurate wchan values,
744 at the expense of slightly more scheduling overhead.
746 If in doubt, say "Y".
748 menuconfig HYPERVISOR_GUEST
749 bool "Linux guest support"
751 Say Y here to enable options for running Linux under various hyper-
752 visors. This option enables basic hypervisor detection and platform
755 If you say N, all options in this submenu will be skipped and
756 disabled, and Linux guest support won't be built in.
761 bool "Enable paravirtualization code"
763 This changes the kernel so it can modify itself when it is run
764 under a hypervisor, potentially improving performance significantly
765 over full virtualization. However, when run without a hypervisor
766 the kernel is theoretically slower and slightly larger.
771 config PARAVIRT_DEBUG
772 bool "paravirt-ops debugging"
773 depends on PARAVIRT && DEBUG_KERNEL
775 Enable to debug paravirt_ops internals. Specifically, BUG if
776 a paravirt_op is missing when it is called.
778 config PARAVIRT_SPINLOCKS
779 bool "Paravirtualization layer for spinlocks"
780 depends on PARAVIRT && SMP
782 Paravirtualized spinlocks allow a pvops backend to replace the
783 spinlock implementation with something virtualization-friendly
784 (for example, block the virtual CPU rather than spinning).
786 It has a minimal impact on native kernels and gives a nice performance
787 benefit on paravirtualized KVM / Xen kernels.
789 If you are unsure how to answer this question, answer Y.
791 config X86_HV_CALLBACK_VECTOR
794 source "arch/x86/xen/Kconfig"
797 bool "KVM Guest support (including kvmclock)"
799 select PARAVIRT_CLOCK
800 select ARCH_CPUIDLE_HALTPOLL
801 select X86_HV_CALLBACK_VECTOR
804 This option enables various optimizations for running under the KVM
805 hypervisor. It includes a paravirtualized clock, so that instead
806 of relying on a PIT (or probably other) emulation by the
807 underlying device model, the host provides the guest with
808 timing infrastructure such as time of day, and system time
810 config ARCH_CPUIDLE_HALTPOLL
812 prompt "Disable host haltpoll when loading haltpoll driver"
814 If virtualized under KVM, disable host haltpoll.
817 bool "Support for running PVH guests"
819 This option enables the PVH entry point for guest virtual machines
820 as specified in the x86/HVM direct boot ABI.
822 config PARAVIRT_TIME_ACCOUNTING
823 bool "Paravirtual steal time accounting"
826 Select this option to enable fine granularity task steal time
827 accounting. Time spent executing other tasks in parallel with
828 the current vCPU is discounted from the vCPU power. To account for
829 that, there can be a small performance impact.
831 If in doubt, say N here.
833 config PARAVIRT_CLOCK
836 config JAILHOUSE_GUEST
837 bool "Jailhouse non-root cell support"
838 depends on X86_64 && PCI
841 This option allows to run Linux as guest in a Jailhouse non-root
842 cell. You can leave this option disabled if you only want to start
843 Jailhouse and run Linux afterwards in the root cell.
846 bool "ACRN Guest support"
848 select X86_HV_CALLBACK_VECTOR
850 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
851 a flexible, lightweight reference open-source hypervisor, built with
852 real-time and safety-criticality in mind. It is built for embedded
853 IOT with small footprint and real-time features. More details can be
854 found in https://projectacrn.org/.
856 endif #HYPERVISOR_GUEST
858 source "arch/x86/Kconfig.cpu"
862 prompt "HPET Timer Support" if X86_32
864 Use the IA-PC HPET (High Precision Event Timer) to manage
865 time in preference to the PIT and RTC, if a HPET is
867 HPET is the next generation timer replacing legacy 8254s.
868 The HPET provides a stable time base on SMP
869 systems, unlike the TSC, but it is more expensive to access,
870 as it is off-chip. The interface used is documented
871 in the HPET spec, revision 1.
873 You can safely choose Y here. However, HPET will only be
874 activated if the platform and the BIOS support this feature.
875 Otherwise the 8254 will be used for timing services.
877 Choose N to continue using the legacy 8254 timer.
879 config HPET_EMULATE_RTC
881 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
884 def_bool y if X86_INTEL_MID
885 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
887 depends on X86_INTEL_MID && SFI
889 APB timer is the replacement for 8254, HPET on X86 MID platforms.
890 The APBT provides a stable time base on SMP
891 systems, unlike the TSC, but it is more expensive to access,
892 as it is off-chip. APB timers are always running regardless of CPU
893 C states, they are used as per CPU clockevent device when possible.
895 # Mark as expert because too many people got it wrong.
896 # The code disables itself when not needed.
899 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
900 bool "Enable DMI scanning" if EXPERT
902 Enabled scanning of DMI to identify machine quirks. Say Y
903 here unless you have verified that your setup is not
904 affected by entries in the DMI blacklist. Required by PNP
908 bool "Old AMD GART IOMMU support"
912 depends on X86_64 && PCI && AMD_NB
914 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
915 GART based hardware IOMMUs.
917 The GART supports full DMA access for devices with 32-bit access
918 limitations, on systems with more than 3 GB. This is usually needed
919 for USB, sound, many IDE/SATA chipsets and some other devices.
921 Newer systems typically have a modern AMD IOMMU, supported via
922 the CONFIG_AMD_IOMMU=y config option.
924 In normal configurations this driver is only active when needed:
925 there's more than 3 GB of memory and the system contains a
926 32-bit limited device.
931 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
932 depends on X86_64 && SMP && DEBUG_KERNEL
933 select CPUMASK_OFFSTACK
935 Enable maximum number of CPUS and NUMA Nodes for this architecture.
939 # The maximum number of CPUs supported:
941 # The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
942 # and which can be configured interactively in the
943 # [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
945 # The ranges are different on 32-bit and 64-bit kernels, depending on
946 # hardware capabilities and scalability features of the kernel.
948 # ( If MAXSMP is enabled we just use the highest possible value and disable
949 # interactive configuration. )
952 config NR_CPUS_RANGE_BEGIN
954 default NR_CPUS_RANGE_END if MAXSMP
958 config NR_CPUS_RANGE_END
961 default 64 if SMP && X86_BIGSMP
962 default 8 if SMP && !X86_BIGSMP
965 config NR_CPUS_RANGE_END
968 default 8192 if SMP && CPUMASK_OFFSTACK
969 default 512 if SMP && !CPUMASK_OFFSTACK
972 config NR_CPUS_DEFAULT
975 default 32 if X86_BIGSMP
979 config NR_CPUS_DEFAULT
982 default 8192 if MAXSMP
987 int "Maximum number of CPUs" if SMP && !MAXSMP
988 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
989 default NR_CPUS_DEFAULT
991 This allows you to specify the maximum number of CPUs which this
992 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
993 supported value is 8192, otherwise the maximum value is 512. The
994 minimum value which makes sense is 2.
996 This is purely to save memory: each supported CPU adds about 8KB
1004 prompt "Multi-core scheduler support"
1007 Multi-core scheduler support improves the CPU scheduler's decision
1008 making when dealing with multi-core CPU chips at a cost of slightly
1009 increased overhead in some places. If unsure say N here.
1011 config SCHED_MC_PRIO
1012 bool "CPU core priorities scheduler support"
1013 depends on SCHED_MC && CPU_SUP_INTEL
1014 select X86_INTEL_PSTATE
1018 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1019 core ordering determined at manufacturing time, which allows
1020 certain cores to reach higher turbo frequencies (when running
1021 single threaded workloads) than others.
1023 Enabling this kernel feature teaches the scheduler about
1024 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1025 scheduler's CPU selection logic accordingly, so that higher
1026 overall system performance can be achieved.
1028 This feature will have no effect on CPUs without this feature.
1030 If unsure say Y here.
1034 depends on !SMP && X86_LOCAL_APIC
1037 bool "Local APIC support on uniprocessors" if !PCI_MSI
1039 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1041 A local APIC (Advanced Programmable Interrupt Controller) is an
1042 integrated interrupt controller in the CPU. If you have a single-CPU
1043 system which has a processor with a local APIC, you can say Y here to
1044 enable and use it. If you say Y here even though your machine doesn't
1045 have a local APIC, then the kernel will still run with no slowdown at
1046 all. The local APIC supports CPU-generated self-interrupts (timer,
1047 performance counters), and the NMI watchdog which detects hard
1050 config X86_UP_IOAPIC
1051 bool "IO-APIC support on uniprocessors"
1052 depends on X86_UP_APIC
1054 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1055 SMP-capable replacement for PC-style interrupt controllers. Most
1056 SMP systems and many recent uniprocessor systems have one.
1058 If you have a single-CPU system with an IO-APIC, you can say Y here
1059 to use it. If you say Y here even though your machine doesn't have
1060 an IO-APIC, then the kernel will still run with no slowdown at all.
1062 config X86_LOCAL_APIC
1064 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1065 select IRQ_DOMAIN_HIERARCHY
1066 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1070 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1072 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1073 bool "Reroute for broken boot IRQs"
1074 depends on X86_IO_APIC
1076 This option enables a workaround that fixes a source of
1077 spurious interrupts. This is recommended when threaded
1078 interrupt handling is used on systems where the generation of
1079 superfluous "boot interrupts" cannot be disabled.
1081 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1082 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1083 kernel does during interrupt handling). On chipsets where this
1084 boot IRQ generation cannot be disabled, this workaround keeps
1085 the original IRQ line masked so that only the equivalent "boot
1086 IRQ" is delivered to the CPUs. The workaround also tells the
1087 kernel to set up the IRQ handler on the boot IRQ line. In this
1088 way only one interrupt is delivered to the kernel. Otherwise
1089 the spurious second interrupt may cause the kernel to bring
1090 down (vital) interrupt lines.
1092 Only affects "broken" chipsets. Interrupt sharing may be
1093 increased on these systems.
1096 bool "Machine Check / overheating reporting"
1097 select GENERIC_ALLOCATOR
1100 Machine Check support allows the processor to notify the
1101 kernel if it detects a problem (e.g. overheating, data corruption).
1102 The action the kernel takes depends on the severity of the problem,
1103 ranging from warning messages to halting the machine.
1105 config X86_MCELOG_LEGACY
1106 bool "Support for deprecated /dev/mcelog character device"
1109 Enable support for /dev/mcelog which is needed by the old mcelog
1110 userspace logging daemon. Consider switching to the new generation
1113 config X86_MCE_INTEL
1115 prompt "Intel MCE features"
1116 depends on X86_MCE && X86_LOCAL_APIC
1118 Additional support for intel specific MCE features such as
1119 the thermal monitor.
1123 prompt "AMD MCE features"
1124 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1126 Additional support for AMD specific MCE features such as
1127 the DRAM Error Threshold.
1129 config X86_ANCIENT_MCE
1130 bool "Support for old Pentium 5 / WinChip machine checks"
1131 depends on X86_32 && X86_MCE
1133 Include support for machine check handling on old Pentium 5 or WinChip
1134 systems. These typically need to be enabled explicitly on the command
1137 config X86_MCE_THRESHOLD
1138 depends on X86_MCE_AMD || X86_MCE_INTEL
1141 config X86_MCE_INJECT
1142 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1143 tristate "Machine check injector support"
1145 Provide support for injecting machine checks for testing purposes.
1146 If you don't know what a machine check is and you don't do kernel
1147 QA it is safe to say n.
1149 config X86_THERMAL_VECTOR
1151 depends on X86_MCE_INTEL
1153 source "arch/x86/events/Kconfig"
1155 config X86_LEGACY_VM86
1156 bool "Legacy VM86 support"
1159 This option allows user programs to put the CPU into V8086
1160 mode, which is an 80286-era approximation of 16-bit real mode.
1162 Some very old versions of X and/or vbetool require this option
1163 for user mode setting. Similarly, DOSEMU will use it if
1164 available to accelerate real mode DOS programs. However, any
1165 recent version of DOSEMU, X, or vbetool should be fully
1166 functional even without kernel VM86 support, as they will all
1167 fall back to software emulation. Nevertheless, if you are using
1168 a 16-bit DOS program where 16-bit performance matters, vm86
1169 mode might be faster than emulation and you might want to
1172 Note that any app that works on a 64-bit kernel is unlikely to
1173 need this option, as 64-bit kernels don't, and can't, support
1174 V8086 mode. This option is also unrelated to 16-bit protected
1175 mode and is not needed to run most 16-bit programs under Wine.
1177 Enabling this option increases the complexity of the kernel
1178 and slows down exception handling a tiny bit.
1180 If unsure, say N here.
1184 default X86_LEGACY_VM86
1187 bool "Enable support for 16-bit segments" if EXPERT
1189 depends on MODIFY_LDT_SYSCALL
1191 This option is required by programs like Wine to run 16-bit
1192 protected mode legacy code on x86 processors. Disabling
1193 this option saves about 300 bytes on i386, or around 6K text
1194 plus 16K runtime memory on x86-64,
1198 depends on X86_16BIT && X86_32
1202 depends on X86_16BIT && X86_64
1204 config X86_VSYSCALL_EMULATION
1205 bool "Enable vsyscall emulation" if EXPERT
1209 This enables emulation of the legacy vsyscall page. Disabling
1210 it is roughly equivalent to booting with vsyscall=none, except
1211 that it will also disable the helpful warning if a program
1212 tries to use a vsyscall. With this option set to N, offending
1213 programs will just segfault, citing addresses of the form
1216 This option is required by many programs built before 2013, and
1217 care should be used even with newer programs if set to N.
1219 Disabling this option saves about 7K of kernel size and
1220 possibly 4K of additional runtime pagetable memory.
1222 config X86_IOPL_IOPERM
1223 bool "IOPERM and IOPL Emulation"
1226 This enables the ioperm() and iopl() syscalls which are necessary
1227 for legacy applications.
1229 Legacy IOPL support is an overbroad mechanism which allows user
1230 space aside of accessing all 65536 I/O ports also to disable
1231 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1232 capabilities and permission from potentially active security
1235 The emulation restricts the functionality of the syscall to
1236 only allowing the full range I/O port access, but prevents the
1237 ability to disable interrupts from user space which would be
1238 granted if the hardware IOPL mechanism would be used.
1241 tristate "Toshiba Laptop support"
1244 This adds a driver to safely access the System Management Mode of
1245 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1246 not work on models with a Phoenix BIOS. The System Management Mode
1247 is used to set the BIOS and power saving options on Toshiba portables.
1249 For information on utilities to make use of this driver see the
1250 Toshiba Linux utilities web site at:
1251 <http://www.buzzard.org.uk/toshiba/>.
1253 Say Y if you intend to run this kernel on a Toshiba portable.
1257 tristate "Dell i8k legacy laptop support"
1260 select SENSORS_DELL_SMM
1262 This option enables legacy /proc/i8k userspace interface in hwmon
1263 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1264 temperature and allows controlling fan speeds of Dell laptops via
1265 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1266 it reports also power and hotkey status. For fan speed control is
1267 needed userspace package i8kutils.
1269 Say Y if you intend to run this kernel on old Dell laptops or want to
1270 use userspace package i8kutils.
1273 config X86_REBOOTFIXUPS
1274 bool "Enable X86 board specific fixups for reboot"
1277 This enables chipset and/or board specific fixups to be done
1278 in order to get reboot to work correctly. This is only needed on
1279 some combinations of hardware and BIOS. The symptom, for which
1280 this config is intended, is when reboot ends with a stalled/hung
1283 Currently, the only fixup is for the Geode machines using
1284 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1286 Say Y if you want to enable the fixup. Currently, it's safe to
1287 enable this option even if you don't need it.
1291 bool "CPU microcode loading support"
1293 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1295 If you say Y here, you will be able to update the microcode on
1296 Intel and AMD processors. The Intel support is for the IA32 family,
1297 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1298 AMD support is for families 0x10 and later. You will obviously need
1299 the actual microcode binary data itself which is not shipped with
1302 The preferred method to load microcode from a detached initrd is described
1303 in Documentation/x86/microcode.rst. For that you need to enable
1304 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1305 initrd for microcode blobs.
1307 In addition, you can build the microcode into the kernel. For that you
1308 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1311 config MICROCODE_INTEL
1312 bool "Intel microcode loading support"
1313 depends on CPU_SUP_INTEL && MICROCODE
1316 This options enables microcode patch loading support for Intel
1319 For the current Intel microcode data package go to
1320 <https://downloadcenter.intel.com> and search for
1321 'Linux Processor Microcode Data File'.
1323 config MICROCODE_AMD
1324 bool "AMD microcode loading support"
1325 depends on CPU_SUP_AMD && MICROCODE
1327 If you select this option, microcode patch loading support for AMD
1328 processors will be enabled.
1330 config MICROCODE_LATE_LOADING
1331 bool "Late microcode loading (DANGEROUS)"
1333 depends on MICROCODE
1335 Loading microcode late, when the system is up and executing instructions
1336 is a tricky business and should be avoided if possible. Just the sequence
1337 of synchronizing all cores and SMT threads is one fragile dance which does
1338 not guarantee that cores might not softlock after the loading. Therefore,
1339 use this at your own risk. Late loading taints the kernel too.
1342 tristate "/dev/cpu/*/msr - Model-specific register support"
1344 This device gives privileged processes access to the x86
1345 Model-Specific Registers (MSRs). It is a character device with
1346 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1347 MSR accesses are directed to a specific CPU on multi-processor
1351 tristate "/dev/cpu/*/cpuid - CPU information support"
1353 This device gives processes access to the x86 CPUID instruction to
1354 be executed on a specific processor. It is a character device
1355 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1359 prompt "High Memory Support"
1366 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1367 However, the address space of 32-bit x86 processors is only 4
1368 Gigabytes large. That means that, if you have a large amount of
1369 physical memory, not all of it can be "permanently mapped" by the
1370 kernel. The physical memory that's not permanently mapped is called
1373 If you are compiling a kernel which will never run on a machine with
1374 more than 1 Gigabyte total physical RAM, answer "off" here (default
1375 choice and suitable for most users). This will result in a "3GB/1GB"
1376 split: 3GB are mapped so that each process sees a 3GB virtual memory
1377 space and the remaining part of the 4GB virtual memory space is used
1378 by the kernel to permanently map as much physical memory as
1381 If the machine has between 1 and 4 Gigabytes physical RAM, then
1384 If more than 4 Gigabytes is used then answer "64GB" here. This
1385 selection turns Intel PAE (Physical Address Extension) mode on.
1386 PAE implements 3-level paging on IA32 processors. PAE is fully
1387 supported by Linux, PAE mode is implemented on all recent Intel
1388 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1389 then the kernel will not boot on CPUs that don't support PAE!
1391 The actual amount of total physical memory will either be
1392 auto detected or can be forced by using a kernel command line option
1393 such as "mem=256M". (Try "man bootparam" or see the documentation of
1394 your boot loader (lilo or loadlin) about how to pass options to the
1395 kernel at boot time.)
1397 If unsure, say "off".
1402 Select this if you have a 32-bit processor and between 1 and 4
1403 gigabytes of physical RAM.
1407 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1410 Select this if you have a 32-bit processor and more than 4
1411 gigabytes of physical RAM.
1416 prompt "Memory split" if EXPERT
1420 Select the desired split between kernel and user memory.
1422 If the address range available to the kernel is less than the
1423 physical memory installed, the remaining memory will be available
1424 as "high memory". Accessing high memory is a little more costly
1425 than low memory, as it needs to be mapped into the kernel first.
1426 Note that increasing the kernel address space limits the range
1427 available to user programs, making the address space there
1428 tighter. Selecting anything other than the default 3G/1G split
1429 will also likely make your kernel incompatible with binary-only
1432 If you are not absolutely sure what you are doing, leave this
1436 bool "3G/1G user/kernel split"
1437 config VMSPLIT_3G_OPT
1439 bool "3G/1G user/kernel split (for full 1G low memory)"
1441 bool "2G/2G user/kernel split"
1442 config VMSPLIT_2G_OPT
1444 bool "2G/2G user/kernel split (for full 2G low memory)"
1446 bool "1G/3G user/kernel split"
1451 default 0xB0000000 if VMSPLIT_3G_OPT
1452 default 0x80000000 if VMSPLIT_2G
1453 default 0x78000000 if VMSPLIT_2G_OPT
1454 default 0x40000000 if VMSPLIT_1G
1460 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1463 bool "PAE (Physical Address Extension) Support"
1464 depends on X86_32 && !HIGHMEM4G
1465 select PHYS_ADDR_T_64BIT
1468 PAE is required for NX support, and furthermore enables
1469 larger swapspace support for non-overcommit purposes. It
1470 has the cost of more pagetable lookup overhead, and also
1471 consumes more pagetable space per process.
1474 bool "Enable 5-level page tables support"
1476 select DYNAMIC_MEMORY_LAYOUT
1477 select SPARSEMEM_VMEMMAP
1480 5-level paging enables access to larger address space:
1481 upto 128 PiB of virtual address space and 4 PiB of
1482 physical address space.
1484 It will be supported by future Intel CPUs.
1486 A kernel with the option enabled can be booted on machines that
1487 support 4- or 5-level paging.
1489 See Documentation/x86/x86_64/5level-paging.rst for more
1494 config X86_DIRECT_GBPAGES
1498 Certain kernel features effectively disable kernel
1499 linear 1 GB mappings (even if the CPU otherwise
1500 supports them), so don't confuse the user by printing
1501 that we have them enabled.
1503 config X86_CPA_STATISTICS
1504 bool "Enable statistic for Change Page Attribute"
1507 Expose statistics about the Change Page Attribute mechanism, which
1508 helps to determine the effectiveness of preserving large and huge
1509 page mappings when mapping protections are changed.
1511 config AMD_MEM_ENCRYPT
1512 bool "AMD Secure Memory Encryption (SME) support"
1513 depends on X86_64 && CPU_SUP_AMD
1514 select DMA_COHERENT_POOL
1515 select DYNAMIC_PHYSICAL_MASK
1516 select ARCH_USE_MEMREMAP_PROT
1517 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1518 select INSTRUCTION_DECODER
1519 select ARCH_HAS_CC_PLATFORM
1521 Say yes to enable support for the encryption of system memory.
1522 This requires an AMD processor that supports Secure Memory
1525 config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1526 bool "Activate AMD Secure Memory Encryption (SME) by default"
1527 depends on AMD_MEM_ENCRYPT
1529 Say yes to have system memory encrypted by default if running on
1530 an AMD processor that supports Secure Memory Encryption (SME).
1532 If set to Y, then the encryption of system memory can be
1533 deactivated with the mem_encrypt=off command line option.
1535 If set to N, then the encryption of system memory can be
1536 activated with the mem_encrypt=on command line option.
1538 # Common NUMA Features
1540 bool "NUMA Memory Allocation and Scheduler Support"
1542 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1543 default y if X86_BIGSMP
1545 Enable NUMA (Non-Uniform Memory Access) support.
1547 The kernel will try to allocate memory used by a CPU on the
1548 local memory controller of the CPU and add some more
1549 NUMA awareness to the kernel.
1551 For 64-bit this is recommended if the system is Intel Core i7
1552 (or later), AMD Opteron, or EM64T NUMA.
1554 For 32-bit this is only needed if you boot a 32-bit
1555 kernel on a 64-bit NUMA platform.
1557 Otherwise, you should say N.
1561 prompt "Old style AMD Opteron NUMA detection"
1562 depends on X86_64 && NUMA && PCI
1564 Enable AMD NUMA node topology detection. You should say Y here if
1565 you have a multi processor AMD system. This uses an old method to
1566 read the NUMA configuration directly from the builtin Northbridge
1567 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1568 which also takes priority if both are compiled in.
1570 config X86_64_ACPI_NUMA
1572 prompt "ACPI NUMA detection"
1573 depends on X86_64 && NUMA && ACPI && PCI
1576 Enable ACPI SRAT based node topology detection.
1579 bool "NUMA emulation"
1582 Enable NUMA emulation. A flat machine will be split
1583 into virtual nodes when booted with "numa=fake=N", where N is the
1584 number of nodes. This is only useful for debugging.
1587 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1589 default "10" if MAXSMP
1590 default "6" if X86_64
1592 depends on NEED_MULTIPLE_NODES
1594 Specify the maximum number of NUMA Nodes available on the target
1595 system. Increases memory reserved to accommodate various tables.
1597 config ARCH_FLATMEM_ENABLE
1599 depends on X86_32 && !NUMA
1601 config ARCH_SPARSEMEM_ENABLE
1603 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1604 select SPARSEMEM_STATIC if X86_32
1605 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1607 config ARCH_SPARSEMEM_DEFAULT
1608 def_bool X86_64 || (NUMA && X86_32)
1610 config ARCH_SELECT_MEMORY_MODEL
1612 depends on ARCH_SPARSEMEM_ENABLE
1614 config ARCH_MEMORY_PROBE
1615 bool "Enable sysfs memory/probe interface"
1616 depends on X86_64 && MEMORY_HOTPLUG
1618 This option enables a sysfs memory/probe interface for testing.
1619 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1620 If you are unsure how to answer this question, answer N.
1622 config ARCH_PROC_KCORE_TEXT
1624 depends on X86_64 && PROC_KCORE
1626 config ILLEGAL_POINTER_VALUE
1629 default 0xdead000000000000 if X86_64
1631 config X86_PMEM_LEGACY_DEVICE
1634 config X86_PMEM_LEGACY
1635 tristate "Support non-standard NVDIMMs and ADR protected memory"
1636 depends on PHYS_ADDR_T_64BIT
1638 select X86_PMEM_LEGACY_DEVICE
1639 select NUMA_KEEP_MEMINFO if NUMA
1642 Treat memory marked using the non-standard e820 type of 12 as used
1643 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1644 The kernel will offer these regions to the 'pmem' driver so
1645 they can be used for persistent storage.
1650 bool "Allocate 3rd-level pagetables from highmem"
1653 The VM uses one page table entry for each page of physical memory.
1654 For systems with a lot of RAM, this can be wasteful of precious
1655 low memory. Setting this option will put user-space page table
1656 entries in high memory.
1658 config X86_CHECK_BIOS_CORRUPTION
1659 bool "Check for low memory corruption"
1661 Periodically check for memory corruption in low memory, which
1662 is suspected to be caused by BIOS. Even when enabled in the
1663 configuration, it is disabled at runtime. Enable it by
1664 setting "memory_corruption_check=1" on the kernel command
1665 line. By default it scans the low 64k of memory every 60
1666 seconds; see the memory_corruption_check_size and
1667 memory_corruption_check_period parameters in
1668 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1670 When enabled with the default parameters, this option has
1671 almost no overhead, as it reserves a relatively small amount
1672 of memory and scans it infrequently. It both detects corruption
1673 and prevents it from affecting the running system.
1675 It is, however, intended as a diagnostic tool; if repeatable
1676 BIOS-originated corruption always affects the same memory,
1677 you can use memmap= to prevent the kernel from using that
1680 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1681 bool "Set the default setting of memory_corruption_check"
1682 depends on X86_CHECK_BIOS_CORRUPTION
1685 Set whether the default state of memory_corruption_check is
1688 config X86_RESERVE_LOW
1689 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1693 Specify the amount of low memory to reserve for the BIOS.
1695 The first page contains BIOS data structures that the kernel
1696 must not use, so that page must always be reserved.
1698 By default we reserve the first 64K of physical RAM, as a
1699 number of BIOSes are known to corrupt that memory range
1700 during events such as suspend/resume or monitor cable
1701 insertion, so it must not be used by the kernel.
1703 You can set this to 4 if you are absolutely sure that you
1704 trust the BIOS to get all its memory reservations and usages
1705 right. If you know your BIOS have problems beyond the
1706 default 64K area, you can set this to 640 to avoid using the
1707 entire low memory range.
1709 If you have doubts about the BIOS (e.g. suspend/resume does
1710 not work or there's kernel crashes after certain hardware
1711 hotplug events) then you might want to enable
1712 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1713 typical corruption patterns.
1715 Leave this to the default value of 64 if you are unsure.
1717 config MATH_EMULATION
1719 depends on MODIFY_LDT_SYSCALL
1720 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1722 Linux can emulate a math coprocessor (used for floating point
1723 operations) if you don't have one. 486DX and Pentium processors have
1724 a math coprocessor built in, 486SX and 386 do not, unless you added
1725 a 487DX or 387, respectively. (The messages during boot time can
1726 give you some hints here ["man dmesg"].) Everyone needs either a
1727 coprocessor or this emulation.
1729 If you don't have a math coprocessor, you need to say Y here; if you
1730 say Y here even though you have a coprocessor, the coprocessor will
1731 be used nevertheless. (This behavior can be changed with the kernel
1732 command line option "no387", which comes handy if your coprocessor
1733 is broken. Try "man bootparam" or see the documentation of your boot
1734 loader (lilo or loadlin) about how to pass options to the kernel at
1735 boot time.) This means that it is a good idea to say Y here if you
1736 intend to use this kernel on different machines.
1738 More information about the internals of the Linux math coprocessor
1739 emulation can be found in <file:arch/x86/math-emu/README>.
1741 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1742 kernel, it won't hurt.
1746 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1748 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1749 the Memory Type Range Registers (MTRRs) may be used to control
1750 processor access to memory ranges. This is most useful if you have
1751 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1752 allows bus write transfers to be combined into a larger transfer
1753 before bursting over the PCI/AGP bus. This can increase performance
1754 of image write operations 2.5 times or more. Saying Y here creates a
1755 /proc/mtrr file which may be used to manipulate your processor's
1756 MTRRs. Typically the X server should use this.
1758 This code has a reasonably generic interface so that similar
1759 control registers on other processors can be easily supported
1762 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1763 Registers (ARRs) which provide a similar functionality to MTRRs. For
1764 these, the ARRs are used to emulate the MTRRs.
1765 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1766 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1767 write-combining. All of these processors are supported by this code
1768 and it makes sense to say Y here if you have one of them.
1770 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1771 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1772 can lead to all sorts of problems, so it's good to say Y here.
1774 You can safely say Y even if your machine doesn't have MTRRs, you'll
1775 just add about 9 KB to your kernel.
1777 See <file:Documentation/x86/mtrr.rst> for more information.
1779 config MTRR_SANITIZER
1781 prompt "MTRR cleanup support"
1784 Convert MTRR layout from continuous to discrete, so X drivers can
1785 add writeback entries.
1787 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1788 The largest mtrr entry size for a continuous block can be set with
1793 config MTRR_SANITIZER_ENABLE_DEFAULT
1794 int "MTRR cleanup enable value (0-1)"
1797 depends on MTRR_SANITIZER
1799 Enable mtrr cleanup default value
1801 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1802 int "MTRR cleanup spare reg num (0-7)"
1805 depends on MTRR_SANITIZER
1807 mtrr cleanup spare entries default, it can be changed via
1808 mtrr_spare_reg_nr=N on the kernel command line.
1812 prompt "x86 PAT support" if EXPERT
1815 Use PAT attributes to setup page level cache control.
1817 PATs are the modern equivalents of MTRRs and are much more
1818 flexible than MTRRs.
1820 Say N here if you see bootup problems (boot crash, boot hang,
1821 spontaneous reboots) or a non-working video driver.
1825 config ARCH_USES_PG_UNCACHED
1831 prompt "x86 architectural random number generator" if EXPERT
1833 Enable the x86 architectural RDRAND instruction
1834 (Intel Bull Mountain technology) to generate random numbers.
1835 If supported, this is a high bandwidth, cryptographically
1836 secure hardware random number generator.
1840 prompt "Supervisor Mode Access Prevention" if EXPERT
1842 Supervisor Mode Access Prevention (SMAP) is a security
1843 feature in newer Intel processors. There is a small
1844 performance cost if this enabled and turned on; there is
1845 also a small increase in the kernel size if this is enabled.
1851 prompt "User Mode Instruction Prevention" if EXPERT
1853 User Mode Instruction Prevention (UMIP) is a security feature in
1854 some x86 processors. If enabled, a general protection fault is
1855 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1856 executed in user mode. These instructions unnecessarily expose
1857 information about the hardware state.
1859 The vast majority of applications do not use these instructions.
1860 For the very few that do, software emulation is provided in
1861 specific cases in protected and virtual-8086 modes. Emulated
1864 config X86_INTEL_MEMORY_PROTECTION_KEYS
1865 prompt "Memory Protection Keys"
1867 # Note: only available in 64-bit mode
1868 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1869 select ARCH_USES_HIGH_VMA_FLAGS
1870 select ARCH_HAS_PKEYS
1872 Memory Protection Keys provides a mechanism for enforcing
1873 page-based protections, but without requiring modification of the
1874 page tables when an application changes protection domains.
1876 For details, see Documentation/core-api/protection-keys.rst
1881 prompt "TSX enable mode"
1882 depends on CPU_SUP_INTEL
1883 default X86_INTEL_TSX_MODE_OFF
1885 Intel's TSX (Transactional Synchronization Extensions) feature
1886 allows to optimize locking protocols through lock elision which
1887 can lead to a noticeable performance boost.
1889 On the other hand it has been shown that TSX can be exploited
1890 to form side channel attacks (e.g. TAA) and chances are there
1891 will be more of those attacks discovered in the future.
1893 Therefore TSX is not enabled by default (aka tsx=off). An admin
1894 might override this decision by tsx=on the command line parameter.
1895 Even with TSX enabled, the kernel will attempt to enable the best
1896 possible TAA mitigation setting depending on the microcode available
1897 for the particular machine.
1899 This option allows to set the default tsx mode between tsx=on, =off
1900 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1903 Say off if not sure, auto if TSX is in use but it should be used on safe
1904 platforms or on if TSX is in use and the security aspect of tsx is not
1907 config X86_INTEL_TSX_MODE_OFF
1910 TSX is disabled if possible - equals to tsx=off command line parameter.
1912 config X86_INTEL_TSX_MODE_ON
1915 TSX is always enabled on TSX capable HW - equals the tsx=on command
1918 config X86_INTEL_TSX_MODE_AUTO
1921 TSX is enabled on TSX capable HW that is believed to be safe against
1922 side channel attacks- equals the tsx=auto command line parameter.
1926 bool "EFI runtime service support"
1929 select EFI_RUNTIME_WRAPPERS
1930 select ARCH_USE_MEMREMAP_PROT
1932 This enables the kernel to use EFI runtime services that are
1933 available (such as the EFI variable services).
1935 This option is only useful on systems that have EFI firmware.
1936 In addition, you should use the latest ELILO loader available
1937 at <http://elilo.sourceforge.net> in order to take advantage
1938 of EFI runtime services. However, even with this option, the
1939 resultant kernel should continue to boot on existing non-EFI
1943 bool "EFI stub support"
1944 depends on EFI && !X86_USE_3DNOW
1947 This kernel feature allows a bzImage to be loaded directly
1948 by EFI firmware without the use of a bootloader.
1950 See Documentation/admin-guide/efi-stub.rst for more information.
1953 bool "EFI mixed-mode support"
1954 depends on EFI_STUB && X86_64
1956 Enabling this feature allows a 64-bit kernel to be booted
1957 on a 32-bit firmware, provided that your CPU supports 64-bit
1960 Note that it is not possible to boot a mixed-mode enabled
1961 kernel via the EFI boot stub - a bootloader that supports
1962 the EFI handover protocol must be used.
1966 source "kernel/Kconfig.hz"
1969 bool "kexec system call"
1972 kexec is a system call that implements the ability to shutdown your
1973 current kernel, and to start another kernel. It is like a reboot
1974 but it is independent of the system firmware. And like a reboot
1975 you can start any kernel with it, not just Linux.
1977 The name comes from the similarity to the exec system call.
1979 It is an ongoing process to be certain the hardware in a machine
1980 is properly shutdown, so do not be surprised if this code does not
1981 initially work for you. As of this writing the exact hardware
1982 interface is strongly in flux, so no good recommendation can be
1986 bool "kexec file based system call"
1991 depends on CRYPTO_SHA256=y
1993 This is new version of kexec system call. This system call is
1994 file based and takes file descriptors as system call argument
1995 for kernel and initramfs as opposed to list of segments as
1996 accepted by previous system call.
1998 config ARCH_HAS_KEXEC_PURGATORY
2002 bool "Verify kernel signature during kexec_file_load() syscall"
2003 depends on KEXEC_FILE
2006 This option makes the kexec_file_load() syscall check for a valid
2007 signature of the kernel image. The image can still be loaded without
2008 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2009 there's a signature that we can check, then it must be valid.
2011 In addition to this option, you need to enable signature
2012 verification for the corresponding kernel image type being
2013 loaded in order for this to work.
2015 config KEXEC_SIG_FORCE
2016 bool "Require a valid signature in kexec_file_load() syscall"
2017 depends on KEXEC_SIG
2019 This option makes kernel signature verification mandatory for
2020 the kexec_file_load() syscall.
2022 config KEXEC_BZIMAGE_VERIFY_SIG
2023 bool "Enable bzImage signature verification support"
2024 depends on KEXEC_SIG
2025 depends on SIGNED_PE_FILE_VERIFICATION
2026 select SYSTEM_TRUSTED_KEYRING
2028 Enable bzImage signature verification support.
2031 bool "kernel crash dumps"
2032 depends on X86_64 || (X86_32 && HIGHMEM)
2034 Generate crash dump after being started by kexec.
2035 This should be normally only set in special crash dump kernels
2036 which are loaded in the main kernel with kexec-tools into
2037 a specially reserved region and then later executed after
2038 a crash by kdump/kexec. The crash dump kernel must be compiled
2039 to a memory address not used by the main kernel or BIOS using
2040 PHYSICAL_START, or it must be built as a relocatable image
2041 (CONFIG_RELOCATABLE=y).
2042 For more details see Documentation/admin-guide/kdump/kdump.rst
2046 depends on KEXEC && HIBERNATION
2048 Jump between original kernel and kexeced kernel and invoke
2049 code in physical address mode via KEXEC
2051 config PHYSICAL_START
2052 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2055 This gives the physical address where the kernel is loaded.
2057 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2058 bzImage will decompress itself to above physical address and
2059 run from there. Otherwise, bzImage will run from the address where
2060 it has been loaded by the boot loader and will ignore above physical
2063 In normal kdump cases one does not have to set/change this option
2064 as now bzImage can be compiled as a completely relocatable image
2065 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2066 address. This option is mainly useful for the folks who don't want
2067 to use a bzImage for capturing the crash dump and want to use a
2068 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2069 to be specifically compiled to run from a specific memory area
2070 (normally a reserved region) and this option comes handy.
2072 So if you are using bzImage for capturing the crash dump,
2073 leave the value here unchanged to 0x1000000 and set
2074 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2075 for capturing the crash dump change this value to start of
2076 the reserved region. In other words, it can be set based on
2077 the "X" value as specified in the "crashkernel=YM@XM"
2078 command line boot parameter passed to the panic-ed
2079 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2080 for more details about crash dumps.
2082 Usage of bzImage for capturing the crash dump is recommended as
2083 one does not have to build two kernels. Same kernel can be used
2084 as production kernel and capture kernel. Above option should have
2085 gone away after relocatable bzImage support is introduced. But it
2086 is present because there are users out there who continue to use
2087 vmlinux for dump capture. This option should go away down the
2090 Don't change this unless you know what you are doing.
2093 bool "Build a relocatable kernel"
2096 This builds a kernel image that retains relocation information
2097 so it can be loaded someplace besides the default 1MB.
2098 The relocations tend to make the kernel binary about 10% larger,
2099 but are discarded at runtime.
2101 One use is for the kexec on panic case where the recovery kernel
2102 must live at a different physical address than the primary
2105 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2106 it has been loaded at and the compile time physical address
2107 (CONFIG_PHYSICAL_START) is used as the minimum location.
2109 config RANDOMIZE_BASE
2110 bool "Randomize the address of the kernel image (KASLR)"
2111 depends on RELOCATABLE
2114 In support of Kernel Address Space Layout Randomization (KASLR),
2115 this randomizes the physical address at which the kernel image
2116 is decompressed and the virtual address where the kernel
2117 image is mapped, as a security feature that deters exploit
2118 attempts relying on knowledge of the location of kernel
2121 On 64-bit, the kernel physical and virtual addresses are
2122 randomized separately. The physical address will be anywhere
2123 between 16MB and the top of physical memory (up to 64TB). The
2124 virtual address will be randomized from 16MB up to 1GB (9 bits
2125 of entropy). Note that this also reduces the memory space
2126 available to kernel modules from 1.5GB to 1GB.
2128 On 32-bit, the kernel physical and virtual addresses are
2129 randomized together. They will be randomized from 16MB up to
2130 512MB (8 bits of entropy).
2132 Entropy is generated using the RDRAND instruction if it is
2133 supported. If RDTSC is supported, its value is mixed into
2134 the entropy pool as well. If neither RDRAND nor RDTSC are
2135 supported, then entropy is read from the i8254 timer. The
2136 usable entropy is limited by the kernel being built using
2137 2GB addressing, and that PHYSICAL_ALIGN must be at a
2138 minimum of 2MB. As a result, only 10 bits of entropy are
2139 theoretically possible, but the implementations are further
2140 limited due to memory layouts.
2144 # Relocation on x86 needs some additional build support
2145 config X86_NEED_RELOCS
2147 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2149 config PHYSICAL_ALIGN
2150 hex "Alignment value to which kernel should be aligned"
2152 range 0x2000 0x1000000 if X86_32
2153 range 0x200000 0x1000000 if X86_64
2155 This value puts the alignment restrictions on physical address
2156 where kernel is loaded and run from. Kernel is compiled for an
2157 address which meets above alignment restriction.
2159 If bootloader loads the kernel at a non-aligned address and
2160 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2161 address aligned to above value and run from there.
2163 If bootloader loads the kernel at a non-aligned address and
2164 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2165 load address and decompress itself to the address it has been
2166 compiled for and run from there. The address for which kernel is
2167 compiled already meets above alignment restrictions. Hence the
2168 end result is that kernel runs from a physical address meeting
2169 above alignment restrictions.
2171 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2172 this value must be a multiple of 0x200000.
2174 Don't change this unless you know what you are doing.
2176 config DYNAMIC_MEMORY_LAYOUT
2179 This option makes base addresses of vmalloc and vmemmap as well as
2180 __PAGE_OFFSET movable during boot.
2182 config RANDOMIZE_MEMORY
2183 bool "Randomize the kernel memory sections"
2185 depends on RANDOMIZE_BASE
2186 select DYNAMIC_MEMORY_LAYOUT
2187 default RANDOMIZE_BASE
2189 Randomizes the base virtual address of kernel memory sections
2190 (physical memory mapping, vmalloc & vmemmap). This security feature
2191 makes exploits relying on predictable memory locations less reliable.
2193 The order of allocations remains unchanged. Entropy is generated in
2194 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2195 configuration have in average 30,000 different possible virtual
2196 addresses for each memory section.
2200 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2201 hex "Physical memory mapping padding" if EXPERT
2202 depends on RANDOMIZE_MEMORY
2203 default "0xa" if MEMORY_HOTPLUG
2205 range 0x1 0x40 if MEMORY_HOTPLUG
2208 Define the padding in terabytes added to the existing physical
2209 memory size during kernel memory randomization. It is useful
2210 for memory hotplug support but reduces the entropy available for
2211 address randomization.
2213 If unsure, leave at the default value.
2219 config BOOTPARAM_HOTPLUG_CPU0
2220 bool "Set default setting of cpu0_hotpluggable"
2221 depends on HOTPLUG_CPU
2223 Set whether default state of cpu0_hotpluggable is on or off.
2225 Say Y here to enable CPU0 hotplug by default. If this switch
2226 is turned on, there is no need to give cpu0_hotplug kernel
2227 parameter and the CPU0 hotplug feature is enabled by default.
2229 Please note: there are two known CPU0 dependencies if you want
2230 to enable the CPU0 hotplug feature either by this switch or by
2231 cpu0_hotplug kernel parameter.
2233 First, resume from hibernate or suspend always starts from CPU0.
2234 So hibernate and suspend are prevented if CPU0 is offline.
2236 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2237 offline if any interrupt can not migrate out of CPU0. There may
2238 be other CPU0 dependencies.
2240 Please make sure the dependencies are under your control before
2241 you enable this feature.
2243 Say N if you don't want to enable CPU0 hotplug feature by default.
2244 You still can enable the CPU0 hotplug feature at boot by kernel
2245 parameter cpu0_hotplug.
2247 config DEBUG_HOTPLUG_CPU0
2249 prompt "Debug CPU0 hotplug"
2250 depends on HOTPLUG_CPU
2252 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2253 soon as possible and boots up userspace with CPU0 offlined. User
2254 can online CPU0 back after boot time.
2256 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2257 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2258 compilation or giving cpu0_hotplug kernel parameter at boot.
2264 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2265 depends on COMPAT_32
2267 Certain buggy versions of glibc will crash if they are
2268 presented with a 32-bit vDSO that is not mapped at the address
2269 indicated in its segment table.
2271 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2272 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2273 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2274 the only released version with the bug, but OpenSUSE 9
2275 contains a buggy "glibc 2.3.2".
2277 The symptom of the bug is that everything crashes on startup, saying:
2278 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2280 Saying Y here changes the default value of the vdso32 boot
2281 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2282 This works around the glibc bug but hurts performance.
2284 If unsure, say N: if you are compiling your own kernel, you
2285 are unlikely to be using a buggy version of glibc.
2288 prompt "vsyscall table for legacy applications"
2290 default LEGACY_VSYSCALL_XONLY
2292 Legacy user code that does not know how to find the vDSO expects
2293 to be able to issue three syscalls by calling fixed addresses in
2294 kernel space. Since this location is not randomized with ASLR,
2295 it can be used to assist security vulnerability exploitation.
2297 This setting can be changed at boot time via the kernel command
2298 line parameter vsyscall=[emulate|xonly|none].
2300 On a system with recent enough glibc (2.14 or newer) and no
2301 static binaries, you can say None without a performance penalty
2302 to improve security.
2304 If unsure, select "Emulate execution only".
2306 config LEGACY_VSYSCALL_EMULATE
2307 bool "Full emulation"
2309 The kernel traps and emulates calls into the fixed vsyscall
2310 address mapping. This makes the mapping non-executable, but
2311 it still contains readable known contents, which could be
2312 used in certain rare security vulnerability exploits. This
2313 configuration is recommended when using legacy userspace
2314 that still uses vsyscalls along with legacy binary
2315 instrumentation tools that require code to be readable.
2317 An example of this type of legacy userspace is running
2318 Pin on an old binary that still uses vsyscalls.
2320 config LEGACY_VSYSCALL_XONLY
2321 bool "Emulate execution only"
2323 The kernel traps and emulates calls into the fixed vsyscall
2324 address mapping and does not allow reads. This
2325 configuration is recommended when userspace might use the
2326 legacy vsyscall area but support for legacy binary
2327 instrumentation of legacy code is not needed. It mitigates
2328 certain uses of the vsyscall area as an ASLR-bypassing
2331 config LEGACY_VSYSCALL_NONE
2334 There will be no vsyscall mapping at all. This will
2335 eliminate any risk of ASLR bypass due to the vsyscall
2336 fixed address mapping. Attempts to use the vsyscalls
2337 will be reported to dmesg, so that either old or
2338 malicious userspace programs can be identified.
2343 bool "Built-in kernel command line"
2345 Allow for specifying boot arguments to the kernel at
2346 build time. On some systems (e.g. embedded ones), it is
2347 necessary or convenient to provide some or all of the
2348 kernel boot arguments with the kernel itself (that is,
2349 to not rely on the boot loader to provide them.)
2351 To compile command line arguments into the kernel,
2352 set this option to 'Y', then fill in the
2353 boot arguments in CONFIG_CMDLINE.
2355 Systems with fully functional boot loaders (i.e. non-embedded)
2356 should leave this option set to 'N'.
2359 string "Built-in kernel command string"
2360 depends on CMDLINE_BOOL
2363 Enter arguments here that should be compiled into the kernel
2364 image and used at boot time. If the boot loader provides a
2365 command line at boot time, it is appended to this string to
2366 form the full kernel command line, when the system boots.
2368 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2369 change this behavior.
2371 In most cases, the command line (whether built-in or provided
2372 by the boot loader) should specify the device for the root
2375 config CMDLINE_OVERRIDE
2376 bool "Built-in command line overrides boot loader arguments"
2377 depends on CMDLINE_BOOL && CMDLINE != ""
2379 Set this option to 'Y' to have the kernel ignore the boot loader
2380 command line, and use ONLY the built-in command line.
2382 This is used to work around broken boot loaders. This should
2383 be set to 'N' under normal conditions.
2385 config MODIFY_LDT_SYSCALL
2386 bool "Enable the LDT (local descriptor table)" if EXPERT
2389 Linux can allow user programs to install a per-process x86
2390 Local Descriptor Table (LDT) using the modify_ldt(2) system
2391 call. This is required to run 16-bit or segmented code such as
2392 DOSEMU or some Wine programs. It is also used by some very old
2393 threading libraries.
2395 Enabling this feature adds a small amount of overhead to
2396 context switches and increases the low-level kernel attack
2397 surface. Disabling it removes the modify_ldt(2) system call.
2399 Saying 'N' here may make sense for embedded or server kernels.
2401 source "kernel/livepatch/Kconfig"
2406 def_bool $(cc-option,-mharden-sls=all)
2408 config CC_HAS_RETURN_THUNK
2409 def_bool $(cc-option,-mfunction-return=thunk-extern)
2411 menuconfig SPECULATION_MITIGATIONS
2412 bool "Mitigations for speculative execution vulnerabilities"
2415 Say Y here to enable options which enable mitigations for
2416 speculative execution hardware vulnerabilities.
2418 If you say N, all mitigations will be disabled. You really
2419 should know what you are doing to say so.
2421 if SPECULATION_MITIGATIONS
2423 config PAGE_TABLE_ISOLATION
2424 bool "Remove the kernel mapping in user mode"
2426 depends on (X86_64 || X86_PAE)
2428 This feature reduces the number of hardware side channels by
2429 ensuring that the majority of kernel addresses are not mapped
2432 See Documentation/x86/pti.rst for more details.
2435 bool "Avoid speculative indirect branches in kernel"
2438 Compile kernel with the retpoline compiler options to guard against
2439 kernel-to-user data leaks by avoiding speculative indirect
2440 branches. Requires a compiler with -mindirect-branch=thunk-extern
2441 support for full protection. The kernel may run slower.
2444 bool "Enable return-thunks"
2445 depends on RETPOLINE && CC_HAS_RETURN_THUNK
2448 Compile the kernel with the return-thunks compiler option to guard
2449 against kernel-to-user data leaks by avoiding return speculation.
2450 Requires a compiler with -mfunction-return=thunk-extern
2451 support for full protection. The kernel may run slower.
2453 config CPU_UNRET_ENTRY
2454 bool "Enable UNRET on kernel entry"
2455 depends on CPU_SUP_AMD && RETHUNK && X86_64
2458 Compile the kernel with support for the retbleed=unret mitigation.
2460 config CPU_IBPB_ENTRY
2461 bool "Enable IBPB on kernel entry"
2462 depends on CPU_SUP_AMD && X86_64
2465 Compile the kernel with support for the retbleed=ibpb mitigation.
2467 config CPU_IBRS_ENTRY
2468 bool "Enable IBRS on kernel entry"
2469 depends on CPU_SUP_INTEL && X86_64
2472 Compile the kernel with support for the spectre_v2=ibrs mitigation.
2473 This mitigates both spectre_v2 and retbleed at great cost to
2477 bool "Mitigate speculative RAS overflow on AMD"
2478 depends on CPU_SUP_AMD && X86_64 && RETHUNK
2481 Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2484 bool "Mitigate Straight-Line-Speculation"
2485 depends on CC_HAS_SLS && X86_64
2488 Compile the kernel with straight-line-speculation options to guard
2489 against straight line speculation. The kernel image might be slightly
2492 config GDS_FORCE_MITIGATION
2493 bool "Force GDS Mitigation"
2494 depends on CPU_SUP_INTEL
2497 Gather Data Sampling (GDS) is a hardware vulnerability which allows
2498 unprivileged speculative access to data which was previously stored in
2501 This option is equivalent to setting gather_data_sampling=force on the
2502 command line. The microcode mitigation is used if present, otherwise
2503 AVX is disabled as a mitigation. On affected systems that are missing
2504 the microcode any userspace code that unconditionally uses AVX will
2505 break with this option set.
2507 Setting this option on systems not vulnerable to GDS has no effect.
2511 config MITIGATION_RFDS
2512 bool "RFDS Mitigation"
2513 depends on CPU_SUP_INTEL
2516 Enable mitigation for Register File Data Sampling (RFDS) by default.
2517 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2518 allows unprivileged speculative access to stale data previously
2519 stored in floating point, vector and integer registers.
2520 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2524 config ARCH_HAS_ADD_PAGES
2526 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2528 config ARCH_ENABLE_MEMORY_HOTPLUG
2530 depends on X86_64 || (X86_32 && HIGHMEM)
2532 config ARCH_ENABLE_MEMORY_HOTREMOVE
2534 depends on MEMORY_HOTPLUG
2536 config USE_PERCPU_NUMA_NODE_ID
2540 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2542 depends on X86_64 || X86_PAE
2544 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2546 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2548 config ARCH_ENABLE_THP_MIGRATION
2550 depends on X86_64 && TRANSPARENT_HUGEPAGE
2552 menu "Power management and ACPI options"
2554 config ARCH_HIBERNATION_HEADER
2556 depends on HIBERNATION
2558 source "kernel/power/Kconfig"
2560 source "drivers/acpi/Kconfig"
2562 source "drivers/sfi/Kconfig"
2569 tristate "APM (Advanced Power Management) BIOS support"
2570 depends on X86_32 && PM_SLEEP
2572 APM is a BIOS specification for saving power using several different
2573 techniques. This is mostly useful for battery powered laptops with
2574 APM compliant BIOSes. If you say Y here, the system time will be
2575 reset after a RESUME operation, the /proc/apm device will provide
2576 battery status information, and user-space programs will receive
2577 notification of APM "events" (e.g. battery status change).
2579 If you select "Y" here, you can disable actual use of the APM
2580 BIOS by passing the "apm=off" option to the kernel at boot time.
2582 Note that the APM support is almost completely disabled for
2583 machines with more than one CPU.
2585 In order to use APM, you will need supporting software. For location
2586 and more information, read <file:Documentation/power/apm-acpi.rst>
2587 and the Battery Powered Linux mini-HOWTO, available from
2588 <http://www.tldp.org/docs.html#howto>.
2590 This driver does not spin down disk drives (see the hdparm(8)
2591 manpage ("man 8 hdparm") for that), and it doesn't turn off
2592 VESA-compliant "green" monitors.
2594 This driver does not support the TI 4000M TravelMate and the ACER
2595 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2596 desktop machines also don't have compliant BIOSes, and this driver
2597 may cause those machines to panic during the boot phase.
2599 Generally, if you don't have a battery in your machine, there isn't
2600 much point in using this driver and you should say N. If you get
2601 random kernel OOPSes or reboots that don't seem to be related to
2602 anything, try disabling/enabling this option (or disabling/enabling
2605 Some other things you should try when experiencing seemingly random,
2608 1) make sure that you have enough swap space and that it is
2610 2) pass the "no-hlt" option to the kernel
2611 3) switch on floating point emulation in the kernel and pass
2612 the "no387" option to the kernel
2613 4) pass the "floppy=nodma" option to the kernel
2614 5) pass the "mem=4M" option to the kernel (thereby disabling
2615 all but the first 4 MB of RAM)
2616 6) make sure that the CPU is not over clocked.
2617 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2618 8) disable the cache from your BIOS settings
2619 9) install a fan for the video card or exchange video RAM
2620 10) install a better fan for the CPU
2621 11) exchange RAM chips
2622 12) exchange the motherboard.
2624 To compile this driver as a module, choose M here: the
2625 module will be called apm.
2629 config APM_IGNORE_USER_SUSPEND
2630 bool "Ignore USER SUSPEND"
2632 This option will ignore USER SUSPEND requests. On machines with a
2633 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2634 series notebooks, it is necessary to say Y because of a BIOS bug.
2636 config APM_DO_ENABLE
2637 bool "Enable PM at boot time"
2639 Enable APM features at boot time. From page 36 of the APM BIOS
2640 specification: "When disabled, the APM BIOS does not automatically
2641 power manage devices, enter the Standby State, enter the Suspend
2642 State, or take power saving steps in response to CPU Idle calls."
2643 This driver will make CPU Idle calls when Linux is idle (unless this
2644 feature is turned off -- see "Do CPU IDLE calls", below). This
2645 should always save battery power, but more complicated APM features
2646 will be dependent on your BIOS implementation. You may need to turn
2647 this option off if your computer hangs at boot time when using APM
2648 support, or if it beeps continuously instead of suspending. Turn
2649 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2650 T400CDT. This is off by default since most machines do fine without
2655 bool "Make CPU Idle calls when idle"
2657 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2658 On some machines, this can activate improved power savings, such as
2659 a slowed CPU clock rate, when the machine is idle. These idle calls
2660 are made after the idle loop has run for some length of time (e.g.,
2661 333 mS). On some machines, this will cause a hang at boot time or
2662 whenever the CPU becomes idle. (On machines with more than one CPU,
2663 this option does nothing.)
2665 config APM_DISPLAY_BLANK
2666 bool "Enable console blanking using APM"
2668 Enable console blanking using the APM. Some laptops can use this to
2669 turn off the LCD backlight when the screen blanker of the Linux
2670 virtual console blanks the screen. Note that this is only used by
2671 the virtual console screen blanker, and won't turn off the backlight
2672 when using the X Window system. This also doesn't have anything to
2673 do with your VESA-compliant power-saving monitor. Further, this
2674 option doesn't work for all laptops -- it might not turn off your
2675 backlight at all, or it might print a lot of errors to the console,
2676 especially if you are using gpm.
2678 config APM_ALLOW_INTS
2679 bool "Allow interrupts during APM BIOS calls"
2681 Normally we disable external interrupts while we are making calls to
2682 the APM BIOS as a measure to lessen the effects of a badly behaving
2683 BIOS implementation. The BIOS should reenable interrupts if it
2684 needs to. Unfortunately, some BIOSes do not -- especially those in
2685 many of the newer IBM Thinkpads. If you experience hangs when you
2686 suspend, try setting this to Y. Otherwise, say N.
2690 source "drivers/cpufreq/Kconfig"
2692 source "drivers/cpuidle/Kconfig"
2694 source "drivers/idle/Kconfig"
2699 menu "Bus options (PCI etc.)"
2702 prompt "PCI access mode"
2703 depends on X86_32 && PCI
2706 On PCI systems, the BIOS can be used to detect the PCI devices and
2707 determine their configuration. However, some old PCI motherboards
2708 have BIOS bugs and may crash if this is done. Also, some embedded
2709 PCI-based systems don't have any BIOS at all. Linux can also try to
2710 detect the PCI hardware directly without using the BIOS.
2712 With this option, you can specify how Linux should detect the
2713 PCI devices. If you choose "BIOS", the BIOS will be used,
2714 if you choose "Direct", the BIOS won't be used, and if you
2715 choose "MMConfig", then PCI Express MMCONFIG will be used.
2716 If you choose "Any", the kernel will try MMCONFIG, then the
2717 direct access method and falls back to the BIOS if that doesn't
2718 work. If unsure, go with the default, which is "Any".
2723 config PCI_GOMMCONFIG
2740 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2742 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2745 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2748 bool "Support mmconfig PCI config space access" if X86_64
2750 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2751 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2755 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2759 depends on PCI && XEN
2762 config MMCONF_FAM10H
2764 depends on X86_64 && PCI_MMCONFIG && ACPI
2766 config PCI_CNB20LE_QUIRK
2767 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2770 Read the PCI windows out of the CNB20LE host bridge. This allows
2771 PCI hotplug to work on systems with the CNB20LE chipset which do
2774 There's no public spec for this chipset, and this functionality
2775 is known to be incomplete.
2777 You should say N unless you know you need this.
2780 bool "ISA bus support on modern systems" if EXPERT
2782 Expose ISA bus device drivers and options available for selection and
2783 configuration. Enable this option if your target machine has an ISA
2784 bus. ISA is an older system, displaced by PCI and newer bus
2785 architectures -- if your target machine is modern, it probably does
2786 not have an ISA bus.
2790 # x86_64 have no ISA slots, but can have ISA-style DMA.
2792 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2795 Enables ISA-style DMA support for devices requiring such controllers.
2803 Find out whether you have ISA slots on your motherboard. ISA is the
2804 name of a bus system, i.e. the way the CPU talks to the other stuff
2805 inside your box. Other bus systems are PCI, EISA, MicroChannel
2806 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2807 newer boards don't support it. If you have ISA, say Y, otherwise N.
2810 tristate "NatSemi SCx200 support"
2812 This provides basic support for National Semiconductor's
2813 (now AMD's) Geode processors. The driver probes for the
2814 PCI-IDs of several on-chip devices, so its a good dependency
2815 for other scx200_* drivers.
2817 If compiled as a module, the driver is named scx200.
2819 config SCx200HR_TIMER
2820 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2824 This driver provides a clocksource built upon the on-chip
2825 27MHz high-resolution timer. Its also a workaround for
2826 NSC Geode SC-1100's buggy TSC, which loses time when the
2827 processor goes idle (as is done by the scheduler). The
2828 other workaround is idle=poll boot option.
2831 bool "One Laptop Per Child support"
2839 Add support for detecting the unique features of the OLPC
2843 bool "OLPC XO-1 Power Management"
2844 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2846 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2849 bool "OLPC XO-1 Real Time Clock"
2850 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2852 Add support for the XO-1 real time clock, which can be used as a
2853 programmable wakeup source.
2856 bool "OLPC XO-1 SCI extras"
2857 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2861 Add support for SCI-based features of the OLPC XO-1 laptop:
2862 - EC-driven system wakeups
2866 - AC adapter status updates
2867 - Battery status updates
2869 config OLPC_XO15_SCI
2870 bool "OLPC XO-1.5 SCI extras"
2871 depends on OLPC && ACPI
2874 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2875 - EC-driven system wakeups
2876 - AC adapter status updates
2877 - Battery status updates
2880 bool "PCEngines ALIX System Support (LED setup)"
2883 This option enables system support for the PCEngines ALIX.
2884 At present this just sets up LEDs for GPIO control on
2885 ALIX2/3/6 boards. However, other system specific setup should
2888 Note: You must still enable the drivers for GPIO and LED support
2889 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2891 Note: You have to set alix.force=1 for boards with Award BIOS.
2894 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2897 This option enables system support for the Soekris Engineering net5501.
2900 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2904 This option enables system support for the Traverse Technologies GEOS.
2907 bool "Technologic Systems TS-5500 platform support"
2909 select CHECK_SIGNATURE
2913 This option enables system support for the Technologic Systems TS-5500.
2919 depends on CPU_SUP_AMD && PCI
2922 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2924 Firmwares often provide initial graphics framebuffers so the BIOS,
2925 bootloader or kernel can show basic video-output during boot for
2926 user-guidance and debugging. Historically, x86 used the VESA BIOS
2927 Extensions and EFI-framebuffers for this, which are mostly limited
2929 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2930 framebuffers so the new generic system-framebuffer drivers can be
2931 used on x86. If the framebuffer is not compatible with the generic
2932 modes, it is advertised as fallback platform framebuffer so legacy
2933 drivers like efifb, vesafb and uvesafb can pick it up.
2934 If this option is not selected, all system framebuffers are always
2935 marked as fallback platform framebuffers as usual.
2937 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2938 not be able to pick up generic system framebuffers if this option
2939 is selected. You are highly encouraged to enable simplefb as
2940 replacement if you select this option. simplefb can correctly deal
2941 with generic system framebuffers. But you should still keep vesafb
2942 and others enabled as fallback if a system framebuffer is
2943 incompatible with simplefb.
2950 menu "Binary Emulations"
2952 config IA32_EMULATION
2953 bool "IA32 Emulation"
2955 select ARCH_WANT_OLD_COMPAT_IPC
2957 select COMPAT_BINFMT_ELF
2958 select COMPAT_OLD_SIGACTION
2960 Include code to run legacy 32-bit programs under a
2961 64-bit kernel. You should likely turn this on, unless you're
2962 100% sure that you don't have any 32-bit programs left.
2965 tristate "IA32 a.out support"
2966 depends on IA32_EMULATION
2969 Support old a.out binaries in the 32bit emulation.
2972 bool "x32 ABI for 64-bit mode"
2974 # llvm-objcopy does not convert x86_64 .note.gnu.property or
2975 # compressed debug sections to x86_x32 properly:
2976 # https://github.com/ClangBuiltLinux/linux/issues/514
2977 # https://github.com/ClangBuiltLinux/linux/issues/1141
2978 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2980 Include code to run binaries for the x32 native 32-bit ABI
2981 for 64-bit processors. An x32 process gets access to the
2982 full 64-bit register file and wide data path while leaving
2983 pointers at 32 bits for smaller memory footprint.
2985 You will need a recent binutils (2.22 or later) with
2986 elf32_x86_64 support enabled to compile a kernel with this
2991 depends on IA32_EMULATION || X86_32
2993 select OLD_SIGSUSPEND3
2997 depends on IA32_EMULATION || X86_X32
3000 config COMPAT_FOR_U64_ALIGNMENT
3003 config SYSVIPC_COMPAT
3011 config HAVE_ATOMIC_IOMAP
3015 source "drivers/firmware/Kconfig"
3017 source "arch/x86/kvm/Kconfig"
3019 source "arch/x86/Kconfig.assembler"